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0:01hi I am aurel Enriquez and this
0:03presentation contains our discussion on
0:05the digestive
0:08system let's begin right away with the
0:10functions of the digestive system first
0:12is to transform food into nutrients for
0:16cells so although they contain nutrients
0:20they're not readily available or usable
0:23for our cells cuz food has a complex
0:26molecular structure or different food
0:29items they have complex molecular
0:31structures that needs to First be broken
0:34down by enzymes into simpler
0:39structures
0:41so diges system to mechanically and
0:45chemically break down food items into
0:48utilizable nutrients again this is
0:50achieved with the help of digestive
0:53enzymes after that no after they've
0:56broken they've been broken down into
0:58smaller uh molecules no they may now be
1:02absorbed into our blood circulation and
1:04then our blood circulation would
1:06transport these nutrients to everywhere
1:09else in our
1:12body definition of
1:14terms first is ingestion and mastication
1:18so ingestion is taking in the food
1:22through the mouth and mastication is
1:24simply chewing right next is propulsion
1:28and mixing so propulsion is the movement
1:32of um food from one segment of the
1:35digestive tract to the other so helima
1:38moving the food from the mouth to the
1:41esophagus and then moving the food from
1:43the esophagus to the stomach and then
1:45from the stomach to the small intestine
1:48and so on until it is defecated so
1:51that's
1:53propulsion mixing this is literally just
1:56moving in the same place until the food
1:59is mixed with the enzymes and fluids
2:02within the different segments or
2:04cavities of the digestive
2:08tract next pair of terms are digestion
2:12and secretion digestion is both
2:15physically breaking apart the food and
2:17chemically breaking down the structure
2:20of the food molecules secretion is the
2:23addition of liquids enzymes and mucus to
2:26the digested food which is supposed to
2:28help with the chemic
2:30process of
2:31digestion absorption is the movement of
2:35molecules out of the digestive tract and
2:38into the blood circulation or lymphatic
2:41system so absorption fully digested food
2:46items and they are readily available no
2:50they're already um in their usable form
2:54cells so they could now already um
2:56acquire and use the nutrients that were
2:59contained in the food items elimination
3:03is the removal of undigested materials
3:07okay
3:11so both physically and chemically
3:15digestive system so they would simply um
3:18get rid of those through defecation or
3:23pooping this illustration shows us all
3:26of the organs and accessory organs of
3:29the
3:30digestive system so of course we would
3:32be discussing all of these one by
3:36one another term for the digestive tract
3:39is the
3:40gastrointestinal tract or git so the git
3:44is just basically one long tube from the
3:47mouth to the esophagus which is quite
3:49disturbing if you really think about it
3:51but it's true though okay so an guys
3:55last bullet point no tal original Power
3:59Point
4:00C I did not just add that for comedic
4:04purposes but
4:08yeah the gastrointestinal tract is just
4:11one long tube from the mouth to the
4:18anus listed here are all these separate
4:21organs that are included in the
4:23digestive system so first up we have the
4:26oral cavity or the mouth so I first area
4:30or entry point food items next is the FX
4:35all right so um this one is
4:38familiar during our discussion on the
4:41respiratory system so again the fairings
4:44is divided into three parts the naso
4:46fairings Oro fairings and lingo fairings
4:51next segment would be the esophagus and
4:53then the stomach and then the small
4:56intestines large intestines and the last
4:59segment of our um gastrointestinal tract
5:02is the
5:07anos
5:09parts aside from the main organs of the
5:12digestive tract which we've already
5:14enumerated on the previous slide we also
5:17have what is known as Associated organs
5:21so these are not directly connected to
5:24the gastrointestinal tract but they do
5:26have ducts that could produce substances
5:29that also go into the gastrointestinal
5:33tract so that would include the salivary
5:36glands the liver Gull platter and the
5:43pancreas as we progress through this
5:47chapter let's now talk about the layers
5:49of the digestive tract wall so the
5:52layers of the digestive tract wall are
5:54also termed tunics all right
5:58so or gamit term tunix for
6:03layers when we talked about blood
6:05vessels so for Our arteries and veins we
6:09have the tun intima media and
6:13advena
6:15tunic digestive tract all right but we
6:18don't add the word tuna in front of them
6:22anymore all right so one word all right
6:25so first up is the mucosa all right so
6:28the mucosa this is the innermost layer
6:31and as the name applies it secretes
6:34mucus all right so that's quite easy to
6:36remember mucosal layer secretes mucose
6:41all right next um the layer sub mucosa
6:46so the sub mucosa is above the mucosa
6:50SOA okay
6:55so but for this case digestive
7:03so sub mucosa it's above the mucosa so
7:07the sub mucosa would contain blood
7:09vessels nerves and small glands all
7:12right so again um you blood supply
7:15digestive system nerves digestive system
7:19that would help us sense different
7:22things located S Sub
7:26mucosa next is the muscularis L here so
7:30this one is above the sub mucosa
7:33so is
7:36muos is the submucosa and the next layer
7:39is the muscularis again this one is
7:42quite easy to remember as the name
7:44implies it is composed of muscles
7:48specifically in a longitudinal circular
7:51and oblique Direction all right so again
7:55the muscularis layer of our digestive
7:58tract is composed most of muscles next
8:01is the sosia or adventia so this one is
8:05the outermost layer okay so I think by
8:08this
8:12time this one is the um layer that is
8:16located on the outside okay so the sosia
8:19or the adventia is the outermost layer
8:23so po um if there is some Peroni
8:27attached to it then it will be referred
8:29to as a serosa but if there is no um
8:34Peroni attached to it then we would
8:36refer to this as adventa okay so it's
8:39basically the same
8:42layer depending on whether there is a
8:45part of the Peroni that is present on
8:49them okay so
8:52Parton
8:56it's it's the adven
8:59but again they're both the outermost
9:03layer this illustration right here shows
9:06us all of those different layers that
9:08we've just discussed in the previous
9:10slide all right so again innermost is
9:12the mucosa or the mucose membrane all
9:16right so next is the sub mucosa so sub
9:21mucosa observe existence known blood
9:24vessels and nerves next is the
9:28muscularis okay so again there are
9:31different directions of muscles that we
9:33may be able to find some muscles may be
9:36um oriented in a circular manner some of
9:39them may be oriented in a longitudinal
9:42Manner and um after that no after the
9:45muscularis the next layer would be the
9:48serosa all right so um if a Peroni is a
9:53attached no if a part of the Peroni is
9:55attached we would refer to it as the
9:58serosa okay so another term that was
10:00used here is the Cirrus membrane or the
10:03visceral Peroni notice it's mostly
10:07composed of connective tissues and
10:10simple squamous
10:14epithelium let's now talk about the
10:17Peroni we have what is known as the
10:19viseral Peroni the viseral Peroni is
10:22otherwise referred to as the Sosa okay
10:26so this is a Cirus membrane that covers
10:28the organ so viseral Peroni this is
10:32directly attached to the organs okay so
10:36word viseral um
10:39again this is something or this is um a
10:42covering that is directly attached to
10:45the organ next is the parietal Peroni so
10:49the parietal Peroni this is a membrane
10:52that lines the wall of the abdominal
10:55cavity so parial
10:58Peroni
11:02orans wall abdominal
11:06cavity
11:08cavity all right so again visceral
11:11organs parietal
11:16cavity still on the Peroni we have what
11:18is known as mesenteries mesenteries are
11:21connective dissu sheets that hold the
11:23organs in place inside of the abdominal
11:27cavity so um some people may be
11:32wondering why aren't our organs um going
11:36out of their place if we do intense
11:39physical
11:42activities diges
11:51orans and this is because of the
11:53mesenteries the mesenteries again they
11:56hold the organs in place or they're they
11:58keep them inside of their usual
12:01positions in the abdominal cavity next
12:05we have what is known as the Lesser omum
12:07this is a part of the mesentery
12:09connecting the Lesser curvature of the
12:12stomach to the liver and diaphrag all
12:15right so
12:19lesser stomach liver diaphrag next is
12:23the greater amum this is a part of the
12:26mesentary connecting the greater
12:28curvature of the stomach to the
12:30transverse colon and posterior body wall
12:34all right so again
12:39greater
12:41transverse body
12:48Wallach lesser the stomach is being
12:51connected to the liver and the diaphragm
12:54greater momentum the stomach is being
12:56connected to the transverse and
13:00body
13:02wall this illustration right here shows
13:05us the location of all our digestive
13:10organs accessory
13:12organs in relation to the placement of
13:15our mesenteries all right so
13:19n greater
13:21momentum um viseral Peroni your peronal
13:26cavity all those other stuff that we
13:27discussed in the pr previous slide so
13:29this gives us a medial
13:32view location structures that we just
13:35talked
13:36about let's now talk about the oral
13:39cavity so um listed here are the
13:42different parts of our oral cavities so
13:45first up is the lips so the lips these
13:47are muscular structures that are formed
13:50by the orbicularis Oris muscle and is
13:53covered by the skin all right so again
13:56we are capable of moving moving our lips
13:59we're capable of talking we're capable
14:01of ingesting food or kind of like moving
14:04food to the inside of our oral cavity
14:08because of our lips and again you
14:10specific muscle that is involved in the
14:13movement of our lips is known as the
14:16orbicularis Oris right next are the
14:19cheeks so the cheeks these are the
14:22lateral walls of the oral cavity
14:25walls GID all right so within the cheeks
14:28we have what is known as the banator
14:31muscles the banator muscles would
14:33flatten the cheeks against the teeth all
14:44right align
14:47cheeks teeth is because of the work of
14:50the buccinator muscles next is the
14:53tongue so the tongue is a large muscular
14:56organ that occupies most of the oral
14:59cavity so aside from being able to help
15:02us taste different
15:05things when we talked about senses so
15:08there are different taste buds within
15:09our tongue that helps us um experience
15:13different flavors and different taste
15:15now aside from helping us taste
15:18different things no the tongue is also
15:20there no to help us um move our food
15:23around as we are performing mastication
15:26or chewing so
15:36because our tongue is there to help keep
15:39the food in place so it's kind of like
15:41working together with all the other
15:43parts of our oral cavity to keep our
15:47food in
15:49place so the tongue would move the food
15:52in the mouth and in cooperation with the
15:55lips and cheeks they would hold the food
15:58in place during mastication again
16:01mastication is just another term for
16:06chewing this slide right here shows us
16:09all the other specific parts and details
16:12of the human oral
16:16cavity let's now talk about the teeth so
16:19for um normal healthy adults no um
16:22normal healthy adults should have a
16:24total of 32 teeth so it's divided into
16:29um different kind of like groups no we
16:31have what is known as the iners the
16:34canine the premolar molers and the
16:37wisdom tooth so there are 20 primary or
16:41deciduous teeth all right so primary or
16:45deciduous teeth initial teeth that we
16:49had during our childhood all right so
16:52these are the ones that would fall off
16:53and then
16:55eventually normal adult tee next each
16:59tooth has a crown cusp neck and
17:03root pictures showing these different
17:06parts and where they are located next
17:08the bulk of the tooth is formed by a
17:11cellular tissue called Dentin okay so
17:15most of the insides tee this was formed
17:19by a cellular tissue referred to as
17:22Dentin next in the crown of the tooth
17:25the Dentin is covered by an extremely
17:27hard a cellular animl so a
17:32cellular cells surface and this surface
17:37is referred to as the
17:40nml the center of the tooth is known as
17:44the pulp cavity and the pulp cavity is
17:47filled with a material called pulp so
17:49this pulp is composed of blood vessels
17:52nerves and connective tissues all
17:57right
17:59blood vessels nerves and connective
18:01tissues
18:02teeth pulp cavity blood vessels nerves
18:06and connective tissue together no
18:08collectively they are referred to as
18:11pulp next teeth are held in place within
18:14the pockets in the bone that are
18:16referred to ASI all
18:21right is you respiratory system Alvi
18:26means the air saxs
18:30the digestive system the aluli means
18:34that these are Pockets within the bone
18:37or pockets in our
18:41skull all right
18:44orow all right next Dental carries more
18:48commonly known as cavities are breakdown
18:52or this happens when there is breakdown
18:55of nml by the acids from bacteria all
18:58right so
19:02expain cavities all right what is the
19:05source of cavities um people um develop
19:09cavities when they don't brush their
19:11teeth now it's it's natural for us to
19:15have bacteria within our oral cavities
19:18okay so
19:19normal bacteria oral
19:27cavity times a day all right so we have
19:30what is known as normal flora or normal
19:33microbiota of our oral
19:40cavity very good at maintaining oral
19:48hygiene now these bacteria after um
19:52after exposure to food
19:57items food items that we inchest so what
20:01would happen there is after um the
20:03metabolic processes of the bacteria
20:07byproduct metabolic processes of a lot
20:10of bacteria is acids all right so
20:13excessive amounts of acids would lead to
20:16the destruction of our enl and that
20:20leads to what is known as cavities or
20:23otherwise referred to as Dental
20:27carries
20:29this illustration right here shows us a
20:31complete set of adult teeth in
20:35comparison to the um 20 deciduous or
20:39baby teeth all right so again for
20:42children teeth that they would start
20:45with eventually um these would fall off
20:48and adult teeth all right
20:57soour canines and premolars and the MERS
21:02and then um lastly we have what is known
21:04as the wisdom tooth so these ones at the
21:08very
21:11back this illustration right here shows
21:14us a tooth in place in the AL bone so
21:21again digestive system specifically oral
21:25cavity alite are the Pockets or the
21:29areas in our skull or on the
21:34boneal teeth all right
21:39so the three main parts that we've
21:41mentioned earlier is the crown the neck
21:45and the root which is right here all
21:47right
21:49so Dentin all right which is composed of
21:52a cellular
21:54material is covered by the enl again you
21:58animal po um this is no longer cellular
22:01all right this is a cellular this is
22:04just a hard substance that would cover
22:06everything else underneath and then this
22:09area right here this hollow space right
22:11here this is the pul cavity so again
22:15together with the blood vessels nerves
22:18and other connective
22:20tissues
22:23pul oh another thing that we we would be
22:26able to see here is the perodontal
22:29ligaments so perodontal
22:32ligaments Anor teeth in place all right
22:39so thanks to the perodontal
22:44ligaments let's now talk about the pet
22:47the pallet is the roof of the oral
22:49cavity
22:50so um it has two parts the hard pallet
22:54is the anterior part that is made of
22:56bone so the hard palette this is closer
22:59to the outside all right and then next
23:02is the soft palette so the posterior
23:04part which is composed of skeletal
23:07muscles and connective tissues so the
23:10soft palette um as the name implies no
23:12um it no longer has um a bony portion
23:16therefore it is much
23:20softer let's now talk about the salivary
23:23glands if you would remember from the
23:25previous slides the salivary glands are
23:28an accessory organ to the digestive
23:30system so the salivary glands produce
23:33saliva which is a mixture of Cirrus and
23:36mucous fluid
23:37so cus this is more watery right so
23:42listed here are the purpose of the
23:44purposes of the salivary glands so
23:48um highlights this dissolves food
23:51particles so they can be tasted all
23:54right so if you would remember our past
23:56discussion on Sensi
23:59is chemical stimuli particles that have
24:03or that contain the taste of the food
24:06items that we're eating they need to
24:08First be
24:13dissolved process taste buds and cells
24:17within the taste buds all right so again
24:20the salivary glands no they produce
24:22saliva which is needed to dissolve food
24:24particles before we would be able to
24:27taste them
24:28next the saliva also protects against
24:31bacteria now um if you remember our
24:34previous discussion on the lymphatic
24:37system um our saliva is part of our
24:41innate immunity but aside from that no
24:45um it also contains substances like
24:47lysozymes lysozymes which are capable of
24:51destroying bacteria and also um in terms
24:54of adaptive immunity it has the immunog
24:57globulin a imunoglobulin a is present in
25:01the saliva tears and mucous membranes so
25:05the saliva could also protect against
25:08some bacteria and this one would begin
25:11the process of digestion all right so
25:15salivary enzymes like the salivary amas
25:19that could help us digest certain food
25:24items we actually have three salivary
25:27glands the partid submandibular and
25:30sublingual so the partid these are cus
25:34glands that are anterior to each ear All
25:46rights and their secretions are mostly
25:49watery next the submandibular produces
25:52more Cirus compared to mucus secretions
25:56so they probably secrete both Cirus and
25:58mucous secretions
26:00Peru watery or Cirus secretions now
26:05these are located along the inferior
26:07border of the mandible all right soang
26:11jaw
26:13area
26:15submandibular salivary glands the third
26:18one is the sublingual so they produce
26:21primarily mucus secretion so muc or
26:25sticky secretions produce sublingual and
26:29they are located in the floor of the
26:32oral cavity so most likely below the
26:37tongue let's now talk about the
26:39components of Cirus saliva and mucus
26:42saliva all right so you cus portion of
26:45the saliva this contains enzymes all
26:47right first up is the salivary amas this
26:51is the digestive enzyme that breaks down
26:54carbohydrates next lysozymes these are
26:57enzymes that um could work against
27:00bacteria okay
27:02so um if you would remember our past
27:05discussion on basic
27:08biochemistry we have different types of
27:12um molecules that could serve as an
27:14energy source for us or that could be
27:16present in our food items and that would
27:18include carbohydrates lipids and
27:24proteins
27:26salivas it has the capability to help us
27:30chemically break down the carbohydrates
27:33in our food next
27:37you in our previous discussion
27:40specifically lymphatic
27:42system it has the capability to fight
27:46against bacteria which could possibly
27:49cause infections and again lysozymes
27:51this is part of our innate
27:55immunity next you m portion saliva it
28:00contains muin which is necessary for
28:03lubrication so the reason why it's easy
28:07for us to chew our food and swallow our
28:10food is because of the presence of mucin
28:13which is lubricating our oral
28:17cavity this illustration right here
28:19shows us the location of all the
28:21structures that we've talked about in
28:23the previous slides
28:26so ped salivary gland sublingual and
28:31submandibular um salivary glands and all
28:34the other muscles that may be found in
28:36our oral cavity or that could help us
28:40with
28:43chewing this one is a familiar character
28:46no it's a familiar body structure that
28:48we've already talked about when we
28:51discussed you respiratory system so I
28:54the FX is otherwise known as the throat
28:57are commonly known as the throat so this
29:00connects the mouth to the esophagus and
29:03from our previous discussion po we've
29:05learned that the ferx is also a common
29:08passageway for both food and air so the
29:12um FX is composed of three parts the
29:15naso FX which
29:17is nasal cavity the orox wherein of
29:22course is you oral cavity and the lingo
29:26fings
29:29next is the esophagus this is a tube
29:32that connects the ferx to the stomach
29:39soach um also mentioned here is the
29:42condition heartburn so heartburn occurs
29:44when gastric juices regurgitate into the
29:48esophagus all right
29:56so
30:06lines so again heartburn happens when
30:09gastric juices that is usually present
30:12or usually contained in the
30:18stomach esag so what are the possible
30:22reasons for heartburn so this may be
30:24caused by excessive caffeine intake
30:27smoking or excessive eating and drinking
30:32all right so um again no all of these
30:35things are not prohibited okay coffe me
30:38means or tea no they also contain
30:41caffeine um smoking no for occasional
30:44smokers um this may be okay um and of
30:48course eating and drinking this is a
30:49normal process but again
30:51excessive um excessive or excessively
30:54doing these behaviors no could lead to
30:58heart
31:00burns this slide talks about swallowing
31:03now there are actually three phases to
31:05swallowing voluntary Fingal and a sural
31:09face so it's a voluntary face but the
31:11Bolis or the mass of food what is a
31:14bolus bolus is a mass or ball of food
31:18that has been chewed up and mixed
31:20together with our saliva all right so
31:24again chewing and the addition of saliva
31:27with food is referred to or would result
31:30to the creation of a bolus so the bolus
31:33would be formed in the mouth and then
31:35this is pushed into the Oro
31:43farings
31:45after which is why this is also referred
31:47to as the voluntary phase next is the
31:51Fingal phase so this one would trigger a
31:54swallowing reflex all right a swallowing
31:57reflex is initiated when the bis
31:59stimulates receptors in the Oro farings
32:02so um after voluntary face after we
32:07voluntarily swallow the food that we
32:09have chewed
32:11up
32:20ISO so this would um trigger a swalling
32:25reflex which is invol
32:28automatic which would help push the food
32:31further down next is the esophagal phas
32:35so um this would move the food from the
32:38FX to the stomach and as the name
32:42implies is the
32:45esophagus next is the term peristalsis
32:49so the peristalsis is W or these are wav
32:53like contractions that moves the food
32:56through the Dig digestive
32:59tra slides wherein I have inserted a gif
33:04which shows us what peristalsis looks
33:08like but basically peristalsis these are
33:11wave no par Alon wav like motions that
33:15would help us move our food um through
33:19our digestive
33:22tract this slide right here just shows
33:25us a visual explanation of the voluntary
33:28phase and then the fing G phase so as we
33:31can see you bolos no you bolos is this
33:34yellow portion right here or this yellow
33:37um kind of like mixture right here so sa
33:41faring gal face no once we voluntarily
33:43swallow the ball of food or BOS it would
33:47move to the oro fings oro fings trigger
33:52receptors to help push the food further
33:55downwards all right right and
33:59then
34:01ESOP
34:04esis
34:06esophagus
34:08food
34:11stomach this slide right here shows us
34:14an illustration as to how peristalsis
34:17would happen so as we can see right here
34:19no if if for example this is the bolus
34:22or the food item that we have already um
34:25chewed and swallowed I'm going if this
34:28is our digestive track now um the way as
34:32to how these Bolas would move through
34:34our digestive track is there is a wave
34:37of relaxation and contraction so
34:42area
34:43um B there is an area of
34:48relaxation open open area and digestive
34:51tra not then notice that um on the back
34:55portion there's a space or area right
34:59here where there is a wave of
35:02contraction so basically par in isqueeze
35:05out or P area food forward or next
35:11segment digestive track all right and
35:14again it does that by Contracting so
35:17contract
35:19area forward
35:22so in this next illustration as there is
35:25a wave of control action no the bolus
35:28would continue to move forward
35:31so illustration on how perisis happens
35:35but this is the general
35:40idea let's now discuss the stomach so
35:43this is located in the abdomen so by now
35:46no um I
35:49hope
35:54befor that the stomach is located in the
35:57abdomen all right so for those who
35:59didn't
36:00know at least now you know that the
36:03stomach is located in the abdomen all
36:11right power points C or power points
36:15Mill they still include things that are
36:18kind of like um very common knowledge no
36:22STX located in the abdomen yeah du we
36:25all knew that but anyway and again where
36:28is the stomach located at the abdomen
36:33all right so the stomach this is um a
36:35storage tank for food all right so
36:37because um this is because our food no
36:41after esophagus it could stay in the
36:44stomach for a few hours so literally it
36:47is storing some of the food that we've
36:49just processed in our oral cavity now
36:53this can hold up to 2 L of food all
36:56right
36:58um amount
37:01of stach so the stomach produces mucose
37:05hydrochloric acid and protein digesting
37:09enzymes all right so again mucose is
37:12there for lubrication hydrocloric acid
37:15is there to help with the chemical
37:17digestion and some enzymes no that is
37:20necessary for digesting
37:23proteins so the stomach this contains a
37:26thick mucous layer that lubricates and
37:29protects the epithelial cells on the
37:31stomach wall from the acidic pH of three
37:35all right so
37:36gun pH hydrochloric acid stomach up to a
37:42very acidic pH of just three okay so of
37:46course no it needs a thick mucous layer
37:50no it needs something to protect all the
37:53other cells of our stomach against this
37:56powerful hydrochloric
38:00acid let's now talk about the regions of
38:03the stomach we have what is known as the
38:05fundus so the fundus this is oriented to
38:09the left all right next the body this is
38:12the largest part
38:15orach
38:19micd and you food items next the body
38:24would turn or curve to the right
38:26creating a greater curvature and a
38:29lesser curvature after that the body
38:32would narrow inferiorly to form the
38:35funnel shape pyloric part of the stomach
38:39all right so from top to bottom Parts
38:42stomach I fundus body greater curvature
38:46lesser curvature and theoric
38:53portion this slide contains a couple
38:55more definition of terms to remember
38:57first is rug so rug these are the large
39:01folds that allow the stomach to stretch
39:04all right so again um the capability of
39:08our stomach to hold up to 2 L of food
39:11and also the
39:15reasonal after is because our stomach
39:19has the capability to stretch all right
39:21it has the capability to stretch and
39:24this is brought about by the RO gay so
39:28um folds or
39:30wrinkles inside stomach so those could
39:33be stretched out if
39:36necessary next is the word Kim so Kim is
39:39a past likee substance that forms when
39:42food begins to be broken down all right
39:49so this is just the food item that has
39:52been masticated and combined with our
39:55saliva so
40:04past substance all right so again this
40:08past like substance that is made up of
40:11food items that have been further broken
40:14down is now referred to as Skye okay so
40:19we refer to as we refer to the food
40:22items as
40:24bolos Sima s stomach onwards we would
40:28now refer to the food items as
40:34Kim still on the stomach we have what is
40:36known as the pyloric opening so the
40:39pyloric opening this is um the opening
40:42or entrance between the stomach and the
40:45small intestine all
40:48right
40:49transation stomach small intestine is
40:53otherwise referred to as the pyloric
40:56opening the pyloric sphincter is a thick
41:00ring of smooth muscle around the pyloric
41:02opening which regulates the movement of
41:05food into the small intestine so um
41:08people might be
41:13wondering
41:18Hydrochloric small
41:21[Music]
41:23int items
41:27small intestine and that is because of
41:29the pyloric spinter all right so again
41:32the pyloric sphincter this would close
41:35or open no depending on the time no
41:38depending on the
41:41time move you food item from the stomach
41:44to the small intestine so this regulates
41:47the movement of the
41:50food small intestine all right so again
41:53the phoric fter this is a ring of smooth
41:57muscle Junction um between the stomach
42:01and the small
42:04intestine this photo right here shows us
42:07all of the parts of the stomach that
42:09we've just discussed earlier all right
42:12so Nas lesser curvature Nas greater
42:15curvature where is the fundus the body
42:18and the boric opening and pyloric fter
42:22so
42:24parts and also right here we're being
42:26shown an illustration and
42:29microscopic anatomy of the cells of the
42:36stomach let's now talk about the cells
42:38present in the stomach first up our
42:40surface mucus cells so they produce
42:43mucus that could coat and protect the
42:46stomach protect the stomach from what
42:49hydrochloric acid because it has a pH of
42:53three so again um to protect all the
42:55other structures in the stomach it needs
42:58to be coated with mucus another type of
43:01cell that could produce mucus is the
43:04mucus neck cells all right so
43:07[Music]
43:10basically muc stomach next are parietal
43:14cells parietal cells produce
43:17hydrochloric acid and intrinsic factor
43:20so both of these are very important in
43:23our
43:25digestion
43:26stomach Endocrine cells Endocrine cells
43:30um these ones would produce hormones and
43:33paracine molecules next are chief cells
43:36so Chief cells they produce pepsinogen
43:39which is a precursor of the protein
43:42digesting enzyme Pepin all
43:45right Chief
43:47cells pepen all right pepsinogen um
43:52eventually no convert it to pepsin and
43:57Pepin it's it helps with the digestion
44:00of
44:02proteins enzy that helps with the
44:05digestion of
44:07carbohydrates
44:11amas hydrochloric acid could produce a
44:15pH of approximately two in the stomach
44:18all right
44:20so as low as two pH hydrochloric acid
44:25stomach so again this could be very
44:27harmful to all the other cellular
44:29structures which is why we have um we
44:32have cells that would produce mucus to
44:37to line or protect um our stomach next
44:41hydrochloric acid no um it could kill
44:44microorganisms so there may be bacterial
44:47organisms or parasitic organisms out
44:53there so one of of our chances of
44:57fighting off or eliminating these
45:00infectious organisms could be through
45:02the acidic pH of our hydrochloric acid
45:06so bacteria and
45:11parasites acidic the
45:13pH another function of hydrochloric acid
45:16is to activate pepsin all right so again
45:21um first up though we have Chief cells
45:23the chief cells would produce pepsinogen
45:27eventually no convert to pepsin and that
45:31is happening with the help of
45:34hydrochloric acid now what is the
45:36function of pepsin it breaks the co
45:39valent Bond of proteins to form smaller
45:43peptide chains So eventually no um after
45:46complete digestion after complete
45:49chemical digestion of proteins
45:53then amino acids for for other
45:57purposes as a nutritional Source but
46:00again before all of that could happen we
46:02need the help of pepsin again pepsin
46:05would help us digest
46:09proteins mucus um in thick layers could
46:12lubricate the mucosa of the stomach and
46:15protect the mucosa of the stomach from
46:17the acidic Kim and pepsin so combination
46:22hydrochloric acid y Kim and Y pepsin
46:26again no that could be harmful if it
46:28makes direct contact with the cells of
46:31our stomach so again purpose mucus to
46:34line or coat the inside of our stomach
46:38or the mucosa of our
46:41stomach intrinsic
46:44factor intrinsic factor so this binds to
46:48vitamin B12 making it more readily
46:51absorbed by the small intestine all
46:54right so basically
46:57intrinsic factor ABS vitamin B12
47:04now vitamin B12 why do we need to
47:08readily absorb this vitamin B12 is
47:11important in DNA synthesis and red blood
47:14cell production all right so again two
47:18things vitamin B12 this is for DNA
47:22synthesis and red blood cell production
47:26so
47:27um thir year when you get to your
47:30parisology classes um you would learn
47:33that there's actually a parasite now
47:35there's a tape worm infection out there
47:38that could cause vitamin B12 deficiency
47:45Anem vitamin
47:48B2 so consequently um when a person
47:52acquires an infection with this parasite
47:55no um
47:57supp vitamin B2 for the
48:01patient RBC production hence leading to
48:05anemia or the decreased number of rbcs
48:08in the circulation all right so again
48:12that's the pathopysiology no
48:15pathopysiology of
48:17booos anemia so again you would learn
48:20more about that in your parasitology
48:24classes
48:26this slide talks about movements in the
48:28stomach mixing waves are just weak
48:32contractions so they are happening to
48:35thoroughly mix food to form Kim all
48:38right so mixing waves mix food so when
48:41food is being mixed with all the other
48:42fluids that is present in our stomach
48:45that would lead to De formation of kind
48:48next are peristaltic waves so in
48:51comparison to mixing waves peristaltic
48:54waves are strong
48:56contractions so this NE this type of
48:59movement would now Force Kim through the
49:02pyloric
49:06f with the help of the peristaltic
49:10waves
49:12move through the pyloric
49:16spinter small intestine so the stomach
49:20empties every 4 hours after a regular
49:23meal and about 6 to 8 hours after a high
49:27fatty meal all
49:30right after a regular meal though it
49:33would take 4
49:35hours small
49:38intestine stomach but if for example um
49:42the food items that we've eaten no are
49:45high in lipids no this is fatty or high
49:48in lipids and cholesterol it may take
49:51from 6 to 8 hours before move
49:56small intestine so basically 6 to 8
50:00hours
50:02stach hydrochloric acid and other
50:05digestive enzymes you food
50:10items this slide right here just shows
50:13us an illustration of the mixing wave
50:16versus the peristaltic wave again for
50:19the mixing Wave It's just attempting to
50:21mix the bolus or the food items with the
50:25hyd chloric acids and other digestive
50:27enzymes in the stomach to form Kim next
50:30in the peristaltic wave it is attempting
50:33to push the Kim from the um stomach
50:37through the um boric sphincter and down
50:40to the first segment of the
50:43stomach or I mean first segment of the
50:46small intestine all right
50:51an let's now proceed to the small
50:54intestine the small intes measures
50:56approximately 6 m in length all right so
50:59again for a normal healthy adult if we
51:02were to lay out the small intestine in
51:05one straight line it would measure
51:08approximately 6 M the small intestine is
51:11the major absorptive organ of the
51:14gastrointestinal tract so most of the
51:16absorption of
51:18nutrients it's a small intestine K would
51:22take about 3 to 5 hours to pass through
51:25the small intestine before it reaches
51:28the large intestine all right
51:31so 4
51:33hours F
51:35item
51:37after another 3 to 5 hours the small
51:42intestine before it goes to the large
51:45intestine so right here we may also find
51:49um enzymes for further breaking down of
51:52food if ever food items or food partic
51:56um break down during its time in the um
52:00stomach next it contains secretions for
52:03protection against the acidity
52:08of
52:10in protection against against the um
52:15acidic nature of the kind so again um we
52:18may be able to find cells in the small
52:21intestine that could secrete
52:24mucus let's now go through the different
52:26segments of the small intestine first up
52:29is the dood denum all right so the dood
52:32denum is the first segment of the small
52:35intestine and this is about 25 cm long
52:40all right so 25 cm in length
52:44approximately Ang dood so this contains
52:47absorptive cells goblet cells granular
52:50cells and Endocrine cells so um it's a
52:53mixture of a lot of different cells all
52:55right but of
52:57course absorptive cells for absorption
53:00of nutrients so the absorptive cells of
53:02course they have microvilli with many um
53:06folds and they also contain bile and
53:09pancreatic substances or pancreatic
53:12ducts no there may be pancreatic ducts
53:14that connect to these small
53:18intestine the next segment is the jum so
53:21the jum this is the second segment of
53:23our small intestine and this is
53:26approximately
53:272.5 M long so the Dum is the primary
53:31side of nutrient absorption All
53:39rights in the small
53:43int that most of the nutrient absorption
53:47happens at the
53:49J the third segment of the small
53:51intestine is the elium this one is
53:54actually the longest it's at
53:56approximately
53:583.5 M
54:01long this slide shows us all the
54:04structures that we've discussed in the
54:06previous slid so again if for example
54:08this is the stomach this is the pyloric
54:10opening and you have right there the
54:13pyloric sphincter you dooom again the
54:16doo denom is only approximately 25 cm in
54:20length and then after that next segment
54:23for is J so again most of absorption
54:26happens here at the Jun all right so I
54:30am after that the next segment is the
54:33Elum so then um the elium this is
54:36approximately
54:383.5 M long all right and then um after
54:43that we would have the ilocal junction
54:46all right which connects to the seeum or
54:49first part large
54:53intestine this slide talks about the
54:55cells that could be found in the small
54:57intestine and what are their purpose
55:00first up are absorptive cells so
55:02absorptive cells have microv Vil or kind
55:05of like the hairlike structures on the
55:07surface they also produce digestive
55:10enzymes and of course as their name
55:12implies they absorb the digested food or
55:15specifically
55:17nutrients digested food next are the
55:21goblet cells so goblet cells they
55:23produce a protective mucus so again um
55:27we need mucus no lining our small
55:30intestine because we still need to be
55:32protected from the acidic pH of the time
55:36next are granular cells granular cells
55:39would help protect the small intestine
55:42from bacteria all right so although
55:45normal bacteria that is present in our
55:48gastrointestinal track there may be
55:50bacteria in the food that we consume
55:53that could cause in infections all right
55:56gastrointestinal infections so of course
55:59granular cells to help us fight off
56:02those bacteria and last one our
56:04Endocrine cells there are still um kind
56:08of like a piece of our endocrine system
56:10need small in small intestine n and they
56:14also produce regulatory
56:19hormones the epithelial cells are
56:21located within tubular glands of the
56:24mucosa then these ones are called
56:26intestinal glands or Crypts of liberen
56:29at the base of the Vila all right so
56:33again we have glands no within our small
56:36intestine all right so these tubular
56:38glands are referred to as intestinal
56:41glands or Crypts of
56:43liberon next granular and Endocrine
56:45cells are located in the bottom of the
56:48gland
56:51so granular and endocine cell
56:55next the sub mucosa of the duodenum
56:59contains mucous glands called duodenal
57:02glands which open into the base of the
57:05intestinal glands all right so basically
57:07this slide just talks about the location
57:10of those different cells that we've
57:11mentioned in the previous
57:14slide let's now talk about the important
57:16secretions of the small intestine
57:19peptidases enzymatically break down
57:21proteins into amino acids for absorption
57:28soep bonds
57:31proteins further divide into amino acids
57:35and after that ready for absorption and
57:38utilization by our cells next are
57:41disaccharidases disaccharidases
57:44enzymatically break down disaccharides
57:46into
57:48monosaccharides for absorption and
57:50utilization all right so disaccharides
57:53is a form of sugar so a sugar composed
57:57of or a it's a sugar composed of two
58:00different sugars all right so again um
58:05disaccharidases would break down
58:08disaccharides
58:11monosaccharides
58:13monches for example glucose this would
58:16now be readily absorbed and utilized by
58:19ourselves to create energy glucose is
58:23very important for the creation of
58:25energy in the form of ATP or adenosine
58:31triphosphate these illustrations show us
58:34the structure of
58:37micro microbiology class specifically
58:40micro one or clinical bacteriology you
58:43would learn that there's actually a
58:45strain of eoli or esara coli that is
58:50capable of causing an infection and
58:53destroying the microb V all right
58:59so pathogenic
59:01ESI micro small intestine and as you
59:05know no um with regards to
59:09cells
59:13structure so this would lead to the
59:16inability to absorb nutrients leading to
59:20some form of
59:22malnutrition or um
59:31it's just
59:33that
59:37nents ESI infection micr n all right so
59:42again that's the pathophysiology of
59:46enteropathogenic
59:48escari
59:50infections um in your future
59:52microbiology one classic
59:55is let's now talk about the movement of
59:58the small intestine so um mixing and
1:00:01propulsion K are the primary mechanical
1:00:04movements that occur in the small
1:00:06intestine so mixing and propulsion
1:00:09discuss so um peristaltic contractions
1:00:13along the length of the intestine cost
1:00:15the time to move along the small
1:00:17intestine all right
1:00:20sotic main goal is to move the food
1:00:24forward
1:00:26or segment small intestine um next are
1:00:30segmental contractions so these are
1:00:33propagated um for only short distances
1:00:37and mixed intestinal contents all right
1:00:40so I um again peristaltic contractions
1:00:43this is to move the Kim um through the
1:00:47small intestine segmental contractions
1:00:50no only in short distances only for
1:00:53mixing
1:00:57contents the ILO seal sphincter at the
1:00:59juncture of the ilum en large intine
1:01:03remains mildly contracted most of the
1:01:06time all right so my ILO
1:01:14[Music]
1:01:17fter seeum or you first segment large
1:01:21intestine all right so peristaltic
1:01:23contraction
1:01:25reaching the ilocal sphincter from the
1:01:27small intestine causes the sphincter to
1:01:30relax and allow kind to move from the
1:01:32small intestine into the seeum again the
1:01:35seeum is the first segment of the large
1:01:39intestine
1:01:47right small
1:01:49intestine um through peristaltic
1:01:51movements it would push the food from
1:01:54the pic
1:01:57opening
1:01:59simum um paralic contractions or
1:02:03peristaltic movement would push the Kim
1:02:06from the ilum seum so the ilio seal
1:02:11valve prevents movement from the large
1:02:13intin back into the helium okay so my um
1:02:20structure so the umum has what is known
1:02:24as a valve or the ilocal valve so again
1:02:28the purpose of this valve is to prevent
1:02:31the movement of back into
1:02:42the from the large intestin small
1:02:46intestine so
1:02:47basically small
1:02:51intestin lar
1:02:53int
1:03:02okay this slide shows us how segmental
1:03:05contractions happen so one area of the
1:03:08small intestine would relax allowing the
1:03:10food to pass
1:03:14through contract all right next segment
1:03:19relax all right relax current location
1:03:23food mag contract pushing the food
1:03:27forward okay so and then after that no
1:03:30it would move to the next segment now
1:03:33since this is a segmental
1:03:35contraction switch
1:03:42or with all the other fluids that is
1:03:45present in our small
1:03:49intestine let's now talk about the liver
1:03:52the liver weighs about three pounds
1:03:55right so um located in the right upper
1:03:58quadrant of the abdomen under the
1:04:00diaphragm all right so
1:04:04again right upper
1:04:07quadrant
1:04:12abdomen diaphragm so the liver consists
1:04:15of a right left Cate and quadrate lo so
1:04:19may
1:04:21loes liver next we have the term Porta
1:04:25so the Porta this is a gate where blood
1:04:28vessels ducts and nerves would enter and
1:04:31exit so the Porta receives blood from
1:04:34the hepatic artery and the hepatic for
1:04:37portal vein all right
1:04:41[Music]
1:04:42so blood vessels and nerves p and if we
1:04:46have any um accessory organs no or
1:04:51ducts gather p
1:04:56this illustration right here shows us
1:04:58the location of the liver these two
1:05:01illustrations right here shows us the
1:05:03different loes of the liver next if we
1:05:07were to take a tissue sample from the
1:05:10liver this illustration shows us no um
1:05:13the other structures that we've
1:05:15mentioned you hepatic portal
1:05:19system the liver has what is known as
1:05:22lobules so the lobules these are
1:05:25divisions of the liver with portal
1:05:28Triads at the corners so again for
1:05:30reference um just kind of like scroll
1:05:33back to the photo that we've seen in the
1:05:35previous slide now um it also has what
1:05:38is known as the portal Triad and
1:05:40component portal Triad so this contain
1:05:44branches of the hepatic artery hepatic
1:05:47portal vein and hepatic duct all right
1:05:51so no artery vein and duct this is what
1:05:55would um what would create the portal
1:06:00Triad the liver also has what is known
1:06:03as hepatic sinusoids so hepatic
1:06:07sinusoids this would contain fosic cells
1:06:10that remove foreign particles from the
1:06:12blood all right so as blood um passes
1:06:15through or flows through our liver all
1:06:18right so um the phagocytic cells would
1:06:21work and remove foreign materals or
1:06:24forign substances that should not be in
1:06:27our
1:06:29blood what is the purpose of the hepatic
1:06:32duck so the hepatic duck would transport
1:06:35bile out of the liver next we have what
1:06:38is known as the cystic duck so the
1:06:40cystic duck this joins to the common
1:06:44hepatic duck and this would drain the
1:06:46Gull Bladder all right so for
1:06:50now all right thetic du
1:06:56bis liver liver next the cystic duck
1:07:01this is um kind of like a passageway
1:07:04that would drain the Gull
1:07:08Bladder this illustration right here
1:07:10just shows us the location of the liver
1:07:13in comparison or with respect to all the
1:07:16other accessory structures of our
1:07:19digestive system such as the pancreas
1:07:23the spleen and of course the
1:07:27gallbladder let's now look into the
1:07:29functions of the liver so this performs
1:07:32Digestive and expiratory functions the
1:07:35liver could also store and process
1:07:38nutrients as we've learned from previous
1:07:41discussions no um glucose could also be
1:07:45stored in the liver in the form of what
1:07:48glycogen so you excess glucose convert
1:07:52into glycogen and then this gly glycogen
1:07:54could be stored in the liver next the
1:07:57liver could also detoxify harmful
1:08:01chemicals and of course the liver has
1:08:03the capability to secrete 700 Mill of
1:08:08bile each day
1:08:14so dilutes and neutralizes the stomach
1:08:18acid and it also breaks down fats Okay
1:08:22so
1:08:25V it could neutralize the stomach
1:08:28acid excessive
1:08:31acidity food items
1:08:34or digestive tract another function of
1:08:37the vile is to break down fat all right
1:08:40help us with the digestion of
1:08:45lipids so at this
1:08:49point um what enzymes would help us
1:08:52digest carbohydrates
1:08:54salivary amas and
1:08:58disaccharidases next um enzyme canina
1:09:02that could help us break down
1:09:04proteins peptidases all right so po um
1:09:09the the substance that could help us
1:09:12break down fats or lipids is
1:09:17bile let's now talk about the pancreas
1:09:20the pancreas is located posterior to the
1:09:23stomach and inferior part of the left
1:09:25upper quadrant so posterior to the
1:09:30stomach stomach all right so um the
1:09:33pancreas is
1:09:36familiar during our discussion on the
1:09:39endocrine system so the pancreas has
1:09:42both cells for endocrine and exocrine
1:09:46function now the pancreas has um kind of
1:09:49like Parts no so it has what is known as
1:09:52a head or the thick ER or wider part so
1:09:55the head is near the midline of the body
1:09:59or next the tail would extend to the
1:10:03left and it touches the spleen all right
1:10:05so tail or man area
1:10:15pancre so the pancreas is endocrine
1:10:17tissues that have pancreatic eyelids
1:10:20that produce insulin and gluc
1:10:24luon now if you would remember from our
1:10:26past discussion on the endocrine system
1:10:29an an substance
1:10:32pool insulin and
1:10:35glucagon yes it is glucose all right so
1:10:40aside from insulin and
1:10:46gluc a
1:10:48pancreas it's
1:10:51somatostatin po so remember um this kind
1:10:54of like meme right here so the alpha
1:10:56cells produces glucagon beta cells
1:10:59produces somtin and Delta cells produces
1:11:07insul all of them have the capability to
1:11:10control glucose
1:11:14levels moving on to the exocrine cells
1:11:18of the pancreas um the exocrine cells of
1:11:21the pancreas would produce prote
1:11:24digesting enzymes all
1:11:26right exocrine portion pancreas it
1:11:30produces enzymes specifically those
1:11:33enzymes that could help us break down
1:11:35protein so listed here are the three
1:11:38Trin kyot tripsin and carboxy
1:11:42peptidase mentioned here are other
1:11:45pancreatic secretions pancreatic amas
1:11:48continues the polysaccharide digestion
1:11:51that began in the oral cavity
1:11:54all right
1:11:55so pancreatic amas is to continue
1:12:00digestion carbohydrates or
1:12:02polysaccharides
1:12:04simulan salivary amas next the
1:12:08pancreatic enzyme lipase is a lipid
1:12:11digesting enzyme so again this one is
1:12:14quite easy to
1:12:16remember substance B break down orad
1:12:19digest again liase would help us Digest
1:12:24lipids next the pancreatic nucleus would
1:12:28degrade DNA and RNA into their component
1:12:33nucleotides
1:12:35so DNA or RNA
1:12:39components food
1:12:41items nucleis to further break those
1:12:47down this illustration right here just
1:12:50shows us the location of our pancreas so
1:12:53again
1:12:55panc is the and then
1:13:02taust
1:13:05pancre is the spleen um this
1:13:08illustration right here shows us the
1:13:10different um cells and glands that we
1:13:13may be able to find in the
1:13:17pancreas let's now proceed to the large
1:13:19intestine the function of the large
1:13:21intestine is to absorb water from from
1:13:23indigestible food and create compact
1:13:26faces all right so small intestine
1:13:30mostly um nutrient
1:13:33absorption large intestine water
1:13:37absorption all right and also of course
1:13:40no this would compact the undigested
1:13:43food materials to create the feces so
1:13:46listed here are the different segments
1:13:48of the large intestine the seum colon
1:13:51rectum and anal Canal so the first
1:13:53segment is the seeum the seeum would
1:13:56join the small
1:13:59intestine small intestine and large
1:14:02intestine specifically they are joined
1:14:05at the
1:14:07ilocal junction um this is also the area
1:14:10where the appendix is attached all right
1:14:14the specific segment in our large
1:14:16intestine where our appendix is attached
1:14:19is at the
1:14:21the appendix this is a 9 cm
1:14:25structure all right approximately 9 cm
1:14:28though size appendix and this is usually
1:14:32removed when the appendix of the patient
1:14:35is already inflamed in cases of
1:14:40appendicitis next segment of the large
1:14:43intestine is the colon but in some
1:14:46discussions or in some references um
1:14:52interchangeably you large intestine and
1:14:55the colon all right
1:14:58so discussions or references no that
1:15:01they mention the colon but actually they
1:15:04are referring to the entire large
1:15:06intestine anyway the colon um this is
1:15:09approximately 1.5 M long all right and
1:15:13it contains um different or kind of like
1:15:16it is made up it is made up of um
1:15:19different segments as well so the colon
1:15:22is made up the ascending transverse
1:15:25descending and sigmoid regions
1:15:29okay the colon is um another segment of
1:15:33the large intestine and it contains the
1:15:36ascending transverse descending and
1:15:39sigmoid
1:15:40regions next is the rectum so the rectum
1:15:43is a straight tube that joins the
1:15:46sigmoid colon and then this would end at
1:15:49the anal
1:15:52canal the last segment of our large
1:15:55intestine and actually the last segment
1:15:58of our digestive tract for that matter
1:16:00is the anal Canal so again the anal
1:16:03Canal this is the last two to three cm
1:16:06of the digestive tract
1:16:09so
1:16:10ending digestive tract or
1:16:13gastrointestinal tract if you would
1:16:16remember from the earlier parts of our
1:16:18discussion what did we say the
1:16:21gastrointestinal tract is just one long
1:16:23tube from the mouth to the anus all
1:16:26right so po food would take about 18 to
1:16:3024 hours to pass through the large
1:16:34intestine
1:16:35so passage um digested food items so
1:16:39large intestine 18 to 24 hours n all
1:16:43right so feces are the product of water
1:16:46indigestible food and microbes so po um
1:16:51basically no basically
1:16:54combination undigested food materials
1:16:57food particles or fibers plus a bit of
1:17:01water and some microbes no so all of
1:17:04those three things together would create
1:17:06the
1:17:10feces this slide right here shows us all
1:17:12these structures that we've talked about
1:17:15in the previous slide all
1:17:18right or last segment small
1:17:22intestine ilocal Junction and the one
1:17:25that we're seeing right here on the
1:17:27inside is the ilocal valve all right so
1:17:30again this is
1:17:32[Music]
1:17:38important large intestine this part
1:17:41right here po this is the ascending
1:17:45colon next this one right here you P
1:17:48cross this is the transverse colon next
1:17:52this one paba no this is the um
1:17:55descending colon and then this one pant
1:17:59this is the sigmoid colon next segment
1:18:03is the rectum and lastly the anal Canal
1:18:06also as you can see right here no um the
1:18:08if this is the seeum an attach
1:18:16appendix mentioned here are the
1:18:18functions of the large intestine first
1:18:20up is feis formation right so the
1:18:23formation of poop all right so this is
1:18:26due to the absorption of water and salts
1:18:28and secretion of mucus and the action of
1:18:31microorganisms so actually a lot of
1:18:34processes come into the formation of
1:18:37faces so the colon stores the feces
1:18:40until defecation all right
1:18:44SOA
1:18:46sto defecate now every 8 to 12 hours
1:18:51strong contractions cause called mass
1:18:53movements would Propel the colon
1:18:55contents towards the anos all right so
1:18:59every 8 to 12 hours contractions would
1:19:02happen on our colon moving the faces
1:19:06towards the anus movement of the feces
1:19:09into the rectum distends the rectal wall
1:19:12and stimulates the defecation reflex all
1:19:15right so you
1:19:17distend
1:19:19orjust rectum that is referred to as the
1:19:23defecation or that would lead to sorry
1:19:25that would lead to the defecation
1:19:30reflex listed here are the three basic
1:19:32steps in the digestive process number
1:19:35one digestion this is the chemical and
1:19:37mechanical breakdown food all right
1:19:40mechanical breakdown chewing process and
1:19:44chemical breakdown of food
1:19:47exposure enzymes salivary amas
1:19:50pancreatic amas peptidases all those
1:19:53other enzymes next is absorption so
1:19:57absorption um most of the absorption
1:19:59occurs in the Dum and
1:20:02jum jum although um some absor
1:20:06absorption may also occur at the stom
1:20:09and
1:20:11Al the two um areas where most of the
1:20:15absorption would occur is a
1:20:21and most of the absorption would greatly
1:20:25occur no at the jum in comparison to the
1:20:30Doom next is transport so transport this
1:20:33moves the food through the digestive
1:20:36tract which would include swallowing and
1:20:38peristalsis so of course your first step
1:20:41is you
1:20:43swallowing um a person needs to swallow
1:20:46the food first before it moves through
1:20:48the digestive tract via
1:20:51peristalsis
1:20:54this slide shows us the different
1:20:55molecular components of food and end
1:20:59product of breaking these down so what
1:21:02forms of these nutrients would be
1:21:04readily usable for our cells so first
1:21:08off for carbohydrates they first have to
1:21:10be digested and chemically converted
1:21:14into monosaccharides for our body to be
1:21:17able to make use of them for lipids and
1:21:21um for lipids or fat F now lipids or
1:21:23fats they first have to be digested and
1:21:27chemically converted to either fatty
1:21:30acids or
1:21:32monoglycerides
1:21:34useful cells and for proteins they first
1:21:37have to be digested and chemically
1:21:40converted into amino acids before the
1:21:44human cells could make use of these
1:21:49proteins this slide further talks about
1:21:52carboh hydrate digestion so
1:21:54polysaccharides would split or break
1:21:57into
1:21:58disaccharides because of salivary and
1:22:01pancreatic anasis next
1:22:04polysaccharides disaccharides these
1:22:07disaccharides are broken down into
1:22:10monosaccharides by
1:22:12disaccharidases on the surface of the
1:22:14intestinal epithelium all right so again
1:22:19notion
1:22:21disaccharidases they split
1:22:27Apes
1:22:29monares next after that glucose is
1:22:32absorbed by the co- transport or by Co
1:22:36transport with um sodium into the
1:22:39intestinal epithelium all right so again
1:22:42my co transport
1:22:45mechanism intestinal epithelium that
1:22:47helps with the absorption of glucose
1:22:51next glucose is car into the hepatic
1:22:53portal vein to the liver and enters most
1:22:56cells via facilitated diffusion so
1:23:03G glucose through
1:23:06facilitated
1:23:08diffusion this illustration right here
1:23:11just shows us the transport of glucose
1:23:13across the intestinal epithelium so
1:23:16again digest both chemically and
1:23:19mechanically food items eventually
1:23:23breakdown polysaccharides into
1:23:30glucose micro
1:23:32intestines and then um let's look at
1:23:35this illustration right here if for
1:23:37example this thing right here is an
1:23:40intestinal epithelial cell
1:23:44glucose as a CO transport with sodium so
1:23:51basically
1:23:53no cell together with sodium after that
1:23:58no um they would go through via
1:24:01facilitated diffusion no and be
1:24:04transported to the liver through our
1:24:10capillaries we are done with
1:24:12carbohydrate digestion let's now talk
1:24:14about lipid or fat digestion so light
1:24:18paste would break down triglycerides
1:24:20into fatty acids and
1:24:23monoglycerides next bile salts bile
1:24:26salts would surround the fatty acids and
1:24:29monoglycerides to form my cells so my
1:24:32cells this would attach the plasma
1:24:34membranes of the intestinal epithelial
1:24:37cells and then the fatty acids and monog
1:24:40glycerides would pass by simple
1:24:43diffusion into the intestinal epithelial
1:24:46cells all
1:24:47right
1:24:50Li structure
1:24:53triglycerides fds
1:25:01monoglycerides
1:25:03so bile or bile salts would surround the
1:25:07molecules of the fatty acids and
1:25:13monoglycerides
1:25:15so they would um they would kind of like
1:25:19pass through our intestinal epithelial
1:25:22cells via simple
1:25:27diffusion within the intestinal
1:25:29epithelial cell the fatty acids and
1:25:31monoglycerides are converted back to
1:25:34their original triglycerides form all
1:25:37right
1:25:40so
1:25:42[Music]
1:25:46stepsides diges
1:25:49system
1:25:51f
1:25:54glycerides
1:25:58cells F and
1:26:01monoglycerides
1:26:02triglycerides all right but anyway those
1:26:05are necessary steps after that no
1:26:08proteins would coat the triglycerides to
1:26:11form kyom microns all
1:26:14right
1:26:16triglycerides proteins they are referred
1:26:19to as kyom microns next they would move
1:26:23out of the intestinal epithelial cells
1:26:25by
1:26:27exocytosis so these kyom microns they
1:26:29would enter um the lacal of the
1:26:32intestinal villi and are carried through
1:26:35the lymphatic system of the
1:26:37blood this illustration right here shows
1:26:40us a visual representation of everything
1:26:42that we've explained in the previous
1:26:45slide all right so again triglycerides
1:26:47would be broken down into um fatty acids
1:26:50and monog glycer ites then they would be
1:26:53covered by bile salts this um structure
1:26:57together is referred to as the myel the
1:26:59Mel enters the cell via simple diffusion
1:27:03after that
1:27:04triglycerides and then proteins would
1:27:07coat them and create kyom microns
1:27:10chylomicrons would move out
1:27:13and
1:27:15Lac lymphatic
1:27:19system this slide talks about lipo
1:27:22proteins lipids are packaged into
1:27:25lipoproteins to allow transport in the
1:27:27lymph in blood all right so again you
1:27:30lipids
1:27:32fsport through our circulation and
1:27:35through our lymphatic system um after
1:27:39they have been um converted into
1:27:43lipoproteins lipoproteins these are
1:27:45molecules that are part water soluble
1:27:47and part lipid soluble so basically par
1:27:51half and half no May um my part that is
1:27:55soluble in water and then my part lipid
1:27:58soluble so that is what A lipoprotein
1:28:01structure would be so since lymph and
1:28:05blood contain water the lipids are not
1:28:08water soluble all right so
1:28:13lipins
1:28:15transport so the different types of
1:28:17lipoproteins would include kyom microns
1:28:19low density lipoproteins or LD L and
1:28:23high density lipoproteins or
1:28:27HDL just a trivia no side note po high
1:28:30density lipoproteins or HDL this is
1:28:33otherwise referred to as our good
1:28:38cholesterol these illustrations right
1:28:40here shows us the difference between
1:28:41kyom microns LDL and HDL so is
1:28:48percentages composition all right so as
1:28:50we can see right here kylo microns are
1:28:5390% triglycerides okay again component
1:28:58kyom microns are
1:29:00triglycerides next LDL or low density
1:29:04lipoproteins component is cholesterol
1:29:08all right mostly
1:29:10cholesterol component low density
1:29:14lipoproteins next high density
1:29:18lipoproteins
1:29:20component the protein portion all right
1:29:24so
1:29:26components high density lipo protein is
1:29:31protein so again these are the
1:29:33differences in composition of kyom
1:29:35microns low density lipoproteins and
1:29:37high density lipoproteins kyom microns
1:29:40are mostly composed of triglycerides low
1:29:43density lipoproteins the greatest
1:29:45component is cholesterol and for high
1:29:48density lipoproteins the greatest
1:29:50component is
1:29:54protein
1:29:56okay liid
1:29:59dig let's now proceed to protein
1:30:02digestion so protein um digestion would
1:30:05begin with the enzyme pepsin so pepsin
1:30:08is a protein diges digesting enzyme that
1:30:11is secreted by the stomach all right
1:30:14stomach secrete pepsin and hydrochloric
1:30:18acid so pepsin specifically it Digest or
1:30:22breaks down proteins
1:30:28next secrete the pancreas so the pancrea
1:30:32or the pancreas secretes protein
1:30:35digesting enzymes such as Trin kimot
1:30:39triin and carboxy peptid okay
1:30:44so okay again the three enzymes secreted
1:30:49by pancreas no that could Digest
1:30:52proteins
1:30:53include Trin kimot triin and carboxy
1:30:57peptidase now in the small intestines
1:31:00these enzymes would be
1:31:04activated work which is to digest
1:31:09proteins in the small intestine other
1:31:11enzymes termed peptidases are bound to
1:31:15the micro Villa of the intestinal
1:31:17epithelia further breaking down small
1:31:19peptides into triep ties so
1:31:24basically function pepis or
1:31:28specifically so again peptidases they
1:31:31could break down small peptides into
1:31:36triptides um eventually absorption of
1:31:39tripeptides dipeptides and individual
1:31:41amino acids would occur in the
1:31:44intestinal epithelial
1:31:48cells this illustration right here shows
1:31:50us the transport of amino acids across
1:31:53the intestinal epithelium so again this
1:31:55would happen sa Vos all right or
1:31:59hairlike
1:32:01structures micro so what happens here is
1:32:05that bre down protein into individual
1:32:08amino acid
1:32:10molecules transport with sodium all
1:32:13right it would also be Co transported
1:32:15with sodium it would pass through um the
1:32:19cell via facilitated diffus
1:32:32and this slide talks about water and
1:32:34mineral absorption so water can move
1:32:37across intestinal wall in either
1:32:40Direction
1:32:43sotal
1:32:46wallos all right so the movement depends
1:32:48on osmotic pressures 99% of the water
1:32:51entering the intestin is
1:32:59absorbed
1:33:01absorb okay so minerals on the other
1:33:04hand they are actively transported
1:33:06across the wall of the small intestin
1:33:09all
1:33:10right
1:33:15specific minerals and again that happens
1:33:18at the small
1:33:20intestine shown here is an illustration
1:33:23of how much fluid each segment of our
1:33:26digestive tract could hold all right so
1:33:31again segment or digestive tra how much
1:33:35fluid would it be able to hold all right
1:33:39so see the gastrointestinal tract is
1:33:41just one long tube from the mouth to the
1:33:45a all right they probably cut out some
1:33:48parts right
1:33:50here the small intestine is quite
1:33:55long if you belong to my lecture classes
1:33:58that ends our discussion on the
1:34:00digestive system thank you so much for
1:34:03listening if you belong to my laboratory
1:34:06classes let's narrow proceed to the
1:34:08slides that would show the microscopic
1:34:10anatomy of our digestive
1:34:15system just a bit of
1:34:19disclaimer images
1:34:22as we go through the next few slides all
1:34:25right number
1:34:26one video all right number two um the
1:34:32more efficient way know the more
1:34:34effective and efficient way of studying
1:34:37this is um I will be sending you a PDF
1:34:40copy of um of the slides D digestive
1:34:45system if you belong to my laboratory
1:34:47classes and then um include links
1:34:51sources to the pictures all right so
1:34:55each of these um photos that you will be
1:34:57seeing here my
1:34:59links so just click on those
1:35:05links Source description and specific um
1:35:11details about each image all right
1:35:14so pictures although they are googleable
1:35:19um googleable um
1:35:22specific
1:35:25sites
1:35:31syst lymphatic system so again I will be
1:35:35sharing my references to these
1:35:40photos so for the next few slides I will
1:35:43only be reading the title Nang po all
1:35:47right so again basang po literal basang
1:35:59title the salivary gland under low power
1:36:05objective the salivary gland under high
1:36:08power
1:36:10objective the
1:36:13esophagus the liver under low power
1:36:19objective the liver under under high
1:36:22power
1:36:24objective the liver under oil immersion
1:36:30objective the pancreas under low power
1:36:35objective the pancreas under high power
1:36:38objective and oil immersion
1:36:43objective the stomach body under low
1:36:47power
1:36:49objective the stomach body under medium
1:36:56power the stomach body under high power
1:37:02objective here are other views of the
1:37:05stomach under high power
1:37:09objective the dood denum under low power
1:37:16objective the dood denum under high
1:37:19power
1:37:20objective
1:37:23the jum under low power
1:37:27objective the Elum under low power
1:37:32objective the elium under high power
1:37:39objective the large intestine
1:37:41specifically the colon under high power
1:37:47objective the appendix under low power
1:37:50OB
1:37:52objective the appendix under high power
1:37:59objective the rectum under low power
1:38:05objective the rectum under high power
1:38:12objective this slide shows us a
1:38:14compilation of the esophagus stomach
1:38:17small intestine and large intestine
1:38:20under low power
1:38:23objective this ends our discussion on
1:38:26the digestive system again I am AEL
1:38:29Enriquez thank you so much for
1:38:31listening

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