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AnatomyCNSpartB — Transcript

by Dr. Naveen Jalota, M.D. · 7,936 words · 1,226 segments · language en · Watch on YouTube

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0:00all right let's talk second half of
0:04central nervous system then let's talk
0:06here now we'll pick up with diencephalon
0:09so the second half of the central
0:12nervous system here that will go with
0:15diencephalon now we talked diencephalon
0:17I like you to know the diencephalon you
0:20can see here now it's going to be made
0:22up of three paired structures now when
0:24we go through and we talk three paired
0:26structures we'll go through and we'll
0:27look at each of these paired structures
0:29individually and talk about them one by
0:32one as we progress so here when we go
0:34through and we talk diencephalon first
0:37I'd like you to know that the
0:38diencephalon is going to form the
0:40central core it will form the central
0:44core of the forebrain this diencephalon
0:48is surrounded by the cerebral
0:50hemispheres it's surrounded by the two
0:52cerebral hemispheres and again when we
0:56talk diencephalon diencephalon is going
0:57to consist of three paired structures
1:00those three paired structures as we can
1:01see here are going to include the
1:03thalamus hypothalamus and the
1:05epithalamus now when we talk about the
1:08diencephalon the diencephalon are gray
1:11matter areas they are gray matter areas
1:15that enclose the third ventricle if you
1:19recall when we talked primary brain
1:21vesicles secondary vesicles we saw we
1:23had ventricles at the center so yeah you
1:25have to go back and recall that and
1:27exactly which ventricle we have there
1:28now you know is the third ventricle
1:29again so what we'll do is we'll go
1:32through and we'll talk first alamos and
1:34I will move the hypothalamus and then
1:35we'll check out epithalamus so we talk
1:37to our mast thalamus it's organization I
1:40want you to know when we talk thalamus
1:41here we can appreciate a nice image
1:44depicting to us first all three
1:46components of diencephalon you've got
1:48first right inside of here the thalamus
1:50and here we've got the hypothalamus and
1:53then right back here is where we're
1:54gonna have the epithalamus now here we
1:57go through and we talk thalamus so
1:59that's what we're looking at here we'll
2:00look at this structure then in greater
2:02detail so here we can see the elements
2:0480% of it is the diencephalon and we're
2:07going to see it's gonna form the
2:08superior lateral walls of the third
2:10ventricles of the third ventricle it
2:12will form the superior
2:13lateral walls of the third ventricle and
2:16when we talked alum and I we talked
2:18Alamos dolmas is described as basically
2:20bilateral nuclei their bilateral nuclei
2:23that are connected by the inner
2:25Ptolemaic adhesion as we can see here
2:28the intermediate mass now when we go
2:31through we talk thalamus thalamus you'll
2:33see is again now bilateral nuclei okay
2:38they're gonna contain several nuclei now
2:40each of these talam i will go through
2:43will look at and they're gonna be named
2:45for their location as well we'll go
2:47through and we'll see that as we
2:48progress and we talk about each of these
2:49different dolemite there as well if each
2:51of the different nuclei inside the
2:52thalamus
2:53now the nuclei they're gonna project and
2:55they're gonna receive fibers from the
2:57cerebral cortex okay so it's important
2:59you remember that super cortex and its
3:00function that we went through we talked
3:02about in the first half of chapter 15
3:05and the latter half of 13 so in the last
3:10lecture of CNS now here when we go
3:12through we talk dynamic functions you'll
3:14see number one it's a gateway to the
3:16cerebral cortex it's a gateway to the
3:18super cortex we could think of it as as
3:21basically as a relay station so you can
3:25think of it as a relay station and when
3:27we compared to a relay station you can
3:29see here what it's gonna do is it's
3:30gonna sort edit and relay this a sending
3:35input okay and now these impulses from
3:39the hypothalamus now impulses from the
3:42hypothalamus are gonna be for regulation
3:45of emotion and visceral function now
3:47these impulses from the cerebral from
3:50the cerebellum and the basal nuclei are
3:52going to be basically to help direct
3:53motor cortices now impulses from memory
3:58or sensation memory or sensory are
4:00involved with integration it pulses for
4:04memory or sensory integration as well
4:07are gonna be basically passing through
4:08so a sorts edits and relays all of this
4:12a sending input is making sure all of
4:13this ins this a sending input is making
4:16its way to the exact right spots also
4:19again you can see mediates sensation
4:21motor activities so mediates sensation
4:27motor activities also cortical arousal
4:30it's involved with it's involved with
4:32learning and memory as well so functions
4:35a relay station for incoming information
4:37that's making its way to the cerebral
4:39cortex it will sort and edit this
4:42information and immediate sensation
4:45responsible for mediating motor
4:47activities cortical arousal learning and
4:50memory as well here we can appreciate
4:54now a nice view of the thalamus in
4:56greater detail now here you can
4:58appreciate all the various nuclei within
5:01the thalamus now each of these nuclei
5:03have their own functional specialties
5:06now here I'll give you one you can see
5:09and I want you to know these in basic
5:11idea they're basically functions you
5:14know here when we go through we talk we
5:17can see here again a whole bunch of
5:18different nuclei and here you can see
5:21you got the ventral posterior lateral
5:24nucleus there's the ventral posterior
5:28lateral nucleus it receives impulses
5:30from your general somatic sensory
5:32receptors like receptors that are
5:36involved with touch pressure and pain so
5:43just like that you can see each of these
5:44are going to have their own functional
5:46specialties next then we're going to see
5:49we have then what we call the
5:51hypothalamus now the hypothalamus it's
5:54named for its position it's gonna form
5:56the inferior lateral walls of the third
5:58ventricle and it also will contain many
6:00nuclei for which you're going to see
6:02you're gonna have to know the functional
6:04specialties for as well so here would we
6:06go through we talk hypothalamus first
6:09let's talk organization it's going to
6:11cap the brainstem it caps the brainstem
6:15and it forms again we said the inferior
6:17lateral walls of the third ventricle and
6:21the hypothalamus it extends from the
6:24optic chiasma so here in this view you
6:25can appreciate it extends from the optic
6:27chiasma and it goes all the way to the
6:30dorsal aspect the posterior aspect you
6:32can think of of the mammillary bodies so
6:36it's making its way all the way from
6:37this optic chiasma all the way to that
6:40posterior aspect of the
6:41mammillary bodies again bunch of nuclei
6:44in here as well okay mammillary bodies
6:46are examples of one pair of nuclei then
6:51we're gonna go through we're gonna see
6:52when you talk mammillary bodies they're
6:54paired like they're paired p like nuclei
6:58they're paired P like nuclei you can see
7:03are bulging from the hypothalamus and
7:07they are relay stations in the olfactory
7:11pathways they are relay stations in the
7:14olfactory pathway so just like this
7:22you're gonna have to go through and get
7:23the functions of each of these various
7:25nuclei down by time we'll get to physio
7:28you're gonna have every single one of
7:29them down that's super optic we're gonna
7:31see here by the time we get to endocrine
7:32suprachiasmatic we're gonna see there
7:34again and periventricular will go
7:36through and we'll talk about and we'll
7:37check out so each of these you're gonna
7:39have to know basically kind of what
7:41their functions are they're next in here
7:44we're gonna go through we're talk
7:45generally speaking a function of the
7:47hypothalamus now with all of these
7:49different nuclei there
7:50we'll talk generally now the functions
7:52here as well now generally speaking the
7:54functions are gonna include number one
7:56you can see it's gonna behave as the
7:58autonomic control center order our
8:01autonomic control center our autonomic
8:03nervous systems control center you can
8:05think up how we talk to ans it's a
8:09system of peripheral nerves that are
8:11gonna regulate cardiac and smooth muscle
8:13and then also the secretions by our
8:17glands hypothalamus and also involved
8:22with the emotional response it's
8:24involved in the perception of pleasure
8:27fear and rage so it's involved in the
8:32perception of pleasure fear and rage as
8:37well as those and biological rhythms as
8:40well as those and biological rhythms and
8:44drives by
8:50temperature regulation another function
8:53we have here body temperature regulation
8:55and we talked body temperature
8:57regulation you'll see hypothalamus is
8:59involved with causing sweating for
9:02cooling and shivering then to help
9:08generate heat regulation of food intake
9:15we can see is another function it
9:17regulates the feelings of hunger and
9:19satiety it regulates the feelings of
9:22hunger and satiety basically hunger and
9:24fullness hypothalamus is also involved
9:30in the regulation of water balance and
9:32thirst water balance and thirst you'll
9:36see we have Osmo receptors and these
9:39Osmo receptors they excite nuclei that
9:43trigger ADH is release they trigger ADH
9:49is released from the posterior pituitary
9:51and an ad H which stands for
9:54antidiuretic hormone also known as
9:59vasopressin ADH causes the kidneys then
10:02to retain water antidiuretic hormone now
10:08the same conditions they stimulate
10:10hypothalamic neurons in the thirst
10:12center making us feel thirsty therefore
10:18causing us to drink more fluids next we
10:25also have another function it's a
10:26regulation of sleep cycles and that's
10:29gonna happen via the suprachiasmatic
10:30nucleus which is your biological clock
10:33again you've got to know that function
10:35there and what it does it sets sleep
10:38cycle timing in response to daylight and
10:41darkness cues that we get from our
10:45visual pathways so you can see how
10:48different parts are gonna be working
10:49together and then another function here
10:54is going to be endocrine system control
10:55endocrine system control will see this
11:01hypothalamus is going to be responsible
11:04for
11:04releasing releasing hormones and it
11:09releases inhibiting hormones which
11:11you'll have to know about when we get to
11:13end up in super optic and
11:17periventricular nuclei there are gonna
11:19be responsible producing as we said ADH
11:21and then oxytocin another one when
11:23you're gonna have to know about an
11:25oxytocin so know which one is doing what
11:28which one is producing Ad Age which one
11:30is releasing and producing oxytocin all
11:33stuff your me response for knowing about
11:35there in greater detail when we get to
11:37endocrine system next time we've got the
11:42epithalamus epithalamus and we talk
11:45epithalamus okay so here you've got all
11:47the different functions we've gone
11:48through we've mentioned there make sure
11:50you've got them down in greater detail
11:52you understand with each of those
11:54functions there are so here that we can
11:56see now the epithalamus now we talked a
11:58Pete Alamos epithalamus we can see now
12:01is going to be found at the most dorsal
12:05portion of the diencephalon found at the
12:08most dorsal portion of the diencephalon
12:10and it forms the roof of the third
12:12ventricle it forms the roof of the third
12:15ventricle when we talk about alamos
12:22epithalamus
12:23main gland we're gonna see here is going
12:24to be the pineal gland and also known as
12:27pineal body
12:28now this pineal gland pineal body is
12:30found extending from the posterior
12:33border it's extending from the posterior
12:35border and you'll see it's visible
12:37externally and it is visible externally
12:43this pineal gland is responsible for
12:46secreting a hormone called melatonin
12:48melatonin melatonin comes from serotonin
12:53comes from serotonin melatonin
13:00is a sleep-inducing signal it's a
13:02sleep-inducing signal and it behaves as
13:05an antioxidant so it helps regulate the
13:08sleep/wake cycle and we believe it
13:10functions as an antioxidant next in here
13:20we can move down and we can appreciate
13:22again that diencephalon thalamus
13:25hypothalamus and then epithalamus right
13:27back in here so when we say it's visible
13:29externally you can see all you have to
13:31do is push the cerebellum down gently
13:33pushing it down very gently and then
13:36you're able to appreciate that
13:37pioneer gland right back inside of there
13:39if we're in the lab and the lab you'd
13:41actually have sheep brains and the sheep
13:42brain then you would be able to see
13:43you'd be able to do that and the whole
13:44sheep brain you'd be able to gently push
13:46this cerebellum down from the cerebral
13:48from the cerebellum basically that
13:52pushed the cerebellum down from the
13:54cerebral from each of these cerebral
14:01basically components I want to say the
14:05proper term the proper term I want to
14:07use now here is from each of the
14:10cerebral hemispheres okay so you'd push
14:12down basically the cerebellum from each
14:14of the cerebral hemispheres basically
14:17gently and you'd be able to see right
14:18underneath there just like you see here
14:19that pineal gland and then you've got
14:22also that corpora basically quarter
14:24quadrigemina you can see them in between
14:26the two the posterior commissure next
14:30I'm moving down we've got then the
14:33pineal gland we've taken care of every
14:35Thomas the brainstem so let's talk that
14:36in green now we've got brain stem we
14:38talked brain stem brain stem we're going
14:41to go through we're gonna see now we
14:42talk brain stem brain stem is going to
14:44be made up of basically a few different
14:47parts so here we can see in green the
14:49brain stem is gonna be made up of number
14:50one midbrain and we're gonna go through
14:52and talk pons and then we'll check out
14:54the medulla oblongata so let's talk
14:55brain stem brain stem so from top to
14:58bottom
14:59you saw all the three major components
15:00there its accounts for about
15:03two-and-a-half percent of the total
15:04brain mass you can see it's not that big
15:07histologically brain stem is similar to
15:10the spinal cord where you have deep gray
15:13matters
15:13by white matter tracks we looked at that
15:15when we looked at the organization and
15:18the brain stem is going to be
15:20responsible for producing so it centers
15:24they produce rigidly programmed
15:28automatic behaviors they produce rigidly
15:31programmed automatic behaviors that are
15:34necessary for survival
15:36now the nuclei here are associated with
15:39ten of the twelve pairs of cranial
15:41nerves you're going to go through and
15:42we're going to check out so first
15:44midbrain midbrain is located between the
15:47diencephalon and the pons you can see
15:49that there very well between the
15:51diencephalon and the pons and here
15:53you've got first-year cerebral peduncles
15:55your cerebral peduncles are going to be
15:58two bulges there are two bulges that are
16:01located on the ventral aspect and they
16:03form vertical pillars they form vertical
16:07pillars these vertical pillars are gonna
16:09help hold up the cerebrum they help hold
16:12up the cerebrum and they contain large
16:14pyramidal or you can say cortical spinal
16:18motor tracts that are descending towards
16:23the spinal cord so again two bulges
16:27located on the ventral aspect they form
16:29vertical pillars that hold up the
16:32cerebrum and they contain large
16:34pyramidal motor tracts descending
16:37towards the spinal cord so let's look at
16:39that in greater detail to appreciate
16:41that in greater detail then here we can
16:43move from this slide here over basically
16:47here and you can appreciate now each of
16:50those cerebral peduncles so here they
16:53are on that ventral aspect so flipping
16:55it around looking at the lateral aspect
16:57here you can see those peduncles there
16:59now now these peduncle okay we can also
17:04appreciate here superior cerebellar
17:07peduncles now the superior cerebellar
17:09peduncles you can see there are again
17:11fiber tracts and they connect the
17:13midbrain to the cerebellum dorsally
17:16excuse me they're going to connect the
17:20midbrain they will connect the midbrain
17:23to the cerebellum dorsally
17:28then you can appreciate here as well the
17:30corpora quadrigemina so here you can see
17:32two of those components here you've got
17:33all four coming back to this view here
17:37you can appreciate that corpora
17:39quadrigemina as we talked about before
17:42so we talk corpora quadrigemina you can
17:45see quadrigemina four components we're
17:47gonna be checking out here
17:48so therefore dull like protrusions there
17:51are four dome-like protrusions on the
17:54dorsal midbrain they are nuclei
17:59scattered in surrounding white matter of
18:03the midbrain first you have your two
18:09superior and then you have the two
18:11inferior so the two superior are gonna
18:13be known as the superior colliculi and
18:15we talk superior colliculi the superior
18:17colliculi are going to be visual reflex
18:20centers they are visual reflex centers
18:23and what they do is they coordinate head
18:26eye movements they coordinate head eye
18:30movements when we visually follow when
18:35we visually follow a moving object so
18:44that's the superior colliculi you can
18:46see they're very nicely and then the
18:49inferior colliculi now are your auditory
18:51relays now they're auditory relays from
18:54your hearing receptors of the ear to the
18:57sensory cortex so they're going to be
19:00auditory relays from hearing receptors
19:03of the ear to the sensory cortex and
19:05they are gonna act in reflexive response
19:08they will act in reflexive response to
19:13sound such as in the startle reflex in
19:17which you turn your head towards an
19:20unexpected sound so it's your inferior
19:25colliculi inferior colliculi next that
19:31we have our periaqueductal gray matter
19:35now we talk periaqueductal gray matter
19:37the periaqueductal gray matter was
19:41we're gonna move over to this picture
19:42here you can appreciate that there very
19:44nicely
19:44now this periaqueductal gray matter you
19:47can see is going to be found
19:49surrounding the cerebral aqueduct it's
19:53found surrounding the Seabrook the
19:55cerebral aqueduct which runs through the
19:58midbrain this periaqueductal gray matter
20:02is involved in pain suppression it's
20:07involved in defensive behaviors
20:12reproductive behavior and in
20:16consciousness and it's involved in
20:18consciousness next that we've got the
20:26substantial when we talk
20:28substantial substantial Niagra are
20:30going to be pigmented nuclei pigmented
20:32nuclei that are embedded in each side of
20:37the midbrain white matter pigmented
20:40nuclei embedded in each side of the
20:43midbrain white matter they're located
20:47deep to the cerebral peduncles located
20:50deep to the cerebral peduncles you can
20:55see the substantial have a nice
20:56dark color this nice dark color it
20:59reflects a high content of melanin it
21:04reflects a high content of melanin
21:07melanin is going to be a precursor of
21:11the neurotransmitter dopamine it's a
21:16precursor of the neurotransmitter
21:18dopamine that's released by these
21:22neurons that's released by these neurons
21:27so if you have a degeneration of the
21:30dopamine releasing neurons of the
21:32substantia so when you have a
21:34degeneration of the dopamine releasing
21:36neurons of the substantia you'll
21:38see this is the ultimate cause of
21:39Parkinson's deep to the substantia
21:46we can appreciate the red nucleus the
21:48red nucleus are also pigmented nuclei
21:50also pigmented nuclei embedded in each
21:54saw
21:54of the mid brain's white matter embedded
21:57into each side of the mid brains white
22:00matter the red nucleus you can see lies
22:05deep to the substantia they lie
22:07deep to the substantia and you can
22:10see they've got a nice reddish color
22:12that reddish color is due to its rich
22:16blood supply it's due to its rich blood
22:19supply and iron pigment and iron pigment
22:25the red nucleus are real a nuclei
22:29they're real a nuclei in descending
22:32motor pathways that are gonna affect
22:37limb flexion next thing we've got our
22:45pons we talk pons here you can
22:48appreciate then the pons right inferior
22:52to then that midbrain
22:54so we talked pons pons is the bulging
22:56brain stem region it is the bulging
23:00brain stem region wedged between the
23:04midbrain and the medulla oblongata
23:07wedged between the midbrain and the
23:09medulla oblongata dorsally dorsally it
23:13forms the anterior wall of the fourth
23:15ventricle dorsally it's going to form
23:21the anterior wall of the fourth
23:23ventricle and as you can see here in
23:26this picture it's composed of conduction
23:28tracts it is composed of conduction
23:31tracts now here
23:38we can appreciate the middle cerebellar
23:40peduncles now these middle cerebellar
23:42peduncles their superficial ventral
23:46fibers they are superficial ventral
23:48fibers and they are orientated
23:50transversely they are orientated
23:53transversely and dorsally so they're
23:57orientated transversely and dorsally and
24:01what they're going to do is they are
24:06going to connect the pons they will
24:09connect the pons bilaterally with the
24:13two sides of the cerebellum dorsally
24:19next and we've got the medulla oblongata
24:22now the medulla oblongata also known as
24:25just medulla it forms the most inferior
24:29portion or the inferior part of the
24:31brainstem it blends in to the spinal
24:35cord at the level of the foramen magnum
24:41the central canal the spinal cord
24:45continues upward into the medulla where
24:50it's gonna broaden out to form the
24:55cavity of the fourth ventricle you have
24:57back there here we can appreciate our
25:02pyramids
25:03now the pyramids we'll see are going to
25:07be so we'll move back out to this
25:10ventral view so here you can appreciate
25:12pyramids bilaterally pyramids are two
25:14longitudinal ridges there are two
25:17longitudinal ridges that are flanking
25:18the midline on the medulla is ventral
25:22aspect they're formed by they are formed
25:29by the large pyramidal tracts descending
25:36from the motor cortex descending from
25:39the motor cortex here you can also
25:44appreciate the decussation of pyramids
25:46we talk deku station it's a crossover
25:49point where most of those fibers
25:52are gonna cross over to the opposite
25:55side where they cross over to the
25:57opposite side and then continue down the
26:04spinal cord so here we would have
26:10something
26:24like this these fibers are coming down
26:26here crossing over and then coming down
26:28on that side fibers from this side are
26:31coming down coming down crossing over
26:38and making their way to it down the
26:41spinal cord on that side so you can see
26:43why now this is also helping explain why
26:45some things are gonna be controlled from
26:46one side of the brain on the opposite
26:48side of the body and whatnot just like
26:50we saw with our optic nerve so here then
26:58we can appreciate next then we're going
27:00to see we've got our in inferior
27:06cerebellar peduncles now inferior
27:08cerebellar peduncles you can appreciate
27:09here inferior cerebellar peduncles fiber
27:12tracts again they're gonna connect the
27:14medulla to the cerebellum dorsally they
27:16will connect the medulla now to the
27:18cerebellum dorsally next so we've got
27:23the olives and the inferior Oliveri
27:25nuclei so let's talk olives all of
27:27they're gonna be found lateral to the
27:28pyramids so here you can see we're to go
27:31back to this ventral view you can't
27:32really appreciate them there you can see
27:34them here off on the sides so what we'll
27:36do is we'll turn this whole brainstem
27:38around turn it around here you can
27:40appreciate now the olives very nicely so
27:43when we talk olives olives they're gonna
27:45be oval swellings so ladder to the
27:48pyramids their oval swellings which are
27:51mainly caused by wavy folds of gray
27:54matter which are mainly caused by wavy
27:57folds of gray matter and what they are
28:02they're relaying what they're doing is
28:05basically they're relaying sensory
28:06information they're going to be reeling
28:12sensory information on the state of
28:16stretch on the state of the stretch of
28:20muscles and our joints to the cerebellum
28:24so it's going to be basically relaying
28:27sensory information on the state of
28:30stretch of muscles and joints to the
28:31cerebellum
28:36then we've got the vestibular nuclear
28:39complex now the vestibular nuclear
28:42complex then we're going to be able to
28:44appreciate now by us moving over and by
28:48us moving over to you can see now this
28:52slide stupido nuclear complex okay
29:04actually no I'm sorry when we talk
29:06vestibule nuclear complex I want you to
29:07be able to basically see it here okay so
29:23here now when we talk vestibular nuclear
29:25complex I want you to know collectively
29:28now it's gonna include basically the
29:30vestibular nuclei so here when we talk
29:33function that's the main thing you need
29:35to get from here is that it's gonna be
29:36responsive or mediating responses that
29:40maintain equilibrium it mediates
29:42responses that maintain equilibrium so
29:48when we talk function function of the
29:50medulla and we talk function of the
29:51medulla you'll see it's gonna have
29:53various functions here first function
29:55i'd like you to know about is that it's
29:56gonna contain our cardiovascular center
29:58it contains a cardiovascular center now
30:00this cardiovascular center itself is
30:02made up of two sub centers we'll see
30:04first you have the Cardiac Center itself
30:06for the Cardiac Center is going to be
30:08responsible for adjusting the force and
30:11the rate it adjusts the force and the
30:15rate of heart contraction now vasomotor
30:20Center you have here as well the
30:22vasomotor Center it changes blood vessel
30:26diameter to regulate blood pressure it
30:30will regulate blood vessels so changes
30:33blood vessel diameter to regulate blood
30:35pressure you also have your respiratory
30:40center here then we talk a respiratory
30:42center will see the respiratory center
30:44is going to be involved with controlling
30:49the rate
30:50and the depth of breathing it's involved
30:53in controlling the rate and the depth of
30:56breathing there's also other visceral
31:02centers here as well now we talked other
31:04visceral centers these other visceral
31:06centers are going to include centers for
31:08vomiting centers for hiccuping
31:15swallowing coughing and even sneezing
31:23are all gonna be found located at that
31:25medulla so it's a very very important
31:28region there and it's functions are very
31:30important there as well next thing we've
31:33got the cerebellum when we talk
31:35cerebellum cerebellum is also known as a
31:38small brain the cerebellum is
31:40cauliflower like it is cauliflower like
31:44it's located dorsal to the pons and the
31:48medulla it's gonna be located dorsal to
31:51the pons in the medulla so let's move
31:53over and check that out you can see that
31:56there you can see that there as well it
32:03protrudes under the occipital lobes it
32:06protrudes under the occipital loads of
32:09the cerebral hemispheres so it protrudes
32:11under the occipital lobes of the
32:13cerebral hemispheres from which it
32:16separated as well from which it's going
32:18to be separated it's gonna be separate
32:20from the cerebral hemispheres by the
32:21transverse cerebral fissure by the
32:24transverse cerebral vision so now some
32:30structures in relation to the cerebral
32:33Hemisphere first you can appreciate this
32:34cerebellar in relation to the cerebellum
32:37are going to be first the cerebellar
32:39hemispheres now we talk cerebellar
32:40hemispheres they're apple sized
32:43hemispheres
32:45they are apple sized and they're
32:48connected medially they're gonna be
32:50connected medially to one another you
32:52can see that right inside of here arrow
32:57went there we go
33:03so here so there are apple sized
33:15connected to one another apple sized
33:19connected to one another medially by the
33:25vermis connected to one another medially
33:28by the vermis so when we talk various
33:29that's the structure you're seeing right
33:30here in the center we talk Verma's
33:32vermis is this worm like structure it's
33:35a worm like structure and it connects
33:38the cerebellar hemispheres as you can
33:41see there it connects the two cerebellar
33:43hemispheres now here you can also
33:45appreciate the folia fully are going to
33:48be plea like gyri they are pleat like
33:53gyri basically found on the surface of
33:56this cerebellum now here you can see the
34:03cerebellum is going to get divided into
34:04an anterior lobe and a posterior lobe
34:06here you can appreciate that anterior
34:09lobe right on top and then here we can
34:12appreciate the posterior lobe now when
34:15we talk anterior lobe and posterior lobe
34:17you can appreciate both of those there
34:19very nicely they're gonna be separated
34:21from one another they will be separated
34:23from one another you can see thanks to
34:25the primary fissure thanks to the
34:29primary fissure so the primary fissure
34:32separating that anterior lobe from the
34:34posterior lobe and then here we can see
34:39in relation to the posterior lobe we've
34:41got the horizontal fissure horizontal
34:45fissure seam running completely
34:46horizontal next and we've got the
34:52flocculonodular lobe so moving back here
34:55you can appreciate now the
34:56flocculonodular lobe
34:58now the flocculonodular lobe small
35:01propeller shaped lobe it's found deep to
35:05the vermis it's deep to the permits and
35:07the posterior lobe deep to the vermis
35:11and the posterior lobe it cannot be seen
35:14on the surface view
35:16cannot be seen on the surface view and
35:20what he does it receives input it
35:22receives input from equilibrium
35:25apparatus it receives input from our
35:29equilibrium apparatus and then it
35:33adjusts posture to maintain balance it
35:38will adjust posture to maintain balance
35:45and then here we can appreciate two
35:47cortex and we talked about the cortex
35:49the cortex I want you to know is this
35:51thin outer layer of gray matter it's
35:54this thin outer layer of gray matter
35:59here we've got also Purkinje cells
36:02they're going to be large cells there
36:05they've got extensively branched
36:08dendrites and what they do is they send
36:12their axons they send axons through the
36:15white matter to synapse with the central
36:21nuclei the cerebellum so these Purkinje
36:25cells are going to be large cells with
36:28branched dendrites and they send axons
36:32through white matter to synapse with the
36:35central nuclei of the cerebellum so you
36:40can see the white matter the white
36:41matter it's got this distinctive pattern
36:44we refer to it as the arbor vitae
36:46it's a white matter you can see then
36:50running to the center of that cerebellum
36:51takes on this distinctive pattern and we
36:55refer to it then as the arbor vitae the
36:58arbor vitae next there is dentate nuclei
37:05deeply situated paired masses of gray
37:09matter dentate two nuclei there as well
37:15paired masses of gray matter so I want
37:18you to go through and get their
37:19functions down as well next let's talk
37:22functions of generally speaking the the
37:25cerebellum so we talk cerebellum it's
37:27involved with coordination and cognition
37:29so
37:30first coordination it coordinates body
37:32movements it uses the cerebellar
37:36peduncles for cerebellar processing
37:45cognition it recognizes and it predicts
37:49sequences of events it's involved with
37:52recognizing and predicting sequences of
37:54events so that way we can adjust and
37:58then some non motor functions non motor
38:03functions are going to include will see
38:04word association and puzzle-solving it's
38:07involved with word association and
38:09puzzle solving and then you've got the
38:15term ipsilateral ization there as well
38:17we've talked contra la ization so
38:19ipsilateral zation basically you've got
38:20there as well talking about functions
38:23being same sided there next we have the
38:27functional brain systems and we talk
38:28functional brain systems networks of
38:30neurons they're going to be networks of
38:32neurons that work together and they span
38:36large distances in the brain so you
38:39can't localize them to a specific region
38:43so first we'll do is we'll talk limbic
38:46system here we can appreciate limbic
38:48system limbic system is a group of
38:51structures now it's cerebral structures
38:55encircle the upper part of the brainstem
38:57so it's a group of structures it's
38:59cerebral structures encircle the upper
39:02part of the brainstem now the functions
39:05it's involved with feelings
39:07basically affective it's the affective
39:10brain so when you talk functions it's
39:12the affective brain meaning it's
39:13involved with feelings and emotional
39:16reactions and emotional reactions so
39:20when you talk location now location it's
39:23located on the medial aspect of each
39:25cerebral hemisphere and diencephalon
39:28located on the medial aspect of each
39:30cerebral hemisphere and diencephalon one
39:36structure I'd like you to know about
39:37here is the amygdala the amygdala you
39:40can appreciate here very nicely and we
39:42talked a mikta lie the amygdala
39:44is going to be a almond-shaped nucleus
39:48it's an almond-shaped nucleus that sits
39:52on the tail of the caudate nucleus and
39:57it recognizes facial expressions and
40:01elicits fear response and it elicits
40:08fear response the second structure we
40:12have here is the cingulate gyrus here we
40:14can appreciate the singhalût gyrus we
40:16talk cingulate gyrus it's gonna play a
40:18role in expressing emotions through
40:24gestures it plays a role expressing
40:29emotions through gestures and resolving
40:33mental conflicts when frustrated and
40:36resolving mental conflicts when
40:38frustrated third structure we have here
40:46is the hippocampus now the hippocampus
40:49you can appreciate here it plays a role
40:51in memory it plays a role in memory and
40:58then we have the fornix fornix is going
41:01to link it links the limbic system it's
41:05gonna link limbic system regions
41:07together along with other fiber tracts
41:11so the fornix links limbic system
41:14regions together along with other fiber
41:16tracts next and we can appreciate
41:21reticular formation so here we talk
41:24particular formation reticular formation
41:25is composed of loosely clustered neurons
41:29it's composed of loosely clustered
41:32neurons in white matter in white matter
41:38when we talk functions the functions of
41:42the reticular formation is to send
41:44continuous streams of impulses to the
41:48cerebral cortex I mean the picture is
41:49depicting to us that there is well very
41:52well so it sends continuous streams of
41:54impulses to the cerebral cortex it also
41:57filled
41:58sensory inputs and as we can see there
42:02it has a motor arm as well and it has a
42:04motor on so the location of reticular
42:08formation it's extending through the
42:09central core of the medulla the pons and
42:13the midbrain and I go to the structures
42:24go through main nuclei want you to know
42:26there is RAF a nucleus so go to the
42:28raphe nuclei and make sure you got the
42:30function down the raphe nuclei there as
42:33well next time let's talk brain
42:35protection
42:36let's talk brain protection so we talk
42:38brain protection here we can see first
42:40the biggest significant source of
42:43protection is gonna be the bone above
42:45the bone you got periosteum and then you
42:46got scalp and above the scalp then
42:47you're gonna have hair at least for the
42:50majority of us next and we move down
42:52you've got you can see now in here we're
42:55going to see meninges meninges are gonna
42:57be three connective tissue membranes
42:59that are going to lie external to the
43:02CNS and what they do is they cover and
43:04they protect the central nervous system
43:06they protect blood vessels they enclose
43:10venous sinuses
43:13they contain CSF they contain cerebral
43:16spinal fluid and they're going to form
43:19partitions and they form partitions so
43:22from external to internal we've got
43:25first dura mater the dura mater is
43:27leathery it's the strongest men inks it
43:33surrounds the brain and what it is it's
43:37a two layered sheet of fibrous
43:39connective tissue it is a two layered
43:42sheet of fibrous connective tissue first
43:45layer you have is the periosteum layer
43:47the periosteum layers we can see in this
43:50picture is the more superficial layer
43:52it's attached to the inner surface of
43:55the skull it is attached to the inner
43:58surface of the skull the meningeal layer
44:02you can see just deep to that so the
44:05meningeal layer is deeper to the
44:07periosteum layer and the maninjau layer
44:09I want you to know form the true
44:11external covering of the brain it forms
44:14the true external covering of the brain
44:16and continues caudally and it's gonna
44:20continue caudally into the vertebral
44:22column as the spinal dura mater as the
44:26spinal dura mater
44:29you've got dural sinuses there they're
44:31gonna be responsible collecting venous
44:33blood and they'll direct this blood then
44:36to the internal jugular vein dural septa
44:42we can see here as well
44:43now drill cept are going to be flat
44:44partitions again you got the term septa
44:46they're flat partitions that are going
44:49to subdivide the cranial cavity there
44:52you can think of inward extensions of
44:54the meningeal dura mater so you can
44:57appreciate them here in this picture
44:59very well so first you have the falx
45:03cerebri the falx cerebri you can see
45:05you're very nicely
45:06it's sickle shaped large sickle shaped
45:10fold that dips into the longitudinal
45:15fissure that dips into the longitudinal
45:18fissure between the two cerebral
45:20hemispheres anteriorly you can see here
45:24it attaches to the crista galli next you
45:31have a Faulks cerebellar fog cerebellar
45:35is going to be the inferior continuation
45:37of the falx cerebri so it's the inferior
45:39continuation or I'm sorry the posterior
45:41continuation you can think of the
45:43posterior inferior because moving down
45:45of the falx cerebri and it's going to
45:49run along the vermis of the cerebellum
45:51in a lot it's gonna run along the vermis
45:53of the cerebellum then you've got the
45:57tentorium cerebelli tentorium cerebelli
46:01resembles attempt it resembles attempt
46:04over the cerebellum so resemble the tent
46:08over the cerebellum and what it is it's
46:11a horizontal fold it's a horizontal fold
46:14that's gonna extend into the transverse
46:16fissure and you can see one half of it
46:19there very nicely it's like a tent you
46:21can think of on top of that cerebellum
46:25so that's one side and the other side
46:26would be proximal to us which we can't
46:28see so moving back we've got then our
46:34arachnoid mater then we talk arachnoid
46:37mater arachnoid mater now you can
46:39appreciate just deep to the dura mater
46:42it's the middle meanings it's the middle
46:45meanings it's a loose brain covering and
46:47it's gonna be separated from the dura
46:49mater thanks to the subdural space so
46:53subdural space is a narrow serous cavity
46:56that separates this arachnoid mater from
46:59that dura mater then you also have a
47:05subarachnoid space the subarachnoid
47:07space is found to be a wide space
47:11beneath the arachnoid membrane this
47:16layer has you'll see CSF and we can
47:20appreciate here the arachnoid villi and
47:24they're just basically nob like
47:26projections that protrude through the
47:29dura mater and into that superior
47:30sagittal sinus third layer then is the
47:36Pia mater
47:37we took Pia mater it's a delicate
47:40connective tissue and this Pia mater is
47:44richly invested with tiny blood vessels
47:47it's richly invested with tiny blood
47:49vessels and this Pia mater is gonna be
47:52found clinging tightly to the brain it
47:55clings tightly to the brain like
47:57cellophane wrap like cellophane wrap
48:01then we have cerebral spinal fluid CSF
48:04you'll see the CSF is going to be found
48:07in and around the brain and spinal cord
48:11found in and around the brain and spinal
48:13cord
48:14it's a watery broth when we talk about
48:17its functions you'll see its functions
48:18is that it nourishes the brain number
48:20one it's gonna nurse the brain and also
48:23what it does is it provides a liquid
48:26cushioned so giving kind of buoyancy you
48:30can think of it gives buoyancy to the
48:32CNS structures then here we can
48:36appreciate the choroid plexus we talk
48:38choroid plexus the choroid plexus now
48:40we'll move over and you can appreciate
48:44here the Cori plexuses the quartic
48:46plexus is there going to be basically
48:48hanging from the roof of each ventricle
48:50as you can see and they form CSF they're
48:55going to form the cerebral spinal fluid
49:00those this cord plexuses are going to be
49:03enclosed by Pia mater and then a layer
49:06of ependymal cells so we talk blood
49:12brain barrier function of the blood
49:14brain barrier is and its protective it's
49:18a protective mechanism that's gonna help
49:19maintain a stable environment for the
49:21brain so there if you recall we talked
49:25about some certain cells we had
49:29astrocytes and basically the major cell
49:33there between that the components of the
49:36brain the neurons those different cells
49:39were helping to connect basically the
49:42nutrient supply line to different parts
49:44of the brain tissue so you got the
49:47components there make sure you got every
49:49one of those understood there and then
49:50understand the variation you see go
49:55through and check that out I want you
49:57guys to go through and look at the
49:57variation of the blood-brain barrier in
49:59the different parts of the brain and the
50:02ventricles next let's move to spinal
50:04cord let's talk spinal cord so when we
50:07talk spinal cord here we're going to be
50:11able to see the spinal cord it's about
50:1342 centimeters long 17 inches long you
50:16can think up about three-quarters of an
50:20inch thick about 3/4 of an inch thick
50:22the spinal cord is located enclosed in
50:28the vertebral column it's found located
50:31enclosed within that vertebral column
50:33and it extends if you recall you can see
50:35here from that foramen magnum down to
50:39the level of the first or second lumbar
50:43vertebra down to the level of the first
50:46or second lumbar vertebra just inferior
50:49to the ribs
50:51so what's the function it's gonna be
50:53involved with conduction Nero
50:56integration locomotion and reflexes so
50:59make sure you go through each of them
51:01and understand each of those functions
51:02they're very well it's got protection as
51:07well so we talk protection first you've
51:09got the vertebral column itself then
51:11we've got the meninges then we talk
51:13meninges we've got spinal dura mater the
51:16spinal dura mater is gonna be a single
51:18layered mater it's not attached to the
51:21bony wall and we're also going to be
51:25able to appreciate here epidural space
51:28the epidural space is gonna contain fat
51:32so it's filled with a soft padding of
51:34fat adipose and a network of veins and a
51:39network of veins so you can see that
51:40here very nicely this epidural spaces
51:43between the bony vertebra between the
51:46bony vertebra and the spinal dura mater
51:49again you got to use simple English like
51:51sixth-grade English right
51:53prefix epi sub ok and so forth so epi
51:59Durell space so between the bony
52:02vertebra and the spinal dura mater here
52:08you can see they're going deeper they're
52:09going to the subarachnoid space so again
52:11you got to use those prefixes to your
52:12advantage
52:13basic English like fifth grade English
52:16fourth grade I think probably next in
52:20here we're going to see we've got after
52:23the epidural space our arachnoid mater
52:25and then Pia mater so arachnoid mater
52:27and Pia mater then you can see right
52:29from this view here but again that views
52:31not doing justice to it you can see here
52:33dura arachnoid and then you got the Pia
52:36mater right on top next in here let's
52:40move through let's talk then
52:43CSF we've mentioned let's talk
52:45microscopic structures here you've got
52:47first-year denticulate ligaments they're
52:49gonna be sawtooth basically shelves of
52:52Pia mater saw-toothed shelves of Pia
52:56mater
53:02a good picture
53:13well you guys can Google that picture
53:15there as well so they're gonna be saw
53:17two shelves of Pia mater and what
53:19they're going to do is they're going to
53:20help secure the spinal cord to the tough
53:23dura mater they're going to help secure
53:25it will help secure the spinal cord to
53:32the tough dura mater next end is a
53:39cervical enlargement then we talk
53:41cervical enlargement cervical
53:43enlargement is the region where the
53:44spinal cord is going to be about the
53:47width of the thumb so we can come over
53:49to this picture here I'm sorry so let's
53:59come back here
54:00so cervical enlargement is gonna be
54:02region where the spinal cord is gonna be
54:03about the width of a thumb about the
54:05width of your thumb so here you can see
54:08right in this area here is where that
54:11kind of enlarge is and it kind of thins
54:13out and then we move down you get to the
54:16cervical management same thing that kind
54:17of thickens up right in that area there
54:19as well moving down then we've got the
54:21medullary cone or conus medullaris now
54:24the medullary cone or conus medullaris
54:25is going to be where the cord terminates
54:29it's where the cord terminates it's
54:32found at the inferior aspect it's a
54:35tapering cone shaped spinal cord
54:38terminating area tapering cone shaped
54:42spinal cord terminating area then we can
54:47appreciate the caudate Keena and we
54:49talked cada Akina the caudate kina is
54:51going to be a collection of nerve roots
54:55it's a collection of nerve roots at the
54:58inferior end of the vertebral column
55:02collection of nerve roots at the
55:05inferior end you can think of the spinal
55:08cord or vertebral column so right inside
55:10of here like a horse tail cada caudal
55:13aquinnah horse phylum terminology you
55:17can appreciate in here as well the term
55:19and terminal phylum filum terminale II
55:21it's a fibrous extension of that conus
55:24medullaris
55:25it's a fibrous extension of the conus
55:29medullaris it's covered by pia mater
55:33it's covered by Pia mater and it extends
55:37inferior ly it extends inferior Lee from
55:41the conus medullaris down to the coccyx
55:44you can see that there very nicely down
55:46to the Coxes to help secure an anchor
55:49that spinal cord in place helps to
55:52secure anchor the spinal cord in place
55:56now some microscopic structures we're
55:59gonna be able to appreciate here when we
56:01talk microscopic structures first we can
56:03appreciate here you can see the anterior
56:05or ventral median fissure and then the
56:07dorsal or posterior median sulcus so
56:11here you've got that Doris or posterior
56:13median sulcus and then anterior ventral
56:15median fissure basically they're running
56:21the length of the cord and dividing the
56:23cord in halves
56:24they run the length of the court and
56:25divide the cord enhance you can
56:35appreciate here now gray matter the gray
56:38matter in this cross-section it looks
56:40like a butterfly er the letter H here
56:44you got first gray commissure gray
56:47commissure is a crossbar of gray matter
56:51that encloses the central canal you can
56:55see that there very nicely and then you
56:58can see the dorsal horns of gray matter
57:00the dorsal horns of gray matter dorsal
57:03projections of gray matter dorsal
57:06projections of gray matter and you've
57:10got your dorsal roots coming from the
57:15basically reutlitz
57:16dorsal roots they're formed by your a
57:20forant fibers they are formed by your
57:23afferent fibers that are gonna be
57:26carrying impulses from peripheral
57:28sensory receptors and bringing them
57:31basically them bringing in these
57:33impulses to the CNS and then your
57:37ventral horns you can appreciate here
57:38the
57:39ventral horns are going to be ventral
57:41projections of gray matter ventral
57:44projections of gray matter now here we
57:46can appreciate the ventral roots also
57:48derived from the rootlets the rental
57:51roots now are small and they're gonna be
57:56basically motor neurons that send out
58:01their axons to skeletal muscle so we
58:05talk ventral roots motor neurons that
58:06send out their axons to skeletal muscle
58:08via these rootlets and then you can see
58:15there the lateral horns lateral horns
58:18they're going to be a pair of gray
58:20matter present in the thoracic and
58:24superior lumbar segments only present in
58:27the thoracic and superior lumbar
58:29segments only and the white matter you
58:31can see surrounding that gray matter and
58:33the white matter is basically myelinated
58:35and unmyelinated nerve fibers and allows
58:41communication between the brain and
58:42spinal cord the white matter gets
58:45divided up as funiculi so here we've got
58:48first dorsal funiculi lateral funiculi
58:54and then we can appreciate ventral
58:57funiculi or anterior funiculi so
59:00anterior ventral lateral dorsal or
59:04posterior funiculus
59:09anything you need to know you've got
59:11various types of fibers some of your
59:13fibers are gonna be again a sending
59:15making their way up some are gonna be
59:16descending making their way down well
59:18are there gonna be transverse fibers so
59:21that will conclude then the second half
59:23of central nervous system here we can
59:25see we've got then this picture
59:28depicting to us basically go a patient
59:31having a needle making their way into
59:34the subarachnoid space so it's a lumbar
59:36puncture basically so they can remove
59:38some CSF cerebrospinal fluid in
59:42situations like meningitis now this can
59:45occur
59:51very nice picture of ganglia so we
59:54already talked about ganglia you can see
59:55them there way greater detail now so no
59:58excuse of not knowing what ganglia are
1:00:00after this
1:01:04you

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