Anatomy dr.ayman Flashcards
1
Q
Neuroglia cells types in CNS
A
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
2
Q
Neuroglia cells types in PNS
A
Schwann cells
Satellite cells
3
Q
What is : Grey matter White matter Basal ganglia Lateral ventricle Cerebral cortex
A
- Neurons body
- axons
- nuclear masses buried within WM
- cavity of hemisphere
- outermost layer of GM
4
Q
3 poles of cerebral hemisphere
A
Frontal
Temporal
Occipital
5
Q
5 borders of each hemisphere
A
Superomedial : seperates superolateral- medial
Inferolateral : S superiolateral- tentorial
Superciliary : S superolateral - orbital
Medial orbital: medial- orbital
Medial occipital : tentorial- medial
6
Q
4 lobes of CH
A
Frontal, parietal , temporal, occipital
7
Q
Insula
A
Gyri lie deep in lateral fissure , sometimes considered as 5th lobe
8
Q
What sulcus on medial aspect of hemisphere
A
Central and parietooccipital sulcus
9
Q
major 3 sulci
A
Central : S frontal- parietal
Lateral: S Parietal- temporal
Parietooccipital : its name , on medial surface
10
Q
Describe the location of :
Precentral sulcus
Precentral gyrus (PC)
Superior and inferior frontal sulci
A
- parallel to central sulcus
- btwn precentral sulcus & central sulcus
- divide it to SF MF IF gyri
11
Q
What invade IF gyri and divided to what?
A
By anterior horizontal & ascending rami of the lateral sulcus
- to 3 parts : opercular part (Op) , triangular part(T), orbital part ( Or)
12
Q
Sulci and gyri of pareital lobe
A
Postcentral sulcus , gyrus
Intraparietal sulcus : dividing it to SP ,IP lobules
IP : 2 gyri : supramarginal : Up end of lateral s
Angular : up end of superior tempolar s
13
Q
Gyri and sulci of temporal lobe
A
S & I temporal suci ; s m i gyri
-Transverse gyri ( heschl’s convolutions ) “superiorly “
14
Q
Sulci and gyri of the medial surface
A
Cingulate sulcus Cingulate gyrus Callosal sulcus Corpus callosum Medial frontal gyrus ; infront of paracentral Paracentral lobule ; cont, of pre &post central Parietooccipital sulcus Calcarine sulcus Precuneus gyrus ; infront of PO s Cuneus g; above calcarine s Lingula g ; below cacarine s
15
Q
Cingulate gyrus is cont wt?
A
Anteriorly wt subcallosal area below CC
Posteriorly wt parahippocampal gyrus at isthmus
16
Q
Sulci and gyri of inferior surface (orbital part)
A
Olfactory s;occupied by olfactory bulb and tract
Medial to it is gyrus rectus
Lateral to it H shaped orbital sulci btwn 4 orbital gyri (A P M L )
17
Q
Sulci and gyri of inferior part ( tentorial part)
A
Collateral s , rhinal s ; lateral to PH and uncus U
Occipito temporal s ; divide it into M & L OT gyri
18
Q
What are the areas in precentral area of frontal lobe ?
Function?
A
Primary motor area 4 Premotor area 6 Frontal eye field 8 Broca’s area 44,45 *motor function
19
Q
Primary motor area ;
Site
Function body representation
Lesion
A
- precentral gyrus &anterior paracentral
- motor orders to voluntary muscles of opposite half of body
- map of contralateral 1/2 of body “motor homunculus”
- contralateral spastic hemiplegia (paralysis)
20
Q
Charactarstic of motor homunculus
A
- Contralateral
- Proportional to The skill ;larger areas wt fine skilled movements
- Inverted ; head inferiorly in precentral , leg and foot in paracentral
21
Q
Premotor area ;
Site
Function
Lesion
A
- posterior parts of S M I frontal gyri also on medial surface in supplementary motor cortex
- planning if movements , stores motor experience ,adjust posture to start the movement, inhibits muscle tone and deep reflexes the opposite side , skilled movements of voluntary m
- apraxia “ impairment in learned movements &absence of paralysis” , contralateral hypertonia +exaggerated deep reflexes .
22
Q
Supplementary motor area ;
Site
Function
Lesion
A
- cont of area 6 ,anterior to paracentral
- motor planning “stereotyped movement”
- hypotonia wt no paralysis
23
Q
Frontal eye field ;
Site
Function
Lesion
A
- Posterior part of middle frontal gyrus infront of area 6
- scanning movement of eyeball , conjugate deviation of both eyes to the opposite side
- impairment of deviation to the opp. ,so deviation of both eyes to the side of lesion .
24
Q
Broca’s area ;
Site
Function
Lesion
A
- OP &T of inferior frontal gyrus of dominant hemisphere ,not in both usually left
- speech area “receive input from the sensory speech (wernicke’s area) in temporal lobe and send output to motor area( broca’s area ) which control speech muscles
- motor (expressive ) aphasia ,but can express it in written form
25
Exner’s area 45 ;
Site
Function
Lesion
- Adjacent to broca’s ,in middle frontal gyrus of dominant hemi
- motor center for writing
- agraphia , cannot express ideas in written words
26
Prefrontal area ;
Site
Function
Lesion
- anterior part of frontal lobe &its inferior and medial surfaces
- highest brain functions (thinking ,decision making ,judgment ,motivation ,feeling of responsibility, emotions , personality ,social behavior)
- changes in social behavior ,personality,mood , disturb in judgment and take decisions or solve problems
27
What are the area in parietal lobe?
```
Primary somatosensory cortex312
Taste area 43
Association sensory cortex 5,7
Angular gyrus 39
Supramarginal gyrus 40
```
28
```
Primary somatosensory cortex ;
Site
Function
Body representation
Lesion
```
- postcentral and posterior paracentral
- receive general sensation (pain ,touch,temp., proprioception)
- called sensory homunculus (contralateral,inverted,proportional to the sensitivity of the part)
- contralateral hemianesthesia
29
Taste area ;
Site
Function
- superior lip of posterior ramus of lateral s(parietal operculum ) extending into anterior part of insula
- receive taste
30
Association sensory cortex;
Site
Function
Lesion
- superior parietal lobe
- interpretation of general sensation based on prev. experience ,and helps in recognizing shape size surface character texture by handling it wtout the help of vision .”” Stereognosis””
- tactile agnosia (asterogenesis) “inability to recognize objs by touch
31
Angular gyrus;
Site
Function
Lesion
- inferior parietal lobule in dominant hemi
- as part of wernicke’s area ,impo. For understanding written language (visual speech and reading )
- alexia “don’t understand the meaning of what he reads “
32
Supramarginal gyrus ;
Site
Function
- inferior parietal lobule
| - part of somatosensory association cortex ,involved in perception of space and limbs location
33
What are the areas in the temporal lobe?
```
Primary auditory area 41,42
Auditory association area
Sensory speech area
Olfactory area
Facial recognition area
```
34
Primary auditory area ;
Site
Function
Lesion
- inferior lip of lateral sulcus (heschl’s convolutions)+part of superior temporal gyrus
- receive auditory information from both ears
- hearing impairment,never deafness
35
Auditory association area ;
Site
Function
Lesion
- posterior to primary auditory area ,”posterior aspect of superior temporal gyrus”
- understanding and recognition of hearing sensation
- auditory agnosia “loss the ability to recognize the familiar sounds “
36
Sensory speech area ;
Site
Function
Lesion
- wernicke’s area
- comprehension of the spoken language
- sensory aphasia
37
Olfactory areas;
| How many are them? And how many regions in each?
2 areas 1ry, 2ry
1ry: 3 regions = uncus ,part of amygdala, apex of insula
2ry :in para hippocampal g which contains center for memory and learning
38
Facial recognition area ;
Site
Lesion
- inferior surface of temporal and occipital lobes
| - prosopagnosia (face blindness )
39
What are the areas in occipital lobe ?
Primary visual area
| Visual association area (and others : Middle and inferior temporal gyri , angular gyrus)
40
Primary visual area ;
Site
Function
Lesion
- medially, above and below calcarine sulcus
- receive input from the ipsilateral half if each of the two retinas ,responsible for vision in the contralateral half of each of the two visual fields
- contralateral homonymous hemianopia “loss of opp. Field of vision
41
Visual association area ;
Site
Function
Lesion
- around the primary area
- receive visual information and relate them to prev. experience
- visual agnosia “cannot understand what he see “
42
How many Subdivisions of the insula?
| Function?
Two long gyri behind and 3-4 short in front
| -cortical taste center and some visceral activities (salivation)
43
Left brain is specialized in?
| Right brain?
- Spoken /written language ,math,science,logic
| - music/art ,3D forms ,insight, imagination(the artist)
44
What are the cortical areas that are important in language?
| Which hemisphere is dominant for language?
```
Broca’s area
Wernicke’s area
Angular area
Exner’s area
* the LEFT
```
45
Which one of the language areas are receptive or expressive area?
Receptive: wernecki +angular
| Expressive : broca’s +exner
46
What is the name of the tract that connect wernicke to broca areas ?
Arcuate fascicules
47
What are the types of language aphasia?
Motor aphasia
Sensory
Global aphasia ”cannot talk,write or read”: due to obstruction of middles cerebral artery
48
What are the types of fibers in white matter?
association fibers
Commissural fibers
Projection fibers
“All are Myelinated nerve fibers”
49
Association fibers ;
What they connect?
What are the kinds?
* connect diff. Regions in same hemi.
| * two kinds ;short and long depending on the distance
50
How many long association fibers ?
| What are them? And what they connect.
* 5
- uncinate fasciculus :frontal to temporal
- superior longitudinal: all 4 lobes
- arcuate : gyri in frontal to temporal
- inferior longitudinal : occipital to temporal
- cingulum: cingulate gyrus to parahippocampal gyrus
51
Commissural fibers ;
What they connect?
Include?
*connect the corresponding regions of two hemi
- corpus callosum
- anterior commissure
- posterior commissure
- hippocampal commissure (com. Of fornix)
52
Corpus callosum ;
What it connects?
What are the foreceps?
Parts ?
* the largest
- connects the corresponding regions of the 2 hemi. except? Temporal that is connected by anterior comm.
* shorter craniocaudally
- anterior foreceps : link the frontal lobes
- posterior foreceps : link the occi. Lobes
*rostrum, genu, body, splenium
53
Anterior commisure
Posterior
Hippocampal
WHAT THEY CONNECT?
A: inferior and middle temporal gyri & olfactory region of the two hemi.
P: left & right mid brain , impo. in the bilateral pupillary reflex
H: the two hippcampi wt each other
54
Projection fibers;
What they connect?
How they arranged?
* connect the cerebral cortex wt lower parts of the brain and spinal cord
- descending & ascending
- deeper to cortex ,they arranged radially as the corona radiata
- then converge downward passing btw thalamus and basal ganglia forming internal capsule
55
```
Internal capsule ;
What is it ?
Run btwn what ?
Shape?
Components?
```
Projection fibers running btwn 3 masses of grey matter :
- thalamus, caudate nucleus (medially) , lentiform nucleus(laterally )
- V shaped
1-anterior limb: anterior thalamic radiation+frontopontine fibers
2-genu: corticonuclear fibers
3- posterior limb: corticospinal , corticorubral , posterior thalamic radiation
4- retrolentiform part: optic radiation
5- sublentiform part: auditory radiation
56
limbic lobe;
what is it?
what is consist of?
- A group of structures on the medial surface of the cerebral hemisphere forming a ring around the diencephalon.
* subcallosal gyrus(paraolfactory gyrus), cingulate gyrus, isthmus, parahippocampal, uncus
57
```
Hippocampal Formation;
where is it located?
formed of?
function?
how is it formed?
where is dentate gyrus lies?
from where the efferent fibers arise?
damaged hippo.?
```
- in temporal lobe as the floor of the inferior horn of the lateral ventricle
- hippocampus,dentate gyrus ,subiculum
* it converts the short term memory into long
- formed by infolding of the inferiomedial part of the temporal lobe into the inferior horn of the lateral ventricle
- btwn hippo. and parahippo.gyrus
- alveus to fimbria to fornix
* anterograde amnesia
58
```
fornix ;
what is it and what it connects?
formed of ?
body of fornix ?
the 2 columns of body of fornix are connected by what?
```
- an arching band of WM , connects the hippo.to hypothalamus (mamillary bodies )
- formed of two posterior columns , from fimbria of hippo. and arched around the thalamus and come closer in the midline to form the body of fornix
- is connected to CC by septum pellucidum then split anteriorly into 2 columns , each dips in the lateral wall of hypo. ending in a mammillary bodies
- by commisure of fornix(hippo. commisure) .
59
amygdala;
where is it located?
from where it receives fibers?
- located wt the WM of the uncus anterior to hippo. and the tail of the caudate nucleus
- from the olfactory bulb ,influencing the emotional response to olfactory stimuli .
60
```
stria terminals ;
what it connects?
start from?
ends on?
impo. for?
```
- amygdala to hypo. , septal area,habenula
- from the amygdaloid nuclei and curves around the thalamus in the groove btwn it and the caudate nucleus ,accompanied by the thalamostriate vein
- on the septal area and the hypothalamic nuceli
- allow communication btwn amygdala and regions of hypo. to REGULATE fear and anxiety responses .
61
```
septal area ;
what it includes?
location?
impo. in ?
connections?
```
- subcallosal gyrus and septal nuclei
- anterior to anterior commissure and extends into the septum pellucidum
* associated wt PLEASURE
- wt habenular nuclei via stria medullaris thalami
wt hippo. via fornix
wt hypo. via medial forebrain bundle
wt amugdala via stria terminalis
62
papez circuit;
what is it?
formed of what?
- a closed circuit involved in the expression of emotions and the consolidation of recent memory
- visual , auditory ,sensory association areas -->cingulate gyrus -->parahippo.&uncus (entorhinal cortex) by CINGULUM--> hippo.-->mammillary body by FORNIX -->antrior nucleus of thalamus by MAMMILLOTHALAMIC TRACT -->cingulate gyrus by ANT. THALAMIC RADIATION
63
lesions in the limbic system?
- alzheimer`s disease
| - kluver -bucy syndrome
64
alzheimer`s disease ;
define it
what happen to hippo.
- chronic neurodegenrative,bilateral loss of neurons in several structures
```
- hippo. is one of first areas to degenerate, leads to
anterograde amnesia ( a loss of the ability to create new memories )
```
65
kluver- bucy syndrome ;
what is it?
symptoms?
- bilateral lesion in temporal lobe including the amygdala
-animals; fearless and placid ,absence of emotional reactions, oral tendency (examine obj. by mouth
hypersexuality
visual agnosia
hyperphagia
66
what are the meninges consist of ?
dura mater
arachnoid mater
pia mater
67
dura mater" tough mother";
| formed of?
- two layers ;the outer endosteal layer (adherent to skull ,not cont. wt DM of spinal cord ), &the inner meningeal layer"dura mater proper" (forms 4 dural folds/septa, cont. wt DM of spinal cord)
- the two layers are seperated to include a venous sinus
68
dural folds;
mention them?
function?
- falx cerebri ,tentorium cerebelli,falx cerebelli, diaphragma sellae
- stabilize the brain within the cranial cavity during movements of head
69
```
the falx cerebri;
shape?
location?
narrow /broad ends?
sinuses?
```
- sickle shaped fold
- lies in the midline btwn the two cerebral hemi.
- narrow end:attached to the internal crest and the crista galli
- broad:posterior part blends in the middline wt the upper surface of the tentorium cerebelli
- -superior sagital sinus ;runs in its upper fixed margin
- inferior sagital ; in its lower concave free margin
- straight ; along its attachment to the tentorium cerebelli
70
tentorium cerebelli;
shape?
location?
covers?
- crescent shaped fold
- roofs over the posterior cranial fossa
- covers the upper surface of the cerebellum and supports the occipital lobes of the cereberal hemi.
71
falx cerebelli;
shape?
location?
contains?
- small sickle shaped fold
- attached to the internal occipital crest and projects forward btwn the two cerebellar hemi.
- contains occipital sinus in its posterior fixed margin
72
diaphragma sellae ;
shape?
forms?
the opening in it?
- small circular fold
- forms the roof for the sella turcica
- small opening in its center --> allows the passage of the stalk of the pituitary gland
73
arachnoid mater;
covering?
seperated from dura and pia by what?
-cover the brain wtout dipping into sulci
- dura by a subdural space (filled by thin film of fluid)
- pia by subarachnoid space(filled wt CSF)
74
subarachnoid space ;
occupied?
contains?
- by spongy tissue consisting of network of arachnoid trabeculae (deliicate CT filaments that extend from arachnoid mater and blend into pia )
- contains CSF and large vessels of brain
75
arachnoid granulations ;
arachnoid villi shape?
what happen in advancing age?
- small finger like process of arachnoid tissue , projecting into cranial venous sinuses
- the size increases ,forming pedunculated tufts called arachnoid granulations which produce depression in bone .
76
pia mater ;
define it
covers?
sheath?
- delicate vascular membrane that is adherent to the surface of brain
- covers gyri and dips into its sulci
- provides sheaths for cranial nerves
- cerebral arteries entering the substance of the brain carry a sheath of pia mater wt them
77
```
ventricular system;
what is it?
composed of?
lined by?
function?
connected by?
```
- a set of communicating cavities within the brain
- two lateral ventricles and two midline ventricles (3rd +4th)
- lined by ependymal cells which form choroid plexus
- transport and removal of CSF
*1- the foramen of monro (lateral-->third)
2- cerebral aqueduct (3-->4)
3- the foramen of magendie and luschka (4-->subarachnoid space)
78
lateral ventricle ;
shape?
component?
separated by?
- two c shaped cavities within the cerebral hemi.
```
*3 horns and central part:
1-anterior horn ;frontal
2-posterior horn ;occipital
3- inferior horn;temporal
4- central part or body ;parietal
```
-by septum pellucidum and do not communicate directly
79
third ventricle ;
shape?
communicates?
- narrow cavity or a slit like cleft btwn 2 thalami
- anteriorly wt lateral v through interventricular foramina (of monro)
- posteriorly wt 4th v through cerebral aqueduct (of sylvius)
80
fourth ventricle ;
shape?
location?
- diamond shaped cavity , wide and flattened cavity
| - anterior to the cerebellum and posterior to the upper half of the medulla oblongata and the pons
81
CSF ;
what is tela chordea?
what is choroid plexus and how its formed and what it produce ?
- folds of pia mater enclosing tufts of capillaries forming it,
- it is tela choroidae fused wt ependyma on the roof of 3rd &4th v and the floor of lateral ventricles
- produce CSF
82
```
what is CSF ?
PRODUCED BY?
where is it found?
describe the movement of it?
where is it absorbed
```
- clear colorless fluid (filtrate of plasma )
- by choroid plexus
- in the ventricles ,subarachnoid space around the brain &spinal cord
- it follows the anatomical tract mentioned above
-mainly in arachnoid villi(project into dural venous sinuses especially superior sagital sinus
83
what is HYDROCEPHALUS?
hydro=water,cephalus=head
| *excessive accumulation of fluid in the brain
84
Diencephalon;
Site?
Consist of?dorsal/ventral?subdivides by?
Relation to 3rd ventricle?
-above the midbrain,btwn the lower parts of the 2 CH
- thalamus &epithalamus (dorsal part)
- hypo.&subthalamus (ventral part)
* by hypothalamic sulcus
-3rd v lies btwn 2 halves of D
85
```
Thalamus;
Definition?
Connected by?
Function?
Relations? L M S I R C
```
-paired ovoid mass of GM ,forming the upper 2/3 of the lateral wall of the 3rd v
-by interthalamic adhesion.
-It relays all sensations except smell. It also
relays motor and limbic impulses going to the
cerebral cortex.
- Lateral: Posterior limb of the internal capsule (IC)
Medial: Together with hypothalamus, forms the lateral wall of the 3rd ventricle
Superior: Caudate nucleus (C) fornix (F) & lateral ventricle (LV)
Inferior: Hypothalamus (H) anteromedially &
Subthalamus (ST) posterolaterally.
rostrally: interventricular foramen
caudally: midbrain
86
Name the 2ends of thalamus?What is pulvinar and L&M geniculate bodies?
. Anterior end of the thalamus is
narrow and rounded, which lies just
behind the interventricular foramen
Posterior end is expanded to form
the pulvinar, which lies above the
superior colliculus
• Lateral & medial geniculate bodies
bulge out from pulvinar
87
```
Medial surface of thalamus;
Forms ?
Lined by ?
What is stria medullaris thalami?
Limited inferiorly by?
```
.• Forms the upper 2/3 of the lateral wall of the
third ventricle.
• It is lined by ependyma (neuroepithelial
lining of the ventricular system)
• ( bundle of nerve
fibers) courses along its dorsomedial margin.
• Inferiorly is limited by hypothalamic sulcus
88
Lateral surface of Thalamus;
Coated by a layer of myelinated fibers named?
Related to?
.external medullary lamina that
divides lateral surface with the reticular
nuclei.
-posterior limb of the
internal capsule
89
#Superior surface of thalamus;
Covered by thin layer of WM called?
Lateral part covered by?
```
#Inferior surface of thalamus;
Rest on?
```
.-stratum zonale.
-ependyma.
-hypothalamus (H) and
subthalamus (ST).
90
Thalamic nuclei ;
| Thalamus is composed of GM ,interrupted by 2sheaths of WM called.......? Name the 2 of them.
```
.-1. External medullary lamina located laterally,
separates reticular nucleus from the rest of
the thalamic mass.
2. Y shaped internal medullary lamina
divides the thalamus into three parts:
Anterior
Medial
Lateral
```
91
```
Anterior part of thalamus;
Contains ?
Afferents receives from?
Efferent sends to?
Function?
```
.• Contains the anterior thalamic nuclei.
* Afferents: from the mammillary bodies.
* Efferents: to the cingulate gyrus.
• Function: emotional
and the mechanisms of recent memory.
92
```
Medial part of thalamus ;
Contains?
Afferent from?
Efferent to?
Function?
```
.• Contains the large dorsomedial (DM) nucleus and
several smaller nuclei.
• Afferent: hypothalamic nuclei, amygdala, and
Olfactory cortex
• Efferent: To the prefrontal cortex
-function:(control of mood and the emotion).
93
Lateral part of thalamus ;
Divided into dorsal tier and ventral tier .
Dorsal tier includes 3 association nuclei ,name them.:
Afferent from ?
Efferent from?
Ventral tier includes 3nuclei :name them.
• Dorsal tier:
1. Lateral dorsal nucleus (LD)
2. Lateral posterior nucleus (LP)
3. Pulvinar (P).
•Afferents: They receive input from the other
thalamic nuclei and integrate these inputs
• Efferents: into sensory association areas in the cerebral cortex
```
• Ventral tier :
1. Ventral anterior (VA)
2. Ventral lateral (VL)
3. Ventral posterior (VP), which is subdivided to:
• Ventral posteromedial (VPM)nucleus
• Ventral posterolateral (VPL)nucleus
```
94
VA N ;
Afferents ?
Efferents?
VL M ;
Afferent?
Efferent?
Function of both?
.• Afferents: Mainly from the ipsilateral globus pallidus and substantia
nigra (basal ganglia).
• Efferents: to the the
premotor and supplementary motor areas.
• Afferents: mainly from contralateral dentate nucleus of cerebellum (also
from ipsilateral globus pallidus and substantia nigra).
• Efferents: to primary motor and premotor areas.
**MOTOR RELAY
95
VP N.
Types?2 and their afferent & efferent
Function?2
#.Ventral posteromedial (VPM)nucleus
• Afferents:
• from the head via the trigeminothalamic tract.
• taste information from the nucleus solitarus of the medulla
• Efferents: to the lower 1/3 (head area) of the postcentral gyrus.
#Ventral posterolateral (VPL)nucleus
• Afferents: Receives information from the trunk and limbs via the medial
lemniscus and spinal lemniscus (spinothalmic tract).
• Efferents: to the upper 2/3 (body area) of the postcentral gyrus.
**Sensory relay:
• All general sensations from body and head
• Taste
96
What are the Other nuclei of the thalamus? 4
1-The medial geniculate body(MGB)
2-the lateral geniculate body(LGB)
3- intralaminar nuclei
4-reticular nucleus
97
MGB&LGB;”metathalamus”
Afferent &efferent?
Function?
#.The medial geniculate body (MGB): part of hearing pathway
• Afferents: Receives auditory input from the inferior colliculus of midbrain.
• Efferents: Projects auditory radiation to the auditory area of cortex.
#The lateral geniculate body (LGB): part of visual pathway
• Afferents: Receives visual input from the optic
tract.
• Efferents: Projects optic radiation to the visual
area of cortex
**vision and hearing
98
```
Intralaminar nuclei;
Located within?
Afferents?
Efferents?
Function?
```
.• Several nuclei within the internal medullary
lamina, centromedian nucleus is the largest
• Afferents: From the reticular formation, the
spinothalmic and trigeminothalamic tracts.
• Efferents: to widespread regions of the
cerebral cortex.
• Function: (responsible for
consciousness and alertness)
99
```
Reticular nucleus ;
Located in?
Afferent?
Efferent?
Function?
Something special about it?
```
• Thin layer of nerve cells btwn the external medullary lamina and
the posterior limb of the internal capsule.
• Afferent: from the cerebral cortex and the reticular formation
-efferent: to other thalamic nuclei.
• Function: Modulates the activity of other thalamic nuclei.
**This is the only thalamic nucleus that does not project to the cerebral cortex.
100
hypothalamus ;
location?
form?
extends?
• lies below the
thalamus, and ventromedial to
subthalamus.
• Forms the floor and the lower part
of the lateral wall of the third ventricle.
• Extends from the region of the optic
chiasma to the caudal border of the
mammillary bodies
101
The floor of hypothalamus is formed by? 3
the infundibulum extends from ?
1. The optic chiasm anteriorly.
2. The mammillary bodies posteriorly.
3. The tuber cinereum in between.
-from the apex of tuber cinereum
102
the hypothalamic nuclei are divided by an imaginay parasagital plane into....... and ......... ,
lying within the plane are the ......... and the .........?
-medial lateral zones ,fornix and the mammillothalamic tract .
103
what lateral and medial zones of hypothalamic nuclei contain?
```
• Lateral Zone
1.Part of the preoptic nucleus
2.Part of the suprachiasmatic
nucleus
3.Supraoptic nucleus
4.Lateral nucleus
5.Tuberomammillary nucleus
6.Lateral tuberal nuclei
```
```
• Medial Zone
1.Preoptic nucleus;
2.Anterior nucleus,
3.Suprachiasmatic nucleus;
4.Paraventricular nucleus;
5.Dorsomedial nucleus;
6.Ventromedial nucleus;
7.Infundibular (arcuate)
nucleus
```
104
what are the Hypothalamus connections and Functions?
| what does it control?
**It interacts with endocrine glands, reticular formation,
autonomic nervous system, and limbic system.
```
1- Control the Pituitary Gland
2- Autonomic Control
3- Control of Hunger and Feeding
4- Temperature Control
5- Control of Water intake & Thirst
6- Control of circadian rhythms
8- Memory
9- Emotions and behavior
```
105
```
nuclei of hypothalamus and its function;
supraoptic N ?
paraventricular N ?
arcute N ?
anterior N?
posterior N?
lateral N?lesion in it cause?
ventromedial N? lesion in it?
suprachiasmatic N?afferent from? connected to?
```
- contain osmpreceptors,ADH secretion
- oxytocin secretion
- releasing and inhibitory releasing hormones
- parasymp. control+ response to heat
- sympath. control +response to cold
- hunger +thirst centers , lesion cause starving and cechaxia
- satiety center, lesion cause hypothalamic obesity
- sleep and circadian rhythm ,Receive some afferent fibers directly from the retina,is connected to pineal gland which secrete melatonin
106
Descending fibers from HT to autonomic centers in the brainstem and spinal
cord descend through a series of neurons in the ?
Inputs to HT that affect autonomic functions come mostly from?
- in the reticular formation
| - the amygdala and limbic cortex.
107
glucose control theory ;what does it stimulate / inhibit??
stimulate ventromedial N (VMN) and VMN inhibit lateral N (LN)
108
* Changes in body temperature affect the activity of?
| * These neurons control the body temperature mainly via ?
-thermosensitive hypothalamic
neurons
- via their output to the
autonomic centers
109
how HT control memory ?
how it control emotion and behavior?how it explain why emotional behavior is often accompanied by autonomic activation?ex?
• Mammillary body in HT is part of limbic system which build and support memory.
• Through communication with limbic system and prefrontal cortex.
• Limbic - hypothalamic interconnections explain this
• EX:
- Blushing when embarrassed
- Sweaty palms & dry mouth when anxious or afraid
110
epithalamus;
located in?
consist of?
-in most caudal and dorsal region of the diencephalon
, Lies immediately rostral to superior colliculus
A. Habenular nuclei and their interconnecting
fibers the habenular commissure
B. Stria medullaris thalami
C. Pineal gland.
111
```
habenular nuclei;
location?
afferents from?
efferents from?
function?
```
• medial to the posterior surface of the thalamus
afferents from:
Amygdala and septal area through the stria medullaris thalami.
Hippocampus through the fornix.
```
# efferents to:
Interpeduncular nucleus and reticular formation of the midbrain.
```
```
# They are part of limbic systems, concerned with mechanisms of
emotion & behavior.
```
112
Stria Medullaris Thalami;
arise from?
terminate in?
- from the septal area
| - in hebenula
113
```
pineal gland ;
location?
attached to?
secretes?
become calcified in ?
```
* Single midline structure lies behind thalami and above superior colliculi.
* Its stalk is attached to habenular commissure above and posterior commissure below.
• secretes Melatonin
which regulate body's circadian rhythms “wake/sleep cycle”.
• in old age (around 20 years)
114
subthalamus;
location?
consist of? 3 nuclei
part of?
•Biconvex mass of grey matter located caudal to thalamus & dorsal to substantia nigra, between the thalamus above and midbrain below , Lies between the hypothalamus medially and the lower part of internal capsule laterally.
.#Separated from thalamus by Zona inserta.
• It contains 3 nuclei:
1. Subthalamic nucleus
2. Upper end of red nucleus,
3. Upper end of substantia nigra
• part of basal ganglia
115
basal ganglia ;
what is it?
Anatomically, the basal ganglia are made of three distinct nuclei:?
Two other regions are functionally associated with the basal ganglia:?
caudate +putamen?
putamen +globus pallidus?
-The basal nuclei ( basal ganglia) are large masses of gray matter situated in the
cerebral hemispheres that have motor function of great importance.
1. The caudate nucleus.
2. The putamen.
3. The globus pallidus.
1. The subthalamic nucleus.
2. The substantia nigra.
```
#referred to as the striatum.
# referred to as the lentiform nucleus.
```
116
What do the Basal Ganglia do?
-involved in generation of goal-directed voluntary
movements( achieving specific, smooth and complicated motor function.)
- The signal becomes increasingly focused and specific as it passes through the basal ganglia by Inhibiting the unwanted and inappropriate voluntary movements and Facilitating the required and appropriate movements.
- involved in motor learning (New learned movements).
- Control automatic movements, like swinging of arms during walking.
- Regulating of muscle tone and help in smoothing the motor activities.
117
The Caudate Nucleus;
contains?shape of each and what do they form?
how many it appears in frontal sections?
1-The Head
Large and rounded , forms the lateral wall of the anterior horn of the lateral ventricle, fused inferiorly with the Putamen of the lentiform nucleus.
2- The Body
Long and narrow, continuous with the head in the region of the interventricular foramen, forms part of the floor of the body of the lateral ventricle.
3- The Tail
Long and slender, forms part of the roof of the inferior horn of the lateral ventricle,
terminates anteriorly in the amygdaloid nucleus
```
#The Caudate appears
twice in many frontal
brain sections,because the Caudate curves around with the lateral ventricle. The
head of the Caudate is
most anterior.
```
118
```
The Lentiform Nucleus;
shape?
divided by a thin layer of WM into?
related medially to?
related laterally to?
```
The Globus pallidus (GP) has 2 different parts,what are they?
-GPi contains?
-appears triangular (Wedge-shaped) in cross sections,
1-A larger, darker outer portion, the Putamen
2-An inner lighter portion, the Globus pallidus
-to the internal capsule, which separates it from the
Caudate nucleus and the thalamus
-to external capsule separating it from the claustrum
- Globus pallidus externa (GPe)
- Globus pallidus interna (GPi),contains the output neurons of the basal ganglia
circuit. They project to ipsilateral motor thalamus (VA,VL)
119
substantia nigra;
located in?
made up of?
divided into 2 parts?
-Motor nucleus located in the midbrain.
-Made up of small unpigmented & large
pigmented nerve cells contains neuromelanin.
1-Pars compacta: contains
dopaminergic (75%) & cholinergic(25%) neurons.
2-Pars reticularis: contains GABAergic neurons.
120
Organization of movement:
What type? >>>>
How to perform? >>>>>
Assist in regulation >>>>>
- Cerebral cortex
- Basal ganglia + Cerebellum
- Thalamus
121
Connections of Basal Ganglia;
what parts receive all the afferents ?
what are the three sources they receive afferents from?
efferents mainly go to?and the efferenr from them go to?
-caudate and putamen
1. cerebral cortex
2. thalamus
3. substantia nigra(pars compacta)
go to:
1. globus pallidus
2. a few to substantia nigra (pars reticularis)
the efferent from them go to : thalamus, subthalamic nucleus , superior colliculus , reticular nuclei.
122
Explain the direct pathway;
.Direct pathway
Striatal cells project directly to GPi
The consequence of this pathway is to INCREASE the excitatory drive from
thalamus to cortex.
The cortical projections to the striatum use the excitatory transmitter Glutamate.
When they are activated, these cortical projections excite striatal neurons.
This excitatory input is enough to turn on the striatal cell. This striatal cell uses the
inhibitory transmitter GABA and its axon passes to, and inhibits, a cell in GP(internal).
The cells in GP(internal) that project to VA/VL also use GABA.
123
Basal ganglia disorders ;
Two types:hypokinetic and hyperkinetic
Ex on both types?
.Hypokinetic
– Increased tone & rigidity
Ex: Parkinsonism
Hyperkinetic
– Abnormal involuntary movements
Ex: Athetosis, Chorea & Hemiballism
124
```
Characteristics and degeneration of what in ;
Parkinsonism
Athetosis
Chorea;2 types
Hemiballismus
```
```
#P: degeneration of dopaminergic neurons from the SN
*characterized by:1-rigidity and slowness (by increased muscle tone) , 2- resting tremor , 3- mask-like facies
4- shuffling gait (short and quick steps
```
```
#A: Due to damage of Putamen – inbirth injury
*characterized by:1-slow writhing ,2- snake-like movements of fingers and wrists
```
```
#C:Due to Degeneration of Striatum.
*characterized by: sudden jerky and purposeless movements .
tow types:
1.Sydenham’s chorea:
In childhood
A complication of rheumatic fever.
Scattered minute hemorrhage and
capillary emboli in striatum).
2.Huntington's chorea:
In middle age.
An inherited disorder.
```
#H:Due to degeneration of
Subthalamic nucleus of
opposite side.
characterized by:A sudden wild flail-like (Swing Widely) movement of one limb.
125
```
Cerebellum ;
Location?
Covered by?
Connected to brain stem by?
Formed of?
Appearance of its surface?
Internal structure?
```
-part of hind brain ,behind the pons and medulla oblongata
- by tentorium cerebelli
- connected by three cerebellar peduncles.
-formed of two cerebellar hemispheres joined
by a median narrow part; the vermis.
-laminated appearance
-Outer gray matter called cerebellar cortex, extensively folded forming folia.
• Inner white matter showing distinctive treelike pattern called Arbor vitae
126
Deep cerebellar nuclei;
How many?
From medial to lateral known as?
-4 on each side
- Fastigial Nuclei
Globose Nucleus
Emboliform Nucleus
Dentate Nucleus
#Constitute the primary source of efferent
fibers from the cerebellum to the other part of the brain.
127
ANATOMICAL Lobes of cerebellum;
How many?mention them.
Which fissure divides A and P lobes?
Which fissure separates P from flocculonodular lobe?
• 3 lobes in each hemisphere
1. Anterior
2. Posterior
3. Flocculonodular
- primary fissure
- posterolateral fissure
128
Zones of cerebellum;
How many?mention them.
What are the nuclei each of them project to?
three zones : 1. Vermis.
2. Intermediate zone.
3. Lateral zone.
* Vermis to fastigial nucleus
* Intermediate zone to interposed nuclei (Globose and Emboliform)
* Lateral zone to dentate nucleus
129
FUNCTIONAL lobes of cerebellum;
mention them?
*check the table for a summary for them *slide20
1. Archicerebellum (Flocculonodular lobe)
2. Paleocerebellum (Vermis and intermediate zone)
3. Neocerebellum (Lateral zone)
130
```
Superior cerebellar peduncle;
Connects?
Formed mostly of?
Afferent?
Efferent?
```
* Connects cerebellum to midbrain.
* formed mostly of efferent fibers.
• Afferent Fibers:
1. Ventral spinocerebellar tract.
2. Tecto-cerebellar tract (from the superior colliculus).
• Efferent Fibers:
1. Fastigio-reticular fibers (from fastigial nucleus) to the reticular formation.
2. Cerebello-rubral fibers (from globose & emboliform nuclei) to red nucleus.
3. Dentato-thalamic fibers (to VLN of thalamus) & dentate-
rubro-thalamic fibers (to the same nucleus of the thalamus via the red nucleus).
131
Middle cerebral peduncle ;
*the largest peduncle*
Connects?
Contains?
* Connects the cerebellum to the pons.
| * Contains cortico-ponto-cerebellar fibers.
132
```
Inferior cerebellar peduncle ;
Connects?
Formed mostly of?
Afferent ?
Efferent?
```
* Connects the cerebellum to the medulla.
* It is formed mostly of afferent fibers.
• Afferent fibers:
1. Posterior spinocerebellar tract
2. Cuneo-cerebellar tract
3. Anterior external arcuate fibres
4. Vestibulo-cerebellar fibres
5. Olivo-cerebellar fibres
6. Reticulo-cerebellar fibres
• Efferent fibers:
1. Cerebello-vestibular Fibers (from flocculonodular lobe to vestibular
nuclei) .
2. Cerebello-reticular Fibers (to the reticular formation).
3. Cerebello-olivary Fibers (to the inferior olive).
133
Functions of cerebellum?5
1- Coordination of voluntary movements
2- Motor learning – NEW SKILLED VOLUNTARY MOVEMENTS (with BG)
3- Store the programs of repetitive automated movements
4-balance
5- control of muscle tone and posture.
134
Cerebellar lesions;
| Cause;
• Disturbance of posture
• Hypotonia
• Ipsilateral “ataxia” - incoordination of
movement:
1. Ataxic gait
2. Intention tremor on performing voluntary
movements (not resting tremors as in Parkinson's disease)
3. Nystagmus (rapid jerky eye movements)
4. Dysdiadokokinesia (impaired ability to perform
rapid, alternating movement).
5. Dysmetria
6. Dysarthria
135
explain the indirect pathway;
Striatal cells project indirectly to GPi (through GPe and STN )
The consequence of this pathway is to DECREASE the excitatory
drive from thalamus to cortex.
Indirect pathway simultaneously inhibits the execution of competing
motor programs
136
what is the function of SNpc (pars comacta) in direct/ indirect pathways?
Direct pathway: The pars compacta sends excitatory input to the striatum via D1 (Dopamine receptor) pathway that excites and activates the striatum.
Indirect pathway: The pars compacta sends inhibitory input to the striatum via D2 pathway that inhibits and deactivates the striatum.
