Topography of the Brain (Anatomy) - recap and blood supply

Question 1

What parts make up the brain?

Answer 1

Cerebral hemispheres

Diencephalon

Cerebellum

Brainstem:

^Midbrain

^Pons

^{Medulla Oblongata}

Question 2

What is white and grey matter?

Answer 2

White matter = myelinated axons

Grey matter = neuronal cell bodies

Question 3

What does white matter in spinal cords and brain form?

Answer 3

various tracts

Question 4

What is a tract?

Answer 4

fibre pathway passing through the CNS carrying a specific modality (e.g. motor fibres or pain sensation or touch sensation

Question 5

What is a nucleus?

Answer 5

Neuronal cell body collection (grey) within CNS = nucleus

Question 6

What is a ganglion?

Answer 6

Neuronal cell bodies outside the CNS = ganglion (e.g. dorsal root ganglion)

Question 7

What are all the ventricles of the brain and where are they located?

Answer 7

Ventricles are spaces within the brain

Within cerebral hemispheres (x2) = lateral ventricle (x2)

Within Diencephalon = III ventricle

Within Midbrain = Cerebral aqueduct

Between Pons + medulla (in front) and Cerebellum (at the back) = IV ventricle

Question 8

Where is CSF?

Answer 8

in the ventricles

in subarachnoid space - between pia and arachnoid mater

Question 9

Where is CSF formed?

Answer 9

By choroid plexus in each ventricle

Question 10

Where is CSF absorbed?

Answer 10

By Arachnoid villi into saggital sinus (venous channel in brain)

Question 11

What arteries provide blood supply tot he braina and how do they enter the skull?

Answer 11

the 2 ICA - enter the skull through the carotid canal (foramen lacerum) to supply the brain

the 2 vertebral arteries (branches of the subclavian artery) - enter the skull through the foramen magnum

Question 12

What is the circle of willis?

Answer 12

The circle of Willis is a circulatory anastomosis that supplies blood to the brain and surrounding structures

Question 13

What are the main arteries forming the circle of willis?

Answer 13

formed by the anastomosis of the two internal carotid arteries with the two vertebral arteries

Question 14

What is the structure of the circle of willis?

Answer 14

Branches of the ICA join with those of the opposite side and with the posterior cerebral arteries (branch of the basilar artery) to form a continuous circle at the base of the brain

Question 15

How does the anastomoses protect against vasoocclusion

Answer 15

This is a protective feature against vaso-occlusion of large arteries due to other areas blood can flow through but branches supplying the cerebral hemispheres, distal to the Circle of Willis are effectively “end-arteries” so this would loead to ischemia of the brain causing a stroke

Question 16

A?

Answer 16

anterior cerebral artery

Question 17

B?

Answer 17

anterior communicating artery

Question 18

C?

Answer 18

middle cerebral artery

Question 19

D?

Answer 19

posterior communicating artery

Question 20

E?

Answer 20

posterior cerebral artery

Question 21

F?

Answer 21

basilar artery

Question 22

G?

Answer 22

vertebral artery

Question 23

What does the anterior communicating artery do?

Answer 23

connects the two anterior cerebral arteries

Question 24

What branches does the ICA give off?

Answer 24

The ICA gives branches - the anterior (ACA), middle cerebral (MCA) and posterior communicating arteries (PComA)

The ACA and the MCA supply a large part of the cerebral hemispheres

Question 25

What do the vertebral arteries make and supply?

Answer 25

The 2 vertebral arteries join together to form a basilar artery on the ventral surface of the brainstem The vertebro-basilar system gives branches that supply the brainstem and cerebellum The basilar artery finally ends at the level of the midbrain by dividing into two Posterior cerebral arteries (PCA) which supplies the posterior part of the cerebral hemispheres

Question 26

What area of the brain does the anterior cerebal artery supply?

Answer 26

medial aspect of the cerebral hemispheres excluding the occipital lobe

Question 27

What areas of the brain does the middle cerebral artery supply?

Answer 27

lateral aspects of the cerebral hemispheres

Question 28

What areas of the brain does the posterior cerebral artery supply?

Answer 28

inferior aspects of the cerebral hemispheres and the occipital lobe

Question 29

Describe the venous drainge of the brain?

Answer 29

superficial and deep veins of the brain drain into venous sinuses which lie between the 2 layers of dura mater the dura mater sinuses join together to ultimatley drain into the internal jugular veins

Question 30

A?

Answer 30

inferior saggital sinus

Question 31

B?

Answer 31

superior saggital sinus

Question 32

C?

Answer 32

transverse sinuses

Question 33

D?

Answer 33

great cerebral vein

Question 34

E?

Answer 34

cavernous sinus

Question 35

F?

Answer 35

petrosal sinus: superior inferior

Question 36

G?

Answer 36

internal jugular veins

Question 37

What is the basic function of the cerebrum?

Answer 37

seat of consciousness

Question 38

What is the basic function of the cerebellum?

Answer 38

balance and coordination

Question 39

What is the function of the brain stem?

Answer 39

viral centres e.g. cardiorespiratory pathway for fibre tracts

Question 40

Describe brefiely how the brain is formed embryologically?

Answer 40

The neural tube develops from the (dorsal) surface ectoderm The cranial end of the tube forms vesicles each of which develops into different parts of the brain

Question 41

What does the neural tube devide into when it is formed?

Answer 41

As soon as the neural tube was formed, it divided into 3 primary vesicles (Week 4) and then into 2ry vesicles (Week 5) these develop into the adult brain

Question 42

On the brain stem what is the order of strucutre that . make it up from superior to inferior

Answer 42

midbrain PONS medulla

Question 43

What cranial nerves emerge from the brainstem?

Answer 43

Cranial nerves 3-12

Question 44

What are the functions of the brainstem?

Answer 44

Pathway for fibre tracts running between higher & lower centres Brainstem nucleii are involved with 10 of the 12 cranial nerves, so innervation of head & neck Brainstem centres produce the rigidly programmed automatic behaviours essential for survival

Question 45

What is the cavity in the medulla?

Answer 45

IV ventircle

Question 46

What does the medulla continue as?

Answer 46

the spinal cord at the foramen magum

Question 47

What is the structure of the medulla?

Answer 47

has pyramids in the middle and olives laterallt

Question 48

What happens between the pyramids of the medulla?

Answer 48

decussation - crossing over of cranial nerves to the opposite side

Question 49

What connects the medulla to the cerebellum?

Answer 49

inferior cerebellar peduncle

Question 50

Where is the IV ventricle in relation to the PONS

Answer 50

posterior to it

Question 51

What peduncle can be seen on the PONS?

Answer 51

middle cerebellar peduncle

Question 52

What is the central cavity of the midbrain?

Answer 52

cerebral aqueduct

Question 53

What peduncles can be seen on the midbrain?

Answer 53

cerebral peduncle superior cerebellar peduncle

Question 54

What cranial nerves coem from the medulla?

Answer 54

Cranial nerves IX, X, XI & XII from its surface

Question 55

What cranial nerves come form the PONS

Answer 55

Cranial nerves V, VI, VII & VIII originate from its surface

Question 56

What cranial nerves come from the midbrain?

Answer 56

Origin of Oculomotor (CN III) & Trochlear (CN IV)

Question 57

What is the only cranial nerve emerging form the back of the brainstem and where does it emerge from?

Answer 57

CN IV Emerges from the midbrain

Question 58

What is the dark line called if you looks at a cross section of the midbrain?

Answer 58

substantia nigra

Question 59

What are the hemispheres of the cerebellum?

Answer 59

right and left seperated by vermis

Question 60

What does each hemisphere of the cerebellum have?

Answer 60

Each hemisphere has an anterior, posterior and flocculonodular lobe

Question 61

WHat is the surface strucutre of the cerebellum made of?

Answer 61

sulci and folia

Question 62

How many cerebellar peduncles connect the cerebellum to the midbrain

Answer 62

3

Question 63

What are the functions of the cerebellum?

Answer 63

posture maintenance fine tuning motor activity

Question 64

Where does the cerbellum recieve information from?

Answer 64

information form pyramidal tracts (motor intention of brain) information from ipsilateral proprioceptors from periphery information from vestibular nuclei re. balance and posture

Question 65

What happens to the infromation in the cerebellum when it arrives?

Answer 65

Calculates best way to coordinate force, direction, extent of muscle contraction to maintain posture prevent overshoot and ensure smooth coordinated muscle contraction

Question 66

What happens to the information in the cerebellum once it has decided what to do?

Answer 66

Sends ‘blueprint’ back to cerebral cortex via superior cerebellar peduncle

Question 67

Does the cerebellum deal with information that is from the same side of the body or opposite?

Answer 67

Ipsilateral is on the same side so cerebellum deals with the same side of the body but the cerebral hemispheres deals with the opposite side of the body Ipsilateral rather than contralateral

Question 68

What tests can be done to test an abnorality of the cerebellum? - ataxia

Answer 68

Finger - nose test Knee-heel test Walking in a straight line

Question 69

What are the 2 main parts that make up the diencephalon?

Answer 69

thalamus hypothalamus

Question 70

Is the diencphalon mianly white or grey matter?

Answer 70

grey matter

Question 71

How would you describe the thalamus?

Answer 71

a sensory relay station

Question 72

Where is the hypothalamus located?

Answer 72

It lies below the thalamus separated from it by the hypothalamic sulcus

Question 73

What is the function of the hypothalamus?

Answer 73

Despite its small size, it is the main visceral control centre & is essential for overall homeostasis

Question 74

What is the homeostatic role of hypothalamus?

Answer 74

Autonomic Control Centre Body temperature regulation Regulation of food intake Regulation of water balance & thirst Regulation of sleep-wake cycle Control of endocrine system functioning

Question 75

What is the venous drainage of the brain?

Answer 75

venous drainage into dural venous sinuses and then into IJV

Question 76

What is the structure of the diencephalon?

Answer 76

Groove below thalamus is your hypothalamus sulcus then hypothalamus then pituitary stalk coming off

Question 77

What is the body of grey mater lateral to the 3rd ventricle?

Answer 77

thalamus

Question 78

Where does all sensory information pass through?

Answer 78

the thalamus

Question 79

What does trh diencephalon develop from?

Answer 79

Develops from diencephalic vesicle (part of forebrain vesicle)

Question 80

What is the thalamus made up of

Answer 80

different groups of nuclei

Question 81

What is the lateral group of the nuclei?

Answer 81

The lateral group are involved in processing sensory information

Question 82

Where does all sensory information synapse?

Answer 82

at the thalamus

Question 83

What happens at the lateral geniculate body of the thalamus?

Answer 83

a relay center in the thalamus for the visual pathway it receives a major sensory input from the retina