Nervous System II

Question 1

Describe the flow of CSF in the ventricles

Answer 1

2 lateral ventricles (temporal horn –> frontal horn) –> (through inter-ventricular foramina) midline 3rd ventricle –> 4th ventricle (via cerebral aqueduct) –> sub-arachnoid space of cranial cavity median aperture and 2 lateral apertures

Question 2

What produces CSF?

Answer 2

choroid plexus

Question 3

Olfactory Nerve

Answer 3

CN I; Sensory; carries olfactory information from olfactory epithelium through the foramina of cribiform plate

Question 4

Optic Nerve

Answer 4

CN II; Sensory; Carries visual information from the retina through the optic canal

Question 5

Vestibulocochlear Nerve

Answer 5

CN VIII; Sensory; Carries balance and hearing from inner ear (cochlea and vestibular apparatus) through the internal auditory meatus

Question 6

occulomotor nerve

Answer 6

CN III; motor; innervates 4 of the 6 extrinsic muscles of the eye, and intrinsic muscles (iris and ciliary body/lens)

Question 7

trochlear nerve

Answer 7

CN IV; motor; innervates superior oblique (down and out muscle)

Question 8

Abducens Nerve

Answer 8

CN IV; motor; innervates lateral rectus (abducts the eye)

Question 9

Spinal Accessory Nerve

Answer 9

CN XI; motor; innervates the sternocleidomastiod (rotates the head) & trapezius muscles (shrugs the shoulders); exits cranium via jugular foramen

Question 10

Hypoglossal nerve

Answer 10

CN XII; motor; innervates the intrinsic and extrinsic muscles of tongue. Exits via hypoglossal canal

Question 11

3 branches of trigeminal nerve

Answer 11

V1 - Ophthalmic
V2 - Maxillary
V3 - Mandibular

Question 12

Ophthalmic nerve

Answer 12

V1 branch of trigeminal nerve V; somatosensory from cornea, nose and forehead; superior orbital fissure

Question 13

Maxillary nerve

Answer 13

V2 branch of trigeminal nerve; somatosensory from maxilla, upper lip & teeth, hard palate; foramen rotundum

Question 14

Mandibular Nerve

Answer 14

V3 branch of trigeminal nerve ; tomato-sensory mandible, lower lip & teeth, anterior 2/3 tongue; motor to muscles of mastication

Question 15

Facial Nerve

Answer 15

CN VII; Internal Aug Meatus;
Sensory - Taste: ant 2/3 of tongue
motor - muscles of facial expression
motor (visceral) - all glands (salivary) of face/oral cavity except parotid gland

Question 16

Where does CSF drain into after the 4th ventricle?

Answer 16

into the sub-arachnoid space of cranial cavity

Question 17

how much CSF is produced per day by the choroid plexus?

Answer 17

500ml

Question 18

where is the choroid plexus located?

Answer 18

It is a vascularized tissue found within all 4 cerebral ventricles

Question 19

What is the choroid plexus made up of ?

Answer 19

specialized epithelial cells which determine which solutes enter the CSF and which don’t

Question 20

what occurs when production of CSF is greater than absorption

Answer 20

hydrocephalus

Question 21

what are the functions of CSF?

Answer 21

1. provides protection
2. maintains constancy of environment for brain tissue (provides nutrients and ions)
3. removes cellular waste products

Question 22

What is the total volume of the subarachnoid space?

Answer 22

150ml

Question 23

How is CSF drained from the subarachnoid space?

Answer 23

It is drained into venous sinuses by arachnoid villi

Question 24

What are arachnoid villi?

Answer 24

tufts of arachnoid that extend through dura (meningeal layer) into venous sinus

Question 25

Where are arachnoid villi most numerous?

Answer 25

superior sagittal sinus; are seen as arachnoid granulations

Question 26

What is the function of the arachnoid granulations?

Answer 26

functions to transport CSF from villi and granulations into venous blood.

Question 27

what 2 sets of arteries supply the brain?

Answer 27

1. internal carotids | 2. vertebrals

Question 28

what would result from occlusion in the middle cerebral artery?

Answer 28

Since this artery supplies the motor and pre-motor areas in the frontal lobe, a large area of the parietal lobe and the superior surface and anterior pole of the temporal lobe, occlusion may result in sensory and motor deficits of the contralateral body( trunk upper limbs, head and face & language deficits.

Question 29

occlusion of the anterior cerebral artery would result in what?

Answer 29

sensory and motor deficits of the contralateral body (lower limbs). This is because this artery supplies the medial and superior surfaces of frontal & parietal lobes

Question 30

What parts of the brain does the anterior cerebral artery supply?

Answer 30

medial and superior surfaces of the frontal and parietal lobes

Question 31

what parts of the brain does the middle cerebral artery supply?

Answer 31

lateral cortical and subcortical areas. Superior surface and anterior pole of temporal lobe

Question 32

what areas does the posterior cerebral artery supply?

Answer 32

occipital lobe and inferior surface of temporal lobe

Question 33

what do the vertebral arteries (before they form the basilar) supply?

Answer 33

cervical spinal cord and the cerebellum

Question 34

What is a stroke?

Answer 34

occurs when blood supply to the brain is interrupted

Question 35

What are the 2 types of strokes?

Answer 35

1. Ischemic stroke - occlusion of vessels 2. Hemorrhagic stroke - more commonly involves smaller vessels under chronic hypertension; also subarachnoid hemorrhage (due to aneurysms)

Question 36

what is a sinus?

Answer 36

channel carrying venous blood and convey that blood from the brain to the internal jugular veins; under low pressure

Question 37

what does the internal jugular vein do?

Answer 37

Drains the blood from the brain and returns it to the heart

Question 38

What cranial nerves are sensory (3) ?

Answer 38

1. olfactory - olfactory information from olfactory epithelium through foramina of cribiform plate 2. optic - carries visual information from retina through optic canal 3. vestibulocochlear - balance and hearing from inner ear

Question 39

What cranial nerves serve motor functions?

Answer 39

3 extraoccular muscles: 1. occulomotor (III) - 4/6 extrinsic muscles of the eye, and intrinsic muscles (iris and ciliary body/lens) 2. trochlear (IV) - superior oblique (down and out muscle) 3. abducens (VI) - lateral rectus (abducts eye) 4. spinal accessory (XI) - trapezius and sternocleidomastoid 5. Hypoglossal (XII) - intrinsic and extrinsic muscles of tongue

Question 40

What cranial nerves are mixed?

Answer 40

1. trigeminal 2. facial 3. glossopharyngeal 4. vagus

Question 41

glossopharyngeal nerve

Answer 41

CNIX; jugular foramen sensory: taste: post 1/3 of tongue motor - assist in swalling motor (visceral) - parotid

Question 42

Vagus

Answer 42

CN X; Vagus; jugular foramen sensory: taste: epiglottis; visceral sensory from reap.tract and viscera motor - swallowing (vomiting) motor (visceral) - respiratory tract, heart, and esophagus, stomach, intestines