Cranial nerves

Question 1

Facial nerve (CN 7)

Answer 1

Innervates the muscles of facial expression (motor)

innervates orbicularis oculi

provides sensory and parasympathetic innervation

frequently monitored during surgery around the face- parotidectomy, acoustic neuroma, cochlear implant

Question 2

Glossopharyngeal (IX)

Answer 2

sensory innervation to the baroreceptors of the carotid sinus - can cause bradycardia and hypotension during CEA

sensory innervation to the chemoreceptors of the carotid body

sensory innervation of the posterior oral mucosa (gag reflex)

motor innervation of the pharynx (swallowing)

provides parasympathetic innervation to the parotid gland

Question 3

Superior laryngeal nerve (CN X)

Answer 3

Internal branch (sensory)

external branch (motor) - cricothyroid muscles

Question 4

Cricothyroid

Answer 4

tenses vocal cords (“cords tense”)

Question 5

thyroarytenoid

Answer 5

relaxes vocal cords

“They Relax”

Question 6

Posterior cricoarytenoid

Answer 6

ABducts vocal cords

“Please Come Apart”

Question 7

Lateral cricoarytenoid

Answer 7

ADDucts vocal cords

“Lets close airway”

Question 8

SLN innervates

Answer 8

Cricothyroid muscle
Underside of epiglottis

Question 9

what 4 nerves innervate the airway?

Answer 9

trigeminal

glossopharyngeal

SLN

RLN

Question 10

External branch of the SLN innervates what?

Answer 10

cricothyroid muscle- which tenses and adducts the vocal cords

Injury to the nerve can produce changes in voice quality but is generally not dangerous

Question 11

RLN (CN X)

Answer 11

innervates all of the intrinsic muscles except for the cricothyroid

Unilateral RLN injury produces abductor vocal cord paralysis- affected cord is in paramedian position = hoarsness

bilateral vocal cord paralysis= airway obstruction–> stridor

Question 12

Vagus (CN X)

Answer 12

Innervates:

heart
lungs- vasodilation and bronchoconstriction
gi system

Question 13

components of the intracranial vault:

Answer 13

brain: 80-85%

blood: 5-10%

CSF: 10-15%

Question 14

what supplies blood to the brain?

Answer 14

carotid arteries
vertebral arteries

Question 15

where does the left carotid artery arise from?

Answer 15

aortic arch

Question 16

where does the right carotid artery arise from?

Answer 16

innominate artery

Question 17

What do the carotid arteries bifurcate into?

Answer 17

external and internal carotid arteries

Question 18

Where does the internal carotid artery enter?

Answer 18

base of the skull

Question 19

Internal carotid arteries (ICA)

Answer 19

arterial supply to the circle of Willis

arterial supply to the eye via the ophthalmic artery

ultimately bifurcates into the anterior and middle cerebral arteries

Question 20

vertebral arteries

Answer 20

Arise from subclavian arteries

arterial supply to the circle of Willis

arterial supply to the: basilar artery, cerebellar arteries, spinal arteries

Question 21

meninges

Answer 21

Covers the brain and spinal cord and consists of:

dura mater- outer layer
arachnoid mater-mid
pia mater- inner most

Question 21

venous system:

Answer 21

venous blood drains into the venous sinuses which lie btwn the layers of the dura mater and drain into the internal jugular vein

sinuses are valveless
blood can flow back and forth
pressure within them is negative (air embolism)

little influence by the autonomic nervous system

Question 22

Pia mater:

Answer 22

anchored to the brain by astrocytes which form the BBB

allows passage/transport of:
small molecules (h20, o2, co2)
lipophilic molecules (etoh, co2)
passive transport of glucose
active transport of amino acids/NT precursors

prevents passage of:
large molecules (dopamine)
charged (ionized) molecules

Question 23

Arachnoid Mater

Answer 23

CSF circulates in the subarachnoid space (btwn arachnoid and pia mater)

The arachnoid mater contains the blood supply to the brain

Question 24

dura mater

Answer 24

consists of an outer (endosteal layer) and the inner (meningeal layer) dural sinus are btwn these layers drains cerebral spinal fluid

Question 25

subarachnoid hemorrhage

Answer 25

neurological emergency hemorrhage in the subarachnoid space less common but an important cause of stroke bleeding btwn the arachnoid membrane and the pia mater usually from a ruptured cerebral aneurysm

Question 26

epidural hematoma

Answer 26

bleeding btwn the skull and dura mater usual arterial in origin (meningeal arteries)

Question 27

subdural hematoma

Answer 27

bleeding btwn the dura and arachnoid mater usually resulting from tears in bridging veins

Question 28

flow of CSF

Answer 28

1.) Lateral ventricles 2.) Foramen of Monro 3.) Third Ventricle 4.) Aqueduct of Sylvius 5.) Fourth Ventricle 6.) Foramen of Laschka 7.) Foramen of Magendie 8.) Subarachnoid Space 9.) Arachnoid Villi 10.) Superior sagittal sinus

Question 29

site of CSF production :

Answer 29

choroid plexus

Question 30

Site of CSF reabsorption:

Answer 30

arachnoid villi

Question 31

pathway btwn lateral and 3rd ventricle

Answer 31

foramen of monro

Question 32

pathway btwn 3rd and 4th ventricle:

Answer 32

aqueduct of sylvius

Question 33

total CSF volume

Answer 33

150mL

Question 34

csf is produced in the choroid plexus at a rate of:

Answer 34

30ml/hr

Question 35

the BBB separates

Answer 35

CSF from plasma

Question 36

ventricles

Answer 36

lined by ependymal cells which help to form the choroid plexus there are 2 lateral ventricles in the cerebral hemispheres third ventricle is located in the diencephalon 4th ventricle is located btwn the pons and cerebellum

Question 37

CSF

Answer 37

surrounds the brain and spinal cord 10-15% of intracranial volume approx 500 ccs are produced per 24hrs total volume is 150ml

Question 38

frontal lobe

Answer 38

motor cortex

Question 39

occipital

Answer 39

vision

Question 40

parietal

Answer 40

sensation

Question 41

temporal

Answer 41

audition

Question 42

wernicke's area

Answer 42

understanding speech

Question 43

broca's area

Answer 43

motor control of speech (located in frontal lobe but is connected to wernicke's area via neural pathways