Quiz 2 - Cranial Nerves and Components of the Intracranial Vault

Question 1

Cranial Nerve I

Answer 1

Olfactory, sensory (nose)

Question 2

Cranial nerve II

Answer 2

Optic, sensory (eye)

Question 3

Cranial nerve III

Answer 3

Oculomotor, motor (all eye muscles except for those from CN IV and VI)

Question 4

Cranial nerve IV

Answer 4

trochlear, motor (superior oblique muscles)

Question 5

Cranial nerve V

Answer 5

Trigeminal, Sensory (face, sinuses, teeth etc.)
Motor: muscles of mastication

Question 6

Cranial nerve VI

Answer 6

Abducent, motor (external rectus muscle)

Question 7

Cranial nerve VII

Answer 7

Facial, motor (muscles of the face)

Question 8

Cranial nerve VIII

Answer 8

Vestibulocochlear, sensory (inner ear

Question 9

Cranial nerve IX

Answer 9

Glossopharyngeal, motor (pharyngeal/musculature)
Sensory: posterior part of tongue, tonsils, and pharynx

Question 10

Cranial nerve X

Answer 10

Vagus, motor (heart, lungs, bronchi, GI tract)
sensory: heart, lungs, bronchi, trachea, larynx, pharynx, GI tract, and external ear

Question 11

Cranial nerve XI

Answer 11

accessory, motor (sternocleidomastoid and trapezius muscles)

Question 12

Cranial nerve XII

Answer 12

Hypoglossal, motor (muscles of the tongue)

Question 13

injury to CN VII

Answer 13

from using mask straps

Question 14

CN VII functions

Answer 14

Innervates the muscles of facial expression (motor)

Innervates the Orbicularis Oculi

Provides sensory and parasympathetic innervation

Frequently monitored during surgery around the face
Parotidectomy, acoustic neuroma, cochlear implant

Question 15

Cranial Nerve IX functions

Answer 15

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 16

Cranial Nerve X forms:

Answer 16

Superior Laryngeal Nerve (CN X)
Recurrent Laryngeal Nerve (CN X)

Question 17

CN X (Heart function)

Answer 17

convey parasympathetic innervation to the sino-atrial and atrio-ventricular nodes of the heart. Vagal stimulation reduces heart rate and is constantly active.

Question 18

CN X (Lungs function)

Answer 18

Parasympathetic stimulation within the pulmonary plexuses causes vasodilation and bronchoconstriction.

Question 19

CN X (GI function)

Answer 19

Provides parasympathetic innervation to abdominal organs. Stimulate smooth muscle contraction and glandular secretions in these organs.
Vagal stimulation during GI surgery and endoscopy can lead to significant bradycardia and even asystole.

Question 20

Recurrent Laryngeal Nerve (L and R locations)

Answer 20

R RLN goes under the subclavian artery and runs posterior
Helps to maintain connection to the larynx
L RLN loops under the aortic arch

Question 21

RLN injury

Answer 21

Bilateral RLN damage/injury = laryngospasm = stridor/resp distress
unilateral RLN injury (cord goes paramedian) produces abductor vocal cord paralysis = hoarseness

Question 22

Superior Laryngeal Nerve

Answer 22

Internal branch (sensory)

External Branch (motor)
cricothyroid muscles

Question 23

SLN injury

Answer 23

The SLN (external branch) innervates the 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 24

Oculocardiac reflex

Answer 24

AKA Aschner phenomenon is a physiological response where the heart rate decreases due to pressure applied to the eye or traction on the extraocular muscles. This reflex is mediated by the trigeminal nerve (cranial nerve V) and the vagus nerve (cranial nerve X).

Question 25

Components of Intracranial vault

Answer 25

Brain 80-85% Blood 5-10% Cerebral spinal fluid 10-15%

Question 26

Blood supply to the brain

Answer 26

B/L Carotid Arteries & B/L Vertebral Arteries

Question 27

Left carotid artery

Answer 27

originates off of aortic arch

Question 28

Right carotid artery

Answer 28

originates off of right innominate artery (Aline in right arm to monitor for injury of innominate artery)

Question 29

The Internal Carotid Artery

Answer 29

enter the base of the skull.

Question 30

The External Carotid artery

Answer 30

remain superficial to the skull

Question 31

Internal Carotid arteries

Answer 31

Arterial supply to the Circle of Willis Arterial supply of the eye via the ophthalmic artery Ultimately bifurcates into the anterior and middle cerebral arteries

Question 32

Blood flow through circle of Willis

Answer 32

Very Big Posterior Polyps Invaded My Aching Ass vertebral, basilar, posterior, posterior communicating, internal carotid, middle, anterior, anterior communicating

Question 33

Vertebral Artery

Answer 33

branch off the innominate artery (r) and the left subclavian artery and enter via the foramen magnum branches off to supply the anterior spinal artery Become the basilar artery which bifurcates to become the posterior cerebral arteries The posterior cerebral arteries communicate with the middle cerebral arteries via the posterior communication artery

Question 34

Venous System

Answer 34

Venous blood drains into the venous sinuses which lie between 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 35

meninges

Answer 35

Covers the brain and spinal cord and consists of: Dura mater Arachnoid Mater Pia mater

Question 36

Pia mater

Answer 36

innermost layer - Anchored to the brain by astrocytes which form the blood-brain barrier

Question 37

Pia Mater Transport

Answer 37

small molecules (H2O, O2, CO2) lipophilic molecules (EtOH, heroin) passive transport of glucose active transport of amino acids/NT precursors Prevents: large molecules (dopamine) and charged (ionized molecules)

Question 38

Arachnoid Mater

Answer 38

midsection - lacelike structure below which is the subarachnoid space CSF circulates in the subarachnoid space (between arachnoid and pia mater) The Arachnoid Mater contains the blood supply to the brain.

Question 39

Dura mater

Answer 39

outer layer - nonelastic dura has an endosteal layer connected to the periosteum meningeal layer - between these two layers is the epidural space. potential spaces under the dura or the subdural space have a lot of vascularity with little supporting structure and may bleed with injury. Drains CSF

Question 40

Meningioma

Answer 40

Type of Tumor: Forms in the meninges (membranes around the brain and spinal cord). Nature: Mostly benign (non-cancerous) and slow-growing. Symptoms: Can include headaches, vision problems, hearing loss, memory loss, weakness, seizures, and speech difficulties.

Question 41

Epidural vs. subural hematoma

Answer 41

EPIDURAL IS TYPICALLY MORE RAPID ONSET AND DANGEROUS d

Question 42

Subarachnoid hemorrhage

Answer 42

neurological emergency in subarachnoid space less common, but important cause of strokes Goal - stop bleed

Question 43

Epidural hematoma

Answer 43

Bleeding between the skull and dura mater Usual arterial in origin (meningeal arteries)

Question 44

Subdural Hematoma

Answer 44

Bleeding between the dura and arachnoid mater Usually resulting from tears in bridging veins

Question 45

Subarachnoid hemorrhage (bleeding site)

Answer 45

Bleeding between the arachnoid membrane and the pia mater Usually from a ruptured cerebral aneurysm.

Question 46

Ventricles of the brain

Answer 46

Lateral Ventricles: There are two lateral ventricles, one in each hemisphere of the brain. They are the largest ventricles and are C-shaped. Third Ventricle: Located in the midline of the brain, between the two halves of the thalamus. Fourth Ventricle: Situated between the brainstem and the cerebellum, it connects to the central canal of the spinal cord.

Question 47

Lateral ventricles

Answer 47

within the cerebral hemispheres and communicate with the third ventricle through the foramen of Monroe

Question 48

third ventricle

Answer 48

inside the substance of the thalamus, dividing it to 2 lateral parts. The floor of this ventricle is the optic chiasm

Question 49

fourth ventricle

Answer 49

communicates with the third ventricle via the aqueduct of sylvius, lies anterior to the cerebellum and has a connection to the subarachnoid space through the median foramen of Magendie and 2 lateral foramen of Luschka

Question 50

Brain ventricles

Answer 50

Lined by ependymal cells which help to form the choroid plexus There are two lateral ventricles in the cerebral hemispheres Third ventricle is located in the diencephalon Fourth ventricle is located between the pons and the cerebellum

Question 51

Cerebrospinal Fluid (CSF)

Answer 51

Produced by the Choroid Plexus in the cerebral ventricles Surrounds the brain and spinal cord 10 - 15% of intracranial volume Approximately 500cc are produced per 24hrs The total volume of CSF is roughly 150cc

Question 52

function of CSF

Answer 52

maintains a milieu in which the brain can function by regulating pH and electrolytes, carrying away waste products, and delivering nutrients

Question 53

flow of CSF

Answer 53

through ventricles, to arachnoid space, to dural sinuses (back to circulation)

Question 54

VP Shunt

Answer 54

Most common area for VP shunt to drain to the gut/abd cavity