brainstem and cranial nerves

Question 1

where is the brainstem located?

Answer 1

posterior part of the brain

continuous with the spinal cord

Question 2

what structures does the brainstem include?

Answer 2

midbrain, pons, medulla oblongata

Question 3

what is sometimes included in the brainstem?

Answer 3

diencephalon

Question 4

how many of the cranial nerves come from the brainstem?

Answer 4

10

Question 5

function of the brain stem?

Answer 5

provides main motor and sensory information to the face and neck via cranial nerves

Question 6

what tracts pass through the brainstem?

Answer 6

corticospinal tract
(motor), dorsal column - medial lemniscus pathway (fine touch, vibration and proprioception) and spinothalamic
tract (pain, temperature and itch

Question 7

where is the pons?

Answer 7

lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum

Question 8

what seperates the pons and cerebellum?

Answer 8

4th ventricle

Question 9

what is the function of the pons?

Answer 9

ventral pons contains pontine nuclei responsible for co-ordinating movement

tegmentum forms part of the reticular formation – a set of nuclei in the brainstem responsible for arousal and attentiveness

Question 10

what does the pons consist of?

Answer 10

ventral pons and tegmentum

Question 11

what is the oldest part of the brainstem?

Answer 11

medulla oblongata

Question 12

what does the medulla oblongata consist of?

Answer 12

ascending and descending nerve tracts as well as brainstem nuclei

Question 13

why does the brain control the opposite side of the body?

Answer 13

due to crossing over of axons at the level of the medulla

Question 14

where are the respiratory and cardiac centres found?

Answer 14

MO

Question 15

what nuclei do the brainstem house?

Answer 15

raphe, locus coeruleus, substantia nigra

Question 16

what pathways originate from raphe nuclei?

Answer 16

serotonergic

Question 17

what pathways originate from locus coeruleus nuclei?

Answer 17

noradrenergic

Question 18

what neurons are in abundance in the substantia nigra?

Answer 18

dopaminergic

Question 19

how many cranial nerves?

Answer 19

12 pairs

Question 20

where do optic and olfactory nerves arise from?

Answer 20

cerebrum (all other arise from brainstem)

Question 21

what are the cranial nerves?

Answer 21

C.I - Olfactory
C.II - Optic
C.III - Oculomotor
C.IV - Trochlear
C.V - Trigeminal (3 branches)
C.VI - Abducens
C.VII - Facial
C.VIII - Vestibulocochlear
C.IX - Glossopharyngeal
C.X - Vagus
C.XI - Accessory
C.XII - Hypoglossal

Question 22

what is the function of the olfactory nerve (I)?

Answer 22

transmits information relating to smell

sense of smell is detected by olfactory receptors in the nasal epithelium

Question 23

how do the olfactory nerves penetrate into the cranial cavity?

Answer 23

through small foramina in the cribiform plate of the ethmoid bone

Question 24

what does the olfactory nerve synapse with?

Answer 24

olfactory bulb

Question 25

function of optic nerve (II)

Answer 25

Special sensory nerve of vision

Question 26

what functions does the oculomotor (III) have?

Answer 26

motor function and parasympathetic motor = Primary source of innervation for 4 of the extraocular muscles parasympathetic = supply Sphincter pupillae (constrict pupils) and Ciliary muscles (lens accommodation)

Question 27

function of trochlear (IV)

Answer 27

only somatic motor functions | - Innervates superior oblique

Question 28

function of Abducens nerve (C.VI)

Answer 28

purely somatic motor functions - Innervates lateral rectus allows eyeball to abduct (move away from the midline)

Question 29

branches of the Trigeminal nerve (C.V)

Answer 29

opthalmic maxillary mandibular

Question 30

functions of the Trigeminal (C.V)

Answer 30

``` Motor nucleus (muscles of mastication) Spinal nucleus (sensory) – thermal/nociception from head and neck Principal nucleus (sensory) –touch, proprioception Mesencephalic nucleus –jaw reflexes ```

Question 31

functions of the Facial (C.VII) nerve

Answer 31

Motor – muscles of facial expression (mimetic muscles) Sensory – skin of ext auditory meatus, eardrum Special sensory – taste (ant 2/3 of tongue); palate Parasympathetic – innervation of salivary glands (but NOT parotid; lacrimal glands

Question 32

functions of the Vestibulocochlear (C.VIII) | nerve

Answer 32

Vestibular branch monitors balance, position and movement Cochlear branch monitors hearing

Question 33

functions of the Glossopharyngeal (C.IX) | nerve

Answer 33

Special sensory – taste (post 1/3 of tongue) Visceral sensory – blood pCO2/[H+] monitoring (carotid body) Sensory – post 1/3 of tongue; oropharynx Motor – upper pharynx Parasympathetic – parotid gland

Question 34

functions of the Vagus (C.X) nerve

Answer 34

Sensory i) somatosensory - mucous membranes of laryngopharynx, larynx and upper trachea ii) visceral - trachea, lungs, carotid sinus, abdominal veins, gut (to splenic flexure) Motor i) somatic - lower pharynx, upper oesophagus (swallowing and vomiting) ii) parasympathetic - cardiac muscle (control of heart beat), smooth muscle in GIT (GI motility), trachea and bronchi (airway diameter)

Question 35

what is the vagus nerve?

Answer 35

A mixed sensory and | motor nerve

Question 36

functions of the Accessory (C.XI) nerve

Answer 36

motor nerves - Innervation of muscles associated with shoulder and head movement (eg sternocleidomastoid and trapezius)

Question 37

functions of the Hypoglossal (C.XII) nerve

Answer 37

- Intrinsic muscles of the tongue | - Most extrinsic tongue muscles