1.5

Question 1

Nucleus in CNS it like ___ in PNS.

Answer 1

ganglion

Question 2

Reticular formation

Answer 2

Weblike
Extends throughout brainstem
Sends signals to entire cerebrum

Question 3

Reticular formation function

Answer 3

Control of consciousness
Somatic and visceral sensation
Regulation of the respiratory and cardiovascular systems
Control of muscle tone
Posture maintenance
Movement

Question 4

Brainstem structure

Answer 4

Tectum is dorsal to cerebral aqueduct (roof)
Tegmentum is ventral to cerebral aqueduct (floor)

Question 5

Nuclei of the brainstem

Answer 5

Cranial nerve nuclei: most are in the brainstem
Other motor and sensory nuclei mediate complex life functions.
Connection points in the brainstem allow decussation, bilateral coordination, and coordination among multiple structures.

Question 6

Brainstem as connection point: Hearing

Answer 6

1. Auditory signal to the brainstem –> arrives at cochlear nucleus
   - This connection is ipsilateral
2. Signal is transmitted to nuclei on both sides of the brainstem
3. Each hemisphere receives auditory signals from both ears.

Question 7

Medulla: location

Answer 7

Cranial end of spinal cord
Contains the distal portion of the 4th ventricle

Question 8

Medulla: Important structures

Answer 8

Medullary pyramids
Pyramidal decussation
Olive

Question 9

Medulla: Pyramidal decussation

Answer 9

Motor nerves from the cortex travel to the pyramids and cross at the distal medulla
Right hemisphere damage = left side effect

Question 10

Medulla: Sensory decussation

Answer 10

Sensory fibers cross rostral to the pyramidal decussation. They form a tract called the medial lemniscus traveling to the sensory cortices

Question 11

Pons: Location

Answer 11

Between medulla and midbrain
Ventral to cerebellum

Question 12

Pons: Important Structures

Answer 12

Cerebellar pathways
Ascending and descending motor pathways
Function: bridge

Question 13

Superior cerebellar peduncles

Answer 13

Form the roof of the 4th ventricle in the pons
Principally carries cerebellar signals to midbrain and thalamus

Question 14

Middle cerebellar peduncles

Answer 14

Carries signals from pons to cerebellum

Question 15

Inferior cerebellar peduncles

Answer 15

Connects the cerebellum with the medulla oblongata and spinal cord

Question 16

Midbrain: Location

Answer 16

Rostral to medulla and pons
Ventral to cerebellum

Question 17

Structure of midbrain

Answer 17

Ventral: cerebral peduncles
Rostral: tectum

Question 18

Midbrain: Important Structures

Answer 18

Superior colliculi - visual coordination
Inferior colliculi - auditory localization
Substantia nigra - subconscious control of movement

Question 19

Which cranial nerves would be spared by brainstem damage?

Answer 19

Olfactory (CN I)
Optic (CN II)
Accessory (CN XI)

Question 20

Common causes of damage to CNS

Answer 20

Vascular disruption - stroke
Trauma
Pressure from a mass (usually intracranial)
Inflammation/infection

Question 21

CN I

Answer 21

Olfactory nerve
Sensory
Collection of receptor cells are in the nasal mucosa
SVA: olfactory sense
The olfactory signal travels from the olfactory bulb, along the olfactory tract, to several areas on the ventral surface of the brain.
Test by identifying familiar odor

Question 22

Olfactory signals

Answer 22

Direct connection to the cerebral cortex
- primary synapse is not the thalamus
Secondary connection to diencephalon, cerebellum
Profound influence on the limbic system

Question 23

CN II

Answer 23

Optic nerve
Sensory
Covered in visual system
Test: visual fields

Question 24

Optic nerve visual fields

Answer 24

Question 25

CN III

Answer 25

Oculomotor nerve 1. Skeletal motor control of EOM (GSE) - superior rectus - medial rectus - inferior rectus - inferior oblique 2. Skeletal motor control of levator palpebrae (GSE) 3. PSNS (autonomic; rest and digest) to pupil and lens (GVE) - sphincter puillea - constrict pupil - ciliary muscle (lens accommodation to change focus) Test upward, downward, and medial gaze; reaction to light Motor

Question 26

CN III, CN IV, CN VI

Answer 26

Extraocular muscles Just skeletal muscle control of eye

Question 27

CN V

Answer 27

Trigeminal nerve Motor: muscles of mastication Sensory: sensation of the face Test corneal reflex: face sensation; clench teeth, push down on chin to separate jaws

Question 28

CN VII

Answer 28

Facial nerve Motor nerve: muscles of facial expression Sensory: taste (SVA) anterior 2/3 of tongue Test: close eyes tight; smile and show teeth; whistle and puff cheeks; identify familiar tastes

Question 29

CN VIII

Answer 29

Vestibulocochlear nerve Two divisions, both SSA Vestibular: balance Cochlear: hearing Test: watch ticking; balance and coordination test

Question 30

CN IX

Answer 30

Glossopharyngeal nerve Motor: swallow, salivation (parotid gland) Sensory: taste and general sensation, posterior 1/3 of tongue; gag reflex sensation Test gag reflex and ability to swallow

Question 31

CN X

Answer 31

Vagus nerve Motor: - PSNS supply to thoracic and abdominal viscera - phonation - gag reflex Sensation: laryngeal area Test gag reflex, ability to swallow and say "ahh"

Question 32

CN XI

Answer 32

Spinal accessory nerve Motor: head rotation and lateral flexion, shoulder raise Test: resisted shoulder shrug

Question 33

CN XII

Answer 33

Hypoglossal nerve Motor: tongue movement Test tongue protrusion - if injured, tongue deviates toward injured side

Question 34

The core of the brainstem contains the reticular formation. List its functions

Answer 34

Control of consciousness Somatic and visceral sensation Regulation of respiratory and cardiovascular systems Control of muscle tone Posture maintenance Movement

Question 35

What happens at the pyramidal (motor) decussation?

Answer 35

Motor nerves from the cortex travel to the pyramids and cross at the distal medulla

Question 36

What happens at the sensory decussation?

Answer 36

sensory fibers cross rostral (cranial) to the pyramidal decussation They form a tract called the medial lemniscus traveling to the sensory cortices (plural for cortex).

Question 37

What are the primary tracts carried by each peduncle?

Answer 37

Ascending sensory and descending motor pathways

Question 38

Which three cranial nerves are atypical and why?

Answer 38

Optic nerve – outgrowth of brain Olfactory nerve – sensory pathways Spinal accessory nerve – partly arises from the cervical spinal cord

Question 39

CN IV

Answer 39

Trochlear nerve Motor Eye movement Test downward and lateral gaze

Question 40

CN VI

Answer 40

Abducens Motor Eye movement Test lateral gaze