pns

Question 2

Peripheral nerves

Answer 2

bundles of axons.
Types:
- Sensory (afferent)
- Motor (efferent)
- Autonomic (also motor, involuntary)

Composed of:
1. Afferent neuron, receptor in PNS to CNS
2. Interneuron, w/i CNS
3. Efferent neuron, from CNS to PNS, connects to effector organ

Question 3

Motor neurons

Answer 3

• Striated muscle
• Cell body in CNS
• release ACh

Question 4

Sensory neurons

Answer 4

• Cell body not in CNS - sensory ganglia

Question 5

Ganglion

Answer 5

Collection of neuronal cell bodies in PNS

Question 6

Autonomic neurons

Answer 6

• Either sympathetic (norepinephrine) or parasympathetic (ACh)
• 2 neurons in CNS -> peripheral organ
  
  • Preganglionic: cell body in CNS
  • Postganglionic: cell body in autonomic ganglion (PNS)
• Sympathetic: ganglion near CNS
• Parasympathetic: ganglion near or in target organ

Question 7

ANS functions

Answer 7

• Homeostasis (maintain stable env, ex. breathing harder when running)
• Vegetative systems (semi-autonomous, coordinated w endocrine system)
• BP
• GI motility
• electrolyte water balance
• Pupil reflexes
• Sexual function

Question 8

Higher centres of ANS

Answer 8

• Some reflexes at spinal cord level
• Medulla, hypothalamus, prefrontal cortex (emotional states, not 100% autonomic)

Question 9

ANS afferent neurons

Answer 9

• Send info into control centres
• Baroreceptors: pressure (blood vessels)
• Osmoreceptors: concentration (ions in plasma)
• Thermosensors
• Cutaneous receptors: sexual stimulus
• Pain fibers
• Stretch receptors: distension in lungs, bladder, stomach, bowel

Question 10

Sympathetic nervous system

Answer 10

Catabolic effects (breaking down, using energy)
- Incr HR, BP
- Incr blood flow to skeletal muscle
- Decr blood flow to skin
- Fight-or-flight: epinephrine and norepinephrine released from medulla, stimulates skeletal muscle glycogenolysis (glycogen->glucose->ATP)

Question 11

Parasympathetic nervous system

Answer 11

Anabolic effects (building)
- Decr HR, BP
- Incr GI tract motility and secretions
- Relaxation of sphincters

Question 12

Paradoxical coactivation:

Answer 12

both symp and parasymp activated during intense conflict

Question 13

Cranial nerves

Answer 13

Carry afferent info, efferent info, ANS fibers

Question 14

Name mnemonic: Ooh, Ooh, Ooh, To Touch And Feel Very Good Vagina. So Heavenly!

Answer 14

olfactory
optic
oculomotor
trochlear
trigeminal
abducens
facial
vestibulocochlear (auditory)
glossopharyngeal
vagus
spinal accessory
hypoglossal

Question 15

Function mnemonic: Some Say Marry Money, But My Brother Says Big Brains Matter More.

Answer 15

S=sensory
M=motor
B=both

Question 16

Which nerves are completely in the CNS?

Answer 16

i olfactory and ii optic

Question 17

olfactory

Answer 17

sensory - smell

Question 18

optic

Answer 18

sensory - vision

Question 19

oculomotor

Answer 19

motor, voluntary - eyeball movement to midline
motor, autonomic - constricts pupil, thickens lens

Question 20

trochlear

Answer 20

motor, voluntary - moves eyeball

Question 21

trigeminal

Answer 21

motor - mastication (chewing)
sensory - touch/temp/pain from head

Question 22

abducens

Answer 22

motor - eyeball movement away from midline
When looking right or left, vi and iii coordinate through medial longitudinal fasciculus

Question 23

facial

Answer 23

motor, voluntary - facial expression
motor, autonomic - lacrimal and salivary glands, taste buds

Question 24

glossopharyngeal

Answer 24

both

Question 25

vagus

Answer 25

both
ix, x, xi all involved in swallowing (vagus x most important)

Question 26

spinal accessory

Answer 26

motor - swallowing and shrugging

Question 27

hypoglossal

Answer 27

motor - tongue

Question 28

Spinal nerves

Answer 28

• 31 pairs, numbered by vertebrae
• All have voluntary motor function
• All (except C.1, first cervical) have sensory fibers

Question 29

Sympathetic nerves

Answer 29

Preganglions arise from all thoracic, and 1st and 2nd lumbar segments

Question 30

parasympathetic nerves

Answer 30

preganglions arise from sacral segments 2,3,4
carried in cranial nerves iii, vii, ix, x, and sacral 2, 3, 4