Chapter 9: PNS

Question 1

Autonomic neurons

Answer 1

composed of the centers of the brain and spinal cord, receives input from sensory neurons and controls activity of involuntary motor neurons

Question 2

Visceral Effector Organs

Answer 2

somewhat independent of innervation
- smooth muscle maintains muscle tone
- cardiac muscle contract without nerve impulse, impulses speed up or slow down intrinsic contractions

Question 3

Denervation hypersensitivity

Answer 3

target becomes more sensitive to stimulation (visceral effector organs)

Question 4

Collateral Ganglion

Answer 4

Many sympathetic neurons exit the spinal cord BELOW the diaphragm and do not synapse in the sympathetic chain ganglia
- splanchnic nerves synapse in collateral ganglia instead of

Question 5

Adrenal Glands

Answer 5

Cortex secretes steroid hormones into bloodstream (endocrine)
Medulla secretes epinephrine and norepinephrine when stimulated by sympathetic nervous system

Question 6

Terminal ganglia

Answer 6

Near or in the effector organs
- supply very short postganglionic neurons

Question 7

Fight or Flight

Answer 7

Sympathetic
- release norepinephrine from postganglionic neurons and epinephrine from adrenal medulla
- increase heart rate and blood glucose levels, divert blood to skeletal muscles

Question 8

Rest and Digest

Answer 8

Parasympathetic
- release ACh from postganglionic neurons
- lowers heart rate and increase digestive activities

Question 9

Cholinergic synapses

Answer 9

Release of ACh from MOST parasympathetic postganglionic neurons and SOME sympathetic postganglionic neurons (those that innervate sweat glands and skeletal muscles)

Question 10

Adrenergic synapses

Answer 10

release norepinephrine by MOST sympatheitc postganglionic neurons
- alpha and beta receptors

Question 11

Alpha adrenergic receptors

Answer 11

A1 = vasoconstriction
A2 = inhibits norepinephrine release

Question 12

Beta adrenergic receptors

Answer 12

B1 = increase heart rate and myocardial contractility
B2 = vasodilation

Question 13

Agonists drugs

Answer 13

drugs that promote the process stimulated by the NT

Question 14

Antagonists drugs

Answer 14

Drugs that block the action of the NT

Question 15

Stimulation by ACh release

Answer 15

in ALL preganglionic neurons (of both para. and sym.)
usually postganglionic neurons of the parasympathetic (depending on receptor)

Question 16

Inhibition by ACh release

Answer 16

from some postganglionic neurons of the parasympathetic (depending on receptor)

Question 17

Nicotinic receptor

Answer 17

Cholinergic receptor
- found in autonomic ganglia
- stimulated by ACh from preganglionic neurons
- serve as ligand-gated ion channels for Na+ and K+

Question 18

Muscarinic receptor

Answer 18

Cholinergic receptor
- found in visceral organs
- stimulated by ACh release from postganglionic neurons
- can be stimulatory or inhibitory opening K+ or Ca2+ channels
- use G-proteins and 2nd messenger system

Question 19

Dual Innervation

Answer 19

most visceral organs are innervated by BOTH sym. and para. neurons
- usually antagonistic (like HR, digestion, and pupil diameter)

Organs WITHOUT dual innervation are innervated by the Sympathetic division ONLY (adrenal medulla, sweat glands, most blood vessels)

Question 20

Complementary effects

Answer 20

occur when both divisions produce similar effects on the same target to perform the same action
- ie. salivary gland secretion (para = stimulates secretion of watery saliva, symp = constricts blood vessels to make secretion thicker)

Question 21

Cooperative effects

Answer 21

occur when both divisions produce different effects that work together
- erection and ejaculation
- urination

Question 22

Autonomic reflexes

Answer 22

Input is sent to brain centers to integrate the information and modify preganglionic neuron activity
- medulla oblongata controls cardiovascular, pulmonary, urinary, reproductive, and digestive functions

Question 23

Aging

Answer 23

associated with high levels of sympathetic activity