Chapter 13 - Physiology of the Peripheral Nervous System

Question 1

The divisions of the nervous system…

Answer 1

CNS - brain and spinal cord.
PNS - Somatic, Autonomic.
Autonomic goes to…Parasympathetic and Sympathetic.

Question 2

The 3 Regulatory functions of the Autonomic Nervous System –

Answer 2

Regulation of heart, Regulation of secretory glands (salivary, gastric, sweat, and bronchial glands) and regulation of smooth muscles (muscles of bronchi, blood vessels, urino genital systems, and gastrointestinal tract.)

Question 3

Main functions of the sympathetic nervous system -

Answer 3

increase energy, regulation of cardiovascular system (increase), regulation of body temp, fight or flight.

Question 4

Parasympathetic Nervous System – regulator functions affect…

Answer 4

heart rate (decrease), gastric secretions (increase digestion), bladder and bowel (increase emptying), vision (constriction of pupil; for near vision.), and bronchial smooth muscle (contraction.)

Question 5

Most organs are innvervated by both…

Answer 5

The parasympathetic and sympathetic systems.

Question 6

Balance by opposition - def

Answer 6

most common, like heart rate - decreased by parasympathetic, increased by sympathetic nerves.

Question 7

Complementary control -

Answer 7

increase overall response or complement each other - erection is mediated by parasympathetic response while ejaculation is controlled by sympathetic nerves. This is very rare - less than 1%.

Question 8

Innervations and regulation by only one of the two branches. -

Answer 8

Blood vessels are innervated only by sympathetic nerves.

Question 9

BP is never done by Sympathetic Nerves. T/F?

Answer 9

FALSE. It is always.

Question 10

2 Mechanisms that regulate autonomic nervous systems.

Answer 10

Feedback regulation (reflex, like baroreceptors) and Autonomic Tone (means steady state, basal level, level of tone.)

Question 11

The Autonomic tone is controlled by both systems. T/F?

Answer 11

False. It is controlled by one, not both.

Question 12

Parasympathetic sites of drug action -

Answer 12

synapses between pre-ganglionic and post ganglionic neurons.

Junctions between post-ganglionic neurons and effector organs.

Question 13

Sympathetic sites of drug actions -

Answer 13

synapses between pre-ganglionic and post ganglionic neurons.

Junctions between post-ganglionic neurons and effector organs.

Question 14

Only __ neuron and site of drug action is the neuromuscular junction.

Answer 14

1

Question 15

Principal neurotransmitters of the PNS are…

Answer 15

Acetylcholine, Norepinephrine, Epinephrine. Dopamine is also a PNS neurotransmitter, but its role is not demonstrated conclusively.

Question 16

Acetylcholine is released by…

Answer 16

all pre-ganglionic neurons of PS nerves, all post ganglionic neurons of PS system, by all pre-ganglionic neurons of the Symp system, most post ganglionic neurons of the Symp system that go to sweat glands, and all motor neurons to skeletal muscles.

Question 17

Norepinephrine is released by…

Answer 17

All post ganglionic neurons of sympathetic system, except Sweat gland nerves, which release acetylcholine at junction.

Question 18

Epinephrine - released by…

Answer 18

major transmitter released by adrenal medulla.

Question 19

Cholinergic - def

Answer 19

mediated by acetylcholine -

Question 20

Adrenergic - def

Answer 20

mediated by norepinephrine and epinephrine. Think “adrenaline.”

Question 21

What are the 3 cholinergic receptors?

Answer 21

Nicotinic N (neuronal), Nicotinic M (muscle), and Muscarinic (everything else.)

Question 22

What are the 3 adrenergic receptors?

Answer 22

Alpha 1 & Alpha 2, Beta 1 & Beta 2, Dopamine

Question 23

Nicotinic N (Neuronal) - def

Answer 23

promotes ganglia transmission, promotes release of epinephrine

Question 24

Nicotinic M (Muscle) - def

Answer 24

contraction of skeletal muscle.

Question 25

Muscarinic - def

Answer 25

activates parasympathetic nervous system.

Question 26

Alpha 1 - Function

Answer 26

Vasoconstriction, Ejaculation, Contraction of bladder neck and prostate.

Question 27

Alpha 2 - function

Answer 27

Located in pre-synaptic junction, minimal clinical significant.

Question 28

Beta 1 - Function

Answer 28

Heart - increases heart rate, force of contraction, velocity of conduction in AV node, Kidney - renin release.

Question 29

Beta 2 - function -

Answer 29

bronchial dilation, relaxation of uterine muscle, vasodilation, glycogenolysis (splitting up of glycogen yielding glucose.)

Question 30

Dopamine - function

Answer 30

dilates renal blood vessel.

Question 31

Life cycle of ACh -

Answer 31

synthesis of ACh from choline+acetylcoenzyme A. Stored in vesicles, release, binds to cholingeric receptors, destroyed almost instantly by acetylcholinesterase, choline released as end product and recycled back into nerves for synthesis (not acetyl co-A.)

Question 32

Drugs act at several points of the ACH life cycle -

Answer 32

botulism blocks Ach release, action at receptor level to block or mimic Ach, inhibition of ACHE (ach accumulates in junction!)

Question 33

Life cycle of Norepinephrine -

Answer 33

synthesis of norepinephrine within vesicles, stored, released, binds to adrenergic receptors, termination by reuptake of norepinephrine back into nerve terminal; following uptake norepinephrine goes under 2 processes - 1. Uptake into vesicle for reuse, 2. Inactivation by monoamine oxidase (MAO - an enzyme found in nerve terminals.)

Question 34

Drugs act at ____ of the life cycle of NE -

Answer 34

each life step.