Lecture 35- Autonomic Nervous System

Question 1

What are reflexes?

Answer 1

unlearned, rapid, predictable motor responses to a stimulus and occur over highly specific neural pathways (reflex arcs)

Question 2

What are inborn/intrinsic reflexes?

Answer 2

Unlearned, unpremeditated and involuntary reflexes

Question 3

What do learned or acquired reflexes result from?

Answer 3

Practice or repetition

Question 4

What is a reflex arc? What are the 5 components?

Answer 4

Very specific neural path that controls reflexes

5 components: receptor, sensory neuron, integration centre, motor neuron, effector

Question 5

What do somatic reflexes activate?

Answer 5

Skeletal muscle

Question 6

What muscle types do autonomic reflexes involve?

Answer 6

Smooth muscle, cardiac muscle and/glands

Question 7

What is the stretch reflex?

Answer 7

Muscle spindle is stretch.

Causes contraction of muscle that has been stretched

Stretch can trigger reflex to protect muscle by contracting to oppose the stretch

Question 8

Autonomic nervous helps maintain….

Answer 8

Homeostasis by controlling smooth muscle, cardiac muscle and glands

Question 9

Autonomic motor pathway

Answer 9

Two neurons in a sequence

The first neuron has cell body in CNS and is referred to as a preganglionic neuron.

Postganglionic neuron has unmyelinated axon and Carries signal to effector

Question 10

Sympathetic division of autonomic nervous system

Answer 10

“fight-or-flight” ,enables the body to cope with potential threats to homeostasis

by stimulating heart rate and force of contraction
increasing breathing
sweat production
pupil dilation

Question 11

Parasympathetic division of autonomic nervous system

Answer 11

“rest-and-digest” system, keeps body energy use as low as possible

stimulates the gastrointestinal tract and directs digestion and waste elimination.

Question 12

What neurotransmitter is released by somatic motor neuron?

Answer 12

Acetylcholine- always has excitatory effect on skeletal muscle

Question 13

What neurotransmitter is released by autonomic nervous system?

Answer 13

Epinephrine and acetylcholine- both can have either excitatory or inhibitory effect

Question 14

What neurotransmitter do preganglionic neurons release?

Answer 14

Acetylcholine

Question 15

What neurotransmitter do postganglionic neurons release?

Answer 15

most postganglionic sympathetic neurons release norepinephrine

most postganglionic parasympathetic neurons release Acetylcholine

Question 16

What do cholinergic neurons release?

Answer 16

Acetylcholine

Question 17

What are the two types of cholinergic neurons? What are they stimulated by?

Answer 17

Nicotinic- stimulated by nicotine
Muscarinic- stimulated by mushroom poison

Question 18

Nicotinic cholinergic receptors

Answer 18

found on all postganglionic neurons, are always excitatory.

Question 19

Muscarinic cholinergic receptors

Answer 19

occur on all parasympathetic target organs and a few sympathetic targets, may be excitatory or inhibitory.

Question 20

What Adrenergic receptors cause excitation?

Answer 20

a1 and B1 (alpha and beta)

Question 21

What adrenergic receptors cause inhibition of sympathetic division?

Answer 21

a2 and B2

Question 22

What is sympathetic tone? Where is is located?

Answer 22

throughout the vascular system

allows the firing rate of sympathetic neurons to control diameter of blood vessels, regulating systemic blood pressure.

Question 23

What is parasympathetic tone? Where is it located?

Answer 23

dominant in the heart, digestive system and urinary tracts, maintains normal levels of function unless overridden by the sympathetic system during stress.

Question 24

When is sympathetic dominant?

Answer 24

During vigorous activity

Question 25

When is parasympathetic dominant?

Answer 25

During rest periods

Question 26

When can sympathetic and parasympathetic show cooperative effect?

Answer 26

In external genitalia during sexual excitement