Autonomic Physiology

Question 1

Give one similarity between the autonomic and somatic nervous systems.

Answer 1

Both involved in efferent nervous system.

Question 2

Give 6 differences between the autonomic and somatic nervous systems.

Answer 2

1. Autonomic nervous system is involuntary. Somatic is voluntary.
2. Autonomic nervous system involves metabotropic receptors. Somatic involves ionotropic.
3. Autonomic nervous system involves pre and post synaptic fibres. Somatic involves one long, uninterrupted system.
4. Autonomic system innervates smooth muscle, cardiac muscle, glands and GI neurons. Somatic system innervates smooth muscle.
5. Autonomic system is less specialised. Whereas, the somatic system involves the specialised NMJ.
6. Autonomic nervous system can be excitatory or inhibitory. Somatic nervous system is always excitatory.

Question 3

Into what two systems is the autonomic nervous system divided?

Answer 3

Parasympathetic and sympathetic systems.

Question 4

What body regions facilitate the outflow of parasympathetic fibres?

Answer 4

Cranial and Sacral

Question 5

What body regions facilitate the outflow of sympathetic fibres?

Answer 5

Thoracic and Lumbar

Question 6

What is the difference in ganglia position between the sympathetic and parasympathetic systems?

Answer 6

In the sympathetic system, ganglia lie close to the spinal cord.
In the parasympathetic system, ganglia lie close to or within the target tissue.

Question 7

What type of receptors does acetylcholine act on?

Answer 7

Cholinergic

Muscarinic and Nicotinic

Question 8

What type of receptors does adrenaline/noradrenaline act on?

Answer 8

Adrenergic

Alpha and Beta receptors

Question 9

Describe the neurotransmitters involved in the sympathetic nervous system.

Answer 9

Preganglionic fibres release Acetylcholine which acts on nicotinic receptors.
Post ganglionic fibres release Adrenaline/Noradrenaline which acts on alpha/ Beta receptors.

Question 10

Describe the neurotransmitters involved in the parasympathetic nervous system.

Answer 10

Preganglionic fibres release Acetylcholine which acts on nicotinic receptors.
Postganglionic fibres release Acetylcholine which acts on muscarinic receptors.

Question 11

How are sweat glands innervated?

Answer 11

By postsynaptic sympathetic fibres which release acetylcholine.
(This is an exception)

Question 12

Describe the effect of the sympathetic system on the control of the eye.

Answer 12

• Activates B2 receptors on the ciliary muscles around the lens to cause relaxation and focus on far away objects
• Activates alpha1 receptors on radial muscle of iris to cause it to contract and increase pupil diameter.

Question 13

Describe the effect of the para-sympathetic system on the control of the eye.

Answer 13

• Activates muscarinic receptors on the ciliary muscles around the lens to cause relaxation and focusing on close up objects
• Activates muscarinic receptors on radial muscles of the iris to cause it to relax and decrease pupil diameter.

Question 14

Describe the effect of the sympathetic system on the control of the heart.

Answer 14

• Activation of B1 receptors on pacemaker cells to increase heart rate.
• Activation of B1 receptors on myocytes to increase strength of contraction

Question 15

Describe the effect of the parasympathetic system on the control of the heart

Answer 15

-Activation of muscarinic receptors on pacemaker cells to decrease heart rate.

Question 16

Describe the effect of the sympathetic system on the control of the lungs.

Answer 16

-Activation of B2 receptors on smooth muscle of airways to relax and dilate vessel

Question 17

Describe the effect of the parasympathetic system on the control of the lungs.

Answer 17

-Activation of muscarinic receptors on smooth muscle of airways to contract and constrict.

Question 18

Describe the effect of the sympathetic system on the control of the gut.

Answer 18

• Activation of alpha/beta receptors on smooth muscle of gut to decrease gut motility
• Activation of alpha receptors on pancreas to decrease enzyme secretion

Question 19

Describe the effect of the parasympathetic system on the control of the gut.

Answer 19

• Activation of muscarinic receptors on the smooth muscle of the gut wall to increase gut motility.
• Activation of muscarinic receptors on pancreas to increase enzyme secretion

Question 20

Describe the effect of the sympathetic system on the control of the blood vessels.

Answer 20

• Activation of alpha one receptors on the blood vessel walls to cause contraction and restrict blood flow.
• Activation of B2 receptors on the blood vessel walls to cause relaxation and allow increased blood flow.

Question 21

Describe the effect of the sympathetic system on the control of the energy stores.

Answer 21

• Activation of alpha/ beta receptors on the liver to stimulate increased glyconeolysis/gluconeogenesis
• Activation of alpha/beta receptors on fat cells to stimulate lipolysis

Question 22

Describe the effect of the sympathetic system on the control of the salivary glands.

Answer 22

-Activation of B receptors to stimulate release of thick enzyme rich secretion

Question 23

Describe the effect of the parasympathetic system on the control of the salivary glands.

Answer 23

-Activation of muscarinic receptors to stimulate release of watery secretion.

Question 24

Describe the effect of the sympathetic system on the control of the bladder.

Answer 24

• Activation of B2 receptors on the smooth muscle of the bladder wall to allow relaxation and decrease in pressure.
• Activation of Alpha1 receptors on the smooth muscle of the sphincter to stimulate contraction to prevent urination.

Question 25

Describe the effect of the parasympathetic system on the control of the bladder.

Answer 25

• Activation of muscarinic receptors on smooth muscle of bladder wall to generate contraction and so increase in pressure.
• Activation of muscarinic receptors on smooth muscle of sphincter to generate relaxation and allow for urination.

Question 26

Describe the effect of the sympathetic system on the control of the reproductive tract.

Answer 26

-Activation of alpha 1 receptors on the smooth muscle of the urethra, causing it to contract and cause ejaculation.

Question 27

Describe the effect of the parasympathetic system on the control of the reproductive tract.

Answer 27

-Activation of muscarinic receptors on the smooth muscle of the corpus cavernosum to relax it and allow erection.

Question 28

What is the role of the baroreceptor reflex?

Answer 28

To detect blood pressure

Question 29

What controls the autonomic nervous system actions?

Answer 29

• Central control via the hypothalamus (co-ordinating autonomic, somatic and endocrine actions)
• Reflexes, such as the baroreceptor reflex