Functioning of the autonomic nervous system

Question 1

What are the autonomic sensory components

Answer 1

The receptors are in the viscera and somatosensory

Question 2

What are the difference motor components of the autonomic compared to the somatic nervous system

Answer 2

• number of neurones
• effector
• neurotransmitter release
• neurotransmitters

Question 3

What is the difference of the number of neurones between CNS and effector

Answer 3

Somatic:
There is one chain of neurones that go from the CNS to the effectors
Autonomic:
There is a chain of neurones that go from the CNS to the effect. The chain is made of pre and post -ganglionic neurones. One pre ganglionic neurone can supply many post-ganglionic neurones

Question 4

What is the difference of effectors for the autonomic and somatic NS

Answer 4

Somatic:
The effector is the skeletal muscle
Autonomic:
The effectors are smooth muscle, cardiac muscle and secretory gland

Question 5

What is the difference in the release of the neurotransmitter in the autonomic and somatic NS

Answer 5

Somatic:
The neurotransmitters are released discretely . This means that one synapse is connected to one muscle fibre
Autonomic:
Broadcasting occurs by several swellings in the axons. This means that neurotransmitters are released to several cells.

Question 6

What is the difference of neurotransmitter in the somatic and autonomic nervous system

Answer 6

Somatic:
Acetylcholine 
Autonomic:
Parasympathetic- ach and ach
Sympathetic- ach and noradrenaline

Question 7

How is the autonomic nervous system arranged

Answer 7

Autonomic nervous system is split into 3 categories of:

• sympathetic
• parasympathetic
• enteric ( in GI tract)

Question 8

What is the autonomic nervous sytem composed of

Answer 8

Pre and post ganglionic neurones

Question 9

What are the exceptions to the sympathetic nervous system neurostransmitters

Answer 9

The sweat glands release both ach in the pre and post-ganglionic neurone. This is Usually classed as the parasympathetic but is in fact a sympathetic nervous system due to the embryonic origin of sweat glands

Question 10

What are the properties of the PNS and the SNS

Answer 10

Dual innervation
Antagonistic
However this may not be the case all the time as there are exceptions

Question 11

What is the role of the autonomic nervous system

Answer 11

• homeostatic
• vision
• reproduction

Question 12

Give examples where the PNS and SNS is dual innervation and antagonistic

Answer 12

1- the heart
SNS: increased heart rate
PNS: decreases heart rate
2- small and large intestine
SNS: decrease motility
PNS: increase motility

Question 13

Give an example where PNS and SNS dual innervation and antagonistic is occurring but on different muscle

Answer 13

The pupil
SNS: this acts on the radial muscle and causes dilation of the pupil
PNS: this acts on the circular muscle and causes contraction of the pupil

Question 14

Give an example where the PNS and SNS has no dual innervation is occurring

Answer 14

Most of the blood vessels have a single innervation of the SNS that causes both vasoconstriction and vasodilation

Question 15

Give an example where dual innervation but no antagonistic effect is occurring

Answer 15

Sweat glands have dual innervation but it is not antagonistic. This means that both the production of saliva is caused.
PNS; causes vasodilation to blood vessel to give large volume and watery saliva
SNS; causes vasoconstriction to give small volume and sticky saliva

Question 16

Give an example where PNS and SNS work together

Answer 16

In male organs
PNS= point
SNS= shoot

Question 17

How do blood vessels control their diameter

Answer 17

As most blood vessels have single innervation of the SNS. The diameter is therefore caused by SNS activity.
1- SNS body wide activation causes adrenaline and noradrenaline release
2- adrenaline acts on beta receptors to cause vasodilation
3- noradrenaline acts on alpha receptors to cause vasoconstriction
4- overall the two effects balance each other out which controls the diameter

Question 18

Why is the adrenal medulla a neuroendocrine organ

Answer 18

The adrenal medulla releases noradrenaline or adrenaline into the bloodstream
The release of the hormones are controlled by pre-synaptic neurones of the SNS.
When adrenal medulla releases the hormones it acts on the effectors

Question 19

When does the somatic and autonomic nervous system work together

Answer 19

1- feeling cold

2- focusing eye from a far object to a close object

Question 20

When dual innervation and antagonist occurs what determines what happens

Answer 20

The activity of the PNS or SNS determines which one is in charge. Although both systems are active.

Question 21

When can SNS take control

Answer 21

Fight or flight response

Question 22

When can PNS take control

Answer 22

Rest and digest