Autonomic Nervous System

Question 1

What’s the purpose of the Autonomic Nervous System?

Answer 1

It ensures we survive despite a lack of conscious, cortical input
(Outside voluntary control)

Question 2

What happens within our bodies when we are sleeping?

Answer 2

1. Digesting and metabolising things
2. Memory consolidation
3. Regulating breathing and heart rate
4. Muscle contraction and movement
5. Sweating

Question 3

What does the sensory part of the peripheral nervous system consist of?

Answer 3

Somatic nervous system and visceral nerves

Question 4

what is the main function of the peripheral nervous system?

Answer 4

The peripheral nervous system is the network of nerves outside your brain and spinal cord. It acts as the communication link between your central nervous system (brain and spinal cord) and the rest of your body

Question 5

What are visceral nerves?

Answer 5

Visceral nerves are part of the peripheral nervous system, responsible for transmitting information between the central nervous system (CNS) and internal organs.
For example visceral nerves in bladder or GI tract

Question 6

What is the somatic nervous system?

Answer 6

Part of the peripheral nervous system that controls voluntary movements of skeletal muscles. It also receives sensory information from the skin, senses, and muscles.

Question 7

What is an afferent nerve?

Answer 7

Afferent nerves transmit nerve impulses from sensory peripheral receptors (PNS) towards the central nervous system.

Question 8

What is an efferent nerve?

Answer 8

Efferent nerves take information from the CNS to the peripheral NS

Question 9

What does the efferent part of the peripheral nervous system consist of?

Answer 9

Somatic nervous system (voluntary for example skeletal) and autonomic nervous system (involuntary for example smooth muscle)

Question 10

what are the 2 efferent pathways of the ANS?

Answer 10

Sympathetic and parasympathetic

Question 11

Can you list the key ideas about parasympathetic NS?

Answer 11

Rest and digest
-Activated during digestion, defecation and urination
-Functions in discrete, organ specific manner

Question 12

Can you list the key ideas about sympathetic NS?

Answer 12

-Fight or Flight
-Activated during exercise, excitement, embarrassment and emergency
-Activated in a whole body response OR discrete and organ specific

Question 13

How do we maintain a balance between the two pathways?

Answer 13

As one system is activated, the activity of the other system decreases.

Question 14

what is the general organisation of the ANS?
*This is for both pathways

Answer 14

1. preganglionic neuron in the CNS
2. postganglionic neuron in the Peripheral ganglion
3. Target cell

Question 15

What happens when the preganglionic neuron is stimulated in the CNS?

Answer 15

When the preganglionic neuron is stimulated in the CNS
1. It will fire action potentials along its axon, which will reach the presynaptic terminal
2. It will initiate neurotransmitter release
3. Release ACh into the synaptic cleft
4. ACh diffuses down the synaptic cleft and binds to the nAChR
5. nAChR opens, allowing positive ions into the cell - depolarising the postganglionic neuron

(This is the same for sympathetic or parasympathetic NS)

Question 16

What do we mean by preganglionic neurons being cholinergic?

Answer 16

They release acetylcholine as their primary neurotransmitter

Question 17

What type is the nAChR?

Answer 17

Ligand gated ion channel

Question 18

What is the peripheral ganglion?

Answer 18

A group of neuronal cell bodies found in the periphery that perform the same job

Question 19

What are the principles of the ANS?

Answer 19

*The two pathways systems generally innervate the same tissue but have opposing effects.

• Although the actions are antagonistic to one another, they work synergistically (symbiotically)
• This allows for the rapid, precise control of tissue function

Question 20

what are the differences between the sympathetic and parasympathetic pathways?

Answer 20

SYMPATHETIC
* Short, cholinergic preganglionic neurons from thoracic and lumbar spinal cord
* Long, adrenergic postganglionic neurons
* Target tissue expresses α- and β- adrenergic receptors

PARASYMPATHETIC
* Long, cholinergic preganglionic neurons from brainstem and sacral spinal cord
* Short, cholinergic postganglionic neurons
* Target tissue expresses muscarinic ACh receptor

Question 21

What type of receptors are the α- and β- adrenergic receptors in the parasympathetic system?

Answer 21

G protein coupled receptors

Question 22

What things are MAINLY controlled by the sympathetic NS?

Answer 22

1. Sweat glands
2. Hair follicles
3. Blood vessels
4. Smooth muscles
5. Adrenal medulla

Question 23

What’s the vagus nerve?

Answer 23

The vagus nerve is the longest and most complex of the cranial nerves, running from the brain through the face and thorax to the abdomen. Without a vagus nerve, we wouldn’t survive.
*it carries 80% of parasympathetic out flow

Question 24

what’s the importance of the vagus nerve ?

Answer 24

It helps regulate many bodily functions, including heart rate, digestion, and your immune response. It plays a key role in the “rest and digest” response and helps maintain overall balance in the body.

Question 25

what can the hypothalamus control / modulate ?

Answer 25

Feeding
thermoregulation
circadian Rhythms
water Balance
Sexual drive
Reproduction

Question 26

What else regulates ANS output?

Answer 26

Forebrain
* Minimal conscious cortical control BUT cortical
processes do regulate autonomic output
* For example:
– anxiety can lead to GI disturbance
– fear initiates fight or flight response (limbic system)