Lecture 9: The nervous system part 1: The autonomic nervous system

Question 1

What are the two divisions of the peripheral nervous system?

Answer 1

Afferent and efferent

Question 2

What information does the afferent division of the PNS transmit via action potentials?

Answer 2

Information from the sensory receptors and visceral stimuli

Question 3

What are the two divisions of the efferent nervous system?

Answer 3

Somatic nervous system and autonomic nervous system

Question 4

What is the somatic nervous system?

Answer 4

Voluntary control of skeletal muscles

Question 5

What makes the autonomic nervous system special?

Answer 5

It does not require conscious regulation

Question 6

What does the autonomic nervous system do?

Answer 6

Regulates activity of the internal organs (smooth muscle, cardiac muscle and glands)

Question 7

What is another major function of the autonomic nervous system?

Answer 7

Homeostasis

Question 8

What can the autonomic nervous system be divided into?

Answer 8

Sympathetic (flight or fight)

Parasympathetic (rest and digest)

Question 9

What nerves are associated with the parasympathetic division of the autonomic nervous system?

Answer 9

Cranial nerves

Sacral nerves

Question 10

What nerves are associated with the sympathetic division of the autonomic nervous system?

Answer 10

Thoracic and lumbar nerves

Question 11

What do lumbar nerves of the sympathetic nervous system do?

Answer 11

Makes kidney secrete epinephrine/norepinephrine, relaxes bladder, inhibits sex organs

Question 12

The ANS does not usually have single neurons connecting the CNS to organs. Instead…

Answer 12

There is usually an autonomic ganglion in between

Question 13

What are the two ganglions in the ANS?

Answer 13

Neurons from the CNS to ganglia are preganglionic

Distal ones are postganglionic

Question 14

In autonomic ganglia, preganglionic nerves are ________ and postganglionic fibres are ________

Answer 14

Myelinated

Unmyelinated

Question 15

Where are sympathetic ganglia located?

Answer 15

Close to the CNS

Question 16

Where are parasympathetic ganglia located?

Answer 16

Close to the target organ, or embedded in it

Question 17

How many cell bodies do sympathetic preganglionic axons innervate?

Answer 17

> 20

Question 18

How many cell bodies do parasympathetic preganglionic axons innervate?

Answer 18

<4

Question 19

How are sympathetic ganglia arranged?

Answer 19

In a row on each side of the spinal cord (Paravertebral ganglia)
Further away called prevertebral ganglia

Question 20

What is the neurotransmitter for the preganglionic neurons of both divisions (para and sympathetic) of the ANS?

Answer 20

Acetylcholine

Question 21

What is the postganglionic neurotransmitter of the sympathetic nervous system?

Answer 21

Norepinephrine

Question 22

What is the postganglionic neurotransmitter of the parasympathetic nervous system?

Answer 22

Acetylcholine

Question 23

Where is ACh broken down after being secreted from the preganglionic neurons?

Answer 23

Synaptic cleft

Question 24

What enzyme breaks down ACh?

Answer 24

Acetylcholineterase

Question 25

What happens once ACh is broken down?

Answer 25

Choline is transported back into the axon terminal and is used to make more ACh

Question 26

What are the two types of ACh receptors?

Answer 26

Nicotinic | Muscarinic

Question 27

What happens when ACh (or nicotine) binds to nicotinic receptors?

Answer 27

They open and allow ions to flow (Na+ in and K+ out)

Question 28

What is the effect of ACh binding to nicotinic receptors and ions flowing?

Answer 28

Ionotropic (the binding of the ligand DIRECTLY alters permeability of the channel_

Question 29

What are two features of ionotropic receptors?

Answer 29

- Fast synaptic transmission | - Often stimulatory

Question 30

What happens when ACh (or mucarine) binds to muscarinic receptors?

Answer 30

They release G proteins which begin a cascade of information

Question 31

What is the effect of ACh binding to muscarinic receptors causing G protein cascade?

Answer 31

Metabotropic: binding of the ligand to the channel INDIRECTLY alters permeability of ion channels

Question 32

What are two features of metabotropic receptors?

Answer 32

- Several types | - May be stimulatory or inhibitory

Question 33

In ANS, where are muscarinic receptors found?

Answer 33

Only in the post ganglionic parasympathetic nervous system

Question 34

Where are nicotinic receptors found within the body?

Answer 34

Neuromuscular junctions, ganglionic neurons and adrenal medulla

Question 35

What is the second messenger pathway of nicotinic vs. muscarinic receptors?

Answer 35

Ion influx | G protein coupled

Question 36

What do epinephrine and norepinephrine bind to?

Answer 36

Adrenoreceptors

Question 37

What happens when adrenoreceptors bind with nor/epinephrine?

Answer 37

They release G proteins, which begin a cascade of information

Question 38

What are the two subtypes of adrenoreceptors?

Answer 38

Alpha and beta (both metabotropic)

Question 39

Epinephrine and norepinephrine are both what type of molecule?

Answer 39

Catecholamines

Question 40

Where are alpha 1 receptors found?

Answer 40

Blood vessels of skin, gut, kidneys and salivary glands

Question 41

What is the effect of alpha 1 receptors in humans?

Answer 41

Vasocontriction

Question 42

Where are beta 1 receptors found?

Answer 42

Heart

Question 43

What is the effect on beta 1 receptors in humans?

Answer 43

Increases heart rate and strength

Question 44

Where are beta 2 receptors found in humans?

Answer 44

Lungs

Question 45

What is the effect of beta 2 receptors in humans?

Answer 45

Dilates bronchial passages

Question 46

What is the first reason for the number of different types of receptors in humans?

Answer 46

Evolution is messy

Question 47

What is the second reason for the number of different types of receptors in humans?

Answer 47

Different needs in different tissues: different combinations gives large range of responses