Autonomic Nervous System

Question 1

What does the autonomic nervous system control?

Answer 1

Myocardium, smooth muscle (eg gut), internal organs, skin

Question 2

Though what PNS division dies the brain receive information? How is this division split)

Answer 2

Sensory (afferent) division, which is divided into somatic and visceral

Question 3

How is the visceral motor division split?

Answer 3

parasympathetic and sympathetic nervous system

Question 4

How does the (para)sympathetic system affect the pupil?

Answer 4

Parasympathetic constrict pupil, sympathetic dilates pupil

Question 5

How does the (para)sympathetic system affect the heart?

Answer 5

Heart rate increases (also contraction) with sympathetic stimulation, and decreases with parasympathetic system

Question 6

How does the (para)sympathetic system affect the stomach?

Answer 6

Motility and secretions increases in parasympathetic system, and does the opposite in reaction to the sympathetic system

Question 7

What happens if your baroreceptors’ firing rate increases?

Answer 7

It will increase its parasympathetic response, thus more acetylcholine is released to lower the heart rate and hence lower blood pressure. This charge will also result in a decrease in sympathetic activity. The opposite happens when the firing rate of baroreceptors decreases.

Question 8

What part of the brain receives information from the autonomic nervous system?

Answer 8

Hypothalamus

Question 9

Where do the nuclei of visceral motor cells originate?

Answer 9

Hypothalamus

Question 10

What is the difference between the parasympathetic system and the sympathetic system in terms of pre-ganglionic fibre, post ganglionic fibre and ganglion?

Answer 10

Parasympathetic system have long pre-ganglionic fibres, short post ganglionic fibres, and a ganglion closer to effector organ. The opposite is true for the sympathetic nervous system.

Question 11

What is the exception to the structure of the sympathetic nervous system?

Answer 11

The arenal gland, where there is no ganglion (so acts similar to post ganglionic fibre)

Question 12

What neurotransmitter is used in the parasympathetic system?

Answer 12

Acetylcholine

Question 13

What neurotransmitters are used in the sympathetic system and where?

Answer 13

In the preganglionic fibres, acetylcholine is used, and in the post-ganglionic fibres noradrenaline is used

Question 14

What is the sensory information relayed in the bladder?

Answer 14

Pressure

Question 15

What happens when pressure builds up?

Answer 15

The sympathetic system will relax the internal sphincter muscle, and the detrusor muscle will be stimulated to contract and empty the bladder

Question 16

What muscle keeps the bladder closed and what nerves innervates this?

Answer 16

The internal sphincter muscle, which is innervated by the sympathetic nerve

Question 17

What types of receptors are used in the autonomic nervous system and why?

Answer 17

Ion channel receptor, because this is the fastest

Question 18

What is the benefit of G-protein coupled receptor?

Answer 18

It is more complicated, so cell has more control over response, as components of the receptor can be altered to control response, although response is slower than in ion gated channels

Question 19

What type of receptors are needed at autonomic ganglia?

Answer 19

Acetylcholine receptor (nicotinic acetylcholine receptor)

Question 20

Outline neurotransmitter biosynthesis and metabolism

Answer 20

1.Precursor enzymatically converted to neurotransmitter
2.Packaged into vesicles
3.Action potential causes Ca2+ influx and exocytosis
4.Exocytosis and neurotransmitter release
5.Receptor activation
6.Removal of neurotransmitter from synapse via uptake into pre-synaptic terminal or glial cell;
Can be metabolised in the synapse prior to uptake

Question 21

Outline acetylcholine biosynthesis and metabolism

Answer 21

1.Choline + acetyl CoA enzymatically converted by choline acetyl transferase
2.Packaged into vesicles
3.Action potential causes Ca2+ influx and exocytosis
4.. Exocytosis and neurotransmitter release
5.. Receptor activation
(Muscarinic or nicotinic)
6.Acetylcholine rapidly degraded by acetylcholinesterase in the synapse.
Choline taken up into presynaptic terminal by choline uptake protein.

Question 22

Outline noradrenaline biosynthesis and metabolism

Answer 22

1.Tyrosine converted to DOPA by tyrosine hydroxylase. DOPA converted to dopamine by DOPA decarboxlase
2.Dopamine packaged into vesicles with dopamine β hydroxylase. Noradrenaline is the product
3.Action potential causes Ca2+ influx and exocytosis
4.Exocytosis and neurotransmitter release
5.Receptor activation
(Adrenergic)
6.Removal of neurotransmitter from synapse via uptake into pre-synaptic terminal or glial cell;
Can be metabolised in the synapse prior to uptake

Question 23

Outline adrenaline biosynthesis and metabolism

Answer 23

1. Tyrosine converted to DOPA by tyrosine hydroxylase. DOPA converted to dopamine by DOPA decarboxlase
2. Dopamine packaged into vesicles with dopamine β hydroxylase. Noradrenaline is the product
3. Noradrenaline converted to adrenaline in the cytoplasm by phenylethanol methyl trasnferase
4. Action potential causes Ca2+ influx and exocytosis
5. Exocytosis and neurotransmitter release
6. Adrenaline diffuses into capillary and is transported to tissues in the blood

Question 24

What effect does the smell/test of food have on the ANS

Answer 24

Parasympathetic response increases whilst sympathetic response is lost, so more acid is released into the stomach.

Question 25

What is the enteric nervous system

Answer 25

It is thought of as a ´mini brain`, which influences gut function

Question 26

What effect does the bright light have on the ANS

Answer 26

Pupil constriction takes places, driven by the parasympathetic system.

Question 27

How many sympathetic nerves innervate the lung tissue? And how does the sympathetic system stimulates the lungs?

Answer 27

Zero, but sympathetic control comes from the release of the hormone adrenaline rather than a neurotransmitter

Question 28

What muscle contracts to fore urine out of the bladder?

Answer 28

The detrusor muscle, innervated by the parasympathetic nerve.

Question 29

How does urine leave the bladder in terms of the ANS?

Answer 29

Sympathetic system is less active, making the internal sphincter relax, and the parasympathetic system activates the detgusor muscle to contract.

Question 30

What is the micturition reflex?

Answer 30

Reflex involved in emptying bladder

Question 31

What receptor are there in post-ganglionic fibres

Answer 31

Muscarinic (ACh) and adrenergic (NA) receptors

Question 32

What receptors are there in receptor cells?

Answer 32

G-coupled receptors

Question 33

Where is ACh metabolised?

Answer 33

Synapse, and then transported to the pre-synaptic neurone

Question 34

Where is NA metabolised?

Answer 34

Pre-synaptic neurone, after being transported from the synapse