Introduction to autonomic nervous system

Question 1

What are the three principal efferent outputs from the central nervous system?

Answer 1

Autonomic nervous system
Somatic nervous system
Neuroendocrine system

Question 2

What is the autonomic nervous system involved with?

Answer 2

Exocrine glands, smooth muscle, cardiac muscle, metabolism and host defence

Question 3

What is the somatic nervous system involved with?

Answer 3

Skeletal muscle including diaphragm and respiratory muscle

Question 4

What is the neuroendocrine system involved with?

Answer 4

Growth, metabolism, reproduction, development, salt and water balance and host defence

Question 5

What are the two branches of the autonomic nervous system and what are they involved in?

Answer 5

Sympathetic- fight or flight

Parasympathetic- rest and digest

Question 6

What effect does the sympathetic have on the eye?

Answer 6

Pupil dilatation

Question 7

What effect does the sympathetic have on the trachea and bronchioles?

Answer 7

Dilates

Question 8

What effect does the sympathetic have on the liver?

Answer 8

Increases glycogenolysis and gluconeogenesis

Question 9

What effect does sympathetic have on adipose?

Answer 9

Lipolysis

Question 10

What effect does sympathetic have on kidney?

Answer 10

Increased renin secretion

Question 11

What effect does sympathetic have on ureters and bladder?

Answer 11

Relaxes detrusor and constricts trigone and sphincter

Question 12

What effect does the sympathetic have on the salivary glands?

Answer 12

Causes thick viscous secretions

Question 13

What effect does the sympathetic have on the skin?

Answer 13

Piloerection and increased sweating

Question 14

What effect does the sympathetic have on the heart?

Answer 14

Increase in rate and contractility

Question 15

What effect does the sympathetic have on the GI tract?

Answer 15

Decreased motility and sphincter contraction

Question 16

What effect does the sympathetic have on blood vessels?

Answer 16

Skeletal muscle- dilatation

Skin, mucous membranes and splanchnic area- constriction

Question 17

What effect does the parasympathetic have on the eye?

Answer 17

Pupil constriction and ciliary muscle contraction

Question 18

What effect does parasympathetic have on trachea and bronchioles?

Answer 18

Constriction

Question 19

What effect does parasympathetic have on ureters and bladder?

Answer 19

Contraction of detrusor and relaxation of trigone and sphincter

Question 20

What effect does parasympathetic have on salivary glands?

Answer 20

Copious watery secretions

Question 21

What effect doe parasympathetic have on gastrointestinal?

Answer 21

Increases motility and tone and secretions

Question 22

Where do all parasympathetic nerves originate?

Answer 22

In the craniosacral region

Question 23

What are their pre-ganglionic and post-ganglionic fibres like in terms of length?

Answer 23

They project a long way out to the tissue- long pre-ganglionic and short post-ganglionic

Question 24

What effect does the length of the pre and post ganglionic fibres have?

Answer 24

Parasympathetic has a discrete localised response with little divergence

Question 25

What neurotransmitters are involved with parasympathetic?

Answer 25

Always acetylcholine

Question 26

Where do sympathetic nerves originate?

Answer 26

Thoracic and lumbar regions

Question 27

What are their pre-ganglionic and post-ganglionic fibres like in terms of length?

Answer 27

Short pre and long post

Question 28

What neurotransmitters are normally involved in sympathetic?

Answer 28

Acetylcholine is released by pre-ganglionic and noradrenaline is released by post-ganglionic

Question 29

What organs are different and why?

Answer 29

The adrenal gland- only has one autonomic fibre innervating it which behaves like a post-ganglionic because it releases adrenaline and noradrenaline Sweat glands- same as parasympathetic (both acetylcholine)

Question 30

How does the enteric nervous system work?

Answer 30

The sensory neurone is connected to mucosal chemoreceptors and stretch receptors which detect chemical substances in the lumen or tension in the gut wall caused by food Interneurones relay information to the submucosal and myenteric plexus Motor neurones then release acetylcholine or substance P to contract smooth muscle or vasoactive intestinal peptide or nitric oxide to relax smooth muscle

Question 31

What two types of membrane bound receptors does acetylcholine bind to?

Answer 31

Muscarinic and nicotinic

Question 32

What is a nicotinic receptor?

Answer 32

Ion-channel linked receptor (type 1) stimulated by nicotine and acetylcholine

Question 33

What is a muscarinic receptor?

Answer 33

G protein coupled receptor (type 2) stimulated by muscarine and acetylcholine

Question 34

Where are nicotinic receptors found?

Answer 34

At all autonomic ganglia

Question 35

Where are muscarinic receptors found?

Answer 35

At all effector organs innervated by post ganglionic parasympathetic fibres

Question 36

What would blockage of nicotinic acetylcholine receptors lead to?

Answer 36

Constipation

Question 37

What are the 5 subtypes of muscarinic cholinoceptors?

Answer 37

M1- Neural (Forebrain- learning and memory) M2- Cardiac (Brain- inhibitory autoreceptors) M3- Exocrine and smooth muscle (Hypothalamus- food intake) M4- Periphery M5- Striatal dopamine release

Question 38

What are the 4 types of adrenoceptor?

Answer 38

Alpha 1 Alpha 2 Beta 1 Beta 2

Question 39

Where are adrenoceptors found?

Answer 39

At all effector organs innervated by post ganglionic sympathetic nerve fibres

Question 40

What is acetylcholine is formed by?

Answer 40

Acetyl-coA and choline

Question 41

What is acetylcholine broken down by and into what?

Answer 41

Acetylcholinesterase and broken down into choline and acetate

Question 42

How is noradrenaline formed?

Answer 42

Tyrosine is converted to DOPA by tyrosine hydroxylase DOPA is converted to dopamine by DOPA decarboxylase Dopamine is packaged into vesicles then converted to noradrenaline by dopamine beta hydroxylase

Question 43

How is noradrenaline broken down?

Answer 43

Not in the synapse Uptake 1- back into neuronal tissue Uptake 2- into extra-neuronal tissue Once it has been taken up, it is broken down by: Monoamine oxidase (MAO)- mainly in neuronal tissue Catechol-O-Methyl Transferase (COMT)- mainly in extra neuronal tissue