drugs and the autonomic nervous system (part 1 - anatomy, parasympathetic) (W5)

Question 1

receptors found in the carotid sinus?

Answer 1

baroreceptors (blood pressure) and chemoreceptors (oxygen content)

Question 2

which area in the brain processes afferent autonomic signals

Answer 2

hypothalamus

Question 3

2 types of nerves in the autonomic nervous system and their function?

Answer 3

afferent autonomic nerves - transmit info from periphery to CNS
efferent autonomic nerves - transmit impulses from CNS to periphery

Question 4

parasympathetic nervous system fibre types?

Answer 4

preganglionic and postganglionic fibres

Question 5

parasympathetic preganglionic location and features

Answer 5

cell bodies in midbrain, pons, medulla, sacral spinal cord
myelinated
synapse with postsynaptic fibres in ganglia

Question 6

preganglionic parasympathetic nerves arising from the brainstem travel in which cranial nerves?

Answer 6

3, 7, 9, 10

Question 7

ganglia meaing?

Answer 7

clusters of synapses

Question 8

ganglia location in parasympathetic nervous system

Answer 8

effector organs

Question 9

parasympathetic postganglionic nerves location and features?

Answer 9

near or within effector organs
unmyelinated
shorter than preganglionic fibres

Question 10

sympathetic preganglionic fibres location and features?

Answer 10

cell bodies in lateral horns of spinal segments T1-L2 (thoraco-lumbar outflow)
myelinated

Question 11

where are ganglia located in the sympathetic nervous system

Answer 11

2 para-vertebral chains from cervical to sacral region

Question 12

sympathetic postganglionic fibres features?

Answer 12

longer than than preganglionic fibres
unmyelinated

Question 13

sympathetic preganglionic fibres that don’t synapse in the sympathetic ganglion chains?

Answer 13

terminate in separate cervical/abdominal ganglia or travel in greater splanchnic nerve and synapse directly in chromaffin cells in the adrenal medulla

Question 14

where are the adrenal glands located

Answer 14

superior aspect of each kidney

Question 15

hormones made by adrenal glands in response to physical/emotional stress?

Answer 15

catecholamines

Question 16

which cells in the adrenal glands synthesise and store catecholamines

Answer 16

adrenal medulla chromaffin cells

Question 17

what does presence of an additional enzyme cause in the adrenal medulla?

Answer 17

conversion of the majority of noradrenaline to adrenaline

Question 18

how does the adrenal medulla response to nervous impulses in the sympathetic cholinergic preganglionic fibres

Answer 18

secretes catecholamines stores into the circulation

Question 19

neurotransmitters involved in parasympathetic nerves

Answer 19

preganglionic parasympathetic - acetylcholine
postganglionic parasympathetic - acetylcholine

Question 20

what receptors do neurotransmitters act at in the parasympathetic nerves

Answer 20

preganglionic parasympathetic nerves act at nicotinic receptor
postganglionic parasympathetic nerves act at muscarinic receptors at effector organs

Question 21

what occurs in the pre-synaptic neurone after an action potential depolarises the membrane of the nerve terminal

Answer 21

calcium channels open, calcium enters cell causing translocation of vesicles containing neurotransmitter to the cell membrane, then exocytosis and extrusion of the neurotransmitter into the synaptic cleft

Question 22

what does the release of neurotransmitter into the synaptic cleft result in

Answer 22

neurotransmitter binds to receptors in postsynaptic membrane. signal transduction occurs in cytosol of postsynaptic cell, leading to generation of secondary messenger molecule enabling a biological response

Question 23

how the response in a synapse be modulated

Answer 23

altering concentration of neurotransmitter in synaptic cleft - enzyme degradation or reuptake

Question 24

what do presynaptic receptors do

Answer 24

bind to neurotransmitter, function as negative feedback loop reducing over-secretion and over-stimulation of postsynaptic cell

Question 25

how is acetylcholine formed?

Answer 25

formed from the precursor molecule choline by transfer of an acetyl from acetyl-CoA, by the enzyme acetylcholinesterase (AChE)

Question 26

what enzyme is responsible for degradation of acetylcholine in the synaptic cleft

Answer 26

acetylcholinesterase (AChE)

Question 27

cholinergic meaning?

Answer 27

relating to nerve cells in which acetylcholine acts as a neurotransmitter

Question 28

2 types of cholinergic receptors in the post-synaptic neurone?

Answer 28

nicotinic and muscarinic cholinergic receptors

Question 29

nicotinic cholinergic receptors action?

Answer 29

depolarise postsynaptic cell membrane by opening ion channels that increase permeability to sodium and potassium - generates action potential

Question 30

muscarinic cholinergic receptor type?

Answer 30

G-protein-coupled receptors

Question 31

what are muscarinic cholinergic receptors linked to

Answer 31

inositol triphosphate (IP3) or cyclic adenosine monophosphate (cAMP)

Question 32

which muscarinic receptor types increase IP3? what does this lead to?

Answer 32

type 1, 3, 5
increase calcium availability or decrease potassium conductance

Question 33

what type of effect do type 1, 3, 5 muscarinic receptors have?

Answer 33

excitatory (yippee!)

Question 34

which muscarinic receptors inhibit cAMP generation? what does this lead to?

Answer 34

types 2 and 4
reduces calcium avaliability

Question 35

what type of effect do type 2 and 4 muscarinic receptors have?

Answer 35

inhibitory

Question 36

how many acetylcholine molecules must bind to open a nicotinic receptor channel

Answer 36

2