Autonomic Nervous System

Question 1

What is the function of the ANS ?

Answer 1

Regulate activity of smooth muscle, cardiac muscle and some glands

Question 2

What structures are involved in the ans ?

Answer 2

• sensory afferent neurones
• effector efferent neurones
• integration centre within the brainstem

Question 3

How many neurones does the CNS contain and how many does the ANS contain ?

Answer 3

• cns= 1
• ans= 2

Question 4

What is the flowchart of the ANS ?

Answer 4

Brain/SC
Pre gang. Neuton myelinated
Autonomic ganglion
Post. Gang. Neuron unmyelinated
Effector

Question 5

What is the preganglionic neurone ?

Answer 5

• cell body in brain (cranial nerves) or spinal chord
• axon is myelinated and extends to autonomic ganglion

Question 6

What is the neurotransmitter at the ganglion ?

Answer 6

Ach

Question 7

What is the post ganglionic neurone ?

Answer 7

• cell body lies outside the CNS
• axon is unmyelinated and terminates in a visceral effector

Question 8

What neurotransmitter is fount at the effector ?

Answer 8

Ach ir Noradrenaline (NA, NE)

Question 9

What are the divisions on the ANS

Answer 9

Parasympathetic
Sympathetic

Question 10

What is dual innervation ?

Answer 10

• one pressor and the other depressor
• yin/yang
• push/pull

Question 11

What are the features of the sympathetic ?

Answer 11

(Thoraco-lumbar)
- preganglionic cell bodies in thoracic and first 2 lumbar segments of SC

• pre. Gang. Fibre is short

Question 12

What is in the parasympathetic ?

Answer 12

(Cranio-sacral)

• preganglionic cell bodies in nuclei of 4 cranial nerves and sacral spinal chord
• pregang. Is long

Question 13

What do neurotransmitters diffuse across ?

Answer 13

Synapse to stim. Receptors on the postsynaptic membrane

Question 14

What is Ach release by ?

Answer 14

• all preganglionic axons
• all parasympathetic postganglionic neurons at synapses
• Ach releasing fibres- cholinergic

Question 15

What is nor-adrenaline released by ?

Answer 15

• most sympathetic postganglionic axons
• nor-adrenaline releasing fibres (adrenergic)

Question 16

What is a noradrenaline releasing fibre called and what is the exception ?

Answer 16

• adrenergic
• sympathetic postganglionic fibres (sweat glands, blood vessels writhing skeletal muscle)

Question 17

Which two receptors bind Ach ?

Answer 17

• nicotinic
• muscarininc

Question 18

Where are nicotinic receptors found ?

Answer 18

• neuromuscular junctions of skeletal muscle cells
• postganglionic neurons (para and sym)
• ## hormone producing cells of adrenal medulla

Question 19

Where muscarinic receptors found ?

Answer 19

• on all effector cells stimulated by postganglionic cholinergic fibres
  ( all parasympathetic target organs/vessels)

Question 20

What do muscarinic receptors usually do ?

Answer 20

• usually excitatory, can be inhibitory (eg. The heart )

Question 21

What are the 2 major adrenergic receptors ?

Answer 21

Alpha and beta

Question 22

Where are adrenergic receptors ?

Answer 22

Can be on post/pre synaptic membrane

If on pre, they are inhibitory

Question 23

What are alpha 1 receptors ?

Answer 23

• post synaptic
• on visceral and skeletal muscle or vascular smooth muscle cells

Question 24

What are alpha 2 receptors ?

Answer 24

Presynaptic

Question 25

What are beta 1 receptors ?

Answer 25

Found in heart and intestinal smooth muscle

Question 26

Where are beta 2 receptors found ?

Answer 26

Bronchial, skeletal muscle, vascular and uterine smooth muscle cells