Autonomic Nervous System I: The Sympathetic Nervous System

Question 1

What is the autonomic system (ANS) broken up into ?

Answer 1

Enteric nervous system
Parasympathetic nervous system
Sympathetic nervous system

Question 2

Explain human nervous system divisions

Answer 2

Question 3

Where does thre parasympathetic nervous system inervate ?

Answer 3

Cranial nerve and sacral area

Question 3

Where does the sympathetic nervous system inervate?

Answer 3

T1-L2

Question 4

What is the autonomic nervse system controled by ?

Answer 4

Hypothalamus

Futher processing in brainstem eg vomiting brseathign ect

Answer 5

Question 6

Atutonomic ganglia within the ANS>

Answer 6

The ANS is disynaptic (as opposed to somatic NS monosynaptic)

ANS nerves pass through nerve cell clusters called “ganglia”.

Parasympathetic ganglia are in or near the target organ

Sympathetic ganglia are located in the sympathetic chain (paravertebral ganglia)

Question 7

What is ganglia ?

Answer 7

A cluster of cells

Question 8

explain sympathetic chain

Answer 8

Sympathetic ganglia are in the sympathetic chain, which is lateral and ventral to spinal cord.

CNS efferents (preganglionic) from the spine run to the sympathetic chain, form synapses with the postganglionic neurone.

Question 9

What is the neurotransmitter present in the autonomic nervous system?

Answer 9

Acetylcholine

They activate nicotinic acetylcholine receptors to generate an action potential.

Question 10

What is the post ganglionic nuerotransmitter in the SNS ?

Answer 10

Noradrenaline

Question 11

Difference between adrenaline and noradrenaline

Answer 11

arenaline is a neurotransmitter, not a hormone.

It’s not released from neurons it’s released from adrenal glands.

This is general maintanence if you need extra adrenelaine will be produced ?

Question 12

Adrenergic a1 receptors

Where are they located what do they do ?

Answer 12

Gq protein coupled: PLC → DAG & IP3 → ↑[Ca2+]

Located: Blood vessels, GI sphincters, Eye, salivary gland

Constriction / secretion

Vasoconstriction (↑BP)
Reduced urine flow
Mydriasis
Salivary secretion

Question 13

Adrenergic a2 receptors

Answer 13

Gi protein coupled: ↓AC → ↓cAMP → (↓[Ca2+]i)

Pre synaptic neuron on sns terminals

DECREASES ACTIVITY !!!

Decreased synaptic output
Decreased sympathetic activity

Question 14

How does Adrenergic a2 receptors work to reduce release of overacitivity in a nueron ?

NEGATIVE FEEDBACK.

Answer 14

Receptors located on presynaptic membrane

Also activated by NT release

Often inhibitory, used as negative feedback systems to prevent overactivity
e.g. α2 adrenoceptors, 5-HT1 receptors

Question 15

Adrenergic b1 receptors

What they do where they are located ?

Answer 15

Gs protein coupled: ↑AC → ↑cAMP

located: Heart
Kidney (renin release)

Increased heart contractility
Increased heart rate
Increased renin secretion

Question 16

Adrenergic b2 receptors

Answer 16

Gs protein coupled: ↑AC → ↑cAMP

Located: Lungs, blood vessels, smooth muscle, other

Bronchodilation
Vasodilation
Smooth muscle relaxation
Uterine dilation
Gycogenolysis

Note that NA has very low affinity for beta-2 receptors its noradrenaline which will do this.

Question 17

Adrenergic b3 receptors

Answer 17

Gs protein coupled: ↑AC → ↑cAMP

Located: Fatty tissues, skeletal muscle, bladder muscle

Lipolysis
Thermogenesis
Bladder relaxation