Autonomic Nervous System

Question 1

What is the difference in the somatic and autonomic nervous systems?

Answer 1

Somatic = we have control of this
Autonomic = this is automatic and done for us

Question 2

What are the functions of the autonomic nervous system?

Answer 2

• Stress response
• Mucturition
• Cardiovascular control
• Sex and reproduction
• Digestion

Question 3

How can the autonomic nervous system be split up?

Answer 3

Sympathetic and parasympathetic

Question 4

What are some similarities between the parasympathetic and sympathetic systems?

Answer 4

• Synapse in ganglions
• Sensory and effector effect
• Acetylcholine in ganglion transmission

Question 5

What are some differences between the parasympathetic and sympathetic nervous systems?

Answer 5

• Anatomical origin
• Location of ganglion
• Post ganglionic neurotransmitters
• Function

Question 6

What is the anatomical origin of the sympathetic system and the exception to this?

Answer 6

Thoracolumbar origins

Exception is ones from the cervical ganglia

Question 7

Where are the ganglia in the symapthetic system compared to parasympathetic?

Answer 7

Sympathetic- next to spinal cord

Parasympathetic- near site of action

Question 8

What are the neurotransmitters in the sympathetic system?

Answer 8

Pre ganglionic synapse = acetylcholine

Post ganglionic synapse = noradrenaline

Question 9

What are the exceptions to the neurotransmitters in the sympathetic system?

Answer 9

Post ganglionic neurotransmitter is always noradrenaline except from sweat glands and deep muscle vessels where it is acetylcholine.

Question 10

What are the functions of the sympathetic system?

Answer 10

• Stress response (fight or flight)
• Sweat, to reduce heat
• Inotropy
• Chronotropy
• Adrenaline release
• More blood around body
• More O2
• Constipation and urinary retention
• Vasodilation

Question 11

What receptors are used by the sympathetic system and why/when?

Answer 11

• Alpha 1 = arteriole constriction
• Alpha 2 = coronary and venous vasoconstriction
• Beta 1 = heart; increases heart rate, increases contractility
• Beta 2 = lungs, uterus, skeletal muscle, blood vessels, smooth muscle relaxation (can stop things being disadvantageous)

Question 12

What is the anatomical origin of the parasympathetic system?

Answer 12

Craniosacral outflow
(Cranial nerves 3,7,9,10.
Sacral nerves 2,3,4)

Question 13

What neurotransmitters does the parasympathetic system use?

Answer 13

Acetylcholine

Question 14

What is the function of the parasympathetic system?

Answer 14

• Nasal engorgement, excess salivation
• Slow heart rate
• Help defecate, ejaculate

Question 15

What types of receptors can the parasympathetic system use?

Answer 15

Nicotinic receptors (will be neuronal or muscular):
N1- motor neurons
N2- autonomic nervous system (also some in brain), used as ganglion blockers

Muscarinic receptors, has 5 subtypes:
M1- neural, emotional response
M2- in heart, cardiac inhibition
M3- in glands (eg. salivary glands, gut, bladder), have stimulatory effct
M4- in CNS, work on K and Ca ion channels
M5- in CNS, to regulate dopamine release

Question 16

What are the principle functions of the autonomic part of the central nervous system?

Answer 16

• Cranial nerve function
• Conduit function (relays activity from brainstem to rest of body)
• Integrative functions (sleep cycle, respiratory cycle, conciousness)

Question 17

What can happen due to brain stem death?

Answer 17

• Paralysis, unconciousness
• apnoea (lose respiratory centre)
• Loss of cranial nerve function

Question 18

How can brain stem death occur?

Answer 18

Brain in non expandable box, so when pressure builds up it gets pushed through hole at bottom.
Causing tonsillar herniation
The pressure on the brainstem makes it choke itself and it cuts off its own blood supply

Question 19

What are signs of brainstem death?

Answer 19

• Dilated pupils

- Single vessel supply to midbrain

Question 20

How can brain stem death be tested?

Answer 20

Important that it is actually brain and brain stem death.
Exclusion criteria must be met
Must have known diagnosis
Must be unconcious and apnoeic
Should have normal temp. normal glucose, electrolytes and should be under no drugs.
2 doctors must be present (1 consultant and one with 5 years experience)
They test the 8 out of 12 cranial nerves and their functions.

Question 21

What is the difference between a receptor agonist and antagonist?

Answer 21

Agonist- mimick action of receptor

Antagonist- does opposite

Question 22

What is an eg of an alpha 1 agonist and antagonist?

Answer 22

Agonist-metaraminol; arteriolar constriction

Antagonist- doxazosin; vascular smooth muscle relaxation

Question 23

What is an eg of an alpha 2 agonist?

Answer 23

Yohimbine-mild erectile dysfunction

Question 24

What are eg of beta 1 agonist and antagonist?

Answer 24

Agonist- isoprenaline; complete heart block

Antagonist- Atenolol; lower blood pressure

Question 25

What is an eg of a beta 2 agonist and antagonist?

Answer 25

Agonist- salbutamol; smooth muscle relaxation and bronchiolar relaxation
Antagonist- butaxamine; experimental use only

Question 26

What is an eg of an M1 receptor agonist?

Answer 26

Xanomeline; alzheimers treatment

Question 27

What is an eg of an M2 receptor antagonist?

Answer 27

Atropine; reduces effect of Ach on heart, increases heart rate.

Question 28

What is an eg of an M3 receptor agonist and antagonist?

Answer 28

Agonist- Pilocarpine; treats glycoma
Antagonist- tiotropium; lungs
oxybutinin; bladder
Mebervine; gut

Question 29

What is an eg of an N1 receptor agonist and antagonist?

Answer 29

Agonist- succinylcholine

Antagonist- burgarotoxin; muscle blocker

Question 30

What is an eg of an N2 receptor antagonist?

Answer 30

Vercuronism