Topic 6: Autonomic Nervous System

Question 1

What are the roles of the autonomic nervous system?

Answer 1

-inhibition/excitation of smooth muscle,cardiac muscle, glandular secretions
-maintain homeostasis by regulating, readjusting and coordinating visceral function
Physiological roles: regulate heart (BP, HR, contractibility), regulate secretory glands (saliva, sweat, bronchiole), regulate smooth muscles (bronchi, blood vessels, urogential system, GI tract)

Question 2

What are three basic patterns of the ANS?

Answer 2

• SNS opposes PNS
• SNS compliments PNS
• innervation by one division of ANS

Question 3

What is the structure of the sympathetic nervous system?

Answer 3

-short preganglionic neuron, long postganglionic neuron

Question 4

What is the structure of the parasympathetic nervous system?

Answer 4

-long preganglionic neuron, short postganglionic neuron

Question 5

What are the neurotransmitters of the ANS?

Answer 5

Preganglionic: acetylcholine
Postganglionic - sympathetic: noradrenaline or adrenaline
Postganglionic - parasympathetic: acetylcholine

Question 6

What are the adrenergic receptors of the ANS?

Answer 6

a1: blood vessels, pupils, urinary bladder sphincter
a2: pancreas
b1: heart
b2: bronchioles of lungs

Question 7

What are the cholinergic receptors?

Answer 7

• nicotinic: first synapse of both SNS and PNS

- muscarinic: effector organ

Question 8

Sympathetic nervous system

Answer 8

• aka thoracolumbar division
• arises from lat horn of T1-L2
• fight or flight

Question 9

Parasympathetic nervous system

Answer 9

• aka craniosacral
• arises from brainstem via CNs III, VII, IX, X and sacral regions of S2-S4
• rest and digest - conserves energy

Question 10

PNS vs SNS - The eye: pupil, ciliary muscle, lacrimal glands

Answer 10

PNS: constricts pupil, contracts ciliary muscles (near vision), increases lacrimal secretion
SNS: dilates pupil, relaxes ciliary muscles (far vision), little effect on lacrimal glands

Question 11

PNS vs SNS - The heart: SA node, atrial muscle, AV node, ventricular muscle

Answer 11

PNS: decreases rate of SA node, decreases force of atrial muscle, decreases conduction velocity of AV node, decreases ventricular muscle force
SNS: increases rate of SA node, increases force of atrial muscle, increases automaticity of AV node, increases force of ventricular muscle

Question 12

PNS vs SNS - The GI tract: smooth muscles, salivary glands, gastric glands

Answer 12

PNS: increased motility of smooth muscles, increased secretion from gastric and salivary glands
SNS: decreased motility of smooth muscles, no effect of salivary or gastric glands

Question 13

PNS vs SNS - The respiratory tract: smooth muscle, glands

Answer 13

PNS: bronchoconstriction of smooth muscle, increased secretion of glands
SNS: bronchodilation of smooth muscles, decreased secretion of glands

Question 14

PNS vs SNS: The renal system: urination, blood vessesls, juxtaglomerular apparatus

Answer 14

PNS: increased urination, no effect on blood vessels or juxtaglomerular apparatus
SNS: decreased urination, vasoconstriction of blood vessels, renin secretion from juxtaglomerular apparatus

Question 15

What is exercise-induced vasovagal syncope?

Answer 15

• fainting during exercise
• common in young people
• may be more sinister - refer

Question 16

What occurs in the blood vessels, heart and kidneys when blood pressure is decreased?

Answer 16

Blood vessels: vasoconstriction
Heart: cardiac center increases heart rate and contractility therefore increasing cardiac output
Kidney: RAAS (renin-angiotensin-aldosterone system): renin secretion into blood –> angiotensinogen I conversion to angiotensin 2 by renin, converted into angiotensin 2 by ACE (angiotensin-converting enzyme) from lungs –> increases BP

Question 17

How does angiotensin 2 increase BP?

Answer 17

1. constrict blood vessels

2. stimulates adrenal cortex to release aldosterone which increases blood volume by increasing retention of H2O and Na+

Question 18

What is anaphylaxis?

Answer 18

acute allergic reaction to an antigen to which the body has become hypersensitive

Question 19

What are the symptoms of analphylaxis?

Answer 19

swelling, itching, hives, shortness of breath, cramps, nausea, vomiting, diarrhea

Question 20

What is in an epipen?

Answer 20

adrenaline to activate sympathic nervous system and reverse symptoms