autonomic nervous systems

Question 1

what components of the nervous system is part of the autonomic nervous system?

Answer 1

visceral efferent component

controls involuntary actions
no conscious though needed

Question 2

what are controlled by visceral efferents in the ANS

Answer 2

smooth muscles

cardiac muscles

various glands

Question 3

what are the 2 divisions on the ANS?

Answer 3

parasympathetic nervous system

sympathetic nervous system

Question 4

where are the cell bodies for the sympathetic nervous system?

Answer 4

cell bodies of pre-ganglionic neurons in the thoracic and lumbar regions of spinal cord

T1-L2

core origin - body wide actions

Question 5

where are the cell bodies for the parasympathetic nervous system?

Answer 5

cell bodies of pre-ganglionic neurons in the:

brain stem
CN 3, 7, 9 - head structures
CN 12 - thoracic and abdominal organs

Sacral Spinal cord
S2, 3, 4 - pelvic organs

top & tail origin - core action

Question 6

organisation of sympathetic nervous system

Answer 6

pre and post ganglionic neurons are similar in length

synapse in sympathetic chain or one of the collateral (or pre-vertebral) ganglia or in adrenal medulla

nervous and endocrine component in SNS
- adrenal medulla part of SNS but secretes adrenaline hormone too

Question 7

organisation of parasympathetic nervous system

Answer 7

long pre-ganglion neuron

short post-ganglionic neuron

ganglion is nearer effector organ

long pre as parasympathetic longer than sympathetic

Question 8

sympathetic nervous system roles

Answer 8

more widespread action - often affecting whole body (endocrine link)

associated with homeostasis - blood pressure, thermoregulation

fight, flight or fright

• meeting demands of active muscles
• anxiety has more active flight/fright mechanism

can have more drastic effect than PNS

doesn’t try to preserve energy

Question 9

parasympathetic nervous system roles

Answer 9

generally has discrete actions on single organs in the body ‘core’
e.g. salivary glands, heart

conservative anabolic effects - Rest & Digest

• storing energy (digestion)
• slowing heart

not a drastic change - often slow and steady
often maintains in a ready to go state

aims to save energy

Question 10

4 example organs/systems that ANS effect

Answer 10

smooth muscle

heart

glands

metabolism

ANS HAS NO EFFECT ON BREATHING
- skeletal muscles controlled by somatic nerves e.g. phrenic innervates diaphragm

Question 11

smooth muscles effected by ANS

Answer 11

blood vessels in various parts of the body

bronchi and bronchioles

Question 12

influence of ANS on heart

Answer 12

rate and force of contraction of heart

GI Tract: circulation reduced to increase volume of blood to other organs and muscles

Question 13

glads effected by ANS

Answer 13

salivary glands

gastro-intestinal glands

sweat glands

Question 14

metabolism connection to ANS

Answer 14

parasympathetic NS - stores energy

sympathetic NS - makes energy available to organs

Question 15

ANS effect on iris (radial and sphincter musclees)

Answer 15

parasympathetic - contraction

sympathetic - contraction

Question 16

ANS effect on ciliary muscle

Answer 16

parasympathetic - contraction

sympathetic - relaxation

Question 17

ANS effect on salivary glands

Answer 17

parasympathetic - copious, watery

sympathetic - viscous, low volume

both cause secretion but of different qualities

Question 18

ANS effect on on lacrimal glands

Answer 18

parasympathetic - secretion

sympathetic - secretion

Question 19

ANS effect on nasal glands

Answer 19

parasympathetic - secretion

Question 20

ANS effect on blood vessels

Answer 20

parasympathetic - no direct effect; indirectly GIT receives more blood as more digestion

sympathetic: change in diameter of vessels and bronchioles
- constriction of alpha NA receptor
- dilation of beta NA receptor

Question 21

parasympathetic ANS transmitters

Answer 21

Acetyl Choline (ACh)

both pre & post ganglion

Question 22

sympathetic ANS transmitters

Answer 22

ACh pre-ganglion

Noradrenalin post-ganglion onto effector organ

Adrenaline from adrenal medulla

Question 23

Noradrenaline ANS receptors

Answer 23

Alpha receptors

Beta receptors

Question 24

why does noradrenaline have different effects on different organs?

Answer 24

due to 2 receptors for NA having different functions

Question 25

effect of NA on alpha recpetors

Answer 25

vaso-constriction

contraction of smooth muscles in blood vessels

Question 26

effect of NA on beta receptors

Answer 26

bronchodilation

relation of bronchiole smooth muscle

Question 27

adrenaline ANS receptors

Answer 27

alpha 1 receptors

beta 1 receptor
beta 2 receptor

Question 28

effect of adrenaline on alpha 1 receptors

Answer 28

contraction of smooth muscle

Question 29

effect of adrenaline beta 2 receptors

Answer 29

relaxation of smooth muscle

Question 30

effect of adrenaline on beta 1 receptors

Answer 30

increase heart rate and force of contraction

Question 31

what are beta blockers?

Answer 31

block beta-1 adrenergic receptors only

so drug effects are restricted to heart cardiac muscles
(can interact with other receptors as not perfect)

lowers HR and force of contraction

Question 32

dental use of adrenaline

Answer 32

usefully neurtransmitter/hormone

many local anaesthetics contain adrenaline as a vasoconstrictor (not all)

keep dose in recommended limits

• circulatory system will move injection from intended area
• vasoconstrictor needed sometimes to reduce clearance so longer treatment time
• reduced blood flow not ideal for treatment as source of immune cells

can have potential side effects in susceptible patients
e.g. those with heart conditions (work on other effectors)

Question 33

what are the 2 types of cholinergic receptors?

Answer 33

muscarinic receptors

nicotinic receptors

distinguished by drugs, overall in areas and can give similar responses

Question 34

muscarininc cholinergic receptors

Answer 34

5 subtypes

important in dentistry as affects salivary glands

post-ganglionic

neuro-effector junctions

blocked by atropine
- if blocked won’t respond to adrenaline

Question 35

nicotinic cholinergic receptors

Answer 35

7 subtypes with different sub levels in each tissue too

pre-ganglionic and post-ganglionic neuron synapses

neuromuscular junctions

Question 36

what organs do parasympathetic and sympathetic auntonomic nervous control?

Answer 36

many organs in head, thorax, abdomen, pelvis

parasympathetic more associated with body core

Question 37

what organs receive sympathetic autonomic nervous control only?

Answer 37

blood vessels

glands in periphery e.g. skin, muscles

Question 38

how is control achieve in organs receive sympathetic autonomic nerve signals only?

Answer 38

by varying amount of sympathetic activity

single control

Question 39

what is the relationship between sympathetic and parasympathetic activity?

Answer 39

opposing effects usually

except genitalia (same effect here)

Question 40

how are organs that receive Both parasympathetic and sympathetic autonomic nervous signals controlled?

Answer 40

dual control
- ‘balancing’ their activity

opposing effects working on same part

Question 41

SA node dual control example

Answer 41

parasympathetic

• vagus nerve
• decreased HR

sympathetic
- increases HR

Question 42

blood vessel single control example

Answer 42

blood vessels supplied by sympathetic nerves only

control of BV diameter is controlled by varying sympathetic activity
- ‘sympathetic tone’

small change in BV diameter has big change on BP

Question 43

increased sympathetic activity on blood vessels

Answer 43

vasoconstriction

- higher BP

Question 44

decreased sympathetic activity on blood vessels

Answer 44

vasodilation

- Lower BP