autonomic nervous system

Question 1

features of the autonomic nervous system

Answer 1

involuntary
2 neuron chain
ACh before ganglion then either ACh(excitatory) or noradrenaline (inhibitory) after
innervates smooth muscle, cardiac muscle and glands
both excitatory & inhibitory

Question 2

features of the somatic nervous system

Answer 2

conscious/voluntary 
single neuron 
ACh 
innervates skeletal muscle 
always stimulatory

Question 3

what does the autonomic nervous system divide into

Answer 3

sympathetic & parasympathetic & enteric

Question 4

functions of sympathetic NS

Answer 4

increase heart rate 
constrict blood vessels 
bronchoconstriction
decrease motility, sphincter contraction, decrease secretions  
male ejaculation

Question 5

functions of parasympathetic NS

Answer 5

decrease heart rate 
dilate blood vessels 
bronchodilation 
increased motility, sphincter relaxation, increased secretions 
male erection

Question 6

sympathetic NS facts

Answer 6

o sympathetic chain vulnerable to spinal injury
o sympathetic chain runs from T1-L2
o White and grey rami communicates, sympathetic chain
o Fight or flight
o Ach at preganglionic synapse – nicotinic receptors
o Effector cell synapse – noradrenaline – adrenergic receptors
o Preganglionic fibres form the lateral grey horn
o Supplies visceral organs and structures of superficial body regions
o Its effects are amplified by the adrenal glands

Question 7

parasympathetic outflow - cranial outflow

Answer 7

comes from brain
cell bodies located in cranial nerve nuclei in the brain stem
cranial nerves: 10, 9, 7, 3
innervates the organs of the head, neck, thorax & abdomen

Question 8

parasympathetic outflow - sacral outflow

Answer 8

supplies remaining abdominal and pelvic organs

Question 9

parasympathetic NS facts

Answer 9

• Ganglia lie within/very close to the organs that the postganglionic neurons innervate
• Ach – preganglionic neurone synapse – nicotinic receptors
• Ach – effector cell synapse – muscarinic receptors

Question 10

what are the sympathetic receptor sub-types

Answer 10

o Alpha: alpha1, alpha2 ( constriction of blood vessels)

o Beta: beta1,2,3 (B1- tachycardia, B2 - dilation)

Question 11

enteric nervous system

Answer 11

o Can work independently from ANS

o Nervous system of the GI tract

Question 12

autonomic cardiovascular control

Answer 12

o Carotid receptor – chemo and mechano receptors (carotid baroreceptor reflex pathway)

Question 13

primary disorders of the autonomic NS

Answer 13

o acute – pan-dysautonomia with neurological features

o chronic – pure autonomic failure, multiple system atrophy, autonomic failure with Parkinson’s disease

Question 14

secondary disorders of the autonomic NS

Answer 14

o diabetes mellitus
o chronic renal failure
o chronic liver failure
o alcohol induced
o inflammatory – Guillain-Barre syndrome
o infections – tetanus, Chagas’ disease, HIV
o Neoplasia – brain tumours, especially of third ventricle or posterior fossa

Question 15

other disorders of ANS

Answer 15

Cardiovascular disorders: postural & supine hypertension, tachycardia & bradycardia, fainting
Sexual disorders: erectile failure, ejaculatory failure
Fainting vasovagal syncope
Disorders of eyes: ptosis, pupillary abnormalities

Question 16

how do you test the ANS

Answer 16

heart rate 
o	Blood pressure 
o	Preferably beat by beat 
o	tilt test 
o	radial artery 
o	baroreflex testing