autonomic nervous system Flashcards
central autonomic nervous system
subconscious but conscious override
peripheral autonomic nervous system
sympathetic and parasympathetic
what is SNS’s job?
fight or flight
SNS origins
thoracolumbar (T1-L2/3) (except the cervical ganglia which supplies the head)
SNS ganglia location
next to the spinal chord
SNS NTs
preganglionic synapse - ACH
postganglionic synapse - noradrenaline (except sweat glands and deep blood vessels - ACH)
SNS response
dilated pupils
dry mouth
uncongested nose
adrenaline release
chronotropy inotropy (heart)
vasodilation
smooth muscle in bronchi relax
constipation -> reduce GI blood supply
urinary retention/ fluid retention
renal (vasoconstriction -> increase renin -> further vasoconstriction)
reduce excessive heat
SNS receptors
Alpha 1 + 2
- 1 = arteriole constriction
- 2 = venous constriction (and coronary artery)
Beta 1 + 2
- 1 = heart (increase heart, increase contractility)
- 2 = lungs, uterus, skeletal blood vessels, bladder, eye, gut ,smooth muscle relaxation
agonist and antagonist of each
SNS receptor-targeted drugs
alpha 2 agonist - yohimbine
- medicine in vet practice
Beta 2 agonist - salbutamol
- asthma inhaler
- also used in premature labour (stop uterine stimulation)
Beta 1 agonist - atenolol
- lowers blood pressure
- taccharrthymia
- secondary MI prevention
what is the role of the parasympathetic nervous system?
rest and digest
PNS origins
craniosacral outflow
- cranial - 3 (oculomotor), 7 (facial/ otic ganglia), 9 (glossopharyngeal), 10 (vagus) nerves
- sacral - S2,3,4
PNS ganglia
near site of action
- cervical -> cervical area
- thoracic -> heart and lungs
- coeliac -> gut and genitourinary
PNS NTs
ACH in pre and post ganglionic synapse
PNS response
- pupillary constriction - improves near vision
- nasal engorgement
- excess salivation
- increased gastric secretions and blood flow
- slow heart rate
- broncho constriction
- micturition/ defecation/ ejaculation
- lacrimation
PNS receptors
muscarinic receptor (muscular)
- most in CNS (M2/M3)
- M2 = heart
- M3 = salivary glands, gut, bladder, blood vessels, eye
nicotinic receptor
- NMJ
- N2 - mainly in autonomic ganglia; some in brain
PNS receptor-targeted drugs
muscarinic receptor antagonist (M2)
- atropine
- reduces effect of ACH on the heart
- increases heart rate
M1 agonist - Xanomeline
- potential treatment of Alzheimer’s and Sz
N1 antagonist - succinylcholine
- stimulation, depolarised, muscle spent ad then paralysed
N2 antagonist - vecuronium bromide
- non-depolarising muscle blocker
autonomic dysfunction - CVS
Brady tachycardia; hypotension
autonomic dysfunction - GI
GI disturbance, excess salivation
autonomic dysfunction - vascular
flushing, excess sweating
autonomic dysfunction - eyes
visual disturbances
autonomic dysfunction - GU
urgency, incontinence
autonomic dysfunction - adrenal
feeling of dread/ panic
autonomic dysfunction - respiratory
wheeze
autonomic dysfunction - sexual
erectile dysfunction
functions of the brain stem
cranial nerve function
conduit function
integrative functions
brain stem death
paralysis and unconsciousness
apnoea
loss of cranial nerve function
- coning
enteric nervous system
manages how the body digests food
testing for brain stem death
two people must be present - one does the procedure and the other watches; few hours later they swap roles
- thin plastic tube placed down throat to see if they gag
- disconnected from ventilator for a short period of time to see if they attempt to breathe on their own
- eye is stroked with paper or cotton to provoke a response
- pressure on the forehead
