Sympathetic NS Flashcards
what is the control and integrative centre for the ANS
hypothalamus
which two ways can the hypothalamus release an output
influence the secretion of hormones from the pituitary gland
discharge impulses down the cord or pre-ganglionic neurons in the brainstem
which three tissues are stimulated by the autonomic nervous system
cardiac muscle
smooth muscle
glands
effects of sympathetic stimulation on:
heart
arteries of the heart and voluntary muscles
arteries of the skin and peripheral areas
liver
peristalsis
pupils
sweat
heart: beats stronger and faster
arteries of the heart and voluntary muscles: dilate
arteries of the skin and peripheral areas: constrict
liver: secretes glycogen
peristalsis: slows down
pupils: dilate
sweat: reduced body temp
where are pre-ganglionic sympathetic cell bodies located
intermediolateral horn of T1 - L2
where do the axons of pre-ganglionic sympathetic fibres connect
leave the cord via the ventral roots and enter the sympathetic trunk
chemical transmitter between post-ganglionic sympathetic axons and the structures they innervate
mostly noradrenaline
in some cases adrenaline
use of adrenaline or noradrenaline in hospitals
cases of hypotension and cardiac arrest
treatment of anaphylactic shock
to dilate the bronchioles in acute asthma
where are the pre-ganglionic cell bodies of sympathetic nerves that supply the heart and lungs
where do they synapse
intermediolateral horn of T1-T5 spinal segments
T1-T5 ganglia along the sympathetic trunk
what is the route of post-synaptic sympathetic fibres that supply the heart
transverse cardiopulmonary splanchnic nerves and cardiac plexus
end in the SA node, AV node and on the coronary arteries
adrenergic receptors on coronary blood vessels
Beta 2
when activated cause relaxation of vascular smooth muscles of the arteries
where are the pulmonary plexuses
posterior to the roots of the lungs
where do the pre-ganglionic sympathetic nerves that supply the abdominal and pelvic organs arise
where do they
abdominal: T5-T12
pelvic: L1-L2
pre-aortic ganglia in front of the abdominal aorta
(do not synapse in the chain ganglia but do pass through it
what path do post-ganglionic sympathetic axons take to reach abdominal and pelvic organs
follow the arteries that supply it
sympathetic supply of the adrenal gland
pre-ganglionic axons synapse on the cells in the adrenal medulla
produces adrenaline
sympathetic supply of the male internal genital organs
causes contraction of these organs
initiates ejaculation
sympathetic supply of female internal genital organs
causes uterine contraction
pre-ganglionic sympathetic supply of the skin
pre-ganglionic fibres leave the cord, peel off from the spinal nerve,
join sympathetic ganglia via white rami communicantes,
synapse in the sympathetic ganglia
post-ganglionic sympathetic supply of the skin
rejoin the spinal nerve via grey rami communicantes
distributes via the spinal nerve to the skin
many supply sweat glands and peripheral arteries of extremities and head
sympathetic supply of the orbit and eye
ganglia in the neck supply the muscle of the upper eyelid, dilator papillae and skin of the face and neck
Horner’s syndrome
damage to the sympathetic system centrally or to the superior cervical ganglion
may result in group of signs on one side of the face:
drooping of upper eyelid
small fixed pupil
flushing of the skin of face and neck
