Autonomic Nervous system Flashcards
sympathetic portion releases NE and tends to
excite an organ
parasympathetic proton releases _____ tends to ____ the same organ
acetylcholin
inhibit
SNS cell bodies of the preganglionic neurons are in the
thoracic and lumbar regions of the SC
SNS fibers leave the spinal cord and enter the sympathetic ganglion also known as the
paravertebral ganglion
pathways of SNS
short pre-ganglionic; long postganglionic
- SNS pre-ganglionic nt:
- Post ganglionic receptor:
- ACH
- nicotinic, Ach receptors
- SNS post ganglionic neurotransmitter
- target tissue receptor
- NE
- Alpha or beta adrenergic receptor
SNS increase
hr
PSNS decrease
hr
PSNS found in
brainstem, sacral spinal cord
PSNS pathways
long pre ganglionic; short post ganglionic
PSNS pre ganglionic and post ganglionic neurotransmitter
ACh
PSNS post ganglionic receptor
Nicotonic Ach receptor
PSNS target tissue receptor
muscarinic Ach receptor
Axon ends in
varicosities
NT synthesized in the
varicosities
Concentration of the ______ influences the strength of the target tissue response
neurotransmitters
What stops when NT is no longer present
target tissue
how is the NT removed
- diffuses away
- reuptake of the NT
- metabolized by enzymes in the ECF
(NE - monoamine oxidase, ACH- acetylcholinesterase)
the receptors of the SNS are called
adrenergic receptors
receptors of the PSNS are called
cholinergic receptors
SNS receptors
- nicotinic receptors (Ach)
- alpha receptors (a1, a2)
- beta receptors (b1 NE, b2 E)
PSNS receptors
- nicotinic receptors (Nn)
- muscarinic receptors (M1-M5)
Epinephrine comes from
adrenal medulla
NE comings from the
post ganglio fiber
NE binds strongly
a1 and a2
E binds strongly to
b2
PSNS - Ach binds to both
nicotinic and muscarinic receptors
Sympathetic B1 and B2 effects on the heart
increase HR
- increase contractility
PSNS M2 effect on the heart
- decrease HR
- slight decrease in contractility
SNS B2 effect on coronary arteries
vasodilator
SNS a1 and a2 effects on coronary arteries
vasoconstrict
PSNS M2 on coronary effects
vasodilate
a1 and a2 on small arteries and arterioles effect
vasoconstriction in skin and viscera
B2 on small arteries and arterioles
vasodilation in skeletal muscles and liver
a1 and a2 effects on veins
stiffening of the vein
A1 and a2 effect on adrenal medulla
release of NE and E
Regulation of HR by PSNS via and effect
- vagus nerve
- slows HR by inhibiting SA and AV node
- decrease contractility of the myocardium indirectly by inhibiting SNS
regulation of HR SNS via and effect
- cardiac accelerator nerves
- increase HR by stimulating SA and AV node
- increases contractility of the myocardium directly
cardiovascular control center is in the
medulla oblagonta
cardiac acceleration
sns
cardiac inhibitory center
psns
vagal stimulation only goes to the
heart
sympathetic stimulation goes to the
heart and blood vessels
NTS
nucleus tractus solitarius
HR is under what control
antagonistic control
what happens to AP of the SA node that is under SNS activation
the resting membrane potential is higher
what causes resting membrane potential to be higher?
increase of sodium and calcium influx leading to increase rate of the depolirzatino and increase HR
vagus nerve –>
aortic baroreceptors
Glossopharyngeal nerve –>
carotid sinus/body
SNS response to a decrease in blood pressure - effects on
- sa node
-myocardium
- arteries
- veins
- increase HR
- HR contractile
- arteries - vasoconstriction
- stiffen
adrenergic stimulation of blood vessels
- vascular smooth muscle is under tonic control by the SNSN
- increased firing rate vessel constricts
- decreased firing rate - vessel dilates
a1 adrenergic stimulation causes
vasoconstriction
b2 adrenergic stimulation vauses
vasodilation