Somatic and ANS Basics Flashcards
functions of general somatic nervous system
- voluntary movement of skeleton
- somatic senses (pressure, touch, pain)
- respiratory movements (diaphragm, accessory)
functions of ANS
- maintain homeostasis via metabolism, digestion, excretion
- respond to changes in environment
- fight or flight
- sexual activity
what regulates nerves running to diaphragm
brain ANS regulatory systems INFLUENCE CNS which then influences somatic system nerves
describe PSNS neurons
long preganglionic, ganglion is on tissues, short postganglionic
describe SNS neurons
short pregang, gang in sympathetic gang, long post synaptic
advantage of short postgang efferects?
more selective pattern of activity
what do nicotininc receptors affect
Na and K conductance
what do muscarinic M1 receptors produce
delayed and longer acting EPSP bc working on 2ndmsgr system
where is Ach released?
- all pregang terminals of ANS
- all PSNS postgang terminals
- sympathetic post gang terminals at sweat glands and BV
- termanls of efferent neurons supplying skeletal muscle
- . CNS
where is NE released
- most sympathetic post gang terminals
- adrenal medulla
- CNS
what is the exception of sympathetic nervous system Ach release?
sympathetic postganglionic terminals release Ach at sweat glands and some blood vessels in skeletal muscle
what is the impact of SNS action on the heart?
B1 adrenergic causes increased HR and force of contraction whole heart
impact of PSNS on action of heart
decreased rate, decrease rate of contraction of atria
impact of SNS on blood vessels
bind to alpha 1 adrenergic to cause constriction
impact of PSNS on blood vessels
dilation of vessels of penis and clitoris only
site of origin of somatic nervous systeem
lateral horn of spinal cord
site of origin of ANS
sympathetic is in lateral horn of lumbar and thoracic spinal cord; parasymp is in the brain and sacral spinal cord
what does it mean that responses of adrenergic receptors are dose dependent?
same transmitter will evoke different overall response depending on its concentration at the target tissue, since both NE and epi activate both alpha and beta adrenergic receptors.
what do all beta adrenergic receptors do
increase cAMP – response depends on location (sm muscle decreases force, cardiac increases force)
effects of alpha1 adrenergic receptors
- vasoconstriction
- increased peripheral resistance
- increased blood pressure
- mydriasis (dilation)
- increased closure of internal sphincter of bladder
effects of alpha2 adrenergic receptors
- inhibition of NE release (bc receptors at presynaptic terminal)
- inhibition of Ach release
- inhibition of insulin release
effects of beta1 adrenergic receptors 1
- tachycardia
- increased lipolysis
- increased myocardial contractility
- increased release of renin (angiotensin II, constriction)
effects of beta2 adrenergic receptors
- vasodilation
- slightly decreased peripheral resistance
- bronchodilation
- increased muscle and liver glycogenolysis
- increased release of glucagon
- relaxed uterine and smooth muscle
what do M1,3,5 do?
increase IP3 and DAG
what do M2,4 do?
decrease cAMP
odd muscarinic receptors do?
increase IP3 and DAG
even muscarinic receptors do?
decrease cAMP
what is the response of hemorrhage on the ANS?
decreased blood volume makes arterial blood pressure drop, stimulating SNS to increase HR
