ANS Part 1 Flashcards
What’s the difference between the somatic vs autonomic nervous system?
Somatic: conscious, voluntary motor control of skeletal muscles
Autonomic: involuntary motor control of primarily visceral organs
Describe where the preganglionic neurons originate in the sympathetic vs parasympathetic nervous system AND their lengths
sympathetic: thoracolumbar spinal cord (T1-L3)/ SHORT
Parasympathetic: brain stem & sacral spinal cord (S2-S4)/LONG
What neurotransmitter does the sympathetic NS release from preganglionic neurons and what receptor is this NT activating?
ACh and nicotinic 2
What neurotransmitter does the parasympathetic NS release from preganglionic neurons and what receptor is this NT activating?
ACh and nicotinic 2
What NT does adrenergic neurons release?
Norepinephrine
What NT does cholinergic neurons release?
ACh
What NTs activate adrenoreceptors?
Norepinephrine AND epinephrine
What NT activates cholinoreceptors?
ACh
How does epinephrine get into circulation?
Adrenal medulla secretes it
What is the junction between the post-ganglionic neuron and effectors (target tissues) called?
Neuroeffector junction
What is the length of the sympathetic VS parasympathetic post-ganglionic neurons?
Sympathetic: LONG
Parasympathetic: SHORT
Where does the cell body of each preganglionic neuron reside?
CNS
Where do axons of pre-ganglionic neurons synapse on?
cell bodies of post-ganglionic neurons in an autonomic ganglia OUTSIDE CNS
Where is the sympathetic autonomic ganglia located?
Paravertebral ganglia (sympathetic chain) and prevertebral ganglia
Where is the parasympathetic autonomic ganglia located?
in or near effector organs
What are the two main types of effector organs the sympathetic NS has impact on?
1) . Smooth muscle/glands
2) . Thermoregulatory Sweat glands
What is the main type of effector organ the parasympathetic NS has impact on?
Smooth muscle/glands
What NT does the parasympathetic postganglionic neuron release? What type of receptor does this activate?
ACh
Muscarinic (cholinergic influence)
What NT does the sympathetic postganglionic neuron release on smooth muscle/glands?
Norepinephrine
What NT does the sympathetic postganglionic neuron release on sweat glands? What receptor does this activate?
ACh
Muscarinic (cholinergic influence)
What are the four types of receptors on sympathetic smooth muscles/glands activated by norepinephrine or epinephrine?
Alpha 1
Alpha 2
Beta 1
Beta 2
What is the receptor type on somatic skeletal muscle end plate?
N1- nicotinic receptor
What action does the sympathetic NS have on the Heart (SA node, HR/AV nodal conduction/Contractility)
Increases all
B1 receptor
What action does the parasympathetic NS have on the Heart (SA node, HR/AV nodal conduction/Contractility)
Decreases all
Muscarinic receptor
What is the action on the bronchioles for sympathetic VS parasympathetic innervation?
sympathetic- dilates (B2 receptor)
parasympathetic- constricts (muscarinic receptor)
What are the actions on GI tract smooth muscle walls vs smooth muscle sphincters by sympathetic innervation?
walls- relaxation (a2, b2 receptors)
sphincters- contraction (a1 receptors)
What are the actions on GI tract smooth muscle walls vs smooth muscle sphincters by parasympathetic innervation?
walls- contraction
sphincters- relaxation
**Both muscarinic receptors
What are the actions on bladder detrusor muscle (wall) vs sphincter by sympathetic innervation?
BLADDER FILLING
wall- relaxes (b2 receptor)
sphincter- contracts (a1 receptor)
What are the actions on bladder detrusor muscle (wall) vs sphincter by parasympathetic innervation?
BLADDER EMPTYING
wall- contraction
sphincter- relaxation
**both muscarinic receptors
What are the male genitalia actions when innervated by sympathetic vs parasympathetic NS?
Sympathetic: ejaculation (a receptors)
parasympathetic: erection (m receptor)
What are the actions on the iris radial muscle vs ciliary eye muscle by sympathetic innervation?
radial muscle- dilates pupil (a1 receptor)
ciliary muscle- dilates for far vision (b receptor)
What are the actions on the iris circular sphincter muscle vs ciliary eye muscle by parasympathetic innervation?
Circular sphincter- constricts pupil
ciliary- contracts for near vision
**Muscarinic receptor
During bladder filling, what is the action of the external sphincter and what NS controls its?
External sphincter is control by somatic NS
contracted (voluntary)
During bladder emptying, what is the action of the external sphincter and what NS controls its?
Controlled by somatic NS
relaxed (voluntary)
What is the action on thermoregulatory sweat glands in skin by sympathetic innervation?
increase in action (MUSCARINIC receptor)
What is the action on thermoregulatory sweat glands in skin by parasympathetic innervation?
Non existent; only sympathetic has innervation
What are the four target tissues for A1 receptors?
GI sphincters
Bladder internal sphincter
Radial muscle, iris
Vascular smooth muscle, skin, renal, splanchnic
What is the target tissue for A2 receptors?
GI tract wall
What is the main target tissue for B1 receptors?
HEART
also salivary glands, adipose tissue, kidney
What are the three main target tissue for B2 receptors?
GI tract wall
Bladder wall
BRONCHIOLES
Where are the three locations for nicotinic receptors?
1) . Skeletal muscle, motor end plate (N1)
2) . Post ganglionic neuron cell bodies PNS & SNS (N2)
3) . Adrenal medulla (N2)
Where are the two main locations for muscarinic receptors?
1) . All effector organs in PNS
2) . Sweat glands in SNS
What is the important NT and receptor type when we think of treating severe hypotension/shock?
Norepinephrine
A1 agonist
What condition do we think about in regards to epinephrine and B2 receptor?
Hypotension
If a patient has asthma but needs to control high BP, what beta blocker should be used?
B1 blocker ONLY (metoprolol)
**B2 blockers would constrict bronchioles
If a patient has a migraine and high BP, what beta blocker should be used?
Propranolol
Because non selective BBs can cross the blood brain barrier into CNS
**also make sure pt doesn’t have asthma
What action does the parasympathetic NS have on saliva secretion?
Increase by muscarinic receptor
Explain what NTs the adrenal medulla has influence on: talk about preganglionic neuron and what is released into circulation
Preganglionic neuron (located in thoracic spinal cord) is releasing ACh on Nicotinic 2 receptor on adrenal medulla chromaffin cells chromaffin cells then secrete epinephrine (80%) & norepinephrine (20%) into general circulation
What are the side effects of using scopolamine for motion sickness? Explain process & why side effects occur
- Medication blocks muscarinic receptors in target tissues
- Usually muscarinic receptor activation increases saliva, constricts pupils, decreases HR, and contracts bladder wall to pee
- Therefore, blocking this receptor gives symptoms of dry mouth, dilates pupils, increases HR, and slow voiding of urine
