Introduction To ANS Flashcards
The nervous system is made up of❓
- Central NS:
Brain
Spinal cord - Peripheral NS:
Somatic NS
Autonomic NS:
Sympathetic(thoracolumbar)
Parasympathetic(craniosacral)
What is the basic anatomical difference btwn the motor pathway of the somatic ND and the autonomic NS❓
Somatic NS:
Cell bodies of motor neurons reside in the CNS and their axons extend to skeletal muscles
Autonomic NS:
usually 2 neurons
preganglionic neuron in CNS Ganglionic(cell body outside CNS) neuron to organ
Say something about the parasympathetic system
- Craniosacral b/c
- preganglionic neurons are in the brain stem or sacral levels of spinal cord
- ACH at preganglionic and postganglionic synapses
Mention the outflows of the parasympathetic system and what they control
•Cranial outflow III- pupils constrict VII- tears, nasal mucus, saliva IX- parotid salivary gland X- visceral organs of thorax and abdomen: -Stimulates digestive glands -⬆️motility of smooth muscles of GI -⬇️heart rate -Causes bronchial constriction
•Sacral outflow(S2-4)
from pelvic splanchic nerves
supply all pelvic organs and 2nd half of large intestine
Mention the outflows of the sympathetic system and what they control
Neurons are in lateral horn of grey matter from T1-L2
Preganglionic NT: ACH
Postganglionic: Norepinephrine
Postganglionic (sweat glands): ACH
Vasoconstriction Dry mouth Pupil dilation ⬆️heart and respiratory rates ⬆️glucose mobilization
The adrenal gland belongs to the ______ division of the NS
What function does it subserve❓
Sympathetic
It caused a body-wise release of epinephrine and norepinephrine in an extreme emergency
A tumor of the adrenal medulla is known as ❓
What are the clinical features❓
Pheochromocytoma
⬆️arterial pressure ⬆️blood flow to muscles ⬆️blood glucose ⬆️mental activity ⬆️cellular metabolism ⬆️glycogenolysis
The amygdala can stimulate sympathetic activity
True or false❓
True
The enteric nervous system refers to a collection of neurons in the walls of the GI
What does it include❓
Myenteric plexus of Auerbach
Submucous plexus of Meissner
Tell me a bit about NTs
ACH-Acetyl CoA+Choline by CAT
-neuromuscular jnctn
Dopamine-in VTA and substantia nigra
NE-found in locus coerulus
EPI-sympathoexcitatory
-found in adrenal medulla and medulla oblongata
5HT- found in raphe nuclei in brainstem
Talk extensively on drug intervention by cholinergic transmission
Precursor transport
🚫
Hemicholinium
Synthesis
Storage
🚫
Vesamicol
Release
🚫
Botulinum toxin
Receptor+action
🚫Atropine (anti M)
🚫Succinylcholine (anti Nm)
🚫Trimethaphan (anti Nn)
✔️Carbachol
✔️Pilocarpine
Degradation
🚫Neostigmine (R)
🚫Organophosphate (NR)
The fate of ACH degradation could either be in ❓
Nerves:
True
Specific
Highly potent
Or Plasma: False Nonspecific, binds to any ester Less potent
Physiostigmine can be correctly described as❓
An indirect agonist of Ach receptors
Talk extensively on drug intervention by adrenergic transmission
Tyrosine
⬇️ 🚫Metyrosine
DOPA
⬇️🚫Reserpine
Vesicle
⬇️
Release 🚫Bretylium
🚫Guanethidine
✔️Amphetamine
✔️Tyramine
✔️Ephedrine
⬇️
Receptor action 🚫Phentolamine
🚫Propanolol
✔️Albuterol
✔️Isoproterenol ⬇️ Recapture by uptake ✔️Cocaine ✔️Tricyclic antidepressants eg imipramine
What are the sites where catecholamines are released❓
NE: Sympathetic postsynaptic endings
Adrenal medulla:
E: 80%
NE: 20%
What is the fate of catecholamines❓
Active reuptake: 80-90%
Destruction: 7%
Excretion: 3%
How does “pargyline” work❓
Antidepressants like parygline are MAO inhibitors
🚫degradation of catecholamines
⬆️catecholamine levels in CNS
What are the effects of the ANS in the skin❓
Skin: apocrine gland
S: secretion
Skin: eccrine gland
P: no action
What are the effects of the ANS in the special senses❓
Iris of eyes:
S: dilation
P: constriction
Tear gland:
S: inhibition
P: secretion
What are the effects of the ANS in the endocrine system❓
Adrenal cortex
S: secretion
Medulla
P: no action
What are the effects of the ANS in the digestive system❓
Gallbladder
S: relaxation
P: constriction
Intestine
S: decreases peristalsis
P: increases peristalsis
Smooth muscles
S: relaxation
P: constriction
Sphincters
S: constriction
P: relaxation
Pancreas
S: decreases
P: increase
What are the effects of the ANS in the respiratory system❓
S: dilate bronchioles
P: constrict bronchioles
What are the effects of the ANS in the heart❓
S: increases heart rate
P: decreases heart rate
What are the effects of the ANS in the blood vessels of skin and others❓
S: constriction
P: dilation
What are the effects of the ANS in the urinary system❓
Bladder
S: relaxation
P: constriction
Urinary sphincter
S: constriction
P: relaxation
What are the effects of the ANS in the reproductive system❓
Penis
S: erection
P: ejaculation
Vagina
S: erection
P: constriction of vagina
Classify PNS receptors
- Cholinergic R.
•Nicotinic:
Nm-neuromuscular/muscle type
Nn-neuronal/ganglion type
•Muscarinic:
M1, M3, M5-Gq coupled
M2, M4-Gi coupled
2. Adrenergic R. alpha1-a1A, a1B, a1D alpha2-a2A, a2B, a2C b1 b2 b3
- Dopamine R.
D1, D2, D3, D4, D5
Where are a1 receptors found❓
What functions do they subserve❓
a1:
•Postsynaptic effector cells- esp. smooth muscle
- vasoconstriction
- hepatic glycogenolysis
Where are b1 receptors found❓
What functions do they subserve❓
Distribution:
•postsynaptic effector cells-
•heart, lipocytes, brain, presynaptic adrenergic/cholinergic terminals
Functions
•⬆️cardiac rate and force
•relaxation of GI smooth muscle
Where are b3 receptors found❓
What functions do they subserve❓
- Postsynaptic effector cells-lipocytes
* lipolysis
Where are b2 receptors found❓
What functions do they subserve❓
Distribution:
•postsynaptic effector cells-
•smooth muscle, cardiac muscles
Functions: • Bronchodilation •Vasodilation •Relaxation of visceral smooth muscle •Hepatic glycogenolysis
Where are a2 receptors found❓
What functions do they subserve❓
Distribution:
•Presynaptic adrenergic nerve terminals (autoreceptor)
•Platelets, lipocytes, smooth muscle
Functions:
•Inhibitor of transmitter release
•Platelet aggregation
•Relaxation of smooth muscles
Describe the effects of adrenergic and cholinergic receptors on the heart
Rate of contraction-
Adrenergic: ⬆️b1
Cholinergic: ⬇️M2
Force of contraction
Adrenergic: ⬆️b1
Cholinergic: ⬇️M2
Describe the effects of adrenergic and cholinergic receptors on the
- Arteries
- Veins
- Skeletal muscles
On arteries
A: a1 causes vasoconstriction
On veins
A: a2 causes vasoconstriction
On skeletal muscle
A: b2 causes vasodilation
Describe the effects of adrenergic and cholinergic receptors on the lungs
A:
b2- Bronchiodilation
C:
M3- bronchioconstriction
Describe the effects of adrenergic and cholinergic receptors on the genitourinary smooth muscle
On bladder wall:
b2-Relaxation
M3-Contraction
On ureter
a1-Contraction
M3-Relaxation
On Sphincter
a1-Contraction
M3-Relaxation
On uterus
b2-relaxation
a1-contraction
Penis/Vas
a1- Ejaculation
M3- Erection
Describe the effects of adrenergic and cholinergic receptors on the GIT
•Salivary glands:
a1- ⬆️secretion
M3- ⬇️secretion
•Smooth muscles:
Walls:
a2, b2- relaxation
M3- contraction
Sphincters:
a1- contraction
M3- relaxation
•Secretion
M3- ⬆️ secretion
Describe the effects of adrenergic and cholinergic receptors on the
- Skin
- Sweat glands
•Skin:
Hair follicles, smooth muscle:
a1- contraction, piloerection
•Sweat glands:
Thermoregulation:
M3: ⬆️secretion
Apocrine(stress):
a1: ⬆️secretion
Describe the effects of adrenergic and cholinergic receptors on the
- Liver
- Fat cells
- Kidney
- Pancreas
Liver:
a1, b2- glycogenolysis and gluconeogenesis
Fat cells:
b1, b3- lipolysis
Kidney:
b1- increase renin secretion
Pancreas:
a2- ⬇️insulin release
Describe the effects of adrenergic and cholinergic receptors on the eye
•Iris: Radial muscle: a1- contraction (mydriasis) Circular muscle: M3- contraction (miosis)
•Ciliary muscle:
b2- relaxation
M3- contraction
Cholinergic effects:
- contraction of pupillary constrictor muscle (miosis-constricted pupil)
- contraction of ciliary muscle (bulge of lens)
- near vision
- ⬆️ outflow of aqueous humor
Adrenergic effects:
- contraction of pupillary dilator muscle (mydriasis- dilated pupil)
- stimulation of ciliary epithelium
- ⬆️production of aqueous humor
•Ciliary epithelium:
b2- ⬆️secretion of aqueous humor
Ach mediated vasodilation works via❓
Muscaranic receptors on the endothelium
⬆️Nitric oxide production from arginine- induces smooth muscle relaxation
⬆️Cyclic GMP
⬆️Protein kinase
⬇️Ca2+
⬇️Ca2+ sensitivity of cross bridge formation
