Flashcards in Lecture 37 Deck (60)
The ANS innervates what tissues?
1. smooth muscle tissue
How does the ANS effect blood vessels?
blood pressure and body temp.
How does the ANS impact the GI?
How does the ANS impact the bladder?
How does the ANS impact the bronchial tree?
bronchial dilation or constriction
how does the ANS impact the eye?
pupillary dilation or constriction
How does the ANS impact the heart?
heart rate and heart contractility
How does the ANS impact the endocrine glands such as the pancreas and ardrenal glands?
how does the ANS impact the exocrine glands such as the sweat glands, salivary glands, and lacrimal glands?
What does the vagus nerve innervate?
Parasympathetic fibers Innervation of the thoracic and
What is a vagomoty?
a surgical operation in which one or more branches of
the vagus nerve are cut, typically to reduce the rate of gastric secretion (e.g. in treating peptic ulcers)
What are the characteristics of the cholinergic fibers and adrenergic fibers of the sympathetic NS?
The adrenergic fibers are much longer than the cholinergic fibers.
short cholinergic preganglionic fiber
long adrenergic postganglionic fiber
adrenergic fiber innervates the effector tissue
What are the characteristics of the cholinergic fibers and adrenergic fibers of the parasympathetic NS?
long cholinergic preganglionic fiber
short cholinergic postganglionic fiber
What is the primary neurotransmitter of the postganglionic neurons in the sympathetic?
What is the primary neurotransmitter of the postganglionic neurons in the parasympathetic?
What kind of fiber innervates the adrenal medulla?
Directly innervated by preganglionic sympathetic fibers.
What fibers innervate sweat glands?
Innervated by cholinergic sympathetic postganglionic neurons
Receptors on the sweat glands are cholinergic muscarinic: M3
What fibers innervate the renal vasculature smooth muscle?
Innervated by dopaminergic sympathetic postganglionic neurons
Receptors on the renal vasculature are dopaminergic: D1
What are chromaffin cells and where are they found?
Chromaffin cells releases catecholamines
into the CIRCULATION: 80% Epinephrine(E),
they are found in the adrenal gland
What fibers synapse with chromaffin cells?
Preganglionic sympathetic axons
What is pheochcromocytoma?
It is the most common tumor found in the adrenal medulla in adults
derived from chromaffin cells
What are the symptoms of pheochcromocytoma?
1. elevated blood pressure
3. excessive sweating
How to determine pheochcromocytoma? (lab)
elevated catecholamines and their metabolites (metanephrine)
how to treat pheochcromocytoma?
surgery (Phenoxybenzamine + Beta-blocker during preop)
Explain the synthesis of acetylcholine?
1. Acetyl CoA synthesized in mitochondria.
2. Choline transported into the neuron terminal by
a sodium-dependent carrier (CHT1).
3. ACh is synthesized in the cytoplasm from acetyl-CoA and choline, a reaction catalysed by choline acetyltransferase (ChAT).
4. ACh transported into vesicles by a the vesicular
ACh transporter (VAChT).
5. ACh released occurs when an action potential reaches the terminal and triggers calcium influx
through voltage-gated calcium channels
What is the rate-limiting step of ACh synthesis?
the uptake of choline
Explain cholinergic transmission of acetylcholine?
1. ACh binds to cholinergic receptors: nicotinic
or muscarinic in the postsynaptic membrane
2. ACh binds to presynaptic M2 Ach receptors,
which inhibit Ach release
3. Acetylcholinesterase (AChE) splits ACh into
choline and acetate
What happens during organophosphate poisoning?
it will irreversibly bind to the enzyme aceytlcholinesterase
symptoms of organophosphate poisoning?
muscarinic: diarrhea, urination, miosis, bronchospasm, bradycardia, emesis, lacrimation, sweating, salivation
Nicotinic: neuromuscular blockade
CNS effects: respiratory depression, lethargy, seizures, coma