WEEK 6 Flashcards
what effectors express alpha receptors
Vasoconstriction (α1)
Iris dilation (α1)
Intestinal relaxation (α1)
Intestinal sphincter contraction (α1) Bladder sphincter contraction (α1) Liver glycogen breakdown (α1) Inhibits neurotransmitter release (α2)
what effectors express beta receptors
Vasodilation (β2)
↑heart rate (β1)
↑ cardiac force contraction (β1) Intestinal relaxation (β2)
Uterus relaxation (β2) Bronchodilation (β2)
↑ glycogen breakdown (β2) Bladder wall relaxation (β2)
fill in.
Adrenergic receptors bind _______ and _______
norepinephrine or epinephrine.
what are the two subtypes of adrenergic receptors?
GPCR: α and β
Fill in.
α1 are widely expressed on ________; Interacts with __________ ; activation causes __________. Found on cells ___________ and activation causes reduction in__________. Causes contraction of radial muscles of ________(dilation)
arteries/arterioles; Gαq/IP3/DAG : vasoconstriction; juxtaglomerular : renin release; iris
Fill in.
α2 are not widely distributed; interacts with _______; found in ________ where it mediates _________ feedback on sympathetic outflow and on presynaptic terminals (↓NE release). On platelets (stimulates aggregation). Beta cells (decreases insulin secretion)
Gαi ; brainstem : negative
Fill in.
β1 Interacts with_______; expressed in _____; increases _______ and force of _______. Found on cells of the ________ kidney; activation increases _______ .
Gαs; heart ; heart rate ; contraction; juxtaglomerular renin secretion
Fill in.
β2 Interacts with_____; expressed on ________; cause _________ and vasodilation b/c smooth muscle relaxation
Gαs; bronchioles ; bronchodilation
Fill-in .
β3 Interacts with_____; found on postsynaptic effector cells in ______ and ________ ; similar effects to β1
Gαs; lipocytes; myocardium
sympathetic activation of the heart causes
Increased heart rate and stroke volume, dilation of coronary arteries
what is the purpose of the fight, flight, or freeze reaction
- delivery oxygen and glucose to working skeletal muscles
what happens in the heart, respiratory system, metabolic system, sweat glands, and eyes in fight, flight or freeze reaction
Cardiac:
- heart rate, contractility increase to increase cardiac output
- Blood vessels: Vascular smooth muscle contracts causing widespread vasoconstriction.
- blood redirected to working muscles
Respiratory:
- bronchial dilation
Metabolic:
- increases glycogenolysis (glycogen break down) and gluconeogenesis
- Enhances lipolysis elevates free fatty acids in the plasma compartment
Sweat glands:
- compensate for the elevated heat production during intense metabolic activity
Eye:
- pupil dilation
- lens adapts for distance vision
Fill in.
Vascular smooth muscle in skeletal muscle contains both _____ and ____ receptors.
α1; β2
Fill in.
Norepinephrine has a high affinity for ____ receptors, causing strong _________ . Epinephrine has high affinity for ______ receptors. this counters α1 mediated vasoconstriction.
α1; vasoconstriction; β2
True or false.
Circulating catecholamines released from the adrenal medulla have a longer duration of effect and a more widespread distribution than neuronally released norepinephrine.
True
How are fight, flight, freeze reactions inactivated
- Neural NE is removed from the synapse by re-uptake mechanisms on the postganglionic neuron. neural catecholamines are available for miliseconds
- circulating catecholamines are inactivated by catechol-O-methly transferase (COMT) in the liver. circulating catecholamines are available for 1-2 minutes.
true or false.
Circulating catecholamines can stimulates cells not directly innervated by sympathetic fibers.
True
Sympathetic fibers release what type of catecholamine?
norepinephrine
adrenal medulla releases what type of catecholamine
Adrenal medulla releases primarily epinephrine.
what is the overall effect of the parasympathetic division?
to conserve energy and regulate basal body functions
Fill in.
Preganglionic neurons of the parasympathetic system arise from nuclei of the______ and the______ segments S2-S4 of the spinal cord.
brainstem; sacral
preganglionic axons of parasympathetic are long or short?
long
Where are postganglionic neurons of parasympathetic division located?
- close to or within the effector tissues
True or false.
Postganglionic axons of parasympathetic division are long
false. they are short
Fill in.
The preganglionic neurons exit through cranial nerves _____ ; _____ ; _____ ; & ______
III ; VII ; IX ; X
Fill in.
The preganglionic axons from the sacral region of the spinal cord form the _______ and innervate the ______ of the pelvic cavity (eg, lower half of the large intestine and organs of the renal & reproductive systems).
pelvic nerves; viscera
True or False. there is divergence in the parasympathetic system
False.
True or false.
The parasympathetic division of the ANS uses a ACh as pre- and post-ganglionic neurotransmitter
True
Fill in.
All preganglionic axons use acetylcholine (ACh) as their neurotransmitters. The cholinergic receptors on all autonomic ganglia is a _______ ______variety called the N2 receptor.
nicotinic ionotropic ;
true or false.
All of the parasympathetic postganglionic axons are also cholinergic.
True
Fill in.
the target effector organs of parasympathetic postganglionic axons express GPCRs known as _______ receptors
muscarinic
N1 receptors are found at the _______; and is blocked by ______
NMJ (neuromuscular junction) ; curare
N2 receptors are found in ________ ganglia; are blocked by _________
autonomic ; hexamethonium
describe M1 MUSCARINIC receptors
effects mediated by Gq/IP3/DAG; expressed in cerebral cortex, hippocampus. Role in cognitive function and memory.
describe Muscarinic-2 (M2) receptors
coupled to Gαi; located in atria, SA and AV nodes and myocardium; decreases heart rate and myocardial conduction velocity
describe Muscarinic-3 (M3) receptors
effects mediated by Gq/IP3/DAG; smooth muscle of various organ systems, e.g. bronchi (constriction), GI tract (contraction), pupils (constriction),
the only cholinergic receptor involved in a sympathetic process, is located where?
in sweat glands of the skin
describe Muscarinic-4 and 5 receptors
M4; coupled to Gαi;
M5; coupled to Gq - located primarily in the CNS, e.g.,
forebrain and substania nigra, respectively
what are the parasympathetic effects on cardiac muscle, respiratory, GI, and eye
Cardiac:
- heart rate decreases
Respiratory:
- bronchial constriction
GI:
- Salivary secretion is enhanced
- Gastric motility and secretion are stimulated
- Intestinal motility and secretion are stimulated
- Both exocrine and endocrine secretion from the pancreas is promoted.
Eye:
- pupil constricts and the lens adapts for near vision
True or false.
both divisions of the ANS are tonically active in the pupil
True
Fill in.
The contains two groups of smooth muscles; a ________ group (constrictor muscles) & a _______ group (dilator muscles).
circular ; radial
Fill in.
Sympathetic fibers from the superior cervical ganglion innervate the _______ muscles.
Parasympathetic fibers innervate the _______ muscles.
dilator; constrictor
Fill in.
__________ is a competitive antagonist for the muscarinic acetylcholine receptor types
atropine
Fill in.
Atropine _______ parasympathetic activation of the ______ smooth muscle. So all that is left is ________ activation of the radial muscle
blocks; circular ; sympathetic
True or false.
Control of the bladder and the timing of urination requires integration of both the parasympathetic and sympathetic division of the ANS
True.
Fill in.
the wall of the bladder is made up of ______ muscle. Also known as the detrusor muscle. The detrusor muscle expresses _____ adrenergic receptors and ________ receptors.
smooth; beta; muscarinic
Fill in.
filling of the bladder happens in it’s ______ (relaxed/contracted) state. This occurs via ________ (sympathetic/parasympathetic) innervation
relaxed state; sympathetic
Fill in.
emptying of the bladder happens in its ________ (relaxed/contracted) state. This occurs via _________ (sympathetic/parasympathetic) innervation.
contracted ; parasympathetic
Fill in.
The internal sphincter is made of _______ muscle, while the external sphincter is made of _________ muscle and under voluntary control.
smooth ; skeletal
Sympathetic activity of the bladder allows the bladder to relax and fill by activating ______ receptors, but maintains contraction of the internal sphincter by activating _______ receptors
beta 2 ; alpha 1
parasympathetic activity causes the detrusor muscle to contract by activating _____ receptors, while the internal sphincter relaxes by activating _______ receptors
Muscarinic- M3 ; Muscarinic- M3
Does the adrenal medulla receive parasympathetic innervation?
No
what is sympathetic tone?
the baseline firing frequency in the innervating sympathetic axons
Increasing the firing frequency __________ the sympathetic tone. while decreasing the firing frequency _____ the sympathetic tone
increases ; decreases
