Cardiac & Smooth Muscle

Question 1

Cardiac Muscle Makeup

Answer 1

• one central nucleus per cell
• contains Atrial natriuretic factor (ANF) & Brain natriuretic factor (BNF), which increases loss of Na+

Question 2

Cardiac Muscle Contraction

Answer 2

1. depolarization signal via SA and AV nodes, via gap junctions
2. voltage-gated Na+ channels open
3. L-type Ca2+ channels open
4. Ca2+ binds to ryanodine channels, opening them in SER
5. Ca2+ leaves sarcoplasmic reticulum

Question 3

cardiac muscle repair

Answer 3

injury in cardiac muscle leads to replacement by fibrous tissue (function is lost)

Question 4

smooth muscle makeup

Answer 4

fibers not arranged as regularly as striated muscle, nuclei are in center of cell

Question 5

what do smooth muscle cells secrete?

Answer 5

cells secrete connective tissue matrix

Question 6

smooth muscle contraction

Answer 6

1. elicited by various stimuli
2. Calcium mediated depolarization
3. opens L-type Calcium channels w/ Calcium binding to ryandodine channels (ligand-gated)
4. Calcium releases

Question 7

Type of Smooth Muscle

Answer 7

multi-unit smooth muscle, and unitary smooth muscle

Question 8

multi-unit smooth muscle

Answer 8

independent unit contraction, less gap junctions

Question 9

multi-unit smooth muscle examples

Answer 9

iris sphincter, iris dilator, ciliary body muscle, arrector pili

Question 10

unitary smooth muscle

Answer 10

more gap junction

Question 11

unitary smooth muscle examples

Answer 11

muscles of GI, uterus, and blood vessels

Question 12

smooth muscle repair

Answer 12

regularly replicates, responds with mitosis

Question 13

atherosclerotic plaques

Answer 13

caused by smooth muscle cells in blood vessels secreting CT

Question 14

initial signal for each contraction

Answer 14

skeletal: acetylcholine binding nicotonic receptor
cardiac: SA/AV nodes
smooth: acetylcholine binding muscarinic receptors

Question 15

ryanodine channels for each contraction

Answer 15

skeletal: mechanically gated
cardiac & smooth: ligand (calcium) gated

Question 16

L-type calcium channel blockers (DVD’s)

Answer 16

amlodipine “-dipines”
verapamil
diltiazem
used for hypertension & arrhythmias

Question 17

duchenne muscular dystrophy

Answer 17

most common muscular dystrophy, a type of dystrophin dystrophy

Question 18

myotonia

Answer 18

sustained involuntary contraction of a muscle

Question 19

myotonic dystrophy

Answer 19

causes myotonia (sustained involuntary contraction of a muscle)
causes Christmas tree cataract & arrhythmias

Question 20

myasthenia gravis

Answer 20

motor weakness due to damage/loss of nicotinic receptors
often drooping of eyelids (ptosis)

Question 21

myasthenia gravis treatment

Answer 21

treated with edrophonium and pyridostigmine, which are acetylcholinesterase inhibitor