final exam Faruqui Flashcards
many organs of the body contain smooth muscle, such as?
walls of hollow organs GI tract bladder uterus ureters blood vessels eye muscles
fiber diameter of type 1/2 muscles
1 small
2 large
twitch (rise and fall) of type 1/2 muscles
1 slow (100msec) 2 fast (7.5msec)
mitochondrial content of type 1/2 muscles?
1 high
2 low
oxidative enzyme activity of type 1/2 muscles
1 high
2 low
glycolytic enzyme activity of type 1/2 muscles?
1 low
2 high
myoglobin content of type 1/2 muscles
1 high
2 low
SR content type 1/2 muscles?
1 LOW
2 high
Capillary density of type 1/2 muscles
1 high
2 low
fatigue resistance of type 1/2 muscles?
1 very high
2 low
Functions of smooth muscle?
Produce motility (propelling chyme) Maintain tension (diameter of blood vessels)
what are the types of smooth muscles?
unitary
multiunit
what type of smooth muscle has gap junctions?
unitary
gap junctions permits fast spread of electrical activity
what is the spontaneous, slow wave activity of unitary smooth muscle called?
pacemaker activity
GI tract during perstalsis
what does hypoxia in the blood vessels cause?
vasodilation and thus relaxation of the smooth muscle
what also causes vasodilation as well as increased hydrogen atoms?
excess CO2
what is the unitary smooth muscle found in the gut walll, with slow rhythmic contractions and cells showing a Calcium A.P?
phasic smooth muscle
voltage sensitive Ca channels
what is the unitary smooth muscle found in arteries and encircles their walls,e exhibits continous contractions, not electrically excitable?
Tonic smooth muscle
contraction and relaxation play an important role in regulating blood flow
what are some examples of multiunit smooth muscle?
iris of the eye ciliary muscle sof the eye lens vas deferens pulmonary air passages arrector pili muscles of hair follicles
what type of smooth muscle has no coupling between cells and each muscle fiber behaves as a single motor unit?
Multiunit smooth muscle
multiunit smooth muscle is innervated by what?
autonomic nervous system
thick myofilaments of the smooth muscle contains what?
myosin
thin filaments of smooth muscle are composed of?
actin and tropomyosin only
smooth muscle does not have transverse tubules, as they are replaced by?
Caveoli
The SR is also less developed than in skeletal or cardiac muscle
what are varicosities?
bulges within motor nerve fibers of both types of smooth muscle
in smooth muscle, as action potential travels down the motor nerve, neurotransmitter is released from where?
synaptic vesicles stored in these varicosities
depolarization of the smooth muscle action potential opens?
Voltage-gated Ca2 channels in the membrane
how else can Ca2+ enter the cell in the smooth muscle membrane?
Ligand Gated channels
another mechanism Ca2+ can be released from the Sarcoplasmic Reticulum is? how is it opened?
Inositol triphospate (IP3)-gated Ca2+ release channels (opened by hormones and neurotransmitters)
a rise in intracellular Ca2+ concentration prompts binding of Ca2+ to?
Calmodulin protein, which can bind 4 Ca2+ ions