11.7 – Cardiac and smooth muscle Flashcards
walls of the heart consist of ___ muscle tissue
cardiac
which describes cardiac muscle tissue?
striated, usually uninucleate, branching
skeletal muscles contain which of the following?
both slow oxidative and fast glycolytic fibers
which structures coordinate contraction in cardiac muscle cells?
gap junctions
cardiac muscle tissue is autorhythmic but the ___ can increase or decrease the heart rate and contraction strength
autonomic nervous system
cardiac and smooth muscle are both considered which of the following?
involuntary
where is cardiac muscle found?
in the heart wall only
in the heart, what triggers the wave of electrical excitation that causes the heart to contract?
pacemaker
___ discs are the thickened notched ends of cardiac muscle cells which contain gap junctions
intercalated
intercalated discs contain ___ that prevent cardiac cells from pulling apart during contraction
mechanical junctions
which muscle type is resistant to fatigue, contracts w/ a regular rhythm, and functions 24 hrs a day?
cardiac
the autonomic nervous system is important int the control of which 2 types of muscle tissue?
cardiac
smooth
cardiac muscle cells are considered ___ because they contract rhythmically and independently.
autorhythmic
what is the function of the cardiac pacemaker?
it triggers contraction in the heart muscle
which muscle tissue is rich in myoglobin, mitochondria, glycogen, and uses aerobic respiration almost exclusively for its energy needs?
cardiac
which describes cardiac muscle tissue?
striated, usually uninucleate, branching
what are the swellings along the length of a nerve fiber that innervates smooth muscle called?
varicosities
why are gap junctions important?
they allow the cells to contract in a coordinated fashion
which tissue makes up the piloerector muscle of a hair follicle?
smooth muscle
which are the characteristics of cardiac muscle cells?
they contract nearly in unison
they contract w/ regular rhythm
they are resistant to fatigue
which describe smooth muscle?
smooth muscle has no T-tubules
smooth muscle is uninucleate
smooth muscle has little SR
what does it mean that cardiac cells are autorhythmic?
they contract rhythmically and independent of nervous stimulation
where is single-unit smooth muscle found?
wall of uterus
wall of bladder
wall of stomach
which statement explains why cardiac muscle is resistant to fatigue?
cardiac muscle uses little anaerobic fermentation
the varicosities of the autonomic neurons that innervate smooth muscle release what when stimulated?
neurotransmitters
how does smooth muscle differ from skeletal muscle?
smooth muscle can be excited in a multitude of ways while skeletal muscle is excited by a neuron
what are the functions of smooth muscle?
to regulate pupil diameter
to move material thru the digestive tract
to constrict or dilate blood vessels to control blood pressure
which 2 types of muscle tissue can be autorhythmic?
cardiac
smooth
how do smooth muscle myocytes differ from cardiomyocytes?
smooth muscle myocytes have no T tubules while cardiac muscles do
what type of smooth muscle is found in the digestive tract, respiratory tract, and urinary tract?
single-unit
what is calmodulin?
a protein that replaces troponin in smooth muscle cells
which are characteristics of cardiac muscle?
it has large stores of glycogen
it is rich in myoglobin
it uses aerobic respiration almost exclusively
the sarcolemma of smooth muscle cells has pockets called ___ that contain calcium channels
caveolae
excitation can be non-electrical in what type of muscle tissue?
smooth
T or F:
smooth muscle often fatigues
false
(consider the consequences of smooth muscle of the gut adn blood vessels fatiguing)
the presence of material in the stomach and urinary bladder stretches the wall, stimulating what type of muscle contraction?
smooth
in which situation would mechanically-regulated calcium gates n smooth muscle cells open?
the tissue is stretched
which describe smooth muscle?
smooth muscle has no T-tubules
smooth muscle is uninucleate
smooth muscle has little SR
what regulatory protein is associated w/ the thick filament of smooth muscle and activates myosin light-chain kinase?
calmodulin
what is the immediate trigger for the contraction of smooth muscle?
calcium ions
which muscle tissue frequently exhibits tetanus and is resistant to fatigue?
smooth
how can the stretching of smooth muscle lead to smooth muscle contraction?
stretching causes the opening of mechanically gated calcium ion channels in the sarcolemma
___ muscle cells have a fusiform shape and taper to a point at the ends
smooth
what is calmodulin?
a protein that replaces troponin in smooth muscle cells
T or F:
smooth muscle often fatigues
false
(consider the consequences of smooth muscle of the gut and blood vessels fatiguing)
in smooth muscle, which protein does calcium bind to?
calmodulin
