PGY/BIO 502 Cardiac Muscle Actual
study set with Questions and
correct/verified Answers
How many chambers does the heart have? - ANSWER-4 chambers - 2 upper (atrium) and 2 lower
(ventricles)
Blood vessels - ANSWER-arteries and veins
arteries - ANSWER-carry blood away from the heart
veins - ANSWER-carry blood to the heart
Steps of blood being carried to the heart - ANSWER--superior and inferior vena cava feeding blood to the
RA
-blood is deoxygenated
-blood travels from RA to the LV
-blood goes out the RV into the pulmonary artery
-goes to the lungs where gas exchange occurs (co2 and o2)
-hemoglobin turns blood red, pulmonary blood brings blood to left atrium
-blood then goes to the LV and then out the aorta and to the systemic circulation
the circulatory system is a - ANSWER-closed system
what comes out of the right heart goes to the - ANSWER-lungs and then back to the left side and vice
versa
right and left heart blood flow is arranged in - ANSWER-series
right ventricular ejected volume must - ANSWER-equal left ventricular ejected volume because it is a
closed system
Is the LV or RV thicker? - ANSWER-LV
there are relative volumes of LV and RV through a - ANSWER-cardiac cycle
What kind of contraction takes place of the myocardium? - ANSWER-synchronous
the left heart pumps blood - ANSWER-from lungs to body
the right heart pumps blood - ANSWER-from body to lungs, respiratory system
the heart contract and relaxes - ANSWER-every couple of seconds on a regular basis everyday
cells excitation and healthy conditions are - ANSWER-synchronous
the heart regulates contractions using - ANSWER-every muscle cell in a chamber, same for relaxation
the respiratory system doesn't produce much - ANSWER-resistance
The myocardium is a - ANSWER-functional syncytium
Each gap junction protein is called a - ANSWER-connexon
Each connexon makes a - ANSWER-hemi-channel
Gap junctions are arranged into ________ at the end of ___________ - ANSWER--plaques
-cardiomyocytes
*means that there's low resistance pathways from one cell to another
, Voltage-gated Na+ channels are also
localized to - ANSWER-junctional plaques
Na+ channels are good for - ANSWER-rapid electrical conduction
Consequences of the syncytial nature of cardiac muscle: - ANSWER-1. Heart chamber contracts as
approximated as a single cell - 100s of cells contract at the same time
2. Understanding single cell function understanding heart function
Cardiomyocytes comprise ____% of heart volume - ANSWER->80
Cardiomyocyte nuclei comprise ______% of nuclei heart - ANSWER-<30
Intercalated discs contain - ANSWER-Gap Junctions
gap junctions allow - ANSWER-low Resistance current flow
How is cardiac muscle similar to skeletal muscle? - ANSWER-both have t-tubules, SR that wraps around
contracting fibers, t-tubules close to SR, and are both mitochondria rich
How is cardiac muscle different than skeletal muscle? - ANSWER-skeletal muscles are coupled by motor
units and don't have gap junctions, where as cardiac muscle is coupled by gap junctions
Key features of cardiomyocyte structure (5): - ANSWER-1. T-tubules - invaginations of surface membrane
2. Sarcoplasmic reticulum (SR) surrounding contractile apparatus
3. T-tubule in close apposition to SR = dyad
4. Intercalated discs
5. Mitochondria-rich
Dimensions of cardiomyocytes vary, ventricular myocardium are
roughly cylindrical with diameters varying from ____ um, and lengths of - ANSWER--20-60
-80-200
Compare & contrast cardiac & sk. Muscle: tension relationship - ANSWER-Skeletal muscle is articulated,
heart is not.
Consequentially, not much degree of stretch
in PGY relevant skeletal muscle contraction.
Is there stretch in the heart? - ANSWER-Yes! Think about blood entering.
Over physiological range of length: Passive or resting tension ____ in the heart - ANSWER-increases
Over physiological range of length: active tension _____ in the heart. But not necessarily in skeletal
muscle. - ANSWER-increases
__________muscle tends to work
from Lmax. _________ muscle works from
lengths shorter than Lmax. - ANSWER--skeletal
-cardiac
Excitation - contraction coupling in cardiac muscle - ANSWER-
A major difference between skeletal & cardiac muscle is
the mechanism of the trigger of - ANSWER-SR Ca2+ release
_________muscle uses Ca2+-entry via _______ to gate open
RyR - ANSWER--cardiac
-LTCC
study set with Questions and
correct/verified Answers
How many chambers does the heart have? - ANSWER-4 chambers - 2 upper (atrium) and 2 lower
(ventricles)
Blood vessels - ANSWER-arteries and veins
arteries - ANSWER-carry blood away from the heart
veins - ANSWER-carry blood to the heart
Steps of blood being carried to the heart - ANSWER--superior and inferior vena cava feeding blood to the
RA
-blood is deoxygenated
-blood travels from RA to the LV
-blood goes out the RV into the pulmonary artery
-goes to the lungs where gas exchange occurs (co2 and o2)
-hemoglobin turns blood red, pulmonary blood brings blood to left atrium
-blood then goes to the LV and then out the aorta and to the systemic circulation
the circulatory system is a - ANSWER-closed system
what comes out of the right heart goes to the - ANSWER-lungs and then back to the left side and vice
versa
right and left heart blood flow is arranged in - ANSWER-series
right ventricular ejected volume must - ANSWER-equal left ventricular ejected volume because it is a
closed system
Is the LV or RV thicker? - ANSWER-LV
there are relative volumes of LV and RV through a - ANSWER-cardiac cycle
What kind of contraction takes place of the myocardium? - ANSWER-synchronous
the left heart pumps blood - ANSWER-from lungs to body
the right heart pumps blood - ANSWER-from body to lungs, respiratory system
the heart contract and relaxes - ANSWER-every couple of seconds on a regular basis everyday
cells excitation and healthy conditions are - ANSWER-synchronous
the heart regulates contractions using - ANSWER-every muscle cell in a chamber, same for relaxation
the respiratory system doesn't produce much - ANSWER-resistance
The myocardium is a - ANSWER-functional syncytium
Each gap junction protein is called a - ANSWER-connexon
Each connexon makes a - ANSWER-hemi-channel
Gap junctions are arranged into ________ at the end of ___________ - ANSWER--plaques
-cardiomyocytes
*means that there's low resistance pathways from one cell to another
, Voltage-gated Na+ channels are also
localized to - ANSWER-junctional plaques
Na+ channels are good for - ANSWER-rapid electrical conduction
Consequences of the syncytial nature of cardiac muscle: - ANSWER-1. Heart chamber contracts as
approximated as a single cell - 100s of cells contract at the same time
2. Understanding single cell function understanding heart function
Cardiomyocytes comprise ____% of heart volume - ANSWER->80
Cardiomyocyte nuclei comprise ______% of nuclei heart - ANSWER-<30
Intercalated discs contain - ANSWER-Gap Junctions
gap junctions allow - ANSWER-low Resistance current flow
How is cardiac muscle similar to skeletal muscle? - ANSWER-both have t-tubules, SR that wraps around
contracting fibers, t-tubules close to SR, and are both mitochondria rich
How is cardiac muscle different than skeletal muscle? - ANSWER-skeletal muscles are coupled by motor
units and don't have gap junctions, where as cardiac muscle is coupled by gap junctions
Key features of cardiomyocyte structure (5): - ANSWER-1. T-tubules - invaginations of surface membrane
2. Sarcoplasmic reticulum (SR) surrounding contractile apparatus
3. T-tubule in close apposition to SR = dyad
4. Intercalated discs
5. Mitochondria-rich
Dimensions of cardiomyocytes vary, ventricular myocardium are
roughly cylindrical with diameters varying from ____ um, and lengths of - ANSWER--20-60
-80-200
Compare & contrast cardiac & sk. Muscle: tension relationship - ANSWER-Skeletal muscle is articulated,
heart is not.
Consequentially, not much degree of stretch
in PGY relevant skeletal muscle contraction.
Is there stretch in the heart? - ANSWER-Yes! Think about blood entering.
Over physiological range of length: Passive or resting tension ____ in the heart - ANSWER-increases
Over physiological range of length: active tension _____ in the heart. But not necessarily in skeletal
muscle. - ANSWER-increases
__________muscle tends to work
from Lmax. _________ muscle works from
lengths shorter than Lmax. - ANSWER--skeletal
-cardiac
Excitation - contraction coupling in cardiac muscle - ANSWER-
A major difference between skeletal & cardiac muscle is
the mechanism of the trigger of - ANSWER-SR Ca2+ release
_________muscle uses Ca2+-entry via _______ to gate open
RyR - ANSWER--cardiac
-LTCC
