Heart Muscles Flashcards
Which chamber of the heart receives blood from the body?
a) Left atrium
b) Right atrium
c) Left ventricle
d) Right ventricle
Right atrium
The superior and inferior Vena cava brings ____________ blood to the right atrium.
oxygen-poor blood
The ____________ is the membrane that surrounds the heart and helps prevent friction between the heart and surrounding organs.
Pericardium
The left ventricle pumps oxygen-rich blood through the ____________ valve and into the aorta.
aortic
Blood from the pulmonary veins enters the right atrium. True or false?
False. Blood from the pulmonary veins enters the left atrium.
The pulmonary artery carries oxygen-rich blood to the lungs. True or false?
False. The pulmonary artery carries oxygen-poor blood to the lungs.
The mitral valve is located between the left atrium and left ventricle. True or false?
True
The semilunar valves are located between which structures?
a) Atria and ventricles
b) Ventricles and blood vessels
c) Atria and blood vessels
d) Coronary arteries and heart muscle
Ventricles and blood vessels
What is the pacemaker of the heart?
a) SA node
b) AV node
c) Bundle of His
d) Purkinje fibers
SA node
Which ion is responsible for the depolarization of the cardiac muscle cells?
a) Sodium
b) Potassium
c) Calcium
d) Chloride
Sodium
Which phase of the cardiac action potential is responsible for the plateau phase?
a) Phase 0
b) Phase 1
c) Phase 2
d) Phase 3
Phase 2
The cardiac cycle consists of two main phases: ___________ and _________.
systole and diastole
The ___________ nervous system, specifically the vagus nerve, slows down the heart rate.
parasympathetic
The refractory period of cardiac muscle cells is longer than that of skeletal muscle cells. True or false?
True
The plateau phase of the cardiac action potential is due to the slow influx of calcium ions. True or false?
True
Cardiac muscle cells can generate action potentials on their own without input from the nervous system. True or false?
True
Which type of muscle tissue is cardiac muscle?
a) Striated
b) Smooth
c) Skeletal
d) Voluntary
Striated
Which protein is responsible for the sliding of actin and myosin filaments during contraction?
a) Troponin
b) Tropomyosin
c) Myoglobin
d) Myosin kinase
Tropomyosin
The ___________ is the intercalated disc structure responsible for electrical coupling between cardiac muscle cells.
gap junction
The ___________ is the functional unit of the cardiac muscle.
sarcomere
The ___________ is the specialized region of the cardiac muscle that contains a high concentration of calcium ions.
sarcoplasmic reticulum
The calcium ions for cardiac muscle contraction come from both the sarcoplasmic reticulum and the extracellular fluid. True or false?
True
The cardiac muscle has a lower energy requirement compared to skeletal muscle due to its slower rate of contraction. True or false?
False. The cardiac muscle actually has a higher energy requirement compared to skeletal muscle.
Cardiac muscle cells are connected by desmosomes to allow for synchronized contraction. True or false?
True
What is the resting membrane potential of cardiac muscle cells?
a) -70 mV
b) -50 mV
c) -80 mV
d) -90 mV
-90 mV
The plateau phase of the cardiac action potential is due to the opening of ___________ ion channels.
L-type calcium
The duration of the cardiac action potential is longer than that of the skeletal muscle action potential. True or false?
True
The opening of the L-type calcium channels during the plateau phase of the cardiac action potential is responsible for the release of calcium ions from the sarcoplasmic reticulum. True or false?
False. The opening of the L-type calcium channels during the plateau phase is responsible for the influx of calcium ions from the extracellular fluid.
An excess of calcium ions causes the heart to go toward _________ contraction.
spastic
The heart usually beats at a rate of ______________ as long as the PS stimulation continues.
20 to 40 beats / min
