52 Questions
What is the stable membrane potential of skeletal muscle?
-70 mV
What causes the extended plateau phase in the myocardium action potential?
Ca$^{2+}$ entry
What is the duration of the action potential in skeletal muscle?
1–2 msec
What is the main cause of hyperpolarization in skeletal muscle?
Excessive K$^+$ efflux
What is the membrane potential at which the lf channels open again in the autorhythmic myocardium cells?
-60 mV
What is the main cause of the rapid rising phase of the action potential in myocardium?
Na$^+$ entry
What is the typical refractory period in skeletal muscle?
Brief
What causes the depolarization in skeletal muscle action potential?
Net Na$^+$ entry through ACh-operated channels
What is the function of arteries in the cardiovascular system?
Carry blood away from the heart
What is the primary function of veins in the cardiovascular system?
Return blood to the heart
Where does the exchange of material with the interstitial fluid primarily occur?
Capillaries
What separates the heart into two halves?
Septum
Which side of the heart receives blood from the tissues and sends it to the lungs for oxygenation?
Right
What is the primary component of plasma in the blood?
Water
Which component of blood is essential for blood clotting?
Platelets
Which type of blood vessels carry blood from the left side of the heart to the tissues and back to the right side of the heart?
Systemic arteries and veins
What is the formula for velocity in a tube?
$v = Q/A$
What determines the mean arterial pressure (MAP)?
Cardiac output and peripheral resistance
What is the main component of the heart?
Myocardium
How many chambers does the heart have?
Four
Which structures emerge from the base of the heart?
Aorta, pulmonary trunk, vena cava, and pulmonary veins
What surrounds the heart valves?
Four fibrous connective tissue rings
Where are electrical signals directed for heart contraction?
Through a specialized conduction system to the apex of the heart
What guards the opening between each atrium and its ventricle?
AV valve
What provides stability for the AV valves?
Chordae tendineae
What supplies blood to the heart?
Coronary circulation through coronary arteries and veins
What do heart valves ensure in the heart?
One-way flow
Which factor does the velocity of blood flow depend on?
Flow rate and cross-sectional area
What is the function of the pulmonary arteries in the systemic circulation?
Carry deoxygenated blood from the heart to the lungs
Which vessel receives blood from the left ventricle and distributes it to the body?
Aorta
What causes the color change from red to blue in the blood as it passes through the capillaries?
Oxygen leaving the blood and diffusing into the tissues
Which vessel carries blood back to the heart from the lower part of the body?
Inferior vena cava
What is the main function of the hepatic portal vein?
Direct blood from the digestive tract to the liver
What happens to blood pressure if blood vessels constrict?
Blood pressure increases
According to Poiseuille’s Law, how does resistance change with an increase in the radius of the blood vessel?
Resistance decreases
What is the primary factor affecting blood flow through a tube?
Pressure gradient
What is the function of the coronary arteries?
Nourish the heart muscle itself
What happens to blood pressure as it moves farther from the heart?
Blood pressure decreases
What is the function of the pulmonary veins in the systemic circulation?
Carry oxygenated blood from the lungs to the heart
What is the role of the hepatic artery in the circulatory system?
Supply oxygenated blood to the liver
What is the role of desmosomes and gap junctions in cardiac muscle cells?
Allow rapid spread of depolarization and simultaneous contraction of heart muscle cells
What is a key feature of excitation-contraction coupling in cardiac muscle?
Entry of calcium into cardiac cells
What determines the force of contraction in the heart?
Number of active crossbridges
What are the distinct characteristics of cardiac muscle cells?
Autorhythmic cells and contractile cells
What is the role of refractory periods and summation in the action potentials of cardiac cells?
Play a role in the action potentials of cardiac cells
What is a key aspect of excitation-contraction coupling in cardiac muscle?
Calcium-induced calcium release
What is the process involved in generating the pacemaker potential in myocardial autorhythmic cells?
Undergo a series of changes involving ion channels
What are the phases involved in the action potential of myocardial contractile cells?
Resting, depolarization, plateau, and rapid repolarization
What is the effect of sarcomere length on the force of contraction in the heart?
Affects the force of contraction in the heart
What is the role of myocardial action potentials in myocardial contractile cells and autorhythmic cells?
Vary between myocardial contractile cells and autorhythmic cells
What are the two primary coronary arteries responsible for?
Supplying blood to different parts of the heart
What are the two main types of cells in cardiac muscle?
Autorhythmic cells and contractile cells
Study Notes
Cardiac Anatomy and Physiology
- The two primary coronary arteries originate at the start of the aorta, supplying blood to different parts of the heart.
- Cardiac muscle cells include autorhythmic cells and contractile cells, each with distinct characteristics.
- Cardiac muscle cells have desmosomes and gap junctions, which allow rapid spread of depolarization and simultaneous contraction of heart muscle cells.
- The entry of calcium into cardiac cells is a feature of excitation-contraction coupling, leading to contraction and relaxation of the heart muscle.
- Cardiac muscle contraction can be graded, with the force generated being proportional to the number of active crossbridges.
- Sarcomere length affects the force of contraction in the heart.
- The action potential of a cardiac contractile cell involves different phases, including depolarization and repolarization.
- Refractory periods and summation play a role in the action potentials of cardiac cells.
- Myocardial action potentials vary between myocardial contractile cells and autorhythmic cells.
- Myocardial contractile cells have resting, depolarization, plateau, and rapid repolarization phases.
- Myocardial autorhythmic cells have an unstable membrane potential and undergo a series of changes involving ion channels to generate the pacemaker potential.
- The process of calcium-induced calcium release is a key aspect of excitation-contraction coupling in cardiac muscle.
Test your knowledge of cardiac anatomy and physiology with this quiz. Explore topics such as coronary arteries, cardiac muscle cells, excitation-contraction coupling, sarcomere length, action potentials, and more. See how well you understand the intricacies of the heart's structure and function.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
