Clinical implication for Beta blockers? (book)
Atrial fibrillation, chronic left heart failure or reduced ejection fraction
Beta Blockers (book)
reduce myocardial demand. By blocking beta receptors.
Myocardial contractility is a change in developed tension at a given resting fiber length, which is
simply the ability of the heart muscle to shorten. At the molecular level, thin filaments of actin slide
over thick filaments of myosin called the cross-bridge cycle of muscle contraction. (video)
Calcium interacts with troponin C which causes tropomyosin to move thus allowing actin and myosin
to work together to cause contraction.
Explain the difference between cardiac hemodynamic measures Video Lecture:
Cardiac Output
Cardiac output is the amount of blood pushed from the left ventricle in 1 minute. It is calculated by
multiplying the heart rate in beats per minute by the stroke volume.
Right Heart (book)
pumps blood through the lungs
Left Heart (book)
sends blood throughout the systemic circulation, which supplies all of the body except the lungs.
Arteries (hint A for away) (Book)
carry blood (away) from the heart to all parts of the body, where they branch into arterioles and even
smaller vessels until they become a fine meshwork of capillaries.
Capillaries (Book)
allow the closest contact and exchange between the blood and the interstitial space, or interstitium—
the environment in which the cells live
Venules and the veins (Book)
carry blood from capillaries back to the heart.
Lymph (Book)
is returned to the cardiovascular system by vessels of the lymphatic system.
, Blood flow through the heart chambers/valves (Book)
The right heart pumps de-oxygenated blood through to the right atrium>through the tricuspid valve>
right ventricle>pulmonary semilunar valve>pulmonary artery>Lungs (now oxygenated
blood)>Pulmonary veins>Left Atrium>Bicuspid or Mitral valve>Left Ventricle>Aortic Semilunar
Valve>Aorta
The coronary arteries provide blood to which part of the heart. (Book)
The myocardium and other heart structures are supplied with oxygen and nutrients by the coronary
circulation
What are the two major coronary arteries? (Book)
The major coronary arteries are the right coronary artery (RCA) and the left coronary artery (LCA)
The transmission of electrical impulses, termed cardiac action potentials move throughout the
myocardium. Analyze the process of action potentials. (Book)
As an electrical impulse passes from cell to cell (fiber to fiber) in the myocardium, it stimulates an
intracellular process that results in fiber shortening—that is, muscular contraction or systole. Between
action potentials, the fibers relax and return to their resting length, causing diastole.
The various phases of the cardiac action potential are related
to changes in the permeability of the cell membrane to sodium,
potassium, chloride, and calcium(Book)
Threshold is the point at which the cell membrane's selective permeability to these ions is temporarily
disrupted, leading to depolarization. If the resting membrane potential becomes more negative as a
result of a decrease in extracellular potassium concentration (hypokalemia), it is termed
hyperpolarization.
How potassium affects myocardial action potentials, contraction, and clinical manifestations.
Hypokalemia
When the resting membrane potential becomes more negative as a result of a decrease in
extracellular potassium concentration (Book)
it is termed hyper-polarization.
Calcium and Excitation-contraction coupling is the process by which an action potential arriving at the
plasma membrane of the muscle fiber triggers the cycle leading to cross-bridge activity and
contraction. (Book)
It enters the myocardial cell from the interstitial fluid after electrical excitation, which increases the
membrane permeability to calcium. Two types of calcium channels (L-type and T-type) are identified
in cardiac tissues.