ECG Ch1 Flashcards
Thin strands of fibrous connective tissue extend from the atrioventricular (AV) valves to the papillary muscles and prevent the AV valves from bulging back into the atria during ventricular systole. These strands are called _____.
Chordae tendineae are thin strands of connective tissue. On one end, they are attached to the underside of the AV valves. On the other end, they are attached to small mounds of myocardium called papillary muscles.
The right atrium receives venous blood from the head, neck, and thorax via the _____, from the remainder of the body via the _____, and from the heart via the _____.
The right atrium receives blood low in oxygen from the superior vena cava, which carries blood from the head and upper extremities; the inferior vena cava, which carries blood from the lower body; and the coronary sinus, which is the largest vein that drains the heart.
The tricuspid valve is _____.
The tricuspid valve is located between the right atrium and right ventricle.
Blood flows from the left atrium through the _____ valve into the left ventricle.
Blood flows from the left atrium through the mitral (bicuspid) valve into the left ventricle.
The thick, muscular middle layer of the heart wall that contains the atrial and ventricular muscle fibers necessary for contraction is the _____.
The myocardium (middle layer) is a thick, muscular layer that consists of cardiac muscle fibers (cells) responsible for the pumping action of the heart.
The primary neurotransmitter of the parasympathetic division of the autonomic nervous system is _____.
Acetylcholine (Ach) is a chemical messenger (neurotransmitter) released when parasympathetic nerves are stimulated. Ach binds to parasympathetic receptors.
Which of the following are semilunar valves?
The pulmonic and aortic valves are semilunar (SL) valves. The semilunar valves prevent backflow of blood from the aorta and pulmonary arteries into the ventricles.
True or False, Stimulation of beta-adrenergic receptor sites will result in peripheral vasoconstriction.
False. Stimulation of beta1 receptor sites in the heart results in increased heart rate, contractility, and ultimately irritability of cardiac cells. Stimulation of beta1 receptor sites in the kidneys results in the release of renin into the blood. Renin promotes the production of angiotensin, a powerful vasoconstrictor. Beta2 receptor sites are found in the arterioles of the heart, lungs, and skeletal muscle. Stimulation results in dilation.
True or False, Blood pressure is the result of cardiac output and peripheral vascular resistance.
True. Blood pressure is equal to cardiac output multiplied by peripheral vascular resistance.
The _____ artery supplies the right atrium and ventricle with blood.
The right coronary artery supplies the right atrium and ventricle with blood.
Name the two main branches of the left coronary artery.
Left anterior descending coronary artery and the circumflex.
The apex of the heart is formed by the _____.
The heart’s apex, or lower portion, is formed by the tip of the left ventricle.
Blood flows from the right atrium through the _____ valve into the right ventricle.
Blood flows from the right atrium through the tricuspid valve into the right ventricle.
Stimulation of beta2 receptor sites results in _____.
Beta2 receptor sites are found in the arterioles of the heart, lungs, and skeletal muscle. Stimulation results in dilation. Stimulation of beta2 receptor sites in the smooth muscle of the bronchi results in dilation.
The primary neurotransmitters of the sympathetic division of the autonomic nervous system are _____.
When sympathetic nerves are stimulated, the neurotransmitters norepinephrine and epinephrine are released.
Stimulation of alpha1 receptors results in _____.
Alpha1 receptors are found in the eyes, blood vessels, bladder, and male reproductive organs. Stimulation of alpha1 receptor sites results in constriction.
When the left ventricle contracts, freshly oxygenated blood flows through the _____ valve into the _____.
aortic; aorta
Blood pressure is determined by _____ multiplied by _____.
Blood pressure is equal to cardiac output multiplied by peripheral vascular resistance.
Chronotropy refers to an effect on _____.
Chrono refers to rate. Chronotropic effect refers to a change in heart rate. Positive chronotropic effect refers to an increase in heart rate. Negative chronotropic effect refers to a decrease in heart rate.
The right ventricle expels blood through the _____ valve into the pulmonary trunk.
The right ventricle expels the blood through the pulmonic valve into the pulmonary trunk. The pulmonary trunk divides into a right and left pulmonary artery, each of which carries blood to one lung (pulmonary circuit).
