Chapter 42 - Circulation and Gas Exchange Flashcards
heart
A muscular pump that uses metabolic energy to elevate the hydrostatic pressure of the circulatory fluid (blood or hemolymph). The fluid then flows down a pressure gradient through the body and eventually returns to the heart.
open circulatory system
A circulatory system in which fluid called hemolymph bathes the tissues and organs directly and there is no distinction between the circulating fluid and the interstitial fluid.
hemolymph
In invertebrates with an open circulatory system, the body fluid that bathes tissues.
closed circulatory system
A circulatory system in which blood is confined to vessels and is kept separate from the interstitial fluid.
blood
A connective tissue with a fluid matrix called plasma in which red blood cells, white blood cells, and cell fragments called platelets are suspended.
cardiovascular system
A closed circulatory system with a heart and branching network of arteries, capillaries, and veins. The system is characteristic of vertebrates.
artery
A vessel that carries blood away from the heart to organs throughout the body.
arteriole
A vessel that conveys blood between an artery and a capillary bed.
capillary
A microscopic blood vessel that penetrates the tissues and consists of a single layer of endothelial cells that allows exchange between the blood and interstitial fluid.
capillary bed
A network of capillaries in a tissue or organ.
venule
A vessel that conveys blood between a capillary bed and a vein.
vein
(1) In animals, a vessel that carries blood toward the heart. (2) In plants, a vascular bundle in a leaf.
atrium
A chamber of the vertebrate heart that receives blood from the veins and transfers blood to a ventricle.
ventricle
(1) A heart chamber that pumps blood out of the heart. (2) A space in the vertebrate brain, filled with cerebrospinal fluid.
single circulation
A circulatory system consisting of a single pump and circuit, in which blood passes form the sites of gas exchange to the rest of the body before returning to the heart.
double circulation
A circulatory system consisting of separate pulmonary and systemic circuits, in which blood passes through the heart after completing each circuit.
pulmonary circuit
A branch of the circulatory system that supplies the lungs.
pulmocutaneous circuit
A branch of the circulatory system in many amphibians that supplies the lungs and skin.
systemic circuit
The branch of the circulatory system that supplies oxygenated
cardiac cycle
The alternating contractions and relaxations of the heart.
systole
The stage of the cardiac cycle in which a heart chamber contracts and pumps blood.
diastole
The stage of the cardiac cycle in which a heart chamber is relaxed and fills with blood.
cardiac output
The volume of blood pumped per minute by each ventricle of the heart.
heart rate
The frequency of heart contraction (in beats per minute).
stroke volume
The volume of blood pumped by a heart ventricle in a single contraction.
atrioventricular (AV) valve
A heart valve located between each atrium and ventricle that prevents a back flow of blood when the ventricle contracts.
semilunar valve
A valve located at each exit of the heart, where the aorta leaves the left ventricle and the pulmonary artery leaves the right ventricle.
heart murmur
A hissing sound that most often results from blood squirting backward through a leaky valve in the heart.
sinoatrial (SA) node
A region in the right atrium of the heart that sets the rate and timing at which all cardiac muscle cells contract; the pacemaker.
electrocardiogram (ECG or EKG)
A record of the electrical impulses that travel through heart muscle during the cardiac cycle.