powers circulation by using metabolic energy to elevate the hydrostatic pressure of the circulatory fluid, which then flows through the vessels and back to the heart
open circulatory system
the circulatory fluid bathes the organs directly
the circulatory fluid in an open circulatory system, and is also the interstitial fluid that bathes body cells
closed circulatory system
a circulatory fluid called blood is confined to vessels and is distinct from the interstitial fluid is pumped though vessels that branch into smaller ones that infiltrate the organs
carry blood AWAY from the heart to organ throughout the body which narrow into arterioles which convey blood to the capillaries
networks of very thin,porous vessels that infiltrate very tissue, passing within a few cell diameters of every cell in the body
vessels that carry blood back to the heart; start at capillaries, into venules, then veins.
a circulatory system consisting of a single pump and circuit, in which blood passes from the sites of gas exchange to the rest of the body before returning to the heart
a circulatory system consisting of separate pulmonary and systemic circuits, in which blood passes through the heart after completing each circuit
One complete sequence of pumping and filling
the contraction phase of the cycle
the relaxation phase
lies between each atrium and ventricle
located where the aorta leaves the left ventricle and where the pulmonary artery leaves the right ventricle
A hissing sound that occurs when blood squirts backward through a leaky valve in the heart.
sinoatrial (SA) node
the pacemaker; highly specialized neurological tissue, embedded in the wall of the right atrium, responsible for initiating electrical conduction of the heartbeat, causing the atria to contract and firing conduction of impulses to the AV node
atrioventricular (AV) node
The second major node of the cardiac conduction system (after the SA node). The cardiac impulse is delayed slightly at the AV node, allowing the ventricles to contract just after the atria contract.
red blood cells
White blood cells
low-density lipoprotein (LDL)
high-density lipoprotein (HDL)
blood fats that transport cholesterol out of the arteries
two large respiratory organs inside the chest where blood picks up oxygen and loses carbon dioxide
A rigid structure at the top of the trachea (so it is part of trachea, I assume) made completely out of cartilage. The larynx has three main functions: (1) its rigidness ensures that the trachea is held open (provides an open airway). (2) the epiglottis folds down to seal the trachea during swallowing, thus directing food the espohagus, and (3) this is where the vocal cords are found (voice production).
windpipe; tube through which air moves
two short branches located at the lower end of the trachea that carry air into the lungs.
progressively smaller tubular branches of the airways
thin-walled microscopic air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place