Chapter 42: Circulation and Gas Exchange


Chapter Summary´╗┐- Breathing ventilates the lungs, and the heart circulates blood throughout the body to exchange gases. Gas exchange occurs across specialized respiratory surfaces. Adaptations for gas exchange include pigments that bind and transport gases. Circulatory systems link exchange surfaces with cells throughout the body. Coordinated cycles of heart contraction drive double circulation in mammals. Patterns of blood pressure and flow reflect the structure and arrangement of blood vessels. Blood components function in exchange, transport, and defense.


´╗┐Circulation Vocabulary:
Alveoli- Where the gas exchange takes place
Heart- a muscle that pumps blood throughout the body
open/closed circulatory system- organs bathed in circulatory fluid/ blood is confined to vessels
hemolymph-circulatory fluid
cardiovascular system- heart and blood vessels
arteries- blood vessels that carry oxygenated blood
capillaries- smallest blood vessels
veins- blood vessels that carry deoxygenated blood
atria (atrium)-chambers of the heart where blood enters.
ventricles- chambers of the heart that pump blood out
single circulation-passes through the heart once in each complete circuit
double circulation-two distinct circuits (mammals)
pulmonary circuit
pulmocutaneous circuit
systemic circuit-course of blood throughout the body
cardiac circuit-the pattern of heart filling with blood and pumping it
systole-contraction phase
diastole-relaxing phase
cardiac output- the volume each ventricle pumps per minute
heart murmur-blood squriting backwards due to a defective valve
systolic pressure-pressure against blood vessels when the heart contracts
pulse-wave of pressure as the heart contracts
vasoconstriction-arterioles narrowing
vasodilation-smooth muscles relaxing
lymph nodes-help defend against viruses
fibrin- framework of blood clotting
plasma-suspends connective tissue of blood
plateletes- fragments of cells that aid clotting
ethrocytes- red blood cells
hemoglobin-iron containing protein that transports oxygen
leukocytes- white blood cells
thrombus-clot that blocks blood flow
stem cells-replenishes bodies blood cells
heart attack- death of cardiac muscle
erythropoietin- hormone that signals production of rbc's
atherosclerosis- hardening of arteries by accumulation of fatty acids
hypertension- high blood pressure

Ventilation Vocabulary:

ventilation-movement of the respiratory medium over the respiratory surface
lungs- localized respiratory organs
larynx- upper part of the respiratory tract
carbonic drive- drives autonomous function of diaphragm
bronchi- branches leading to lungs
diaphragm- main respiratory organ
tidal volume-volume of air inhaled and exhaled in one breath
tidal capacity-maximum tidal volume

Heart circulation cycle


Figure 42.6- the mammalian cardiovascular system


Figure 42.7 - the mammalian heart


Figure 42.10- The structure of blood vessels


Figure 42.25- Negative pressure breathing (how we breathe)


Other Web Sites

"How Your Heart Works"

"the invention of the artificial heart"