Circulation and Gas Exchange

These flashcards cover key terms and concepts related to circulation and gas exchange.

Circulatory System

A system that connects aqueous environments of body cells to organs that exchange gases.

Open Circulatory System

A circulatory system found in arthropods and most mollusks where hemolymph bathes organs directly.

Closed Circulatory System

A circulatory system found in earthworms and vertebrates where blood is confined to blood vessels.

Cardiac Cycle

The rhythmic cycle of contraction and relaxation of the heart.

Cardiac Output (CO)

The volume of blood pumped into systemic circulation per minute, calculated by CO = HR x SV.

Blood Pressure

The hydrostatic pressure that blood exerts against the walls of a vessel.

Erythrocytes

Red blood cells that transport oxygen via hemoglobin.

Leukocytes

White blood cells responsible for defense and immunity.

Platelets

Cell fragments involved in blood clotting.

Gas Exchange

The uptake of oxygen (O2) and release of carbon dioxide (CO2) across respiratory surfaces.

Ventilation

The movement of a respiratory medium (air or water) over a respiratory surface.

Partial Pressure

The pressure exerted by a particular gas in a mixture of gases.

Respiratory Pigments

Molecules that increase the amount of oxygen carried in the circulatory fluid.

Thrombus

A blood clot formed within a blood vessel that can block blood flow.

Atherosclerosis

The buildup of plaque in arteries, which can lead to cardiovascular diseases.

Pacemaker

The sinoatrial node that sets the rate and timing of heart contractions.

Vasoconstriction

The contraction of smooth muscle in arterioles that increases blood pressure.

Vasodilation

The relaxation of smooth muscles in arterioles that decreases blood pressure.

Pulmonary Circuit

The circuit that delivers O2-poor blood to the lungs and returns O2-rich blood to the heart.

Systemic Circuit

The circuit that delivers O2-rich blood to the body and returns O2-poor blood to the heart.

Counter-current Exchange

A mechanism in fish that maximizes gas exchange efficiency; water flows opposite to blood flow.

Alveoli

Tiny air sacs in the lungs where gas exchange occurs.