Circulation and Gas Exchange ch 42

Gas Exchange

Process of O2 intake and CO2 release.

Gastrovascular Cavities

Two-cell thick walls for digestion and distribution.

Circulatory System

Transport system for materials in multicellular organisms.

Cardiovascular System

Human circulatory system for gas and nutrient exchange.

Heart

Muscular organ pumping blood through vessels.

Arteries

Blood vessels carrying blood away from the heart.

Veins

Blood vessels returning blood to the heart.

Capillaries

Sites of chemical exchange between blood and tissues.

Arterioles

Small arteries branching from larger arteries.

Venules

Small veins collecting blood from capillaries.

Single Circulation

Blood flows through the heart once per cycle.

Double Circulation

Blood returns to the heart before systemic circulation.

Four-chambered Heart

Heart structure in mammals and birds for efficient oxygenation.

Atrioventricular Valves

Valves preventing backflow between atria and ventricles.

Semilunar Valves

Valves controlling blood flow to aorta and pulmonary artery.

Cardiac Cycle

Rhythmic contraction and relaxation of the heart.

Diastole

Relaxation phase when heart chambers fill with blood.

Coronary Arteries

Arteries supplying oxygen to the heart muscle.

Lub-dup Sound

Heartbeat sound from valve recoil during contraction.

Heart Murmur

Abnormal sound from backflow through defective valves.

Inferior Vena Cava

Vein returning blood from lower body to heart.

Superior Vena Cava

Vein returning blood from upper body to heart.

Pulmonary Arteries

Arteries carrying deoxygenated blood to the lungs.

Pulmonary Veins

Veins carrying oxygenated blood from lungs to heart.

Aorta

Main artery distributing oxygenated blood to the body.

Systole

Contraction phase of the cardiac cycle.

Stroke Volume

Blood volume pumped by ventricle per contraction.

Average Stroke Volume

Approximately 70 mL in humans.

Cardiac Output

Blood volume pumped by each ventricle per minute.

Cardiac Output Formula

Cardiac Output (ml/min) = heart rate X stroke volume.

Autorhythmic Cells

Cardiac muscle cells that contract independently.

Sinoatrial (SA) Node

Pacemaker that regulates heart contraction rate.

Electrocardiogram (ECG)

Recording of electrical activity of the heart.

Atrioventricular (AV) Node

Delays impulses before ventricles contract.

Heart Rate Regulation

Controlled by nervous system, hormones, and temperature.

Myocardial Infarction

Death of cardiac muscle due to artery blockage.

Hypertension

High blood pressure, >140 mm Hg systolic.

Angina Pectoris

Chest pain from partial coronary artery blockage.

Stroke

Death of brain tissue from artery rupture/blockage.

Partial Pressure

Pressure exerted by a specific gas in a mixture.

Respiratory Surfaces

Thin, moist areas for gas exchange.

Types of Respiratory Organs

Gills, tracheae, and lungs for gas exchange.

Mammalian Respiratory System

Includes nostrils, trachea, bronchi, and alveoli.

Mucus Escalator

Cilia and mucus clear respiratory system debris.

Erythrocytes

Red blood cells that transport O2.

Erythropoietin (EPO)

Hormone stimulating red blood cell production.

Anemia

Condition of low erythrocyte or hemoglobin levels.

Sickle-Cell Disease

Abnormal hemoglobin distorts erythrocytes into sickle shape.

Leukocytes

White blood cells involved in immune defense.

Platelets

Cell fragments that aid in blood clotting.

Coagulation

Formation of a solid clot from liquid blood.

Atherosclerosis

Hardening of arteries due to fatty deposits.

Thrombus

Blood clot formed within a blood vessel.