Circulation

Abstract

Two transport systems transfer materials between body cells and tissues: the blood circulation and the lymphatic circuit. They move nutritional materials from the digestive tract to cells for catabolism, synthesis, and deposit. The blood takes oxygen from the lungs to the consuming cells; it carries carbon dioxide to the lungs to be expelled, lactic acid to the liver and kidneys for processing, and it takes heated body fluid, water, to the skin and lungs for heat dissipation. The blood stream also is part of the body control system by carrying hormones from endocrine glands to receptive cells.

Glossary

Absorption

Here, passing through cell walls.

Anastomosis

A shunt (shortcut) from arteriole to venule.

Arteriole

Terminal branch of an artery, especially a small artery joining a larger artery to a capillary.

Artery

A muscular elastic tube that carries blood away from the heart.

Assimilation

Transformation of digested nutriment into a part of the organism.

Blood groups

Classification of blood (into four groups: A, B, AB, 0) according to the content of certain antigens and antibodies.

Blood pressure

The internal pressure in the arteries near heart.

Cardiac minute volume

Heart stroke volume multiplied with heart rate: the volume of blood injected into the main artery per minute.

Cardiac output

Heart stroke volume multiplied with heart rate: the volume of blood injected into the main artery per minute.

Catabolism

Metabolic breakdown of complex molecules into simpler ones, often with release of energy.

Diastole

Relaxiation of the heart ventricle.

Diffusion

Here, permeation of cell walls.

ECG

Electrocardiogram,

GlossarySeeAlsoSee there.

EKG

Electrokardiogram,

GlossarySeeAlsoSee there.

Electrocardiogram (ECG, also spelled electrocardiogram, EKG)

The electrical events associated with the heart beat.

Electrokardiogram (EKG, also spelled electrocardiogram, ECG)

The electrical events associated with the heart beat.

Erythrocytes

Red blood cells.

Granulocytes

White blood cells.

Heart rate (same as pulse rate)

Number of ventricular contractions per minute.

Hematocrit

The percentage of red cell volume in the total blood volume.

Hemoglobin

An iron-containing protein molecule in the red blood cell.

Leukocytes

White blood cells.

Lumen

The open cross-section of a blood vessel.

Plasma (of blood)

The fluid portion of blood.

Platelets

Thrombocytes.

Plethysmograph

Instrument to record variations in the size of parts of the body, such as of the finger circumference with blood pressure pulses.

Pressure

Force per surface unit.

Pulmonary system

The portion of the blood circulation supplied by the right side of the heart.

Pulse rate (same as heart rate)

Number of ventricular contractions per minute.

Red blood cells

Erythrocytes.

Sinoatrial nodes

The natural “pacemakers” of the heart.

Specific heat

The amount of heat required to raise the temperature of a mass unit by 1°; as compared to the amount of heat required to raise the temperature of a gram of water by 1°.

Stroke volume

The volume of blood ejected from the heart into the main artery during each ventricular contraction.

Synthesis

Formation of a compound from simpler compounds or elements.

Systemic system

The portion of the blood circulation supplied by the left side of the heart.

Systole

Compression of the heart ventricle.

Thrombocytes

Platelets.

Vasoconstriction

Reducing the lumen of a blood vessel below its lumen at regular vasomotor tone.

Vasodilation

Opening of a blood vessel beyond its lumen at regular vasomotor tone. Must be compensated by vessel constriction.

Vein

A large membranous tube that carries blood to the heart.

Venule

A small vein joining a capillary to a larger vein.

Viscosity

Resistance to flow, “internal friction” of a fluid.

White blood cells

Leukocytes, granulocytes.