Circulation

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SECTION A

BLOOD

Plasma

The Blood Cells

Erythrocytes

Leukocytes

Platelets

Regulation of Blood Cell Production

SECTION A SUMMARY SECTION A KEY TERMS SECTION A REVIEW QUESTIONS

SECTION B

OVERALL DESIGN OF THE CARDIOVASCULAR SYSTEM Pressure, Flow, and Resistance

SECTION B SUMMARY SECTION B KEY TERMS SECTION B REVIEW QUESTIONS

SECTION C THE HEART Anatomy

Cardiac Muscle Heartbeat Coordination

Sequence of Excitation

Cardiac Action Potentials and Excitation of the SA Node The Electrocardiogram Excitation-Contraction Coupling Refractory Period of the Heart Mechanical Events of the Cardiac Cycle

Mid-Diastole to Late Diastole

Systole

Early Diastole

Pulmonary Circulation Pressures Heart Sounds The Cardiac Output Control of Heart Rate Control of Stroke Volume Measurement of Cardiac Function

SECTION C SUMMARY SECTION C KEY TERMS SECTION C REVIEW QUESTIONS

SECTION D

THE VASCULAR SYSTEM Arteries

Arterial Blood Pressure Measurement of Systemic Arterial Pressure

Arterioles

Local Controls Extrinsic Controls

Endothelial Cells and Vascular Smooth Muscle

Arteriolar Control in Specific Organs Capillaries

Anatomy of the Capillary Network Velocity of Capillary Blood Flow Diffusion across the Capillary Wall: Exchanges of Nutrients and Metabolic End Products Bulk Flow across the Capillary Wall: Distribution of the Extracellular Fluid

Veins

Determinants of Venous Pressure

The Lymphatic System

Mechanisms of Lymph Flow

SECTION D SUMMARY SECTION D KEY TERMS SECTION D REVIEW QUESTIONS

Vander et al.: Human I III. Coordinated Body I 14. Circulation I I © The McGraw-Hill

Physiology: The Functions Companies, 2001

Mechanism of Body

SECTION E INTEGRATION OF CARDIOVASCULAR FUNCTION: REGULATION OF SYSTEMIC ARTERIAL PRESSURE Baroreceptor Reflexes Arterial Baroreceptors The Medullary Cardiovascular Center Operation of the Arterial Baroreceptor

Reflex Other Baroreceptors Blood Volume and Long-Term

Regulation of Arterial Pressure Other Cardiovascular Reflexes and Responses

SECTION E SUMMARY SECTION E KEY TERMS SECTION E REVIEW QUESTIONS

SECTION F

CARDIOVASCULAR PATTERNS IN HEALTH AND DISEASE Hemorrhage and Other Causes of Hypotension

Shock

The Upright Posture Exercise

Maximal Oxygen Consumption and Training Hypertension Heart Failure

Coronary Artery Disease and Heart Attacks

SECTION F SUMMARY SECTION F KEY TERMS SECTION F REVIEW QUESTIONS

SECTION G

HEMOSTASIS: THE PREVENTION OF BLOOD LOSS Formation of a Platelet Plug Blood Coagulation: Clot

Formation Anticlotting Systems

Factors That Oppose Clot Formation The Fibrinolytic System Anticlotting Drugs

SECTION G SUMMARY SECTION G KEY TERMS SECTION G REVIEW QUESTIONS CHAPTER 14 CLINICAL TERMS CHAPTER 14 THOUGHT QUESTIONS

Beyond a distance of a few cell diameters, diffusion—the random movement of substances from a region of higher concentration to one of lower concentration—is not sufficiently rapid to meet the metabolic requirements of cells. In large multicellular organisms, therefore, some mechanism other than diffusion is needed to transport molecules rapidly over the long distances between internal cells and the body's surface and between the various specialized tissues and organs. In the animal kingdom this is achieved by the circulatory system, which comprises the blood, the set of interconnected tubes (blood vessels, or vascular system) through which the blood flows, and a pump (the heart) that produces this flow. The heart and blood vessels together are termed the cardiovascular system.

BLOOD

Blood is composed of cells and a liquid, called plasma, in which they are suspended. The cells are the erythrocytes (red blood cells), the leukocytes (white blood cells), and the platelets, which are not complete cells but cell fragments. More than 99 percent of blood cells are erythrocytes, which carry oxygen. The leukocytes protect against infection and cancer (Chapter 20), and the platelets function in blood clotting (Section G of this chapter). In the cardiovascular system, the constant motion of the blood keeps all the cells well dispersed throughout the plasma.

The hematocrit is defined as the percentage of blood volume that is occupied by erythrocytes. It is measured by centrifuging (spinning at high speed) a sample of blood, the erythrocytes being forced to the bottom of the centrifuge tube and the plasma to the top, the leukocytes and platelets forming a very thin layer between them (Figure 14-1). The normal hematocrit is approximately 45 percent in men and 42 percent in women.

Vander et al.: Human Physiology: The Mechanism of Body Function, Eighth Edition

Circulation CHAPTER FOURTEEN

Circulation CHAPTER FOURTEEN

Nervous System Tube Tests

Leukocytes and platelets _

Erythrocytes = 45% (hematocrit = 45%)

Leukocytes and platelets _

"Buffy coat"

Erythrocytes = 45% (hematocrit = 45%)

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