The Cardiovascular System:
Heart, Blood Vessels,
and Circulation
The Heart Pumps Blood through Blood
Vessels to all Tissues
310
The Heart Is Located in the Thoracic Cavity
311
Valves Keep the Blood Flowing the Right
Direction through the Heart
312
Blood Flows through the Heart Because
of Pressure Gradients
314
Electrical Signals Control Heart Rate
315
The Cardiac Cycle Alternates Between
Systole and Diastole
316
Many Factors Affect Cardiac Output
318
What Can Go Wrong with Blood Flow
Through the Heart?
319
Blood Vessels Are the Body’s Plumbing
320
Arteries and Arterioles Are Thick-Walled Vessels
321
Capillaries Are Thin Exchangers Between
Blood and Tissues
324
Veins and Venules Are Thin-Walled
Blood Collectors
326
The Pulmonary and Hepatic Portal
Circulations Are Somewhat Different
330
Maintaining Blood Pressure Is Critical for Survival
332
Pressure Drives the Flow of Blood
332
Many Factors Influence Blood Pressure
332
Blood Pressure Is Closely Regulated
334
■ WHAT A HEALTH PROVIDER SEES: Shock
335
The Lymphatic System
and Immunity
The Lymphatic System
and Immunity
Components of the Lymphatic System
Are Found Throughout the Body
344
The Lymphatic System Has Three Functions:
Drainage, Transport, and Immunity
344
The Lymphatic System Consists of Lymph,
Lymphatic Vessels, and Several Structures
and Organs
344
Immune Reactions Occur in the Lymph
Nodes, Spleen, and Lymphatic Nodules
348
Immune Responses Help Protect
the Body Against Disease
350
Innate Immunity Includes Two Levels
of Nonspecific Defense
351
Adaptive Immunity Allows You to Respond
to a Variety of Invaders
354
Immune Response Time Speeds Up After
the Initial Exposure
359
Allergies Are Caused by an Overreaction
to an Antigen
360
There Are Many Ways to Develop Immunity
360
■ WHAT A HEALTH PROVIDER SEES:
When Your Own Immune System Attacks You
361
HIV Causes a Breakdown of the
Immune Response
362
It Is Not Easy to Get Infected with HIV
362
The Symptoms of HIV Infection Progress
in Severity
362
Contents xxvii
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