Human physiology

Описание

Fitness Application Boxes
These readings explore physiological principles as applied
to well-being, sports
medicine, exercise
physiology, and
aging. They are also
placed at relevant
points in the text to
highlight concepts
just covered in the
chapter.
Chapter-Opening Clinical Case Investigations, Clues,
and Summaries
These diagnostic clinical case studies open every chapter
with intriguing scenarios based on physiological concepts
covered in that particular chapter. Clues to the case are
given at key points where applicable material is discussed,
and the case is fi nally resolved at the end of the chapter.
Clinical Relevance Woven into Every Chapter
The framework of this textbook is based on integrating
clinically germane information with knowledge of the
body’s physiological processes. Examples of this
abound throughout the book. For example, in a clinical
setting we record electrical activity from the body: this
includes action potentials (chapter 7, section 7.2);
EEG (chapter 8, section 8.2); and ECG (chapter 13,
section 13.5). We also record mechanical force in
muscle contractions (chapter 12, section 12.3). We
note blood plasma measurements of many chemicals
to assess internal body conditions. These include
measurements of blood glucose (chapter 1, section
1.2) and the oral glucose tolerance test (chapter 19,
section 19.4); and measurements of the blood
cholesterol profi le (chapter 13, section 13.7). These
are just a few of many examples the author includes
that focus on the connections between the study of
physiology and our health industry.
“This is an excellent text with a clinical orientation
that makes discussion of disease processes and
pathophysiology easy.”
—John E. Lopes, Jr.,
Central Michigan University
Systems Interactions pages
These special pages appear at the end of all of the
systems chapters and list the many ways a major
concept applies to the study of different body systems,
in addition to how a given system interacts with other
body systems. Each application or interaction includes a
page reference.
“The clarity of the explanations is superb. The
Clinical boxes are excellent introductions to future
material in the text and its medical relevance. They
draw the student into the drier, more theoretical
material by giving it physiological meaning.”
—Gail Sabbadini,
San Diego State University
Case Investigation
Jason, a 19-year-old college student, goes to
the doctor complaining of chronic fatigue. The doctor palpates (feels) Jason’s radial pulse, and comments that it is
fast and weak. He orders various tests, including an echocardiogram, an electrocardiogram, and later an angiogram.
He also requests that particular blood tests be performed.
Some of the new terms and concepts you will
encounter include:
■ Red blood cell count, hemoglobin, and hematocrit
measurements and anemia
■ Ventricular septal defect and mitral stenosis
■ ECG waves and sinus tachycardia
■ LDL cholesterol and atherosclerosis
Case Investigation CLUES
Jason’s blood tests reveal that he has a low red
blood cell count, hematocrit, and hemoglobin concentration.
■ What condition do these tests indicate?
■ How could this contribute to Jason’s chronic fatigue?
FITNESS APPLICATION
Interestingly, the blood contributed by contraction of the atria
does not appear to be essential for life. Elderly people who
have atrial fibrillation (a condition in which the atria fail to
contract) can live for many years. People with atrial fibrillation,
however, become fatigued more easily during exercise
because the reduced filling of the ventricles compromises the
ability of the heart to sufficiently increase its output during
exercise. (Cardiac output and blood flow during rest and exercise are discussed in chapter 14.)
Case Investigation
SUMMARY
Jason has anemia, and the reduced delivery of oxygen to his
tissues probably contributed to his chronic fatigue. He also
has a heart murmur due to the ventricular septal defect and
mitral stenosis, which were probably congenital. These conditions could reduce the amount of blood pumped by the left
ventricle through the systemic arteries, and thus weaken his
pulse. The reduced blood flow and consequent reduced
oxygen delivery to the tissues could be the cause of his
chronic fatigue. The lowered volume of blood pumped by
the left ventricle could cause a reflex increase in the heart
rate, as detected by his rapid pulse and the ECG tracing
showing sinus tachycardia. Jason’s high blood cholesterol is
probably unrelated to his symptoms. This condition could be
dangerous, however, as it increases his risk for atherosclerosis. Jason should therefore be placed on a special diet, and
perhaps medication, to lower his blood cholesterol.
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