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Ch. 10 Blood
Marieb - Essentials of Human Anatomy & Physiology 13th Edition
Marieb13th EditionEssentials of Human Anatomy & PhysiologyISBN: 9780135624340Not the one you use?Change textbook
All textbooksMarieb 13th EditionCh. 10 BloodProblem 25
Chapter 10, Problem 25

Brittany, a healthy young woman, had a battery of tests during a physical for a new job. Her RBC count was at the higher end of the normal range at that time, but four weeks later it was substantially elevated beyond that. When asked if any circumstances had changed in her life, she admitted to taking up smoking. How might her new habit explain her higher RBC count?

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1
Understand the role of red blood cells (RBCs): RBCs are responsible for transporting oxygen from the lungs to tissues and removing carbon dioxide from the body. Their production is regulated by the body's oxygen needs.
Recognize the impact of smoking on oxygen levels: Smoking introduces carbon monoxide (CO) into the bloodstream. CO binds to hemoglobin in RBCs with a much higher affinity than oxygen, reducing the oxygen-carrying capacity of the blood.
Explain the body's compensatory mechanism: To counteract the reduced oxygen delivery caused by CO binding, the body increases erythropoiesis (RBC production) to ensure adequate oxygen transport to tissues.
Connect Brittany's smoking habit to her elevated RBC count: Brittany's new smoking habit likely led to increased CO exposure, triggering her body to produce more RBCs to compensate for the reduced oxygen availability.
Conclude with the physiological adaptation: The elevated RBC count is a normal physiological response to chronic exposure to CO from smoking, as the body attempts to maintain oxygen homeostasis despite the interference caused by CO.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Red Blood Cell (RBC) Count

The red blood cell count measures the number of red blood cells in a volume of blood. RBCs are crucial for transporting oxygen from the lungs to the body's tissues and returning carbon dioxide for exhalation. A higher than normal RBC count, known as erythrocytosis, can indicate various physiological changes or health conditions, including increased oxygen demand or reduced oxygen availability.
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Effects of Smoking on Health

Smoking introduces harmful substances into the body, leading to various health issues, including respiratory problems and cardiovascular disease. It can also cause chronic hypoxia, where the body experiences lower oxygen levels. In response, the body may produce more red blood cells to compensate for the reduced oxygen availability, resulting in an elevated RBC count.
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Compensatory Mechanisms

Compensatory mechanisms are physiological responses that the body employs to maintain homeostasis when faced with stressors or changes. In the context of smoking, the body may increase RBC production as a response to chronic low oxygen levels, thereby enhancing oxygen transport capacity. This adaptive response can lead to elevated RBC counts, reflecting the body's attempt to counteract the effects of reduced oxygenation.
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Related Practice
Textbook Question

Lymphocytes continuously circulate through the body using blood and lymph as their transport vehicles. What is the importance of this recirculation behavior?

Textbook Question

A middle-aged college professor from Boston is in the Swiss Alps studying astronomy. He arrived two days ago and plans to stay the entire year. However, he notices that he is short of breath when he walks up steps and that he tires easily with any physical activity. His symptoms gradually disappear; after two months, he feels fine. Upon returning to the United States, he has a complete physical exam and is told that his erythrocyte count is higher than normal.

(a) Attempt to explain this finding.

(b) Will his RBC count remain at this higher-than-normal level? Why or why not?

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Textbook Question

A woman comes to the clinic complaining of fatigue, shortness of breath, and chills. Blood tests show anemia, and a bleeding ulcer is diagnosed. What type of anemia is this?

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