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💀anatomy and physiology i review

Red Blood Cell Count

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

The red blood cell count, also known as the erythrocyte count, is a measurement of the number of red blood cells present in a sample of blood. Red blood cells, or erythrocytes, are the most abundant type of blood cells and are responsible for carrying oxygen from the lungs to the body's tissues.

5 Must Know Facts For Your Next Test

  1. The normal range for red blood cell count is typically 4.2 to 5.4 million cells per microliter (μL) for men and 3.6 to 5.0 million cells per μL for women.
  2. Red blood cell count can be influenced by factors such as age, gender, altitude, and certain medical conditions.
  3. A low red blood cell count, or anemia, can be caused by blood loss, nutritional deficiencies, or underlying medical disorders.
  4. An elevated red blood cell count, known as polycythemia, can be a result of dehydration, lung diseases, or certain genetic or acquired disorders.
  5. Measurement of red blood cell count is an important part of a complete blood count (CBC) test, which provides valuable information about overall blood health and function.

Review Questions

  • Explain the significance of the red blood cell count in the context of erythrocytes.
    • The red blood cell count is a crucial measure of erythrocyte health and function. It provides information about the body's ability to transport oxygen effectively, as red blood cells are responsible for carrying oxygen from the lungs to the body's tissues. A normal red blood cell count indicates sufficient oxygen delivery, while abnormal values can signify underlying conditions that may impair this vital process.
  • Describe how factors such as age, gender, and altitude can influence the red blood cell count.
    • The normal range for red blood cell count can vary based on several factors. For example, men typically have a higher red blood cell count than women due to hormonal differences. Age can also play a role, as red blood cell count tends to decrease with advancing age. Additionally, living at higher altitudes can lead to an increase in red blood cell production as the body adapts to the lower oxygen levels, resulting in a higher red blood cell count.
  • Analyze the relationship between red blood cell count, hemoglobin, and the body's oxygen delivery system.
    • The red blood cell count, hemoglobin levels, and the body's oxygen delivery system are closely interrelated. Red blood cells contain hemoglobin, the iron-rich protein that binds to and transports oxygen. A higher red blood cell count typically indicates a greater capacity for oxygen transport, as there are more cells available to carry hemoglobin and deliver oxygen to the body's tissues. Conversely, a low red blood cell count or hemoglobin level can impair oxygen delivery, leading to the condition of anemia and its associated symptoms.