Hemopoiesis in adults takes place in the?

AIIMS Nagpur NO - 2018

Applied Physiology

Easy

Appeared in: AIIMS Nagpur NO - 2018

Explanation

Hemopoiesis is the medical term for the formation and development of all types of blood cells, including erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets).
In adults, the primary site for this continuous process is the red bone marrow.
This active (hematopoietic) marrow is concentrated in the flat bones such as the pelvis, vertebrae, ribs, and sternum, as well as the proximal ends of long bones like the femur and humerus.

Option A: The lungs are the primary organs of the respiratory system. Their main function is gas exchange (supplying oxygen to the blood and removing carbon dioxide), not the production of blood cells.
Option B: Arteries are blood vessels that are part of the circulatory system. Their function is to carry oxygenated blood away from the heart to the body's tissues. They are conduits for blood, not sites of its production.
Option D: The heart is a muscular organ that acts as a pump to circulate blood throughout the body. While essential for transporting blood cells, it does not produce them.

Visual 1: Diagram - An illustration of the human skeleton highlighting the areas of active red bone marrow in an adult (e.g., pelvis, sternum, vertebrae, ribs, and ends of long bones). This helps visualize the specific locations of adult hemopoiesis.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The primary anatomical site of hemopoiesis (blood cell formation) in adults as background academic context rather than a clinical decision trigger.
Knowledge of hematopoietic sites is fundamental for nurses in oncology and hematology. Diseases like leukemia, aplastic anemia, and multiple myeloma directly affect the bone marrow's ability to produce healthy blood cells.
Diagnostic procedures such as bone marrow aspiration and biopsy are performed on sites with active red marrow, most commonly the posterior iliac crest (part of the pelvis), to evaluate blood cell production.
What if? - What if the question asked about a fetus? In a fetus, the primary sites of hemopoiesis change during development. It begins in the yolk sac, then shifts to the liver and spleen during the second trimester, with the bone marrow gradually becoming the main site by the third trimester and after birth.

How to Approach the Question

This is a factual recall question testing your knowledge of basic human physiology.
First, identify and define the key term in the question: 'Hemopoiesis' means the formation of blood cells.
Next, consider the specific context provided: 'in adults'. The site of hemopoiesis changes from fetal life to adulthood.
Systematically evaluate each option based on its primary physiological function.
Eliminate the lungs, as their function is respiration.
Eliminate the arteries, as their function is blood transport.

Concept Tested & Keywords

Concept Tested: The primary anatomical site of hemopoiesis (blood cell formation) in adults.
Stem keywords: Hemopoiesis, adults
Lead-in keywords: takes place in

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