Life span of RBC is?

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

The average lifespan of a mature red blood cell in a healthy adult is approximately 120 days.
RBCs are produced in the bone marrow and are anucleated (lack a nucleus), which limits their ability to synthesize proteins for repair, thus defining their finite lifespan.
After circulating for about 120 days, aging RBCs become fragile and are removed from circulation by macrophages, predominantly in the spleen.

Option A: 90 days is not the average lifespan for a typical adult red blood cell.
Option B: 100 days is an incorrect value and is shorter than the established average lifespan of an adult RBC.
Option C: 110 days, while closer to the correct answer, is still shorter than the accepted average lifespan of a healthy adult RBC.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of Red Blood Cells (RBCs) as background academic context rather than a clinical decision trigger.
Understanding the 120-day RBC lifespan is crucial for managing blood bank inventories and determining blood donation intervals (typically every 3-4 months) to ensure donors have replenished their RBCs.
This knowledge is fundamental to the diagnosis and management of hemolytic anemias, where RBCs are destroyed prematurely, leading to a shortened lifespan (e.g., 10-20 days in sickle cell disease).
What if? If a patient has their spleen removed (splenectomy), the primary site for removing old RBCs is gone. This results in an increased number of older, and sometimes abnormally shaped, RBCs circulating in the blood, which can be observed on a peripheral blood smear.

How to Approach the Question

Recognize that the question asks for a specific, standard physiological value.
This is a factual recall question, requiring knowledge from physiology or hematology.
Review the options, which are all time durations.
Recall or deduce the average lifespan of a mature human red blood cell.
Select the option that matches the well-established value of 120 days.

Concept Tested & Keywords

QFNYy7Ou1r4nbgl-f09mc7

E6 Physiology Guyton 4SAE Part 1 p. 172-174

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 716-718

Practise the full RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Attempt every question from this paper in a timed mock, then review the full solution for each one.