Red Blood Cells: Shape and Size

Questions and Answers

What effect does a decrease in atmospheric oxygen levels have on red blood cell (RBC) production?

Increases the RBC production (correct)

Keeps it balanced to the outer environment

Decreases the RBC production

Does not affect the RBC production

What role does erythropoietin play in response to hypoxia?

It inhibits erythropoiesis.

It promotes increased RBC production. (correct)

It does not affect RBC production.

It decreases RBC lifespan.

How long do red blood cells typically live in conditions of reduced oxygen if fragility is increased?

Normal lifespan, around 120 days

Lifespan is unaffected

Shortened lifespan, about 1 to 3 years

Shortened lifespan, one half to one third of normal (correct)

Which of the following statements about erythropoietin's activation is correct?

It causes a marked increase in RBC production during hypoxia. Signup and view all the answers

What happens to RBC production when there is consistent hypoxia and erythropoietin is functional?

Production increases until hypoxia resolves. Signup and view all the answers

What is the primary factor that regulates red blood cell production?

Tissue Oxygenation Signup and view all the answers

What is the first-generation cell in the maturation of red blood cells called?

Basophil erythroblast Signup and view all the answers

What occurs to the nucleus of developing red blood cells during maturation?

It condenses to a smaller size Signup and view all the answers

What significant change occurs to the reticulocyte during its maturation into a mature red blood cell?

Increase in hemoglobin concentration Signup and view all the answers

Which of the following conditions prompts an increase in red blood cell production?

Hypoxia Signup and view all the answers

In what scenario does erythropoietin have little or no effect on stimulating red blood cell production?

In the absence of tissue oxygenation Signup and view all the answers

What is the main characteristic of basophil erythroblasts that distinguishes them at this developmental stage?

Staining with basic dyes Signup and view all the answers

What is typically observed in the peripheral blood smear regarding reticulocytes and erythrocytes?

Reticulocytes show remnants of endoplasmic reticulum Signup and view all the answers

What is the primary shape of red blood cells?

Biconcave discs Signup and view all the answers

What is the mean diameter of a red blood cell?

7.8 micrometres Signup and view all the answers

How does the thickness of a red blood cell vary?

Thickest point of 2.5 micrometres and less than 1 micrometre in the center Signup and view all the answers

What is the average volume of a red blood cell?

90 to 95 cubic micrometres Signup and view all the answers

How do red blood cells change shape as they pass through capillaries?

They can be deformed into almost any shape Signup and view all the answers

What happens to the membrane of red blood cells during deformation?

It stably maintains integrity without significant stretching Signup and view all the answers

What specific characteristic of RBC shape is identifiable in a peripheral blood smear?

Shape and deformation capabilities Signup and view all the answers

What role does erythropoietin play in the physiology of red blood cells?

It influences the production of RBCs Signup and view all the answers

Which statement about erythropoietin is accurate?

It plays a role in regulating RBC production. Signup and view all the answers

What happens when there is a lack of vitamin B12?

There is abnormal DNA formation and failure in maturity. Signup and view all the answers

Which of the following components is essential for the final maturation of RBCs?

Folic acid Signup and view all the answers

Which organ is not associated with the formation of thymidine triphosphate?

Kidneys Signup and view all the answers

What characterizes the fragility of RBCs with aging?

Decreased resistance to lysis. Signup and view all the answers

Where is the production of reticulocytes primarily observed?

Bone marrow Signup and view all the answers

Which of the following is NOT a characteristic of red blood cells?

They contain a nucleus. Signup and view all the answers

Many RBCs undergo self-destruction in which organ?

Spleen Signup and view all the answers

What is the primary role of erythropoietin in the body?

To increase red blood cell production Signup and view all the answers

Where is erythropoietin primarily secreted within the kidney?

In the tubules of the cortex and outer medulla Signup and view all the answers

What causes an increase in the production of erythropoietin?

Decreased blood flow through peripheral vessels Signup and view all the answers

What happens to erythropoietin production when the required number of red blood cells is reached?

It decreases to maintain balance Signup and view all the answers

What molecular weight is attributed to erythropoietin?

34,000 Signup and view all the answers

What deficiency can lead to maturation failure in erythropoiesis?

Vitamin B12 or folic acid deficiency Signup and view all the answers

Which diseases are associated with decreased oxygen absorption that may stimulate erythropoietin production?

Lung diseases and cardiac failure Signup and view all the answers

What is the effect of erythropoietin on haematocrit and total blood volume?

Increases haematocrit and blood volume Signup and view all the answers

Study Notes

Shape and Size of Red Blood Cells (RBC)

RBCs are biconcave discs with a mean diameter of approximately 7.8 micrometres.
Maximum thickness is about 2.5 micrometres, while the center measures around 1 micrometer or less.
Average volume of an RBC is between 90 to 95 cubic micrometres.
RBC shapes can change to navigate through capillaries, allowing deformation without rupturing the cell.

Genesis and Differentiation of RBCs

Proerythroblasts undergo multiple divisions, leading to the formation of mature RBCs.
The first-generation cells, called basophil erythroblasts, stain with basic dyes but have low haemoglobin content initially.
As the cells mature, they achieve about 34% concentration of haemoglobin.
The nucleus condenses and eventually is either absorbed or extruded from the cell during maturation.

Regulation of RBC Production

Tissue oxygenation is a crucial regulator for producing RBCs; low oxygen states stimulate production.
Erythropoietin is the primary hormone that increases RBC production, primarily secreted by kidney interstitial fibroblast-like cells.
Inadequate erythropoietin leads to insufficient RBC formation, particularly under hypoxic conditions.
As RBC levels increase and oxygen transport improves, erythropoietin production decreases to maintain balance.

Requirements for RBC Maturation

Vitamin B12 (cobalamin) and folic acid are essential for the final maturation of RBCs.
These vitamins are required for synthesizing thymidine triphosphate, vital for DNA formation.
Deficiencies in B12 or folic acid lead to abnormal cell division and maturation failures.

RBC Lifespan and Degradation

RBCs have a relatively short lifespan compared to other cells, often self-destructing in the spleen.
Aging impacts RBC fragility, contributing to their limited longevity within the circulatory system.

Summary of Erythropoietin and Production Factors

Erythropoietin directly stimulates RBC production in low oxygen conditions.
Conditions affecting blood flow and oxygen absorption prompt increased RBC production.
A functional erythropoietin system results in heightened production during hypoxia until adequate oxygen transport is restored.

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Description

Explore the fascinating structure of red blood cells, including their unique biconcave shape and size specifications. This quiz covers essential characteristics and measurements of RBCs, providing a comprehensive understanding of their role in the body.