Red Blood Cell Lifespan and Breakdown

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Questions and Answers

What processes account for the degradation of red blood cells after their lifespan of 120 days?

90% are engulfed by macrophages and 10% hemolyze. (correct)
Only 90% are engulfed by macrophages while the rest do not degrade.
All RBCs are destroyed by hemolysis in the plasma.
Only macrophages degrade the RBCs without any hemolysis.

What is the first product formed during the breakdown of heme in the macrophages?

Amino acids
Bilirubin
Biliverdin (correct)
Iron ($Fe^{2+}$)

Where is bilirubin transported after its formation in macrophages?

To the kidneys for filtration.
To the heart for circulation.
To the lungs for respiration.
To the liver for secretion with bile. (correct)

What component is NOT released from heme during RBC degradation?

<p>Cholesterol (B)</p> Signup and view all the answers

What role do agglutinogens serve in the context of red blood cells?

<p>They are crucial for determining blood type. (C)</p> Signup and view all the answers

Flashcards

RBC Destruction and Recycling

The process where old red blood cells (RBCs) are broken down and their components are recycled. This happens after 120 days.

Macrophage Engulfment

Special cells called macrophages engulf about 90% of old red blood cells. This is a major way RBCs are broken down.

Heme to Biliverdin

Heme is a molecule within red blood cells that carries oxygen. When RBCs are broken down, heme is converted into a greenish pigment called biliverdin.

Bilirubin Formation

Bilirubin is a yellow pigment produced from biliverdin. It's transported to the liver and eventually eliminated from the body in feces.

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Iron Recycling

Iron (Fe) is a crucial component of red blood cells. When old RBCs are broken down, iron is recycled and used to create new red blood cells in the bone marrow.

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Study Notes

Red Blood Cell (RBC) Lifespan and Breakdown

RBCs have a lifespan of 120 days.
90% of damaged or dead RBCs are engulfed by macrophages.
10% of RBCs hemolyze (burst open) in the plasma.
Macrophages break down the engulfed RBCs.
Digestive enzymes from lysosomes break RBCs into pieces.
Amino acids and iron (Fe2+) are released.
Iron and amino acids are recycled to create new RBCs in bone marrow.
Heme is broken down into biliverdin, then bilirubin.
Bilirubin is transported to the liver.
Bilirubin is excreted in bile.

RBC Breakdown Location

Macrophages in the spleen and liver are the primary sites for RBC degradation.
10% of dead/damaged RBCs hemolyse in plasma, and are collected and cleared by the kidneys.