Negative feedback loop

What is the negative feedback loop for erythropoiesis?

↓ O2 → Kidney → EPO → Bone Marrow → Erythropoiesis → ↑ RBCs → ↑ O2

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A: Erythropoiesis is regulated by a negative feedback loop. When oxygen levels decrease (hypoxia), the kidneys detect the low O2 and release erythropoietin (EPO). EPO stimulates the bone marrow to produce more red blood cells (RBCs), increasing the RBC count and thereby improving the oxygen-carrying capacity of the blood, which restores oxygen levels to normal.

What is the stimulus for the negative feedback loop in erythropoiesis?

Hypoxia (inadequate O2 delivery) due to decreased RBC count, decreased hemoglobin, or decreased O2 availability.

How does altitude training affect erythropoiesis (RBC production)?

It can lead to polycythemia (increased RBC production) due to decreased O2 availability, stimulating erythropoiesis.

How does emphysema affect erythropoiesis?

It can lead to polycythemia due to chronic low oxygen levels in the blood, stimulating erythropoiesis.

What organs release EPO in response to hypoxia?

The kidneys and a small amount of the liver.

What is the function of EPO in erythropoiesis?

EPO stimulates the bone marrow to produce RBCs, increasing the oxygen-carrying capacity of the blood.

What triggers the inhibition of EPO secretion?

Homeostasis is reached when oxygen levels return to normal, signaling the inhibition of EPO secretion.

Where are most RBCs formed in adults?

From the bone marrow in the vertebral column, sternum, and rib cage.