Erythrophysiology

Question 1

List the components of the RBC membrane.

Answer 1

• It is a phospholipid bilayer
• It has lipids that can cause shape changes, such as acanthocytes in liver disease
• Has carbohydrates such as glycolipids and glycoproteins that determine blood group antigens
• Membrane proteins contribute to the negative charge of RBS, act as surface receptors and transport proteins, maintain the osmotic gradient inside RBCs, and bind to cytoskeletal proteins
• Cytoskeletal proteins maintain RBC shape and flexibility
• Membrane ion pumps maintain RBC volume. An ATP pump exchanges Na and K.

Question 2

List the components of the RBC cytoplasm. in mammalian and non-mammalian species.

Answer 2

• Mammalian: lack nuclei, mitochondria, and ribosomes
• Non-Mammalian: retain nuclei
• Reddish cytoplasm caused by hemoglobin

Question 3

Describe the reticulocyte response in dogs, cats, cattle, and horses.

Answer 3

• Dogs and cats show increased reticulocytes in peripheral blood 2-3 days and peaks at 4-7 days
• Cattle release fewer reticulocytes than dogs and cats
• Horses rarely release reticulocytes

Question 4

List the major functions of RBCs.

Answer 4

-Transport oxygen to tissues and carbon dioxide to the lungs

Question 5

Describe how hemoglobin is synthesized and metabolized, including bilirubin metabolism.

Answer 5

• Heme synthesis occurs in mitochondria and cytoplasm. Iron in the heme must be in the ferrous (Fe2+) state to bind oxygen.
• Globin synthesis occurs on ribosomes in the RBC cytoplasm

Question 6

Describe the erythropoietin and RBC response to hypoxia.

Answer 6

• Erythropoietin: Increased production, increasing erythropoiesis and oxygen transport to tissues
• RBC: Immediate release of reticulocytes from BM and spleen; nucleated RBCs may be released