Lesson 1: RBCs - Blood Cells

What are the roles of blood

• Delivering nutrients & oxygen to tissues; metabolism

• Removing waste products

• Defence against infection

• Maintaining acid-base balance

What are the 3 distinct layers of blood formed after centrifuge?

• Top → plasma

• Middle → Buffy coat (leukocytes, thrombocytes)

• Bottom → erythrocytes

What is the percentage of Plasma that makes up total blood volume?

50-55%

What can be found in plasma?

• Proteins

  • Albumin

  • Globulins (antibodies)

  • Fibrinogen (clotting)

• Solutes

  • Sodium, potassium, calcium

Functions of plasma

• Clotting

• Defence

• Transport

• Regulation

• Enzymatic inhibitors

• Hormones

Erythrocytosis

Elevated RBC count because low O2 → increased EPO production

• Caused by chronic lung diseases

Anemia

Decreased; too little RBCs in blood or insufficient Hgb

• Caused by loss/destruction of RBCs, decreased EPO, bone marrow suppression (cancer)

What is hematocrit

RBC % in proportion to plasma volume

What happens to HCT levels during Hypovolemia?

HCT levels increase

What should you expect HCT levels to be IMMEDIATELY after blood loss?

Normal because the body hasn’t compensated for the blood loss yet

A day after a patients initial injury that caused excessive blood loss, what do you expect HCT levels to be?

Low, because the body has compensated for the blood loss by moving more fluid into the Intravascular compartment from cells

How does dehydration affect HCT levels?

Makes them appear higher even though RBC levels don’t change, only plasma volume decreased

Why should you always interpret Hgb in relation to HCT?

Because fluid balance can significantly affect these values