Chapter 18- Blood

Functions of Blood

Transport, protection, and homeostasis.

Transportation

Carrying oxygen, hormones, carbon dioxide, waste, and nutrients to organs.

Leukocytes (WBCs)

White blood cells that defend against pathogens.

Blood Clotting

Prevention of bleeding through clotting substances.

Homeostasis

Regulation of body temperature, blood pH, and water content of body cells.

Hematocrit

Percentage of erythrocytes (RBCs) in blood, normal is approximately 45%.

Packed Cell Volume (PCV)

Volume of erythrocytes in centrifuged blood.

Erythrocytes (RBCs)

Carry oxygen and are the heaviest components of blood.

Buffy Coat

Thin middle layer of centrifuged blood containing WBCs and platelets.

Plasma

Top layer of blood, pale straw-colored fluid.

Viscosity of Blood

The texture of blood, which is viscous and sticky.

Normal Blood Temperature

38°C (100.4°F), slightly warmer than body temperature.

Blood pH

Range of 7.35–7.45, indicating a slightly alkaline nature.

Average Blood Volume in Females

4–5 liters.

Average Blood Volume in Males

5–6 liters.

Major Plasma Protein: Albumin

Most abundant plasma protein, regulates osmotic pressure.

Major Plasma Protein: Globulins

Second most abundant plasma protein, includes antibodies and is important for immunity.

Major Plasma Protein: Fibrinogen

Required for blood clotting.

Hematopoiesis

Blood cell formation, primarily occurs in red bone marrow after birth.

Erythropoietin (EPO)

Stimulates RBC production in response to low oxygen.

Thrombopoietin

Stimulates platelet production.

Cytokines

Stimulate WBC production.

Erythrocyte Lifespan

Approximately 120 days.

Hemoglobin (Hgb) in RBCs

Each RBC contains 250–300 million hemoglobin molecules.

Oxyhemoglobin

Hemoglobin with oxygen attached.

Deoxyhemoglobin

Hemoglobin after oxygen has been released.

Carbon Dioxide Transport

Mostly travels as bicarbonate ions in plasma.

Pulse Oximeter Function

Measures percent saturation of hemoglobin with oxygen.

Hypoxia

Condition of low oxygen levels in the blood.

Removal of Old RBCs

Carried out by macrophages mainly in the bone marrow, liver, and spleen.

Blood Type Antigens

Determined by antigens on the RBC membrane.

Universal Donor Blood Type

O− blood type.

Universal Recipient Blood Type

AB+ blood type.

Most Common Formed Element in Blood

RBCs (erythrocytes).

Most Common WBC

Neutrophil.

Thrombocytopenia

Low platelet count.

Thrombocytosis

High platelet count.

Hemostasis

Process of stopping bleeding, involves vascular spasm, platelet plug formation, and coagulation.