Bio163Ch11

Functions of Blood

Transport (gases, nutrients, waste, hormones), Regulation of pH and osmosis, Temperature maintenance, Protection (immune response), Clot formation.

Components of Blood

Plasma (55%) - Liquid portion with proteins (albumin, globulins, fibrinogen) and Formed Elements (45%) - RBCs, WBCs, Platelets.

Hematopoiesis

Process of blood cell formation occurring in the liver, spleen, thymus, lymph nodes, and red bone marrow in fetuses, and only in red bone marrow in adults.

Erythrocytes (RBCs)

Function: Transport oxygen & carbon dioxide; Structure: Biconcave, no nucleus, flexible; Lifespan: ~120 days; Main protein: Hemoglobin.

Hemoglobin

Red-pigmented protein in RBCs that carries oxygen (O₂) & carbon dioxide (CO₂). Oxygen binds to iron (Fe) in the heme group.

Old RBC Breakdown

Macrophages in spleen & liver remove RBCs; Globin → amino acids; Iron → recycled for new hemoglobin; Heme → converted to bilirubin (excreted in bile).

Leukocytes (WBCs)

Cells that fight infections & remove dead cells; Larger than RBCs, contain a nucleus; Types: Granulocytes & Agranulocytes.

Types of Granulocytes

Neutrophils (phagocytic, first responders), Eosinophils (attack parasites, reduce inflammation), Basophils (release histamine).

Types of Agranulocytes

Monocytes (develop into macrophages) and Lymphocytes (specific immunity - B cells, T cells, NK cells).

Platelets (Thrombocytes)

Cell fragments from megakaryocytes; Function: Clot formation & prevent blood loss; Lifespan: 5–9 days.

Three Steps of Hemostasis

1. Vascular spasm - Constriction of the blood vessel; 2. Platelet plug formation - Platelets stick to the damaged vessel; 3. Coagulation - Fibrin network forms a clot.

Clotting Factors

Proteins in plasma that activate clot formation; Made in the liver; Require Vitamin K.

Blood Types

Based on the presence of A & B antigens on RBCs; Type A - A antigen, anti-B antibodies; Type B - B antigen, anti-A antibodies; Type AB - A & B antigens, no antibodies; Type O - No antigens, both anti-A & anti-B antibodies.

Rh Factor

Rh-positive (Rh⁺): Has Rh antigen; Rh-negative (Rh⁻): No Rh antigen, can develop anti-Rh antibodies; Important in pregnancy.

Hemolytic Disease of the Newborn (HDN)

Condition where Rh⁻ mother’s immune system attacks Rh⁺ baby’s RBCs; Prevented by RhoGAM injection.

Sickle-cell Anemia

Genetic disorder causing abnormally shaped RBCs; Autosomal recessive inheritance; Provides natural resistance to malaria.

Common Blood Disorders

Leukopenia (low WBC count), Leukocytosis (high WBC count), Hemophilia (blood doesn’t clot properly).

Diagnostic Blood Tests

Complete Blood Count (CBC), Hematocrit (Hct), Prothrombin Time.