Chapter 19 A & P

19.1A - Blood and Homeostasis

Blood helps maintain homeostasis by:

1. Transporting substances – Delivers oxygen and nutrients to cells and removes waste.

2. Regulating pH and ions – Buffers in the blood maintain a stable pH.

3. Regulating temperature – Blood distributes heat throughout the body.

4. Clotting – Prevents blood loss after injury.

5. Immune defense – White blood cells and antibodies fight infections.

19.2A - Components of Blood

• Plasma (55%) – Fluid containing water, proteins, nutrients, and waste.

• Formed elements (45%) – Red blood cells (RBCs), white blood cells (WBCs), and platelets.

19.2B - Blood Volume

• Males: 5–6 liters

• Females: 4–5 liters

19.3A - Blood Plasma Components

• Water (92%)

• Proteins (7%)

• Nutrients, gases, waste, and hormones (1%)

19.3B - Major Plasma Proteins

• Albumin – Maintains osmotic pressure.

• Globulins – Involved in immunity (antibodies).

• Fibrinogen – Essential for blood clotting.

19.4A - Three Formed Elements

• Erythrocytes (Red Blood Cells - RBCs)

• Leukocytes (White Blood Cells - WBCs)

• Thrombocytes (Platelets)

19.4B - Origin & Production of Formed Elements

• Produced in red bone marrow (hematopoiesis).

• Hemocytoblasts (stem cells) differentiate into RBCs, WBCs, and platelets.

19.4C - Hemoglobin Structure & Function

• Structure: 4 polypeptide chains, each with an iron-containing heme.

• Function: Carries oxygen and carbon dioxide.

• Oxygen binds to iron, CO₂ binds to globin.

9.4D - Fetal vs. Adult Hemoglobin

Fetal hemoglobin has a higher affinity for oxygen, allowing better oxygen transfer from mother to fetus.

19.4E - Red Blood Cell Life Cycle

• Lifespan: ~120 days.

• Old RBCs are broken down in the liver & spleen.

• Iron is recycled, and bilirubin is excreted in bile.

19.4F - Types of White Blood Cells

• Neutrophils – Fight bacterial infections.

• Lymphocytes – Produce antibodies.

• Monocytes – Become macrophages and engulf pathogens.

• Eosinophils – Combat parasites and allergies.

• Basophils – Release histamine in allergic reactions.

19.4G - Platelet Origin & Structure

• Origin: Made from megakaryocytes in bone marrow.

• Structure: Small cell fragments without a nucleus.

19.4H - Platelet Function

• Forms platelet plugs at injury sites.

• Releases clotting factors to prevent blood loss.

19.5A - Hemostasis (Stopping Bleeding)

• Vascular Spasm – Blood vessel constriction.

• Platelet Plug Formation – Platelets stick to injury.

• Coagulation (Clotting) – Fibrin forms a stable clot.

19.5B - Clot Regulation & Removal

• Regulation: Anticoagulants like heparin prevent excessive clotting.

• Clot Removal: Plasmin dissolves clots (fibrinolysis).

19.6A - ABO Blood Group System

• Determined by antigens (A & B) on RBCs.

• Four types: A, B, AB, O.

19.6B - ABO Incompatibility in Transfusion

• Mismatch can trigger an immune response.

• Type O = universal donor; Type AB = universal recipient.

19.6C - Rh Blood Group

• Rh-positive (has Rh antigen).

• Rh-negative (lacks Rh antigen).

19.6D - Hemolytic Disease of the Newborn (HDN)

• Occurs when an Rh-negative mother carries an Rh-positive baby.

• Mother’s immune system attacks fetal RBCs in future pregnancies.

• Prevented with RhoGAM injection.

19.7A - Diagnostic Blood Tests & Normal Values

1. Hematocrit (RBC %): Males 42-52%, Females 37-47%.

2. Hemoglobin: Males 13-18 g/dL, Females 12-16 g/dL.

3. WBC Count: 4,000-11,000 per μL.

4. Platelet Count: 150,000-450,000 per μL.

19.7B - Disorders with Abnormal Blood Test Values

1. Anemia: Low RBCs or hemoglobin.

2. Leukemia: High WBC count due to cancer.

3. Thrombocytopenia: Low platelet count, causing bleeding.