Cardiovascular System

Function of the Cardiovascular System:

  • Transports nutrients, gases, and wastes around the body.

Major Organs

  • Heart

  • Blood Vessels

  • Blood

Blood

Functions of Blood

  • Transportation:

    • Transports oxygen, waste, hormones.

  • Defense:

    • Prevents infection and blood loss.

  • Regulation:

    • Regulates body temperature, pH, and fluid volume.

Composition of Blood

  • Blood is a connective tissue made of:

    • Cells:

    • Known as formed elements.

    • Fluid Matrix:

    • Known as plasma.

Separation of Blood Components

  • When a sample of whole blood is separated in a centrifuge:

    • Plasma rises to the top.

    • Formed elements fall to the bottom.

Composition Breakdown

  • Composition of Blood:

    • 55% Plasma:

    • Yellowish liquid.

    • 1% White Blood Cells and Platelets:

    • This layer is known as the buffy coat.

    • 44% Red Blood Cells:

    • Known as the pellet.

  • Hematocrit:

    • The percentage of red blood cells tested during a standard blood test.

Implications of Low Red Blood Cell Count

  • Low RBC Count (Anemia):

    • Affects the body's ability to transport oxygen and nutrients.

    • Symptoms may include fatigue, dizziness, and heart palpitations.

    • Common type: Iron Deficiency Anemia.

    • Can result from blood loss, malnutrition, or kidney issues.

Physical Properties of Blood

  • Viscosity:

    • Blood is 5 times more viscous than water.

  • Color Variations:

    • Ranges from bright red to purplish depending on the oxygen amount.

  • pH Range:

    • Small range of 7.35-7.45.

  • Volume:

    • Approx. 5-6 liters in the body.

Plasma Composition

  • Plasma Composition:

    • 90% Water

    • 10% Dissolved Substances:

    • Gases, salts, minerals, nutrients, enzymes, hormones, waste, proteins.

    • Three Basic Types of Proteins in Plasma:

    • Albumin:

      • Regulates osmosis between blood and tissues.

    • Globulins:

      • Transport substances or fight infection.

    • Fibrinogen:

      • Used in blood clotting.

    • Plasma composition is regulated by homeostasis.

Formed Elements

  • Formed Elements:

    • Known as such because they have a specific shape.

    • Three Types of Formed Elements:

    • Erythrocytes (red blood cells)

    • Leukocytes (white blood cells)

    • Platelets

Erythrocytes (Red Blood Cells)

  • Function:

    • Transport oxygen throughout the body via hemoglobin molecules.

  • Quantity:

    • Approximately 5 million per milliliter of blood.

  • Production:

    • Produced in red bone marrow.

Structure of Erythrocytes

  • Shape:

    • Biconcave (like an inner tube) for greater surface area.

    • Round sides for efficient flow through blood vessels.

  • Nucleus and Organelles:

    • Erythrocytes lack a nucleus and have few organelles to avoid consuming oxygen.

Oxygen Transport by Erythrocytes

  • Solubility:

    • Oxygen is nonpolar and not soluble in blood; hence erythrocytes transport oxygen.

  • Color Change:

    • Blood color changes from bright red (oxygenated) to darker red/purple (deoxygenated).

Hemoglobin Structure

  • Composition:

    • Hemoglobin consists of 4 chains called globins.

    • Each globin contains a heme molecule that holds one iron atom.

  • Oxygen Binding Capacity:

    • One hemoglobin can bind 4 O2 molecules.

Leukocytes (White Blood Cells)

  • Function:

    • Protect the body from foreign cells or substances.

  • Types:

    • Multiple types with unique functions.

  • Characteristics:

    • Leukocytes:

    • Outnumbered by erythrocytes (1,000 to 1).

    • Mature cells contain nuclei.

    • Lifespan varies (few days to years).

    • Can move out of blood vessels (diapedesis).

Categories of Leukocytes

  • Granulocytes:

    • Include Neutrophils, Basophils, and Eosinophils.

    • Characterized by lobe-shaped nuclei and visible granules.

  • Agranulocytes:

    • Include Lymphocytes and Monocytes.

    • Lack visible granules, feature spherical or kidney-shaped nuclei.

Functions of Specific Leukocytes

  • Neutrophils:

    • Most common leukocyte; engulf and destroy bacteria.

    • Increased production during infections.

  • Eosinophils:

    • Kill parasitic worms; lessen allergic reactions (release histamines).

  • Basophils:

    • Function not fully described in the notes.

  • Lymphocytes:

    • Found mostly in lymph nodes (T-cells & B-cells).

  • Monocytes:

    • Differentiate into macrophages in tissues; attack viruses, parasites, and bacteria.

Mnemonics for Leukocyte Types

  • Mnemonic Device:

    • Never (Neutrophils)

    • Let (Lymphocytes)

    • Monkeys (Monocytes)

    • Eat (Eosinophils)

    • Bananas (Basophils)

Leukocyte Formula

  • Percentage of Different Types of Leukocytes:

    • Neutrophils (Segmented): 40-50%

    • Lymphocytes (T-Lymphocytes): 20-45%

    • Neutrophils (Stab): 1-5%

    • Eosinophils: 1-5%

    • Basophils: 0-1%

    • Monocytes: 3-8%

Thrombocytes (Platelets)

  • Definition:

    • Thrombocytes are platelets made of tiny fragments of other cells.

  • Function:

    • Responsible for clotting blood when a vessel is broken.

Additional Formed Elements

  • Besides erythrocytes, leukocytes, and thrombocytes, each serves specific functions in the immune response and blood clotting.

Hematopoiesis

  • Definition:

    • The process of blood cell formation.

  • Location:

    • Occurs in red bone marrow of adults.

  • Stem Cells:

    • All formed elements arise from common stem cells (hemocytoblasts).

Differentiation of Stem Cells

  • Hemocytoblasts differentiate into:

    • Lymphoid Stem Cells:

    • Create lymphocytes.

    • Myeloid Stem Cells:

    • Create all other types of blood cells.

Hormonal Regulation of Blood Cell Production

  • Erythropoietin:

    • Stimulates red blood cell production.

  • Colony Stimulating Factors (CSFs) and Interleukins:

    • Stimulate white blood cell production.

  • Thrombopoietin:

    • Stimulates platelet production.

Hemostasis

  • Definition:

    • The process of blood clotting; vital for limiting blood loss after injury.

Steps in Hemostasis

  1. Blood vessel contraction occurs, reducing blood loss.

  2. Platelets stick together and are attracted to the wounded epithelium.

  3. Injured tissues release tissue factor causing the production of thrombin which interacts with fibrinogen to form fibrin filaments creating a mesh for clotting.

Abnormal Clots

  • Thrombus:

    • An abnormal clot that forms within a blood vessel.

  • Embolus:

    • A thrombus that dislodges and floats through the bloodstream, potentially causing serious health issues (e.g., stroke, heart attack).

Blood Types and Antigens

  • Antigen Definition:

    • A substance recognized as foreign that triggers an immune response, resulting in antibody production.

  • Erythrocyte Antigens:

    • ABO and Rh antigens are most harmful during transfusions.

ABO Blood Groups

  • Type A: Has A antigens.

  • Type B: Has B antigens.

  • Type AB: Has both A and B antigens.

  • Type O: Has neither A nor B antigens.

Antibody Presence in Plasma

  • Red Blood Cell Types:

    • Type A: Anti-B antibodies in plasma.

    • Type B: Anti-A antibodies in plasma.

    • Type AB: No antibodies in plasma.

    • Type O: Anti-A and Anti-B antibodies in plasma.

  • Key Concept:

    • Antibodies are not produced for the antigens the individual already possesses.

Importance of Blood Typing

  • Safety in Transfusion:

    • Essential to match blood types to avoid serious health complications or death.

  • Compatibility Chart:

    • Type O = Universal donor.

    • Type AB = Universal recipient.

Compatibility in Blood Donation

  • Types of donations:

    • A can donate to A.

    • B can donate to B.

    • AB can donate to AB only.

    • O can donate to A, B, or AB.

    • A can donate to AB.

    • B can donate to AB.

Rh Blood Group

  • Definition:

    • Determined by the presence or absence of Rh antigen on red blood cells.

  • Statistics:

    • Approximately 85% of Americans are Rh positive (Rh+).

  • Antibody Production:

    • Rh- individuals form anti-Rh antibodies upon contact with Rh+ blood, which persist in the blood.

Rh in Pregnancy

  • Risk Factors:

    • If an Rh- mother has an Rh+ baby, the mother’s blood can produce anti-Rh antibodies, causing issues with subsequent Rh+ pregnancies.

  • Monitoring and Management:

    • RhoGam can be administered to prevent complications during pregnancy.

Conclusion

  • Summary of Concepts:

    • Antigen presence prompts antibody production leading to agglutination.

    • Blood type compatibility is critical for safe transfusions, highlighting the importance of identifying ABO and Rh antigens accurately.