BIO 2061: Human Anatomy & Physiology Lab II - Blood

The Circulatory System: Blood

Overview of the Circulatory System

  • Components: Heart, Blood Vessels, Blood.
  • Cardiovascular System: Comprised of the heart and blood vessels.
  • Hematology: The study of blood.
  • Function: To transport substances from one part of the body to another.

Functions of Blood

  • Transport:
    • Oxygen ( ext{O}_2) from the lungs to the tissues.
    • Carbon dioxide ( ext{CO}_2) from the tissues to the lungs.
    • Nutrients from the gastrointestinal (GI) tract to the tissues.
    • Metabolic wastes from tissues to the kidneys for removal.
    • Hormones from endocrine cells to target organs.
    • Stem cells from the bone marrow to tissues.
  • Protection:
    • Plays a significant role in inflammation.
    • While Blood Cells (WBCs) destroy microorganisms and cancer cells.
    • Antibodies and other blood proteins neutralize toxins and aid in destroying pathogens.
    • Platelets secrete factors that initiate blood clotting.
  • Regulation:
    • Stabilizes fluid distribution in the body.
    • Stabilizes the pH of the extracellular fluid.
    • Shifts in blood flow help control body temperature.

Blood Components

  • Adults typically have between 4-6 liters of blood in circulation.
  • Blood is a liquid connective tissue, composed of cells and an extracellular matrix.
  • Matrix: Plasma (a clear, light-yellow fluid).
  • Formed Elements:
    1. Erythrocytes (Red Blood Cells or RBCs).
    2. Platelets.
    3. Leukocytes (White Blood Cells or WBCs).
  • RBCs constitute \text{37-52%} of the total blood volume; this percentage is known as Hematocrit. The overall composition is approximately:
    • RBCs: \text{37-52%}
    • WBCs & Platelets: <1\%
    • Plasma: \text{47-63%} (Note: There is a slight overlap in percentages provided in the source which should sum to 100%)

Blood Plasma

  • Plasma is the matrix of blood connective tissue.
  • Constituents: Water, proteins, nutrients, electrolytes, nitrogenous wastes, hormones, and gases.
  • Difference between Plasma and Serum: SERUM is PLASMA minus FIBRINOGEN (\text{SERUM = PLASMA – FIBRINOGEN}).
  • Proteins: The most abundant plasma solute, typically \text{6-9 g/dL}.
  • Functions of Plasma Proteins:
    • Clotting.
    • Defense.
    • Transport.

Blood Plasma: Proteins

  • Albumin:
    • Smallest and most abundant plasma protein.
    • Transports solutes and buffers the pH of the plasma.
    • Contributes to the viscosity of the blood.
    • Contributes to the osmolarity of the blood.
  • Globulin:
    • Categorized into Alpha (\alpha), Beta (\beta), and Gamma (\gamma) globulins.
    • Plays roles in transport, clotting, and immunity.
  • Fibrinogen:
    • A precursor of fibrin, a sticky protein that forms the framework of a blood clot.
  • Production: All plasma proteins (except gamma globulins) are produced by the liver at a rate of \text{4g} per hour.

Blood Plasma: Nitrogenous Wastes

  • Toxic end products of metabolism.
  • Catabolic Waste Products of Various Types of Food:
    • Sugar + Oxygen \rightarrow \text{CO}2 \text{ + H}2\text{O}
    • Fats + Oxygen \rightarrow \text{CO}2 \text{ + H}2\text{O}
    • Proteins + Oxygen \rightarrow \text{Urea, Uric acid, Salts} ( \text{CO}2 \text{ + H}2\text{O} are also general byproducts from protein metabolism but the specific wastes highlighted are urea, uric acid, and salts).

Blood Plasma: Electrolytes

  • Sodium (Na): Constitutes \text{90%} of the plasma cations (+. Increases in salt intake (\uparrow salt intake) lead to increased sodium in plasma (\uparrow\text{ Na in plasma}), which in turn leads to increased water retention (\uparrow\text{ H}_2\text{O}) and consequently increased blood pressure (\uparrow\text{ BP}).

Blood Viscosity

  • Defined as the resistance of a fluid to flow due to the cohesion of its particles, or its