25Sp PHA 404 on 1/31/2025 (Fri)

Class Overview

  • Introduction to the day: Brief mention of various systems, focusing on blood and cardiovascular system

  • Reiteration of the importance of class outlines in determining exam content

  • Reminder of study resources, including the textbook and provided copies

  • Discussion of the first exam information and topics to study

Blood Overview

  • Importance of blood:

    • Function in delivering oxygen, transporting hormones, and regulating temperature

    • Involvement in immune response and clotting mechanisms

Blood Components

Blood Plasma

  • Composes approximately 55% of blood

  • Dynamic; can increase or decrease depending on fluid loss/gain

  • Regulated by kidneys ensuring proper water and electrolyte balance

  • Components of plasma include:

    • Water (dominant component)

    • Ions, hormones, and proteins

    • Osmolarity and its role in fluid balance

Formed Elements

  • Comprises 45% of blood

  • Includes:

    • Red blood cells (erythrocytes)

    • White blood cells (leukocytes)

    • Platelets

  • Dynamics of production and breakdown of these elements

Erythrocytes (Red Blood Cells)

  • Primary function: Oxygen transport via heme group containing iron

  • Lifecycle: About 120 days, produced in the bone marrow from large progenitor cells

  • Importance of shape: Loss of shape affects oxygen-carrying capacity (e.g., sickle cell anemia)

  • Control of production regulated by erythropoietin (EPO) hormone

Blood Circulation Systems

Systemic vs. Pulmonary Circuits

  • Systemic circuit: High pressure; delivers oxygenated blood from heart to body

  • Pulmonary circuit: Lower pressure; carries deoxygenated blood to lungs for oxygenation

  • Understanding blood flow and pressure differences critical for diagnosing heart failure and related conditions

Blood Disorders

Anemia

  • Defined as an abnormally low red blood cell count

  • Common causes:

    • Iron deficiency

    • Chronic blood loss (e.g., menstruation, gastrointestinal bleeding)

    • Nutritional deficiencies (e.g., vitamin B12)

  • Variants include:

    • Hemolytic anemia: Red blood cells breaking apart; includes sickle cell anemia

    • Pernicious anemia: Malabsorption of vitamin B12

Polycythemia

  • Excessive number of red blood cells leading to increased blood viscosity

  • Can result in complications due to impaired blood flow

Hormones and Homeostasis

  • Role of hormones in regulating blood volume and composition

  • Homeostasis: Maintaining internal stability (e.g., temperature, osmolarity)

  • Importance of kidneys in fluid regulation through filtration and reabsorption

Blood Typing and Immune Response

  • Antigens: Surface indicators that determine blood type (A, B, AB, O)

  • Antibodies: Proteins produced by immune cells in response to foreign antigens

  • Importance of matching blood types for transfusions to prevent adverse immune reactions

Conclusion

  • Encouragement to review materials and prepare for upcoming classes and exams

  • Reminder about the next session focusing on diseases of the blood