HIM 401: FOCUS REVIEW Anatomy & Physiology

Page 1: Introduction to Blood

• Blood is a vital fluid in the body responsible for various essential functions and consists of numerous components

Page 2: Blood Plasma Composition

• Plasma Composition: Blood plasma is the liquid portion of blood, approximately 55% of the total blood volume.

• Albumins: Comprising about 58% of plasma proteins, they play a critical role in maintaining osmotic pressure, which helps manage fluid balance in the blood and tissues.

• Globulins: Representing 38% of plasma proteins, they are involved in immune responses and can be categorized into alpha, beta, and gamma globulins.

• Fibrinogen: At 4%, it is crucial for blood clotting by converting to fibrin during the coagulation process.

• Water Content: Water constitutes around 91% of plasma, serving as a solvent and medium for transporting nutrients, gases, and waste products.

• Electrolytes and Other Solutes: Accounting for about 2%, electrolytes such as sodium, potassium, calcium, and bicarbonate help maintain pH and osmotic balance, while solutes include nutrients and waste products.

Page 3: Blood Cells Overview

Red Blood Cells (Erythrocytes)

• Function: Primarily responsible for the transport of oxygen from the lungs to body tissues and carbon dioxide from tissues back to the lungs.

White Blood Cells (Leukocytes)

• Different types and their functions:

  • Neutrophils: The most abundant type, they play an essential role in the immune response by fighting bacterial infections. They can engulf and digest pathogens through phagocytosis.

  • Basophils: Involved in allergic reactions and inflammation; they release histamine, contributing to vasodilation and increased blood flow to tissues.

  • Eosinophils: Combat parasitic infections and are also involved in allergic reactions and asthma by modulating inflammatory responses.

  • Monocytes: Differentiate into macrophages and dendritic cells, playing a significant role in phagocytosis and antigen presentation.

  • Lymphocytes: Including B cells (produce antibodies) and T cells (cell-mediated immune response), they are crucial for adaptive immunity and recognizing specific pathogens.

Page 4: Hemopoiesis – Blood Cell Production

• Types of Hemopoiesis:

  • Thrombopoiesis: The process by which platelets are produced from megakaryocytes under the influence of thrombopoietin, primarily secreted by the liver and kidneys.

  • Leukopoiesis: The formation of white blood cells, regulated by various colony-stimulating factors, significantly affecting lymphocyte and macrophage populations.

  • Erythropoiesis: The production of red blood cells from erythroid progenitors stimulated by erythropoietin, which is secreted by kidneys in response to low oxygen levels.

• All processes occur in the red bone marrow from a precursor cell known as the hemocytoblast, which differentiates into various blood cell lineages based on the body's requirements.

Page 5: Breakdown of Hemoglobin

• Components of Hemoglobin:

  • Heme: Its breakdown product, bilirubin, is processed by the liver and excreted in bile.

  • Globin: This component consists of amino acids, which are recycled by the body for protein synthesis.

  • Iron: A critical nutrient for oxygen transport; iron is either stored in the liver and spleen or transported in the bloodstream bound to transferrin.

• Waste elimination routes: Bilirubin is excreted via bile into feces, while iron-bound waste is primarily eliminated through urine.

Page 6: Hemostasis – Stopping of Bleeding

• Stages of hemostasis:

  • Vascular Spasm: The immediate constriction of a damaged blood vessel to reduce blood loss.

  • Platelet Plug Formation: Platelets adhere to the injury site and aggregate to form a temporary plug to stop bleeding.

  • Blood Clotting (Coagulation): The formation of a stable fibrin mesh that solidifies the plug and stops bleeding permanently.

Page 7: Prevention of Inappropriate Clotting

• Thrombus vs. Embolus: A thrombus is a stationary clot that can block blood vessels, while an embolus is a clot that has moved through the bloodstream and can cause obstruction in distant vessels.

• Risks associated with abnormal clotting: Conditions such as thrombosis can lead to serious complications like stroke or myocardial infarction by obstructing blood flow.

Page 8: Blood Typing

• ABO Blood Group System: Determines individual blood types based on the presence or absence of specific antigens on red blood cell surfaces.

• Type AB: Known as the universal recipient, it has no antibodies against A or B antigens.

• Type O: Renowned as the universal donor, it lacks both A and B antigens on red blood cells, making it safe for transfusions to any blood type.

• Role of Antibodies: Antibodies present in the plasma seek out foreign antigens and facilitate agglutination, which is critical in transfusion compatibility.

Page 9: Antigens and Antibodies for Each ABO Blood Type

• Blood Type Summary:

  • Type A: Has Antigen A on red blood cells and contains anti-B antibodies in plasma.

  • Type B: Has Antigen B on red blood cells and contains anti-A antibodies in plasma.

  • Type AB: Has both Antigen A and Antigen B, with no antibodies present, allowing it to receive blood from any type.

  • Type O: No antigens on red blood cells, and contains both anti-A and anti-B antibodies, making it a universal donor but not viable for receiving blood from other types.

Page 10: Mother-Fetus Blood-Type Compatibility

• Rh Factor Impact: An Rh-negative mother with an Rh-positive child risks developing anti-Rh antibodies following exposure during childbirth, potentially leading to hemolytic disease of the newborn in subsequent pregnancies. There is no incompatibility if both the mother and child are Rh-negative.