Anatomy and Physiology: Blood and Blood Vessels

Lecture by Christel Ann Crisostomo, 1-PSY 7

Blood and Its Functions

• Transfer of Gases, Nutrients, and Waste Products
• Transport of Molecules
  • Processed and Regulatory
• Regulation
  • pH and Osmosis
• Thermoregulation (Body Temperature Maintenance)
• Protection
  • Against Harmful Substances
• Clot Formation

Components of Blood

• Plasma (Liquid)
  • 55% of Total Blood
  • Composition: 91% Water, 7% Proteins, 2% Other Substances
• Formed Elements (Solid)
  • 45% of Total Blood
  • Erythrocytes (RBC), Leukocytes (WBC), Thrombocytes (Platelets)

Plasma Proteins

• Albumin
  • 58%, Maintains Water Balance
• Globulin
  • 38%, Immune System
• Fibrinogen
  • 4%, Clot Formation

Hematopoiesis

• Process Producing Formed Elements
• Derived from Stem Cells (Hemocytoblasts)

Erythrocytes (RBC)

• Disk-shaped, Biconcave
• Live for 120 Days, Transport O2
• Hemoglobin
  • Main Component, Transports O2
  • Composed of Globin and Heme

Production of Erythrocytes

1. Low O2 levels trigger kidneys to release erythropoietin.
2. Stimulates red bone marrow.
3. Increases RBC production and O2 levels.

Fate of Old Erythrocytes and Hemoglobin

• Removed by Spleen and Liver
• Broken Down and Recycled
• Heme Converted to Bilirubin

Leukocytes (WBC)

• No Hemoglobin, Larger than RBC
• Function: Fight Infection, Phagocytosis

Types of Leukocytes

• Granulocytes
  • Neutrophils: Phagocytes
  • Eosinophils: Reduce Inflammation
  • Basophils: Release Histamine
• Agranulocytes
  • Monocytes: Produce Macrophages
  • Lymphocytes: Immune Response, T & B Cells

Platelets

• Cell Fragments from Megakaryocytes
• Prevent Blood Loss; Involved in Clotting

Blood Loss and Clot Formation

• Blood Loss: Needs Replacement
• Preventing Blood Loss
  • Vascular Spasm, Platelet Plug, Blood Clotting
• Steps in Clot Formation
  1. Activation of Clotting Factors
  2. Formation of Thrombin
  3. Thrombin Converts Fibrinogen to Fibrin

Blood Grouping

• ABO Blood Groups

  • Type A: A antigens, Anti-B Antibodies
  • Type B: B antigens, Anti-A Antibodies
  • Type AB: Universal Recipient
  • Type O: Universal Donor

• RH Blood Group

  • RH+ or RH- Based on Presence of RH Antigens

Diagnostic Blood Tests

• Complete Blood Count, Hematocrit, Hemoglobin Levels
• WBC Differential Counts

White Blood Disorders

• Leukopenia: Low WBC Count
• Leukocytosis: High WBC Count

Blood Vessels

• Carry Blood, Exchange Substances, Regulate Pressure
• Types: Arteries, Veins, Capillaries

Vessel Structures

• Arteries: Thick, Elastic, Carry Blood Away
• Veins: Thin, Less Elastic, Carry Blood Toward
• Capillaries: Exchange Sites

Blood Flow

• Arteries ➔ Arterioles ➔ Capillaries ➔ Venules ➔ Veins ➔ Heart

Blood Vessel Walls

• Tunica Intima: innermost
• Tunica Media: middle
• Tunica Adventitia: outermost

Circulatory Systems

• Pulmonary: Heart to Lungs and Back
• Systemic: Heart to Body and Back

Blood Vessels of the Body

• Aorta: Major Arteries
• Upper/Lower Limbs Arteries and Veins
• Hepatic Portal System: Liver Processing

Blood Pressure

• Measured as Systolic/Diastolic
• Capillary Exchange Controlled by Blood Pressure

Control of Blood Flow

• Local Control: Precapillary Sphincters
• Nervous and Hormonal Control
  • Sympathetic, Epinephrine, and Norepinephrine

Effects of Aging on Blood Vessels

• Arteriosclerosis: Stiffening of Arteries
• Atherosclerosis: Plaque Build-Up