Exercise 26 Blood

Cardiovascular System Overview

• Components:

  • Heart

  • Blood vessels

  • Blood

Introduction to the Circulatory System

• Main Functions:

  • Transportation: Oxygen, nutrients, hormones, and waste materials.

  • Protection: Immune functions and blood clotting mechanisms.

  • Regulation: Body temperature, pH levels, and fluid balance.

Blood Components

• Blood Types:

  • Arteries: Carry blood away from the heart.

  • Veins: Carry blood towards the heart.

  • Capillaries: Site of exchange with cells and air sacs.

Functions of the Blood

• Transport:

  • Carries oxygen (O2) and carbon dioxide (CO2).

• Protection:

  • Made up of Red blood cells (RBC), White blood cells (WBC), and Platelets.

• Regulation:

  • Maintains proper pH levels through buffer systems (pH 7.35-7.45).

Hematology and Blood Formation

• Definition: Study of blood and blood-forming tissues.

• Daily Production:

  • 200 billion RBCs (3 million/sec)

  • 10 billion WBCs

  • 400 billion platelets

Buffer Systems for pH Maintenance

• Chemical Buffering Systems:

  1. Phosphate Buffering System

  2. Protein Buffers

  3. Bicarbonate Buffering System

• Physiological Buffering Systems:

  1. Respiratory System (minutes)

  2. Urinary System (hours/days)

Blood Volume and Replacement

• Donation: 1 pint of blood weighs about 1 pound, accounting for 13% of total blood volume.

• Replacement Time:

  • Plasma: 2-3 days

  • WBCs and Platelets: 1-2 days

  • RBCs: Up to 6 weeks

Sites of Hemopoiesis (Blood Formation)

• Locations:

  • Flat bones of the skull

  • Bodies of vertebrae

  • Sternum

  • Ribs

  • Iliac portions of hip bones

  • Proximal epiphyses of humerus and femur

Components of Blood

• Plasma (liquid portion): 91% water, 7% proteins, 2% other solutes.

• Formed Elements:

  • Erythrocytes (RBCs)

  • Leukocytes (WBCs)

  • Platelets

Micro-Hematocrit Test

• Purpose: Measures the percentage of RBCs in whole blood to test for anemia.

  • Normal Ranges:

    • Men: 42-52%

    • Women: 37-47%

White Blood Cells (Leukocytes) Characteristics

• Granulocytes:

  • Neutrophils: Phagocytize pathogens (60-70% of total WBCs).

  • Eosinophils: Fight parasites (1-4%).

  • Basophils: Release histamine (0.5-1%).

• Agranulocytes:

  • Lymphocytes: Immune response (20-40%).

  • Monocytes: Phagocytes (3-8%).

Platelets (Thrombocytes)

• Definition: Cell fragments that help stop bleeding by forming a plug and releasing clotting factors.

• Normal Count: 150,000 to 400,000 per microliter.

Hemostasis (Stopping Bleeding)

• Phases of Hemostasis:

  1. Vascular spasm

  2. Platelet plug formation

  3. Coagulation (clotting phase)

Coagulation Mechanisms

• Intrinsic Pathway: Initiated by damage inside the vessel.

• Extrinsic Pathway: Initiated by damage outside the vessel.

Types of Blood Groups

• ABO Blood Types:

  • Type A: Surface antigen A, Anti-B antibodies.

  • Type B: Surface antigen B, Anti-A antibodies.

  • Type AB: Both A and B antigens, no antibodies.

  • Type O: No antigens, both antibodies.

• Rh Factor: Presence of D antigen indicates Rh positive (+), absence indicates Rh negative (-).

Transfusion Reactions

• Hypersensitivity Reactions: Mismatched transfusions can lead to severe health complications, including death.

Blood Types Characteristics & Compatibility

• Testing Method: Blood type determined by agglutination reactions with anti-A and anti-B antibodies.

Conclusion

• The cardiovascular system is crucial for maintaining homeostasis, and an understanding of blood components and their functions is vital for medical practices.

More detailed notes

Cardiovascular System Overview

Components:

• Heart: A muscular organ responsible for pumping blood throughout the body.

• Blood Vessels: Include arteries, veins, and capillaries that transport blood.

• Blood: The fluid containing red blood cells, white blood cells, platelets, and plasma.

Introduction to the Circulatory System

Main Functions:

1. Transportation:

   • Transports oxygen (O2) from the lungs to the body's tissues while carrying carbon dioxide (CO2) back to the lungs for exhalation.

   • Carries nutrients absorbed from food to cells and also transports hormones from glands to target organs.

   • Removes waste materials, such as urea and lactic acid, from cells to be excreted.

2. Protection:

   • Immune functions: White blood cells (WBCs) defend the body against pathogens, while antibodies in the blood help neutralize toxins.

   • Blood clotting mechanisms prevent excessive bleeding when injuries occur, involving a complex series of reactions.

3. Regulation:

   • Helps regulate body temperature by adjusting blood flow to the skin.

   • Maintains pH levels through its buffer systems to prevent acidosis or alkalosis (normal pH range: 7.35-7.45).

   • Aids in the regulation of fluid balance by distributing water and electrolytes across different compartments of the body.

Blood Components

Blood Types:

• Arteries: Carry oxygenated blood away from the heart (except pulmonary arteries, which carry deoxygenated blood to the lungs).

• Veins: Return deoxygenated blood towards the heart (except pulmonary veins, which carry oxygenated blood from the lungs).

• Capillaries: Microscopic vessels where exchange of gases, nutrients, and wastes occurs between blood and cells.

Functions of the Blood

Transport:

• Oxygen (O2) is bound to hemoglobin in red blood cells (RBCs); carbon dioxide (CO2) is carried dissolved in plasma and also as bicarbonate ions.

Protection:

• Blood composition:

  • Red Blood Cells (RBCs): Carry oxygen.

  • White Blood Cells (WBCs): Key defenders in immune response.

  • Platelets: Critical in clot formation and bleeding control.

Regulation:

• Maintains body’s electrolytic balance and temperature through vasodilation and vasoconstriction.

Hematology and Blood Formation

Definition:

• The study of blood, blood-forming organs, and blood diseases.

Daily Production:

• Approximately 200 billion RBCs are produced daily (around 3 million per second).

• About 10 billion WBCs and 400 billion platelets are generated daily.

Buffer Systems for pH Maintenance

Chemical Buffering Systems:

1. Phosphate Buffering System: Important in intracellular fluids and urine.

2. Protein Buffers: Proteins in blood bind excess acids and bases.

3. Bicarbonate Buffering System: Central to maintaining blood pH, utilizes CO2 and HCO3- ions.

Physiological Buffering Systems:

• Respiratory System: Adjusts CO2 exhalation.

• Urinary System: Modifies H+ excretion and bicarbonate reabsorption over hours/days.

Blood Volume and Replacement

Donation:

• Approximately 1 pint of blood weighs about 1 pound, which is roughly 13% of an adult's total blood volume.

Replacement Time:

• Plasma: Replenishes in 2-3 days.

• WBCs and Platelets: Usually take 1-2 days.

• RBCs: Can take up to 6 weeks to fully recover after donation.

Sites of Hemopoiesis (Blood Formation)

Locations for Hematopoiesis:

• Flat Bones: Such as the skull and sternum.

• Vertebrae: The bodies contain red marrow.

• Ribs: Contribute to blood cell formation.

• Iliac Portions of Hip Bones: Significant site for blood formation.

• Proximal Epiphyses: Ends of long bones like the humerus and femur also participate in blood cell production.

Components of Blood

Plasma:

• The liquid portion of blood, consisting of 91% water, 7% proteins (such as albumin, globulins, and fibrinogen), and 2% other solutes (electrolytes, nutrients, waste products).

Formed Elements:

• Erythrocytes (RBCs): Transport oxygen and CO2.

• Leukocytes (WBCs): Part of the immune system.

• Platelets: Crucial for blood clotting.

Micro-Hematocrit Test

Purpose:

• Measures the proportion of blood volume occupied by RBCs, aiding in diagnosis of conditions such as anemia.

Normal Ranges:

• Men: 42-52%

• Women: 37-47%

White Blood Cells (Leukocytes) Characteristics

Granulocytes:

• Neutrophils: Most abundant WBCs, responsible for phagocytizing pathogens (60-70%).

• Eosinophils: Combat multicellular parasites and certain infections (1-4%).

• Basophils: Release histamine during inflammatory responses (0.5-1%).

Agranulocytes:

• Lymphocytes: Major players in adaptive immune response (20-40%).

• Monocytes: Differentiate into macrophages and dendritic cells that phagocytize pathogens (3-8%).

Platelets (Thrombocytes)

Definition:

• Cell fragments derived from megakaryocytes in bone marrow, crucial for hemostasis by forming a plug at injury sites and releasing factors that initiate clotting.

Normal Count:

• Ranges from 150,000 to 400,000 platelets per microliter of blood.

Hemostasis (Stopping Bleeding)

Phases of Hemostasis:

1. Vascular Spasm: Immediate constriction of blood vessels.

2. Platelet Plug Formation: Activated platelets adhere to the site of injury and to each other.

3. Coagulation (Clotting Phase): Fibrin mesh forms to stabilize the platelet plug, preventing further blood loss.

Coagulation Mechanisms:

• Intrinsic Pathway: Triggered by blood vessel damage.

• Extrinsic Pathway: Initiated by external trauma leading to activation of tissue factor.

Types of Blood Groups

ABO Blood Types:

• Type A: Has surface antigen A and produces anti-B antibodies.

• Type B: Has surface antigen B and produces anti-A antibodies.

• Type AB: Possesses both A and B antigens, with no antibodies (universal recipient).

• Type O: Lacks A and B antigens and has both anti-A and anti-B antibodies (universal donor).

Rh Factor:

• Presence of D antigen on RBCs designates Rh positive (+), while its absence designates Rh negative (-).

Transfusion Reactions

• Hypersensitivity Reactions: Unmatched transfusions can elicit severe immune responses, leading to complications such as hemolytic reactions and organ failure.

Blood Types Characteristics & Compatibility

Testing Method:

• Blood type is determined via agglutination reactions with anti-A and anti-B antibodies, crucial for safe transfusion practices.

Conclusion

The cardiovascular system is a vital network that maintains homeostasis in the body through its mechanisms of transport, protection, and regulation. A comprehensive understanding of the components and functions of blood is essential for effective medical interventions and practices.