Chapter 18: The Cardiovascular System

Overview

• Cardiovascular System Components:
  • Pump: The heart.
  • Transport System: Blood vessels.
  • Fluid Medium: Blood.

Functions of Blood

• Transportation: Oxygen, carbon dioxide, nutrients, metabolic waste, hormones.
• Regulation: Temperature, pH balance, blood pressure.
• Protection: Immune defense, blood clotting.

Blood Composition

• Blood as Connective Tissue
  • Plasma: Extracellular matrix, fluid.
  • Formed Elements: Cells and cell fragments (erythrocytes, leukocytes, platelets).

Physical Characteristics of Blood

• Color: Always red; varies from bright to dark.
• Temperature: ~38°C (100.4°F).
• pH Level: Normally between 7.35 and 7.45.
• Volume:
  • Males: ~5-6 liters.
  • Females: ~4-5 liters.
• Blood Pressure: Higher blood volume generally means higher blood pressure.

Plasma Composition

• Water Content: ~92% of plasma.
• Plasma Solutes:
  • Electrolytes (sodium, potassium, calcium).
  • Dissolved gases (oxygen, carbon dioxide, nitrogen).
  • Nutrients (vitamins, lipids, glucose, amino acids).
  • Metabolic wastes.

Formed Elements of Blood

• Erythrocytes (Red Blood Cells):

  • Function: Carry oxygen and some carbon dioxide.
  • Not true cells; no nucleus or mitochondria.

• Leukocytes (White Blood Cells):

  • Function: Fight infection.
  • Types: Granular (neutrophils, eosinophils, basophils) and agranular (lymphocytes, monocytes).

• Platelets:

  • Function: Blood clotting.
  • Cell fragments, not full cells.

Blood Formation (Hematopoiesis)

• Occurs in red bone marrow.
• Myeloid Line: Produces erythrocytes, platelets, granular leukocytes.
• Lymphoid Line: Produces lymphocytes (T cells, B cells).
• Hormones:
  • EPO (erythropoietin): Produced by kidneys for red blood cell production.
  • TPO (thrombopoietin): Produced by liver/kidneys for platelet production.

Red Blood Cells & Hemoglobin

• Hemoglobin: Comprised of heme and globin components.
  • Transports oxygen (98.5%) and carbon dioxide.
• Oxygen transport: Oxyhemoglobin when bound, deoxyhemoglobin when released.
• Carbon Dioxide Transport: Carbaminohemoglobin, carbonic acid.
• Sickle Cell Disease: Mutation causing sickle-shaped cells obstructing blood flow.

Anemia Types

• Iron-deficiency: Low dietary iron.
• Megaloblastic: Low dietary folate.
• Pernicious: Lack of vitamin B12.
• Thalassemia: Genetic mutation affecting globin.

White Blood Cells (Leukocytes)

• Granular Leukocytes:

  • Neutrophils: Most common, fight bacteria.
  • Eosinophils: Fight parasites, involved in allergies.
  • Basophils: Release histamine and heparin.

• Agranular Leukocytes:

  • Monocytes/Macrophages: Phagocytosis, alert immune response.
  • Lymphocytes (T and B cells): Immune response, antibody production.

Hemostasis (Blood Clotting)

• Process:
  • Vascular spasm, platelet plug formation, coagulation.
• Key Proteins: Fibrinogen, clotting factors.

Blood Types

• ABO Blood Groups: A, B, AB, O.
  • Universal recipient: AB+.
  • Universal donor: O-.
• Rh Factor: Positive or negative based on presence of RhD antigen.
  • Important in pregnancy and transfusions.

Blood Disorders

• Jaundice: Caused by bilirubin buildup.
• Sickle Cell Disease: Inherited disorder affecting hemoglobin shape and function.

Summary

• Blood is a critical component of the cardiovascular system, essential for transporting nutrients, gases, and waste, regulating temperature and pH, and providing immune responses and clotting mechanisms.