circulatory

• Circulatory system


  Consists of the heart, blood vessels, and blood
• Blood + cardiovascular system

  Circulatory system
• Cardiovascular system


  Only consists of heart and blood vessels
• Hematology


  Study of blood
• Functions of circulatory system


  • Transport
  • Protection
  • Regulation
• Transport


  1. Blood carries oxygen from lungs to tissues

  2. Blood picks up CO2 from tissues and carries it to lungs

  3. Blood picks up nutrients from digestive tract and delivers them to tissues

  4. Blood carries metabolic wastes to kidneys for removal

  5. Blood carries hormones from endocrine cells to target organs

  6. Blood transports stem cells from bone marrow to tissues
• Protection


  1. Inflammation limits spread of infection

  2. WBCs fight and destroy cancer cells

  3. Antibodies and blood proteins neutralize toxins and destroy pathogens

  4. RBCs bind foreign antigens and transport them to liver and spleen

  5. Platelets secrete factors that initiate blood clotting and contribute to tissue growth and blood vessel maintenance
• Regulation


  1. Fluid distribution stabilized by blood capillaries

  2. Stabilizes pH of extracellular fluid

  3. Regulates temperature through vasodilation and vasoconstriction
• Blood


  Liquid connective tissue composed of cells and extracellular matrix
• Blood plasma


  Clear, light yellow fluid constituting a little over 1/2 of the blood volume
• Formed elements in blood

  • Erythrocytes (RBCs)
  • Leukocytes (WBCs)
  • Granulocytes (Neutrophils, Eosinophils, Basophils)
  • Agranulocytes (Lymphocytes, Monocytes)
  • Platelets
• Order of abundance of blood cells (least to greatest)


  • Neutrophils
  • Lymphocytes
  • Monocytes
  • Eosinophils
  • Basophils
• Components of blood plasma


  • Water
  • Proteins
  • Nutrients
  • Electrolytes
  • Wastes (nitrogenous)
  • Hormones
  • Gases
• Albumin


  Most abundant plasma protein, transports solutes, buffers pH, affects viscosity and osmolarity
• Globulins


  Solute transport, clotting, immunity
• Fibrinogen


  Precursor of fibrin, important for clotting
• Nitrogenous wastes


  Toxic end products of protein catabolism, excreted through kidneys
• Nutrients in blood plasma


  • Glucose
  • Amino acids
  • Fats
  • Cholesterol
  • Vitamins
  • Minerals
• Blood viscosity


  Blood is 5 times more viscous than water, governs flow through vessels
• Blood osmolarity


  Solute concentration in blood, influences fluid distribution and volume
• Hemopoietic tissues


  • Spleen
  • Thymus
  • Bone marrow
  • Liver (prenatal)
• Erythrocytes (RBCs)


  Pick up oxygen from lungs and deliver it to tissues, pick up CO2 from tissues and unload it in lungs, lose nucleus and organelles, use anaerobic fermentation for energy
• Clinical significance of RBCs


  • Hematocrit
  • Hemoglobin concentration
  • RBC count
• RBC homeostasis


  RBC count is maintained through negative feedback, kidneys detect hypoxemia and increase EPO output to stimulate RBC production
• Causes of hypoxemia


  • Low atmospheric oxygen
  • Lethargy and exercise
  • Emphysema
• Blood doping


  Produces more RBCs to carry more oxygen, using erythropoietin and blood transfusions
• Polycythemia


  Overproduction of RBCs, can lead to high blood pressure, volume, viscosity, and strain on the heart
• Types of anemia


  • Hemorrhagic
  • Hemolytic
  • Inadequate erythropoiesis
  • Nutritional
• Sickle-cell disease


  Genetic, recessive allele causing a hemoglobin defect that leads to sickle-shaped, rigid, and sticky RBCs that can block small blood vessels
• Blood types


  • A
  • B
  • AB
  • O
• Rh factor


  Genetic antigen on RBC surface, Rh- mother carrying Rh+ child can develop antibodies that can agglutinate the child's RBCs
• Leukocytes (WBCs)


  • Neutrophils
  • Eosinophils
  • Basophils
  • Lymphocytes
  • Monocytes
• Neutrophils


  Most common WBC, aggressively antibacterial, phagocytize bacteria
• Eosinophils


  Abundant in mucous membranes, have granules that destroy large parasites, also elevated with allergies
• Basophils


  Rarest WBC, have granules containing histamine and heparin that promote blood flow and clotting
• Lymphocytes


  Destroy cancer cells and virus-infected cells, coordinate actions of other immune cells, present antigens, secrete antibodies, provide long-term immunity memory
• Monocytes


  Largest WBC, can transform into macrophages that phagocytize pathogens, dead neutrophils, and cell debris