A&P FINAL

• Relationship between flow, pressure, and resistance

  1. Changes in vessel diameter, blood viscosity, and vessel length affect resistance

  2. Resistance influences blood flow and pressure within the vascular system
• ↓Flow


  △P/R↑
• Higher resistance


  Slower flow
• ↑Flow


  △P/R↓
• Lower resistance


  Faster flow
• NO PRESSURE DIFF. = NO FLOW
• Pressure in vena cava


  Central venous pressure (CVP)
• Factors that affect Resistance


  • Radius of vessel (r)
  • Length of vessel (L)
  • Viscosity of fluid
  • Vasoconstriction
  • Vasodilation
• Radius of vessel


  (in arterioles & small arteries) can regulate radius
• Vasoconstriction


  • Decreased radius → increased resistance
  • Decreases blood flow
• Vasodilation


  • Increased radius → decreased resistance
  • Increases blood flow
• Total peripheral resistance (TPR)

  Combined resistance of all blood vessels within the systemic circuit
• If TPR increases


  MAP increases
• Net filtration pressure (NFP)

  Balance between hydrostatic pressure (pushing fluid out of capillaries) and oncotic pressure (pulling fluid into capillaries)
• Starling forces

  Play a vital role in determining fluid movement across capillary walls, impacting processes like filtration and reabsorption in tissues
• Hydrostatic Pressure


  Force exerted by the fluid inside the capillaries and pushes fluid out of the capillary into the surrounding tissues
• Oncotic Pressure


  Force due to the presence of proteins in the blood, such as albumin, which pulls fluid back into the capillary from the surrounding tissues
• Mean Arterial Pressure (MAP)


  Represents the average pressure in the arteries during one cardiac cycle
• Regulation of MAP


  • Neural control
  • Hormonal control
• Determinants of MAP


  • Heart rate
  • Stroke volume
  • TPR
• Increase in cardiac output

  Leads to an increase in the volume of blood contained in the aorta and increase in MAP when TPR remains the same
• Constant cardiac output


  Leads to an increase in the volume of blood contained in the aorta & an increase in MAP when TPR increases
• Erythrocytes (red blood cells)


  Undergo a series of developmental stages, including production in the bone marrow (erythropoiesis), maturation, circulation, and eventual breakdown (eryptosis or senescence)
• Erythrocytes synthesis


  Stimulated by erythropoietin
• Erythropoietin

  • Hemoglobin growth factor
  • Secreted from kidneys under conditions of low oxygen levels in blood flowing to kidneys
• Differentiation of erythrocytes


  1. Erythropoietin triggers differentiation of stem cells to erythrocytes

  2. Developing erythrocytes produce hemoglobin

  3. Developing erythrocytes lose nuclei and organelles
• Need iron, folic acid, and vitamin B12 for production of erythrocytes
• Life cycle of erythrocytes


  1. Filtering and destruction of erythrocytes

  2. Spleen filters and removes old erythrocytes

  3. Hemoglobin is catabolized

  4. Liver metabolizes byproducts from breakdown of erythrocytes
• Erythrocytes


  • Biconcave disk shape
  • Large surface area
  • Favors diffusion
  • Flexible membrane
  • No nucleus or organelles
  • No mitochondria
  • No aerobic glycolysis
  • Major function - transport O2 and CO2
• Hemostasis


  1. Preventing and stopping bleeding

  2. Vasoconstriction

  3. Clot formation
• Clot formation


  1. Platelet adhesion

  2. Platelet aggression

  3. Fibrin
• Platelet adhesion


  Activated platelets adhere or stick to the exposed collagen fibers at the site of injury
• Vascular spasm


  • Damage blood vessel
  • Vessel constricts to minimize blood loss
• Platelet plug


  • Forms around the site of vessel damage
  • Decreases blood loss
  • Necessary for production of blood clot
• Platelet aggregation


  Activated platelets stick together forming a plug that seals a wound and stops bleeding
• Coagulation/clotting cascade


  • Leads to the formation of a stable fibrin clot (blood clot)
  • Crucial for maintaining vascular integrity and preventing excessive blood loss
• Anatomy of respiratory system


  • Upper airways
  • Respiratory tract
  • Structures of the thoracic cavity
• Cellular structure of alveoli


  • Type I alveolar cells: make up wall of alveoli
  • Type II alveolar cells: secrete surfactant
• Alveolar ventilation


  Volume of air reaching the gas exchange areas per minute
• Minute ventilation


  Total volume of air entering and leaving the respiratory system each minute (Vt x RR)