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2010-05-25 11:53:40
physiology bio262

exam 3 review
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  1. Where do blood cells form after birth?
    After birth and into adulthood the bone marrow is the primary source of hemopoiesis.
  2. What % of the blood is plasma vs. formed elements?
    Plasma accounts for 55% of the total blood composition. The formed elements include all the cells and cell fragments and account for the remaining 45%.
  3. What is found in the plasma of the blood?
    • The blood plasma is the liquid that contains dissolved substances.
    • RBCs, WBCs, & platelets

    The contents of the plasma include 91.5% water, 7% proteins, and 1.5% solutes
  4. How do erythrocytes and leukocytes differ in terms of life cycle?
    Most agranular leukocytes live 100-300 days and granular leukocytes about 12 hours to 3 days (in contrast to the 120 days for a RBC).
  5. Which are the granular/agranular leukocytes?
    granular leukocytes - Neutrophils, Eosinophils and Basophils

    agranular leukocytes - Lymphocytes and Monocytes
  6. What is erythropoiesis?

    What hormone regulates it?
    The erythrocytes develop originally from a reticulocyte in the red bone marrow. The entire process is stimulated by the hormone erythropoietin (EPO) that is secreted by the kidneys whenever oxygen levels in the blood go down.

    • 1. Oxygen carrying capacity of blood falls (hypoxia)
    • 2. Kidneys release erythropoietin (EPO) into the blood
    • 3. The EPO travels to the bone marrow to stimulate erythropoiesis (in addition to vitamin B12 and globin)
    • 4. Results in increased number of RBC’sIncreased oxygen now carried in the blood.
  7. What are the “raw ingredients” needed to continue the life cycle?
    iron, B12, & globin
  8. What are the 8 different blood types?
    • A+, A-
    • B+, B-
    • AB+, AB-
    • O+, O-
  9. Define term antigen and antibody. Understand how they apply to blood typing.
    An antigen is a cell marker that is found on the surface of the red blood cell. It is a way that a cell is “recognized” or identified as part of the host or “self”.

    Antibodies are found in the plasma and will produce an immune response or cause agglutination (clumping) if they come in contact with a foreign antigen.
  10. What are the 3 steps to hemostasis overall?
    • 1) Vascular Spasm or vasoconstriction
    • 2) Platelet Plug Formation
    • 3) Blood clotting or coagulation.
  11. What initiates plug formation?
    Platelet adhesion
  12. What are the 3 steps for just the platelet plug?
    • 1) Platelet adhesion,
    • 2) Platelet release action
    • 3) Platelet aggregation and formation of the plug
  13. Differentiate between the extrinsic and intrinsic pathways. How are they the same/how are they different?
    The extrinsic pathway occurs when damaged tissue releases TF (tissue factor). The TF eventually is converted into prothrombinase. It is very rapid in comparison to the intrinsic pathway since it does not require as many steps to form the prothrombinase.

    The intrinsic pathway occurs when the endothelial cells become damaged and provide signals to begin releasing prothrombinase from inside the blood vessel. (This is also how blood in a collection tube will clot as well) It takes several minutes or longer than the extrinsic pathway to form the prothrombinase.
  14. After fibrin forms, how does it form a clot?
    insoluble fibrin clot will tighten over time and pull the edges of the damaged vessel together.
  15. What is clot retraction and what is responsible for it occurring?
    • The insoluble fibrin clot will tighten over time and pull the edges of the damaged vessel together. The platelets contain a very high
    • concentration of actin and myosin which are stimulated to contract in aggregated platelets
  16. What is fibrinolysis and what role does plasmin play?
    Normally, clots dissolve in a process called fibrinolysis. This occurs when plasminogen is incorporated into a clot. Plasminogen activates into plasmin and once activated Plasmin begins to digest the previously insoluble fibrin threads into soluble fibrin threads.
  17. How does the body limit clot growth?

    What do endothelial cells produce to keep the clot from spreading to other areas?
    To keep the clot from spreading, adjacent endothelial cells synthesize also produce two important secretions: Prostacylin (PGI2) and nitric oxide (NO). These substances inhibit platelet adhesion, activation, and aggregation in the area of the endothelium that has not been damaged so that the clot doesn’t abnormally spread to adjacent areas.
  18. How does aspirin, Plavix, Coumadin (Wayfarin), TPA work to prevent clotting?
    • Tissue Plasminogen Activator (TPA) and streptokinase convert plasminogen to plasmin and works to break down the fibrin threads to increase the clot dissolution. They can be injected into circulation or the clot directly but are only effective if done so in a timely manner.
    • Wayfarin or Coumadin work by inhibiting the cellular activity of vitamin K which is needed for some of the clotting factors to form.
    • Aspirin decreases Thromboxane A2 production.
    • Plavix prevents ADP and therefore decreases adhesion of platelets.
  19. What is ventilation?
    Ventilation or breathing is the flow of air in and out of lungs. This is the physical movement of air into and out of the lungs.
  20. How does external and internal respiration differ?
    • External (pulmonary) respiration is the gas exchange between the alveoli and pulmonary capillaries. This is where the oxygen enters the blood and carbon dioxide leaves the blood.
    • Internal (tissue) respiration is the gas exchange between blood in systemic capillaries and tissue cells throughout the body. The oxygen is going to leave the blood here and the carbon dioxide enters the blood.
  21. Differentiate between atmospheric pressure, intrapulmonic pressure and intrapleural pressure
    • Atmospheric Pressure (Patm) is the air outside the body and is about 760 mmHg on average.
    • Intrapulmonic Pressure is the pressure inside the lungs or alveoli . It is also called alveolar pressure or Palv. This pressure varies with the respiratory cycles.
    • Intrapleural Pressure is the pressure inside the pleural cavity. It is also called intrathoracic pressure.
  22. What drives inspiration?
    changes in volume and subsequent changes in pressure that occur as a result of the diaphragm and external intercostals contracting
  23. What does the volume increase do to the pressure inside the lungs?
    pressure inside the lungs drops
  24. What muscles are involved with inspiration and expiration?
    • diaphragm (mm.?)
    • external intercostals
    • internal intercostals
    • abdominals
  25. Know whether inspiration is an active or passive process.
  26. Is exhalation passive or active at rest?

    When does it change - what types of activities?
    at rest - passive

    • forced exhalation - active
    • occurs when speaking loudly in public speaking, playing a wind instrument and singing. Now the internal intercostals and abdominal muscles are employed to further compress the lung volume and increases intrapulmonic pressure to drive the air out with more effort.
  27. Define compliance
    A characteristic change in volume which is produced by a change in pressure.
  28. What 2 factors contribute to the normal compliance of the lungs?
    The compliance of lungs, due to the elasticity of the lung tissue and thoracic cage, and the lower surface tension in alveoli keeps them from collapsing and maximizes the surface area available for diffusion.
  29. What does it mean to have high compliance, decreased compliance or increased compliance?
    High compliance - high elasticity and low surface tension makes healthy lungs easy to expand and compliant.

    decreased compliance - there is stiffness of the lungs

    increased compliance - elastic recoil decreases and the lungs become “floppy” and are prone to collapse
  30. What conditions are associated with decreased compliance?
    • Restrictive Airway Diseases such as pulmonary fibrosis, TB and pneumonia
    • drop in surfactant production
    • decrease in the size of rib cage as seen in osteoporosis
  31. What conditions are associated with increased compliance?
    obstructive airway diseases such as in Asthma, COPD or emphysema
  32. Know what TV, MV, IRV, ERV, RV, VC and TLC are.
    • Tidal volume (TV) is the volume of one resting breath.
    • Minute ventilation (MV) is the total volume of air inhaled and exhaled each minute.
    • Inspiratory Reserve Volume (IRV) Amount in addition to tidal volume during a forceful or maximal inspiration
    • Expiratory Reserve Volume (ERV) Amount in addition to tidal volume during a forceful or maximal exhalation
    • Residual Volume (RV) Amount left in lungs between breaths. This averages about 1,000 mL’s in an average person.
    • Vital Capacity (VC) = IRV + ERV + TV
    • Total Lung Capacity (TLC) = IRV + ERV + TV + RV or (VC + RV)
  33. What equipment measures lung volumes?
  34. What is the respiratory membrane?

    What occurs at the respiratory membrane?
    The Respiratory Membrane is the area over which O2 & CO2 must diffuse. It consists of the alveolar cells, epithelial basement membrane /capillary basement membrane and the endothelial cells of the capillary.
  35. Why does oxygen diffuse OUT of the capillaries in the tissues and CO2 INTO the capillaries?

    What are the gradients that drive this movement? (know pressures that drive it in each direction)
    PO2 of blood in systemic capillaries is 100mm Hg and PO2 in tissue cells is 40mm Hg at rest. Therefore, O2 flows out of capillaries and into the tissues throughout the body. CO2 flows in the opposite direction from about 46mm Hg to 40mm Hg.
  36. What drives the oxygen INTO the capillaries and CO2 OUT in the alveoli? (know pressures)
    O2 diffuses from the alveolar air where it’s partial pressure is 105mm Hg to the capillaries where PO2 is 40mm Hg (high to low) and the CO2 diffuses in the opposite direction from 46mmHg to 40mmHg
  37. What is ventilation-perfusion coupling? How is this accomplished?
    Gas exchange requires not only good ventilation of the alveolus, but also good perfusion of its capillaries. Ventilation–perfusion coupling is the ability to match ventilation and perfusion to each other.

    Poor ventilation causes local constriction of the pulmonary arteries, reducing blood flow to that area and redirecting this blood to better-ventilated alveoli. Good ventilation, by contrast, dilates the arteries and increases perfusion so that most blood is directed to regions of the lung where it can pick up the most oxygen
  38. What are the 2 ways that oxygen is carried in the body?
    Oxygen is transported by hemoglobin as well as dissolved in the plasma
  39. What makes the oxygen release more easily from the hemoglobin?
    • Four factors adjust the rate of oxygen unloading to the metabolic rates of different tissues:
    • Ambient PO2.
    • Temperature.
    • The Bohr effect.
    • BPG. (bisphosphoglycerate)
  40. Understand what causes the oxyhemoglobin curve to shift and change the affinity for oxygen to bind to hemoglobin.
    When factors such as a change in the partial pressure of oxygen and carbon dioxide occurs, an increase in hydrogen ions or decrease in pH occurs, or temperature increases this will cause more oxygen to be released from the hemoglobin.
  41. What are the 3 ways that CO2 is transported in the body? What % is each way?
    • dissolved in the plasma (7%)
    • carbaminohemoglobin (23%)
    • bicarbonate ion (70%)
  42. What is the chloride shift? When does it happen?
    Once bicarbonate ions diffuse back out to plasma the – ions out must be balanced by + moving into cells. Chloride ions (-) diffuse back into RBC’s to balance charge.

    Result of aerobic respiration.
  43. Why is carbon monoxide so dangerous?
    Carbon monoxide binds to same binding site on hemoglobin as Oxygen.
  44. Where in the brain is the respiratory control center?

    What area controls the rate and depth and which are the transition from inhalation to exhalation?
    medulla oblongata

    the Medulla controls basic rhythm of breathing or regulates the rate and depth of breathing; the Pons regulates the transition from inhalation to exhalation
  45. Where is respiration regulated?
    both the medulla and pons
  46. Where is the pneumotaxic center, where is the apneustic center?
  47. What guards against over inflation of the lungs?
    • the Hering Breuer Inflation Reflex
    • stretch receptors in interstitial tissues when stimulated will trigger a forced exhalation so that the lungs do not stretch “too” much
  48. Why is it we can't hold our breaths forever or that a drowning victim will have water in their lungs?
    central chemoreceptors in the medulla oblongata will bypass cortical control and force respiration when CO2 levels get too high (pH gets too low)
  49. What happens when one goes to a higher altitude when it comes to respiration and oxygen saturation levels?
    pressure gradient for oxygen is lower, making it more difficult to pull oxygen into the blood. respiration will increase and oxygen saturation will decrease.
  50. Where are the peripheral chemoreceptors found?

    What chemicals do they detect in the blood?
    carotid bodies, aortic bodies

    They respond to changes in H+ ion concentration, carbon dioxide and to a much lesser extent the oxygen level in the blood.
  51. Where are the central chemoreceptors found and what do they detect?
    medulla oblongata

    They respond to increases in H+ concentration in the brain’s extracellular fluid which can result from changes in blood PCO2 or systemic changes in pH.
  52. What is the normal pH of the blood?
  53. What is the pH of the blood/range for pH of the urine?
    • Blood : 7.35 – 7.45
    • Urine: 4.5 – 8.0 (more variability since it will depend on dietary intake and metabolic processes)
  54. What is acidosis/alkalosis?
    • alkalosis - pH goes above 7.4
    • acidosis - pH goes below 7.4
  55. What are the 3 buffers in the body?

    How long does it take each one to work?
    intracellular buffers in the blood, also from respiratory and renal mechanisms

    The respiratory response to altered plasma H ion concentration is very rapid (minutes) and keeps this concentration from changing too much until the more slowly responding kidneys (hours to days) can actually eliminate the imbalance.
  56. How do you determine whether a pH imbalance is respiratory or metabolic in origin?
    in respiratory origin, CO2 levels in the blood will be consistent with the direction of the imbalance (i.e. high CO2, low pH)
  57. How does the body “compensate” for changes in pH regardless of the origin?
    stimulating/inhibiting ventilation
  58. How can vomiting/diarrhea lead to pH imbalances?
    • vomiting - expels acids from the body (stomach contents)
    • diarrhea - expels bases from the body (intestinal contents)

    both decrease the body's ability to maintain normal pH ranges
  59. What is conduction, convection, radiation and evaporation?

    How do they work to regulate body temperature?
    • Radiation is the process by which the surfaces of all objects constantly emit heat in the form of electromagnetic waves.
    • Conduction is the loss or gain of heat by transfer of thermal energy during collisions between adjacent molecules.
    • Convection is the process whereby conductive heat loss or gain is aided by movement of air or water next to the body.
    • Evaporation occurs when water vaporizes from the skin and membranes lining the respiratory tract.

    all effect both heat loss & gain except evaporation (loss only)
  60. How is body temp measured?
    The body monitors temperature through thermoreceptors.
  61. How does moderate/profound hypothermia and heat exhaustion/stroke differ?
    • moderate hypothermia & heat exhaustion
    • body retains thermoregulatory ability through homeostatic mechanisms

    • profound hypothermia & heat stroke
    • homeostatic mechanisms no longer function and body is unable to effect a temperature change
  62. What is BMI (body mass index) and what are the recommended ranges?

  63. what health consequences result from an increased BMI?

    why is it sometimes misleading?
    increased statistical risk for obesity related health concerns including hypertension, heart disease, diabetes, gastrointestinal and reproductive health problems.

    can be misleading b/c muscle weighs more than fat, so a very muscular person could have a high BMI
  64. Physiologically what happens when you have a fever?

    What happens during the chill stage?

    What happens when you break a fever?
    A fever occurs when the hypothalamus resets the body’s thermostat or set point for body temperature.

    Shivering occurs to help to increase body temperature to the new set point.

    “breaking” a fever attempts to return to the body’s normal set point by sweating to release more heat and lower the temperature.