BIOL 273.txt

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bchang13
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212230
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BIOL 273.txt
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2013-04-08 18:10:53
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Human physiology
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Physiology of a human..
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    • author "Bchang"
    • tags ""
    • description "Human Physiology"
    • fileName "BIOL 273"
    • freezingBlueDBID -1.0
    • Respiratory pumping system?
    • Bones and muscles of the thorax
  1. Alveoli are wrapped with an extensive capillary network which covers __________% of the alveolar surface.
    80 - 90
  2. Gas exchange occurs by (active transport/diffusion)?
    Diffusion
  3. Characteristics of type 1 alveolar cells:
    Large and thin, rapid gas diffusion
  4. Characteristics of type 2 alveolar cells:
    Smaller and thicker, synthesize and secrete surfactant --> reduces surface tension of alveolus
  5. About ___% of total blood volume is in pulmonary circulation at any one time
    10
  6. Pumping system is closed off by:
    • Top - neck muscles and connective tissue
    • Bottom - diaphragm
    • Wall - ribs and intercostal muscles
  7. Total pressure of a mixture of gases are = ?
    Sum of partial pressure of individual gases
  8. Volume and ________ are inversely related
    Pressure
  9. Amount of gas dissolved in a liquid is determined by:
    • - Partial pressure of the gas
    • - Solubility of the gas in the liquid
  10. Pressure Volume relationships are described by:
    • Boyle's Law: P1V1= P2V2
    • - critical for VENTILATION
  11. Lung volume depends on:
    1. Transpulmonary pressure - difference between alveolar and intrapleural pressure

    2. Degree of elasticity (more elastic, easier to breath)
  12. Ventilation is the exchange between the lungs and __________ (the atmosphere/blood)
    Atmosphere
  13. What is refered to as the 'mucus escalator'?
    Pharynx
  14. Steps during INSPIRATION:
    • 1. Somatic motor neurons trigger contraction of diaphragm and inspiratory muscles
    • 2. Thorax expands - thoracic volume increases
    • 3. Intrapleural pressure decreases
    • 4. Results in increase in transpulmonary pressure
    • 5. Lungs expand
    • 6. Alveolar pressure decreases
    • 7. Air flows into lungs
  15. Steps during EXPIRATION:
    • 1. Impulses from somatic motor neurons stop
    • 2. Muscle of diaphragm and thorax relax
    • 3. Returns thorax to original position - volume decreases
    • 4. Intrapleural pressure increases
    • 5. Elastic recoil of the lungs decreases lung volume
    • 6. Alveolar pressure increases
    • 7. Air flows out of the lungs
  16. Active expiration depends on:
    contraction of internal intercostals and abdominal muscles (Heimlich manoeuvre)
  17. Pneumothorax is:
    When air getsinside intrapleural cavity and pressure increases, lung collapses

    Treatment: suction to remove air and seal the hole

    *having a lower pressure in the pleural fluid (outside) than inside the lung (at rest) helps keep the lung expanded and open
  18. The work required to breathe depends on two main factors:
    • 1. Complaince (stretchability of lungs)
    • 2. The resistance - to air flowing in the airways
  19. Lung compliance is:
    The magnitude of change in lung volume produced by a given change in pressure
  20. Diseases that affect lung compliance:
    • Fibrotic lung disease (reduces complaince)
    • - scar tissue
    • Inadequate surfactant production
    • - new-born respiratory distress syndrome: babies born before 8 weeks have very low compliance dur to inadequate surfactant production --> amniocentesis
  21. Structure & function of SURFACTANTS:
    Structure: mixture of lipoproteins

    Function: disrupt the cohesive forces between water molecules, thus reducing surface tension. Makes lungs more compliant (easier to stretch)
  22. Surfactants are secreted by type ___ alveolar cells.
    II
  23. Lung elastance is :
    The degree and/or speed of return to resting volume after lung is stretched

    Low elastance --> lung does not return to resting volume passively

    Elastin fibres are destroyed.

    Have high compliance but low elastance

    Emphysema (damaged alveoli) affects lung elastance
  24. Airway resistance is determined by:
    Airway diameter

    R = 8Ln/(pi)r^2
  25. Bronchiole diameter can be affected by the ____________ , ___________, and ___________.
    Nervous system, hormones (circulating epinephrine), and paracrines.
  26. _______ causes bronchodilation.
    CO2
  27. Neural control of bronchioles primarily by ________________ neurons that cause bronchoconstiction.
    Parasympathetic
  28. _____________ is an instrument that measures movement of air during breathing. Allows for the diagnosis of:
    Spirometer; asthma, emphysema, chronic bronchitis
  29. Tidal volume is:
    Volume of air moved in a single normal inspiration or expiration
  30. Inspiratory reserve volume is:
    Maximum amount of air that can be inspired ABOVE tidal volume
  31. Expiratory reserve volume is:
    Amount of air that can be exhaled AFTER a normal expiration
  32. Residual volume is:
    Amount of air left in the lungs after MAXIMAL expiration
  33. Vital capacity is:
    Maximum amount of air hat can be volu tarily moved into or out of the respiratory system

    Vc = IRV + ERV + Vt
  34. Total lung capacity =
    Vital capacity + Residual volume
  35. Minute volume =
    Tidal volume x respiratory rate (breaths per minute)
  36. Alveolar ventilation =
    Ventilation rate x ( tidal volume - dead space volume)

    Dead space cvolume is the air inside the trachea, bronchi, and bronchioles
  37. Gas exchange occurs by diffusion. The rate of diffusion across the lungs is:
    • 1. Proportional to the partial pressure gradient.
    • 2. Propoetional tothe available surface area.
    • 3. Inversely proportional to membrane thickness.
    • 4. Greatest over short distances.
  38. Diseases and conditions that can impact gas exchange:
    Emphysema - results in physical loss of alveolar surface area.

    Fibrotic lung disease - scarring thickens the alveolar membrane.

    Pulmonary edema - increase in interstitial fluid in lungs leads to increase in diffusion distance.

    Asthma - increase airway resistance (constricted bronchiole) decrease ventilation.
  39. Gases are transported throught the body either dissolved in ____________ or _________.
    • Plasma (2%)
    • Red blood cells (98%)
  40. Each haemoglobin molecule can bind up to ____ oxygen molecules.
    4
  41. ___________________ is a competitive inhibitor of O2 binding.
    Carbon monoxide
  42. Carbon dioxide is transported by what three mechanisms?
    • 1. Dissolved in plasma.
    • 2. Interact with proteins.
    • 3. Converted to bicarbonate.
  43. Carbon dioxide diffuses out of ______ → ______→_________.
    RBC → plasma → alveoli
  44. Diaphragm and intercostals are (skeletal/smooth/cardiac) muscles
    Skeletal.

    • - not able to contract spontaneously
    • - therefore, innervared by SOMATIC motor neurons

    Contraction of respiratory akeletal muscles is initiated at the medulla oblongota by a group of neurons called the central pattern generator (brain)
  45. What type of neurons are in the dorsal respiratory group snd what do they control?
    Inspiratory neurons (I neurons); control external intercostals muscles and the diaphragm
  46. What type of neurons are in the ventral respiratory group snd what do they control?
    Active expiratory neurons (E neurons); control internal intercostal and abdominal muscles
  47. Chemoreceptors modify or adjust the ____________ of the central pattern generator neurons.
    Rhythmicity
  48. ________ and _________ chemoreceptors are responsible for ventilation regulation.
    Peripheral and central
  49. _________ chemoreceptors are located in the medulla oblongota and ___________ chemoreceptors are located in carotid & aortic bodies (glomus cells).
    Central ; peripheral
  50. Two types of mechanoreceptors:
    • Irritant receptors
    • - triggers parasympathetic neurons hat innervate bronhiolar smooth muscle → bronchoconstriction

    • Stretch receptors
    • - triggered if lungs are over inflated
    • - terminate ventilation
    • - only important during strenuous exercise
  51. _________ receptors are located in airway smooth muscle and ________ receptors are located in airway mucosa.
    Stretch; irritant
  52. During exercise, ventilation may increase as much as:
    20-fold
  53. Possible stimuli that cause an increase in ventilation are:
    • 1. Increased PCO2
    • 2. Decreased PO2
    • 3. Increased H^+
  54. Does PCO2 increase during exercise?
    • Venous PCO2 increases but arterial doesn't
    • - Arterial PCO2 is set by alveolar PCO2
  55. Does PO2 decrease during exercise?
    Venous PCO2 decreases, but arterial doesn't

    - haemoglobin is already 98% saturated
  56. Does H^+ increase during exercise?
    Increase only during severe exercise (as a result of lactic release into the blood from glycolysis)
  57. __________ is the ability of the body to fight off invaders
    Immunity
  58. Key features of the immune system (2):
    Lymphoid tissues and immune cells

    Chemicals that coordinate and execute function
  59. Three major functions of the immune system:
    1. Protect the body

    • - microbes (bacteria, viruses, fungi, protozoa)
    • - parasites (worms)
    • - toxins produced by microbes
    • - other foreign proteins or substances

    2. Removes dead/damaged tissues and cells

    - immune cells scavenge extracellular compartments

    3. Tries to recognize and remove abnormal cells

    - cells that are unable to control growth detected by immune system
  60. What are the diseases of the immume system when it does not perform normally?
    • Autoimmunity
    • - incorrect responses
    • - ex. Destroying own cells

    • Allergies
    • - overactive responses

    • Immunodeficiency
    • - lack of response
  61. Three types of pathogens:
    • - paracites
    • - bacteria
    • - viruses
  62. Characteristics of parasites:
    • - generally extracellular
    • - enter the body via a variety of routes
    • - cause chronic illness, nutritional deficiencies, death
    • - malaria
  63. Characteristics of bacteria:
    • - intracellular or extracellular
    • - cells surrounded by a cell membrane and usually a cell wall
    • - can survive & reproduce outside of host
    • - most can be killed by drugs (antibiotics)
  64. Characteristics of viruses:
    • - intracellular
    • - not cells → nucleic acid core w/ protein coat
    • - cannot reproduce alone
    • - cannot be killed by antibiotics (only some antiviral drugs)
    • - takes over host cell
    • - ruptures host cell or buds off
  65. Immune system organs are called ________ organs because _________ are found here.
    Lymphoid; lymphocytes

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