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Anatomy & Physiology Lecture Notes - Respiratory system

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Text of Anatomy & Physiology Lecture Notes - Respiratory system

  • Name the organs forming the respiratory passageway from the nasal cavity to the alveoli of the lungs.

    Explain how the respiratory muscles cause volume changes that lead to breathing.

    Sally has a vital lung capacity of 3900 ml. Her tidal volume is 400 ml. Her expiratory reserve volume is 1000 ml. What is her inspiratory reserve volume?

  • Function: supply O2 to the blood and remove CO2

  • Nose/mouth: filtered, warmed, humidifiedMucus traps bacteria & foreign debrisCilia sweep mucus toward throat digested by stomachPharynx: throat (passage for food/air)Tonsils: clusters of lymphatic tissueLarynx: contains vocal cordsEpiglottis: covers larynx when liquids/food swallowedTrachea: windpipe; lined with cartilage (C-shaped)Bronchi: branches to lungsBronchioles: smaller branchesLungs Alveoli: air sacs for gas exchange

  • Inspiration: air flowing into lungsExpiration: air leaving lungs

    Muscles:Diaphragm: dome-shaped muscle separating thoracic and abdominal cavities External intercostals: pulls ribs to elevate rib cage inspiratory musclesInternal intercostals: depresses rib cage

  • InspirationExpirationDiaphragm contracts & flattensExternal intercostals lifts rib cageLungs stretched to larger sizeAir pressure inside lungs decreaseAir sucked into lungs

    Inspiratory muscles relaxRib cage descends, lungs recoilGases forced out

  • Factors that affect capacity: size, age, sex, physical condition

  • Vital Capacity (VC): total exchangeable airVC = TV + IRV + ERV

    Tidal Volume (TV): amount of air in/out during normal breath (~500ml)Inspiratory Reserve Volume (IRV): forced in air over tidal volume (~3100)Expiratory Reserve Volume (ERV): air forcibly exhaled (~1200)Residual Volume (RV): air still left in lungs (~1200)allows gas exchange to continue between breaths

  • Used to measure respiratory capacities

  • Oxygen: attaches to hemoglobin molecules inside RBCs

    Hemoglobin: respiratory pigment, contains 4 heme groups with iron (Fe)

  • Carbon dioxide:Transported as bicarbonate ions (70%)Bound to hemoglobin (23%)Dissolved in plasma (7%)

  • Control center = medulla oblongataResponds to pH changes in bloodHigh CO2 carbonic acid forms lowers pHO2 sensors in the aorta and carotid arteries

  • Group of lung diseases blocks airflow and makes breathing difficultEmphysema (lose elasticity of lung tissue) & chronic bronchitis (excess mucus)Features:History of smokingLabored breathing (wheezing, shortness of breath)Coughing & frequent pulmonary infectionsHypoxic (inadequate O2 delivery bluish skin)

  • Uncontrolled growth of abnormal cells in lungs#1 cause of cancer deathsLeading cause = SMOKINGLow survival rate (avg. 9 mths after diagnosis)Contributes to atherosclerosis, heart diseaseTreatment: remove diseased lobes, radiation, chemotherapy

  • Asthma: inflamed, hypersensitive bronchial passages that respond to irritantsBronchitis: bronchi swollen and cloggedPneumonia: inflammation of lung caused by infectionTuberculosis (TB): infectious disease caused by M. tuberculosis bacterium


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