RESPIRATORY SYSTEM

RESPIRATORY SYSTEM

1. COMPONENTS

   • NOSE AND NASAL CAVITY
     • FUNCTION: Filters, warms, and humidifies incoming air.
     • STRUCTURES: Includes nasal hairs, conchae, and sinuses.
   • PHARYNX (THROAT)
     • FUNCTION: Passageway for air moving from the nasal cavity to the larynx and for food moving form the mouth to the esophagus.
     • REGIONS: Nasopharynx, oropharynx, and laryngopharynx.
   • LARYNX (VOICE BOX)
     • FUNCTION: Routes air and food into the proper channels and plays a role in speech.
     • STRUCTURES: Includes the epiglottis, vocal cords, and thyroid cartilage.
   • TRACHEA (WINDPIPE)
     • FUNCTION: Connects the larynx to the bronchi.
     • STRUCTURE: Supported by cartilage rings to prevent collapse during breathing.
   • BRONCHI AND BRONCHIOLES
     • FUNCTION: Conduct air from the trachea into the lungs.
     • STRUCTURE: : Branch into smaller bronchi and bronchioles, eventually leading to the alveoli.
   • LUNGS
     • FUNCTION: Main organs of respiration where gas exchange occurs.
     • LOBES: Right lung has three lobes; left lung has two lobes.
   • ALVEOLI
     • FUNCTION: Tiny air sacs where the exchange of oxygen and carbon dioxide occurs.
     • STRUCTURE: Surrounded by capillaries, allowing for efficient gas exchange.

2. FUNCTIONAL ZONES OF THE RESPIRATORY SYSTEM

   • CONDUCTING ZONE
     • INCLUDES: Nose, nasal cavity, pharynx, larynx, trachea, bronchi, and bronchioles.
     • FUNCTION: Filters, warms, and moistens air, and conducts it into the lungs.
   • RESPIRATORY ZONE
     • INCLUDES: Respiratory bronchioles, alveolar ducts, and alveoli.
     • FUNCTION: Site of gas exchange.

3. MECHANICHS OF BREATHING (VENTILATION)

   • INSPIRATION (INHALATION)
     • PROCESS: Diaphragm contracts and moves downward, external intercostal muscles contract to expand the chest cavity.
     • RESULT: Decreases intrapulmonary pressure, causing air to flow into the lungs.
   • EXPIRATION (EXHALATION)
     • PROCESS: Diaphragm and intercostal muscles relax.
     • RESULT: Increases intrapulmonary pressure, causing air to flow out of the lungs.

4. GAS LAWS RELEVANT TO RESPIRATION

   • BOYLE'S LAW
     • PRINCIPLE: At a constant temperature, the pressure of a gas decreases as its volume increases, and vice versa. In simple terms, if you squeeze a gas into a smaller space (decreasing its volume), its pressure goes up, and if you let it expand (increasing its volume), its pressure decreases.
     • APPLICATION: Explains how changes in lung volume affect air pressure, facilitating breathing.
   • DALTON'S LAW
     • PRINCIPLE: When you have a mix of gases, the total pressure from all the gases together is the sum of each gas's pressure by itself.
     • APPLICATION: Helps understand the behavior of gases like oxygen and carbon dioxide during gas exchange.
   • HENRY'S LAW
     • PRINCIPLE: This means that the more pressure a gas has above a liquid, the more of that gas will dissolve into the liquid.
     • APPLICATION: Explains how oxygen and carbon dioxide dissolve in blood.

5. GAS EXCHANGE

   • EXTERNAL RESPIRATION
     • LOCATION: Alveoli and pulmonary capillaries.
       • Pulmonary capillaries are tiny blood vessels in the lungs that swap oxygen and carbon dioxide.
     • PROCESS: Oxygen diffuses from alveoli into the blood; carbon dioxide diffuses from blood into alveoli.
       • Oxygen moves from the air sacs (alveoli) in the lungs into the blood, while carbon dioxide moves from the blood into the air sacs to be exhaled.
   • INTERNAL RESPIRATION
     • LOCATION: Systematic capillaries and body tissues.
       • Systemic capillaries are tiny blood vessels that deliver oxygen to cells and pick up waste.
     • PROCESS: Oxygen diffuses from blood into tissues; carbon dioxideo diffuses from tissues into blood.

6. TRANSPORT OF GASES

   • OXYGEN TRANSPORT
     • METHOD: Oxygen is carried in the blood by attaching to a protein called hemoglobin in red blood cells.
     • TRANSPORT EQUATION: O2 + Hb --> HbO2 (oxyhemoglobin)
   • CARBON DIOXIDE TRANSPORT
     • METHODS: Carbon dioxide is transported in the blood in three ways: dissolved in plasma, bound to hemoglobin, and as bicarbonate ions.

7. LUNG VOLUMES AND CAPACITIES

   • TIDAL VOLUME (TV)
     • DEFINITION: Air volume inhaled or exhaled in a normal breath.
     • NORMAL VALUE: ~500 mL.
   • INPIRATORY RESERVE VOLUME (IRV)
     • DEFINITION: Extra air volume inhaled after a normal breath.
     • NORMAL VALUE: 1900-3300 mL.
   • EXPIRATORY RESERVE VOLUME (ERV)
     • DEFINITION: Extra air volume exhaled after a normal breath.
     • NORMAL VALUE: 700-1200 mL.
   • RESIDUAL VOLUME (RV)
     • DEFINITION: Air left in lungs after a maximal exhalation.
     • NORMAL VALUE: 1200 mL.
   • VITAL CAPACITY (VC)
     • DEFINITION: Total air exhaled after a maximal inhalation.
     • NORMAL VALUE: 4800 mL.
     • CALCULATION: VC = TV + IRV + ERV.
   • TOTAL LUNG CAPACITY (TLC)
     • DEFINITION: Max air volume lungs can hold.
     • NORMAL VALUE: 6000 mL.
     • CALCULATION: TLC = TV + IRV + ERV + RV.

8. RESPIRATORY SYSTEM

   • PULMONARY FUNCTION TESTS
     • SPIROMETRY
       • PURPOSE: Measures how much air you can inhale and exhale, and how quickly you can do so.
       • TESTS: Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 second (FEV1)
     • BODY PLETHYSMOGRAPHY
       • PURPOSE: Measures the volume of gas in the lungs, including air that remains after exhalation.
     • DIFFUSION CAPACITY (DLCO)
       • Measures how well gases like oxygen and carbon dioxide are transferred from the lungs to the blood.
   • SPECIAL CONDITIONS AFFECTING RESPIRATION
     • OBSTRUCTUVE LUNG DISEASES
       • EXAMPLES: Asthma, chronic bronchitis, emphysema.
       • CHARACTERISTICS: Difficulty in expelling air from the lungs.
     • RESTRICTIVE LUNG DISEASES
       • EXAMPLES: Interstitial lung disease, chest wall pathology.
       • CHARACTERISTICS: Difficulty in expanding the lungs fully.
     • AGING EFFECTS
       • CHANGES: Loss of lung elasticity and stiffening of the chest wall, leading to reduced lung function.