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Respiratory System, alveolar ventilation (VA) - Coggle Diagram

- - - - more stretch = more compliance
      - Think of faster inflation rate of balloon
    - - amount of elastic tissue in walls of alveoli, blood vessels and bonchi
        
        Elastic tissue
        
        Elastin
        
        Easily stretched
        
        More of this decreases compliance
        
        Collagen
        
        Hard to stretch
        
        more collagen decreases compliance
        
        Geometric arrangement
        
        contribute to 1/3 of total compliance
      - Surface tension of surfactant (film of liquid covering alveoli)
        
        Contribute 2/3 of lung elastic behaviour
        
        if no surfactant
        
        Forces in the H2O go inwards (no outward balancing force)
        
        Pull alveoli into a tight ball
        
        Decreases compliance by collapsing alveoli
        
        Made of phospholipids
        
        Hydrophobic tail
        
        Hydrophilic head
        
        Head balances out forces with water at air-water interface
        
        Water flattens
        
        Decrease surface tension
        
        having surfactant increases compliance, making it easier to breath
    - - pulmonary fibrosis
        
        Breathing of fine particles like asbestos, coal dust or air pollution (bypass imm. system)
        
        scars the tissue
        
        Decrease compliance
      - Normal aging and pulmonary emphysema
        
        chronic condition due to smoking
        
        destroy elastin fibers
        
        Increase compliance
        
        Makes it hard to exhale
      - Infant respiratory distress syndrome
        
        Not enough surfactant is made
        
        decrease compliance
      - open-heart surgery
        
        no surfactant is released
        
        decrease compliance
  - - - Measures lung volumes and capacities
      - Can diagnose pulmonary diseases
    - - Air filled chamber
        
        During inhalation, chamber falls and pulls a pen up
        
        Marks a path indicating lung volumes
        
        During exhalation, the chamber fills and the pen falls down
  - - - max air volume that can enter lungs additional to tidal volume
    - - Max air volume that can leave lungs beyond tidal volume
    - - volume of air leaving/entering during 1 breath at rest
    - - Remaining air in lungs after max expiration
  - - - Max air inhaled after exhaling the tidal volume
        
        tidal vol + inspiratory reserve vol
    - - Air left in lungs after exhaling tidal volume
        
        expiratory reserve vol + residual vol
    - - Max amount of air exhaled after max inhalation
        
        inspiratory reserve vol + tidal + expiratory reserve vol
    - - Max air capacity lungs can hold
        
        Vital capacity + residual volume
  - - - Conducting zone (anatomical dead space)
        
        no gas exchange area with no alveoli
        
        Dead space volume (VD)= body weight in pounds
      - Respiratory zone
        
        Gas exchange with alveoli
      - definition of VE
    - - At rest
        
        VE =7500ml/min (in conducting and respiratory zones)
        
        Only air entering respiratory zone is used for gas exchange
- - - - Lymphocytes
        
        Found in respiratory membrane
      - Macrophages
        
        Inside the alveoli
- - - - Nasal cavity
        
        pharynx
        
        larynx (voice box)
        
        Trachea
        
        Left Bronchi
        
        Bronchioles
        
        1 more item...
        
        Collagen and elastin
        
        1 more item...
        
        Right Bronchi
        
        Bronchioles
        
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      - Mouth
  - - - For maximum gas exchange
        
        Large Cross sectional area
        
        Very low blood velocity
        
        Thin endothelial walls
        
        O2 diffuses in, CO2 diffuses out
      - O2 rich blood
        
        Pulmonary vein
        
        Left side of heart
    - - Alveoli
      - Collagen and Elastin (found in all other blood vessels as well)
- - - - controlled by the medulla respiratory center in the medulla oblongata of the brain stem
        
        neurons in these areas creates rhythmic breathing patterns resulting in spontaneous breathing
        
        the medulla respiratory center has two areas
        
        inspiratory center
        
        stimulates inspiratory muscles
        
        expiratory center
        
        stimulates expiratory muscles
        
        when activated, inhibits the inspiratory center
        
        inhalation
        
        is an active process that requires the diaphragm and external intercoastal muscles
        
        stimulates inspiratory muscles
        
        inhibits expiratory muscles
        
        exhalation
        
        is normally a passive process
        
        only need to relax inspiratory muscles
        
        forceful exhalation (exercise)
        
        abdominal muscles need to contract
        
        signal to contract comes from the expiratory center in the medulla
        
        internal intercostal muscles of the ribs need to contract
        
        inhalation and exhalation working together
        
        when body is at rest inspiratory center is active (2 sec)
        
        activates the muscles of inspiration (diaphragm and external intercoastal muscles)
        
        expiratory center is inhibited during this time
        
        inspiratory center shuts down
        
        expiratory center activates
        
        expiration can be active
        
        1 more item...
        
        expiration can be passive
    - - controlled by the voluntary center of the cerebral cortex
        
        this can override the brain stem
        
        cerebral cortex can then modify ventilation by affecting signals coming from the apneustic or pneumotaxic center
  - - - pneumotaxic center
        
        regulation of breathing rate
        
        work together to ensure ventilation is smooth and coordinated
      - apneustic center
        
        controls the depth of inhalation and exhalation
  - - - right concentration of gases
        
        medullary respiratory centers
        
        muscles of respiration
        
        lung ventilation
        
        chemoreceptors
        
        sensor
        
        works to detect concentration of oxygen, CO2 or H+ ion concentration in blood
        
        groups of chemoreceptors
        
        2 more items...
        
        controlled variable
        
        effector
        
        control center
        
        set point
- - - - Outer layer of lungs
    - - Inner layer of lungs
    - - Pleural fluid
        
        Decrease friction between membranes during breathing
        
        Contains
  - - - Alveolar (intrapulmonary) pressure
        
        760 mmHg (Between breaths)
    - - Intrapleural pressure
        
        756 mmHg (Between breaths)
    - - Atmospheric pressure
        
        760 mmHg (Between breaths) always
    - - Transpulmonary pressure
        
        Helps keeps lungs open
        
        Transpulmonary = Alveolar - Intrapleural
        
        If difference = 0
        
        causes pneumothorax
        
        Caused by Intrapleural space puncture
        
        Alveolar pressure = Intrapleural pressure
        
        Usually only 1 lung collapses due to them being isolated
- - - - Move air into lungs
        
        High atmospheric pressure, low alveoli pressure
        
        Diaphragm contracts downwards
        
        External intercostal muscles of rib contracts
        
        Rib cage lifts up and out
        
        Lung volume increases
        
        1 more item...
        
        Alveolar pressure drops to 759 mmHg
        
        1 more item...
      - Move air out of lungs
        
        Low atmospheric pressure, high alveoli pressure
        
        Diaphragm relaxes
        
        External intercostal muscles of rib relaxes
        
        Lungs recoil to original size
        
        Lung volume decreases
        
        1 more item...
        
        Alveolar pressure rises to 761 mmHg
        
        1 more item...
        
        exercise
        
        Force air out of lungs
        
        Contract abdominal muscles
        
        Greater lung volume decrease
        
        Larger pressure gradient forcing air out
        
        1 more item...
        
        Contract internal intercostal muscles of ribs
- - - - PO2
        
        105 mmHg
        
        Moves from High (alveoli) to low (bloodstream)
      - PCO2
        
        40 mmHg
        
        Moves from high (blood stream) to low (alveoli)
      - Moves with partial pressure gradient
        
        Moves from high partial pressure to low partial pressure
      - Can describe amount of O2 and CO2 dissolved in plasma
      - equilibrates with alveolar air when leaves alveoli
      - O2 and CO2 in circulatory system
        
        Blood leaves lungs (high in PO2, low in PCO2)
        
        blood returns to left side of heart
        
        systemic circulation to tissues
        
        PO2 and PCO2 is unchanged
        
        Cells have low PO2 and high PCO2
        
        1 more item...
  - - - transport by plasma
        
        makes up only 1.5% of total O2 transported. (is not very efficient)
      - transport by hemoglobin(Hb)
        
        dominant way for how O2 is carried in the body (98.5% of total O2 transported)
        
        Each Hb molecule can carry 4 molecules of oxygen because it has 4 subunits
        
        each subunit has 1 heme molecule attached to a polypeptide called globin (1 of each in each subunit)
        
        Each heme has 1 iron atom which gives it a red color and allows each heme to carry 1 oxygen
        
        Red blood cells (erythrocytes)
        
        can go through the smallest capillaires
        
        mature stage has no nucleus
        
        no nucleus=no more hemoglobin can be made
        
        in early development stage, they have a nucleus
        
        this nucleus directs the production of hemoglobin
        
        males have more RBC per cubic millimeter due to the influence of testosterone on RBC production
        
        RBC production
        
        process is called erythropoiesis
        
        requires many substances
        
        iron
        
        1 more item...
        
        folic acid
        
        1 more item...
        
        amino acids
        
        1 more item...
        
        Vitamin B12
        
        1 more item...
        
        They have a short lifespan and are destroyed by the spleen and liver
        
        controlled by the hormone erythropoietin(EPO) which stimulates the bone marrow
        
        mostly secreted by kidneys (90%)
        
        also secreted by the liver (10%)
        
        EPO secretion is low in normal conditions to ensure RBC production keeps up with RBC loss
        
        EPO secretion can increases when O2 levels in the kidney decreases, such as when:
        
        4 more items...
        
        process in low O2 conditions
        
        2 more items...
        
        an avg human has ~900 gm(2 lbs) of hemoglobin and each RBC has around 29 pg of hemoglobin
        
        process
        
        Hb becomes saturated with O2 after blood leaves lungs
        
        O2 binds to Hb forming oxyhemoglobin(HbO2)
        
        this reaction is reversible
        
        when more O2 present than HbO2, rxn favors formation of HbO2 (HbO2)
        
        1 more item...
        
        When more HbO2 present than O2, rxn favors O2 unloading from Hb (Hb + O2)
        
        1 more item...
        
        O2 + Hb ⇌ HbO2
        
        hemoglobin dissociation curve
        
        1 more item...
    - - how CO2 is carried in the blood
        
        dissolved and carried by the plasma (PCO2)
        
        much more soluble in plasma than O2
        
        7-10% of CO2 is carried this way
        
        PCO2 is higher on the venous side, compared to arterial side
        
        CO2 on the arterial side is useful to keep arterioles dilated as mentioned by the metabolic theory
        
        carried as a bicarbonate ion (HCO3)
        
        70% of total CO2 is carried in the blood this way
        
        CO2 + H2O ⇌ H2CO3 ⇌ HCO3- + H+
        
        to make carbonic acid, the enzyme carbonic anhydrase is needed
        
        Carbonic is quickly dissociated afterwards
        
        the enzyme is found in RBC, so entire rxn happens in the RBCs
        
        as bicarbonate (HCO3-) is made, the H+ binds to Hb
        
        prevents blood from being too acidic
        
        HCO3- leaves the RBC, making the membrane more positive
        
        Chloride shift occurs to balance positive charge inside RBC
        
        1 more item...
        
        carried by proteins in the blood, forming carbamino compounds CO2 binds to proteins
        
        20-23% of the blood is transported in the blood this way
        
        CO2 binds to Hb after Hb unloads O2
        
        forms HbCO2
        
        CO2 + Hb ⇌ HbCO2
        
        when CO2 attaches to Hb, it forms carbamino hemoglobin(HbCO2)
        
        These reactions will shift depending on the PO2
        
        If PCO2 is high, loading of CO2 on Hb and formation of HCO3- is favored
        
        1 more item...
        
        If PCO2 is low, unloading of CO2 from Hb and conversion of HCO3 into CO2 is favored
        
        1 more item...
        
        When Hb CO2 forms, it returns to the lungs where it will CO2 will detach
        
        CO2 diffuses to alveolar space
        
        O2 diffuses into the RBC
        
        Note O2 and CO2 binds to different parts of Hb