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Chapter 22: The Respiratory System - Coggle Diagram

- - - - Mechanisms of Ventilation
        
        2 phases of pulmonary ventilation
        
        Inspiration (inhalation)
        
        Expiration (exhalation)
        
        Inspiration
        
        Volume of thoracic cavity increases
        
        Decreases internal gas pressure
        
        Diaphragm flattens
        
        External intercostal muscles contract & raise the ribs
        
        Deep Inspiration
        
        Requires
        
        Scalenes
        
        Sternocleidomastoid
        
        Pectoralis major
        
        Erector spinae
        
        Extends the back
        
        Expiration
        
        Quiet Expiration
        
        Chiefly a passive process
        
        Inspiratory muscles relax
        
        Diaphragm moves superiorly
        
        Volume of thoracic cavity deceases
        
        Forced Expiration
        
        An active process
        
        Produced by contraction of
        
        Internal & external oblique muscles
        
        Internal intercostals
        
        Transversus abdominis muscle
      - Neural Control of Ventilation
        
        Ventral Respiratory Group (VRG)
        
        Most important respiratory center
        
        Located in the reticular formation in the medulla oblongata
        
        Neurons generate respiratory rhythm
        
        Chemoreceptors
        
        Central chemoreceptors
        
        Peripheral chemoreceptors
        
        Central Chemoreceptors
        
        Located in medulla
        
        Sensitive to rising & falling CO2 levels (blood pH)
        
        Not enough CO2 will cause pH to become more alkaline/basic, so respiratory rate to fall
        
        Too much CO2 will cause pH to become more acidic, so ventilation rate will increase (hyperventilation) to blow off more CO2
        
        Primary driver of respiration because they're more sensitive
        
        Hyperventilation
        
        When given a brown paper bag when hyperventilating:
        
        Exhaling & inhaling CO2 into the bag, so you build back up CO2 levels to normalize blood pH
        
        Peripheral Chemoreceptors
        
        Sensitive to O2 levels
        
        Has less influence
        
        Aortic Bodies
        
        Carotid Bodies
  - - - Conducting Zone
        
        Respiratory passageways that convey air
        
        Filter, humidify & warm incoming air
        
        Moves air from external environment into lungs
        
        Carries the air to gas exchange sites
        
        Has nothing to do with gas exchange
        
        Contains all structures from nose to terminal bronchioles
        
        Nose, nasal cavity, paranasal sinuses, pharynx, larynx, trachea, bronchi, bronchioles & terminal bronchioles (green)
      - Respiratory Zone
        
        Site of gas exchange in the lungs
        
        Includes structures that have alveoli
        
        Contains: respiratory bronchioles, alveolar ducts & alveolar sacs/alveoli (teal)
        
        Respiratory Bronchioles
        
        Gas exchange occurs where smooth muscle is absent
        
        Branch from terminal bronchioles
        
        Lead to alveolar ducts
        
        Lead to alveolar sacs
        
        Hyaline cartilage is phased out & replaced by smooth muscle as you go down bronchioles
        
        Little if any cartilage in respiratory bronchioles
        
        Less & less mucus epithelium deeper in the lungs
        
        Mucus makes gas exchange hard
        
        Alveoli
        
        ~400 million alveoli account for tremendous surface area for gas exchange
        
        Alveolar pores allow air in alveoli to interact with other alveoli & equalize air pressure across the sac & lung
        
        Structures of Alveoli
        
        Type 1 Alveolar Cells
        
        Single layer of simple squamous epithelial cells
        
        Surrounded by basal lamina
        
        Respiratory Membrane
        
        Alveolar & capillary walls + their basal lamina
        
        Type 2 Alveolar Cells
        
        Are scattered among type 1 alveolar cells
        
        Are cuboidal epithelial cells
        
        Secrete surfactant
        
        Surfactant
        
        Reduces surface tension with alveoli
        
        Metaphor: when you put water on a glass slide & put on a coverslip, it's hard to pull off the slip straight up because of surface tension
        
        Surfactant makes it easier to separate the coverslip & the slide
        
        During expiration, the walls of the alveoli separate easily during expiration
        
        Makes inhalation easier because the walls of the alveoli aren't stuck together
        
        Inhalation & Exhalation
        
        Inhalation is active
        
        Diaphragm & external intercostals contract
        
        Thoracic cavity is bigger
        
        Exhalation is passive
        
        Diaphragm release & elastic fibers around alveolus recoil
        
        Alveolar Macrophages
        
        Remove tiniest inhaled particles
        
        Migrate into bronchi
        
        Ciliary action takes alveolar macrophages to pharynx
        
        Features of Alveoli
        
        Surrounded by elastic fibers
        
        Interconnect by way of alveolar pores
        
        Internal surfaces
        
        A site for free movement of alveolar macrophages
    - - The Nose
        
        Provides an airway for respiration
        
        Moistens & warms air
        
        Filters inhaled air
        
        Resonating chamber for speech
        
        Houses olfactory receptors
      - Nasal Cavity
        
        External nares: nostrils
        
        Divided by nasal septum
        
        Continuous with nasopharynx
        
        2 types of mucous membrane
        
        Mucous Membranes
        
        Respiratory Mucosa
        
        Lines nasal cavity
        
        Cilia of the epithelium move contaminated mucus posteriorly to the pharynx
        
        Filtered particles & mucus are swallowed
        
        Eventually digested by digestive juices in the stomach
        
        May also be expectorated
        
        Olfactory Mucosa
        
        Near roof of nasal cavity
        
        Houses olfactory (smell) receptors
        
        Nasal Conchae
        
        Superior & middle nasal conchae
        
        Part of the ethmoid bone
        
        Inferior nasal conchae
        
        Separate bone
        
        Project medially from the lateral wall of the nasal cavity
        
        During inhalation: filter, heat & moisten incoming air
        
        During exhalation: moisture & heat are reclaimed
      - Paranasal Sinuses
        
        Located within:
        
        Frontal bone
        
        Maxillary bones
        
        Sphenoid bone
        
        Ethmoid bone
        
        Sinuses open into nasal cavity
        
        Lined with mucous epithelium
        
        Warms & humidifies air
        
        Adds resonance to the voice
      - Pharynx
        
        Funnel-shaped passageway
        
        Connects nasal cavity & mouth
        
        Divided into 3 sections by location
        
        Nasopharynx
        
        Oropharynx
        
        Laryngopharynx
        
        Type of mucosal lining changes along its length
        
        Nasopharynx
        
        Superior to the point where food enters
        
        Only an air passageway
        
        Closed off during swallowing
        
        Prevent food from entering the nasal cavity
        
        Uvula reflects superiorly
        
        Continuous with nasal cavity
        
        Pharyngeal Tonsil
        Adenoids
        
        Located on posterior wall
        
        Destroys entering pathogens
        
        Pharyngotympanic Tube
        Auditory Tube
        
        Nasopharynx contains the opening to the pharyngotympanic tube
        
        Tubal Tonsil
        
        Provides some protection from infection
        
        Oropharynx
        
        Arch-like entranceway
        
        Extends from soft palate to the epiglottis
        
        Stratified squamous epithelium
        
        2 types of tonsils in the oropharynx
        
        Palatine Tonsils
        
        In the lateral walls of the fauces
        
        Lingual Tonsils
        
        Cover the posterior surface of the tongue
        
        Laryngopharynx
        
        Passageway for both food & air
        
        Stratified squamous epithelium
        
        Continuous with esophagus & larynx
        
        Extends into inferior boundary of cricoid cartilage
      - Larynx
        
        Attaches to hyoid bone superiorly
        
        Opens superiorly to laryngopharynx
        
        Inferiorly is continuous with the trachea
        
        Where vocal folds are
        
        Vibrates as air passes between them
        
        Closed during swallowing by epiglottis
        
        Framework is arrangement of 9 cartilages
        
        3 functions
        
        3 Functions
        
        Voice production
        
        Routes air & food into the proper channels
        
        Superior opening is
        
        Closed during swallowing
        
        Opening during breathing
        
        Thyroid Cartilage
        
        Shield-shaped
        
        Forms laryngeal prominence (Adam's apple)
        
        Biggest cartilage in the larynx
        
        Inferior to the cricoid
        
        Epiglottis
        
        Tips inferiorly during swallowing
        
        Vocal Ligaments of the Larynx
        
        Vocal Folds
        
        True vocal cords
        
        Act in sound production
        
        Changing length of vocal folds changes pitch
        
        Loudness depends on the force of air across the vocal folds
        
        Glottis
        
        Medial opening between vocal folds
        
        Vestibular Folds
        
        False vocal cords
        
        No role in sound production
    - - Trachea
        
        Descends into the mediastinum
        
        C-shaped cartilage rings keep airway open
        
        Trachealis muscle are located between open ends of the C-shaped cartilage rings along length of posterior trachea
        
        Carina
        
        Marks where trachea bifurcates into 2 primary bronchi
        
        Psudostratified ciliated columnar
      - Bronchi in the Conducting Zone
        
        Bronchial tree
        
        Extensively branching respiratory passageways
        
        Primary (Main) Bronchi
        
        Largest bronchi
        
        Right & left main bronchi
        
        Right main bronchi is wider & shorter than the left
        
        Secondary (Lobar) Bronchi
        
        3 on the right
        
        2 on the left
        
        Tertiary (Segmental) Bronchi
        
        Branch into each lung segment
        
        Bronchioles
        
        Little bronchi
        
        Less than 1mm in diameter
        
        Terminal Bronchioles
        
        Less than 0.5mm in diameter
        
        Changes in Tissue Composition of the Bronchial Tree
        
        Supportive connective tissues change
        
        C-shaped rings replaced by cartilage plates
        
        Epithelium changes
        
        Initially is psuedostratified ciliated columnar
        
        Replaced by simple columnar, then simple cuboidal epithelium
        
        Smooth muscle becomes important
        
        Airways widens with sympathetic stimulation
        
        Airways constricts under parasympathetic direction
- - - - 1
        
        Tobacco smoke & air pollution
        
        2
        
        Continual bronchial irritation & inflammation
        
        Chronic Bronchitis
        
        Excess mucus production
        
        Chronic productive cough
        
        Results In
        
        Airway obstruction or airway trapping
        
        Dyspnea
        
        Frequent infections
        
        2*
        
        Breakdown of elastin in connective tissue of lungs
        
        Emphysema
        
        Destruction of alveolar walls
        
        Loss of lung elasticity