Docstoc

Intoduction

Document Sample
Intoduction Powered By Docstoc
					Respiratory System

     Chapter 24
Respiratory system
           Respiratory system
• Functions in respiratory gas exchange between
  air & blood
• Moves Air
• Delivers oxygen to cells
• Removes carbon dioxide from cell
  – Product of cellular respiration
• Defense
  – Respiratory epithelium
• Sound production- phonation
• Regulation
  – Blood volume, blood pressure, fluid pH
Respiratory system
         Respiratory system
• Organized by location
  – Upper respiratory system
  – lower respiratory system
• Organized by function
  – Conducting
  – Respiratory
     Upper respiratory system
• Structurally comprised of
  – Nasal cavity
  – Paranasal sinus
  – Pharynx
• Functionally
  – Filter, warm, humidify
Upper respiratory system
Respiratory Epithelium
Mucus Membrane
          Nasal cavity Functions
• Air preparation
   – Filters inhaled particulates
       • Nose hair
       • mucus
   – Warm air to body temperature
       • Highly vascularized
   – Humidifies- mucus membrane
       • Prevents desiccation & damage
       • Provide environment for efficient gas exchange
• Olfactory sensations
   – Smell receptors
• Air circulated by turbinal bones
   – Increases surface area
Filter System




External Nares
Mucus Membrane & Cilia
Highly Vascularized
Warms & moistens Air
Air Flow
             Nasal Concha
• Increase Surface area
• Circulate air
Nasal Cavity
Sensory System
Modified Epithelium
Modified Cilia of Olfactory
       Receptors
          Olfactory Fatigue
• Binding sites on olfactory receptors are
  saturated and are not cleared
• Stop transmitting signal
• Mechanisms for “clearing signal”
             Paranasal Sinuses
• Mucous membrane
  lined cavities in skull
  bones
• Found in skull bones
   –   Frontal
   –   Sphenoid
   –   Maxillary
   –   ethmoid
Paranasal Sinuses
     Paranasal Sinus Functions
• Aid in phonation
  – Production of sound
  – Resonate sound to produce tone
• Aid in humidification
• Reduces skull weight
• Produce mucus that drains into nasal
  cavity- cleans
Sinus Infection
Capsicin & Colds
                         Pharynx
• Conveys ingested & inhaled substances
• Nasopharynx- superior region
• Houses:
  – Pharyngeal tonsils (adenoids)
     • Posterior lateral wall
     • Immune tissue
  – Auditory tube (Eustachian) opening
     • Lateral wall
     • Equalizes middle ear pressure
     • Route for ear infections
         – Children short, narrow, horizontal
NasoPharynx
                 Adenoids
• Immune function
• Recede in adults
           Eustachian Tube
• Equalizes pressure in middle ear
• Drains mucus
     Lower Respiratory System
• Conducts
• Comprised of
  – Larynx
  – Trachea
  – Bronchi
                          Larynx
• Aka Voice box, Adam’s Apple
• Structure
  – Glottis
     • Opening into larynx
  – Epiglottis
     • Shoe-horn shaped elastic cartilage
• Functions
  – Protected entrance into lower respiratory structures
     • Prevents passage of Food/liquid into respiratory structures
  – Phonation
     • Sound production
Larynx
Larynx
Glottis
Epiglottis
Protection
Automatic Reflex
Larynx Made of 9 Cartilages
         Laryngeal cartilage
• Thyroid cartilage
  – Largest laryngeal cartilage
  – Anterior, lateral, shield
• Cricoid Cartilage
  – Ring shaped
• Arytenoid cartilage
  – Regulates vocal cord tension
  – Changes sound pitch (tone)
Laryngeal cartilage- Thyroid &
           Cricoid
Laryngeal cartilage-
     Arytenoid
                   Phonation
• Vocal folds (cords)
  – Produce initial sounds by vibrations
  – Fibrous structures covered with mucus membrane
• Vestibular folds
  – Protects vocal cord
• Sound modified & refined
  – Pharynx, paranasal sinus, nasal & oral cavity (lips &
    teeth)
Vocal Cords
Phonation- Vestibular fold & True
         Vocal Cords




    http://oldsite.vislab.usyd.edu.au/CP3/Images/Vocal_chords/cord_movie.html
Sound Modification
                   Trachea
•   Aka Wind pipe
•   4.5” flexible tube
•   Anterior to esophagus
•   Supported by “C” shaped hyaline cartilage
    – Prevents collapse
Trachea Structure
Trachea Structure
                Trachea Function
• Conducts air toward lungs
• Prepares air
   – Filters
   – Warms
   – humidifies
• Ciliated mucous membrane
   –   Ciliary ladder
   –   Mucus lining traps particles
   –   Cilia moves particle laden mucus up
   –   Swallowed
• Branches to both lungs
   – Rt & Lt primary Bronchi
Ciliated mucous membrane
Carina
             Bronchi Structure
• Branching of trachea
  – Carina
     • Internal ridge at bronchi entrance
• Supported with “C” shaped cartilage rings
• Right bronchus
  – Shorter, wider, more vertical
  – More prone to aspirations
  – Divides into 3 secondary bronchi
• Left bronchus
  – Divides into 2 secondary bronchi
Bronchi
Bronchi
                Bronchi tree
• Primary bronchi & all successive branches found
  within lungs
• Secondary bronchi
  – Enter each lung lobe
  – 3 in rt, 2 in lt
• Tertiary bronchi
  – Enter a bronchopulmonary segment
  – Supported by cartilage plate
  – 10 in rt, 8-9 in lt
Bronchi tree
                Bronchus
• Airway that contains cartilage plates
  – Reinforces wall of bronchus
  – Permits flexibility
• As decrease in size cartilage plates
  become reduced and smooth muscle
  increases
• Collapsible wall
Bronchi
Bronchus
Folds for collapsibility
              Bronchiole
• Small branches of bronchiole tree
  – No Cartilage plates
  – Supported by smooth muscle
Bronchiole
                        Bronchiole




No cartilage plates
Diameter less than 0.5 mm can be supported by muscle alone
          Terminal Bronchiole
•   Bronchiole branches
•   ~6,500 terminal bronchioles
•   Lack supportive cartilage
•   Dominated by smooth muscle
    – Controlled by autonomic NS
    – Bronchodialation
      • open
    – Bronchoconstriction
      • closed
Terminal Bronchiole
Terminal Bronchiole
      Respiratory Bronchioles
• Smallest branches of bronchiole tree
  – No Cartilage plates
• Deliver air to gas exchange surfaces
• Lack
  – muscle
  – cilia
  – mucus cells
• Empty into alveoli
  – Exchange surface
  – Small air filled sacs
Respiratory Bronchioles
Respiratory Bronchioles
Respiratory Bronchioles
                 Asthma
• Disease caused by inflammation of airway
  usually due to an allergic reaction
• Muscles of the bronchial tree tighten and
  mucus membranes of air passages swell
• Result in restricted airflow into & out of
  lungs
Asthma
Asthma
Asthma
                          Lungs
• Gas exchange organs
• Delicate structure of Airways, Alveoli, capillaries
• Right lung
   – 3 lobes
   – Superior, middle, inferior
• Left lung
   – 2 lobes
   – Superior, inferior
• Cardiac notch accommodates heart
• Located in separate pleural cavities
Lung
               Alveoli Structure
• 3 cell types
• Epithelial Cells (type I)
   – Simple Squamous
• Alveolar macrophages
   – Phagocytic WBC
   – Engulf inspired particles (dust)
• Surfactant secreting cells (Type II)
   – Secrete surface active agent
   – Surfactant
      • Decreases intra-alveolar surface tension
      • Prevents alveolar collapse
Alveoli Structure
                Type I




Exchange gas with capillaries
Type II aka Septal Cell




Regeneration & surfactant production
Macrophages
Macrophages “Eat” Debris &
        Bacteria




     Macrophages eating soot
Alveoli Structure
             Alveoli Function
• Simple squamous epithelium
• Provide favorable diffusion surface
  – Small diffusion distance
  – Large surface area
     • 300 million alveoli produce ~760 sq ft
• Contribute to respiratory membrane
           Gas Exchange
• Gas exchange between air in alveoli &
  blood in capillaries
• High blood perfusion to lungs
• Alveolar capillaries surround alveoli
Highly Vascularized
Alveoli
Alveolar Capillaries
Alveoli
       Respiratory Membrane
• 2 cell layers of simple squamous
  – Alveolar epithelial cells
  – Capillary endothelial cells
• Total diffusion distance
  – ~0.1 – 1.5 microns
• Efficient diffusion distance
  – Carbon dioxide diffuses into alveoli
  – Oxygen diffuses out of alveoli
Respiratory Membrane
Diffusion distance
                Respiration
• Breathing
• Cycle of inhalation & exhalation
• Involuntary contraction of diaphragm
• Driven by change in pressure
• Body creates negative pressure in body
  cavity
• Regulated chemically
    – Amounts of CO2 in blood stream
                Respiration
• Ventilation
  – Movement of air in & out of lungs
• Systemic respiration
  – Exchange of gas between inhaled air & blood
• Cellular respiration
  – Cell use of O2 to make ATP
                   Ventilation
• Involves changes in pressure to move air in &
  out
• Respiratory muscles
• diaphragm
   – Increases volume of thoracic cavity by “dropping”
     floor
• External intercostal
   – Elevate ribs expanding chest cavity
• Internal intercostal
   – Depress ribs to reduce volume of thoracic cavity
Muscles Associated with Breathing
Diaphragm
Diaphragm
         Serous membranes
• Parietal pleura
  – Lines pleural cavity
• Visceral pleura
  – Covers lung
• Ventilation
  – Movement of chest wall
  – Membranes adhere to each other
  – Movement of chest wall “pulls” lungs open
Ventilation
                Breathing
• Inhalation
  – Rib cage expands- incr volume
  – Diaphragm contracts
  – Negative pressure
  – Air rushes in
• Exhalation
  – Rib cage relaxes- decr volume
  – Diaphragm relaxes
  – Increases pressure IN lungs
  – Air rushes out
Breathing
Breathing
                                  Respiration



http://chickscope.beckman.uiuc.edu/explore/embryology/day15/focuson_humans.html - blank
       Systemic Respiration
• Exchange of gas across respiratory
  membrane
• Passive transport down concentration
  gradient
Systemic Respiration
            Neural control
• Blood gas levels monitored by breathing
  control centers
• Adjust breathing to meet body’s needs
             Lung disease
• Lining of respiratory surface- delicate
• Molecules bind & impair function
• Protected by
  – Mucus
  – cilia
• Lung cancer
• emphysema
              Emphysema
• Alveoli over-inflate because of a
  breakdown of alveolar walls
• Resulting decrease in respiratory function
• 3 million americans
  – 15th most common chronic condition
• Leading cause
  – Cigarette smoking
Emphysema
Emphysema
Smoking is the leading cause of
      death in America
              Pneumonia
• Inflammation of lung tissue
• Bacteria
• Viruses
                    Hiccup
• Spasm of diaphragm
• Rush of air into glottis = “hic”
• Causes
  – Irritation to diaphragm
  – Pressure to phrenic nerve
• Why?
  – Possibly vestigial function
  – Circulate water over gills

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:5
posted:12/4/2011
language:English
pages:144