ANSC 3050 Final: Animal Physiology 3080 Final Notes
11 Jan 2017
School
Department
Course
Professor
Agricultural Animal Physiology
Respiratory I: Structure and Function
Function of the Respiratory System
Respiratory Function: Gas transport for metabolism
- Move O2 from the air to pulmonary blood
- Clearance of CO2
Non-Respiratory Function: Filter blood
- Lungs receive 95% cardiac output (right heart)
- Filter blood, chemical processing, maintenance and defences (part of first line of defense)
- Facilitate venous return (respiratory pump)
Definitions
Respiration = interchanges of gases between atmosphere and the cells of the body
Ventilation (Breathing) = transport of air to and from the lungs
Gas Exchange = O2/CO2 exchange between the air in the lungs and cells in the body
Cellular Respiration = oxidation of cellular molecules that produces CO2, water and ATP
Overall Gas Transport
(1) Ventilation: movement of bulk airflow, delivering air to the respiratory zone where gas exchange
occurs
(2) Lung Diffusion: gas exchange between respiratory zone and blood – O2 moves across alveolar
membrane -> rbc reverse process for CO2
(3) Circulation (Blood <-> tissues): requires adequate function of the pulmonary and systemic
circulations
(4) Tissue Diffusion: Erythrocyte/plasma <-> tissue cells = passive diffusion
(5) Internal respiration: metabolism using O2 and producing CO2
Ventilation – air transported into airways from the atmosphere to the respiratory zone of the lungs
Airways = system of tubular structures
Nasal, oral cavities > Pharynx, larynx > Trachea > Bronchi > Bronchioles > Alveoli (Gas Exchange!)
Main Functions:
Delivering gas to respiratory zone (alveoli)
Conditioning of the inhaled air: air warmed to core body temp. (Prevents temp. shock in the
alveoli)
Gas humidification: Saturation with vapour to prevent dehydration of the respiratory epithelium
in alveoli
Filtration Cleansing: prevents foreign objects and microorganisms to enter the lungs
find more resources at oneclass.com
find more resources at oneclass.com
Structures:
Nasal/oral cavities: inner surface: mucous membrane that warms and humidifies air
-Some hair in nostrils ~ some species acts as filtration
-Epithelium contains ciliated cells and mucus cells (goblet): traps foreign objects, moves mucus
towards pharynx)
Pharynx: connection between nasal/oral cavity and larynx
Larynx: connects pharynx and trachea: glottis and epiglottis ~ cartilage that prevents food from
entering trachea
-contains vocal cords
Trachea: Flexible tube kept open by cartilage rings
-inner surface lined with ciliated and mucus cells
-mucus traps particles and coordinated cilia push trash back towards pharynx
Bronchi: possess cartilage plates to maintain the shape
-1 tube /lung – primary bronchi then branches off to narrower tubes
Bronchioles: lack cartilage ~ depend on lung recoil to maintain potency (smooth muscle)
Airway Cross-sectional Area:
- Increases dramatically moving from trachea to respiratory zone
-geometric increase in number of small airways, reduces velocity of airflow to virtually 0
-movement of gas in respiratory zone by diffusion only
Velocity = flow/cross-section area
Airway clearance:
- Cilia and goblet cells work to move thin sheet of mucus from lower parts of lungs to the throat
regions
Defensins: Lysol~ destroys bacteria (first line of defence)
Alveoli (Respiratory Zone)
- Clusters around terminal bronchioles
- Formed by a single layer of epithelia cells
- Surrounded by capillary network
- Air separated by 2 layers of cells (epithelium and endothelium) ~ best for gas exchange
- Some Epithelial cells (Type II) produce fluid: surfactant which reduces surface tension
- If small particles reach alveoli = Phagocytized by macrophages (immune defense)
find more resources at oneclass.com
find more resources at oneclass.com
Thoracic Cavity: space with thoracic cage between:
Thoracic vertebras, Ribs and intercostal muscles, sternum
Diaphragm: separate thoracic and abdominal cavity, sheet of skeletal muscles and tendon
Mediastinum: Divide thoracic cage in 2 halves
- Connective tissues containing vessels, nerves, trachea, esophagus and heart (everything but
lungs)
- Each lung fills 2 half
Plural Membranes: wet epithelial surfaces, cover lungs
Intrapleural space: filled with small amount of fluid = lubrication
Ventilation: Resistance & Change of Pressure (P)
- Follos las of Phsis: flo fo high to lo pessue = depeds o ΔP
Resistance to flow (R): due to friction of air particles with each other
If R↑ ΔP↑ to aitai ai flo
If ΔP↓ R↓
Ventilation Pump (mechanics)
- Compression/epasio of the lugs espiato usles = otols ΔP
Inspiration = active mechanism
-Diaphragm contracts-> expands thoracic volume, creates negative pressure -> lungs expand ->
Increase in alveolar volume -> negative pressure gradient facilitates flow down airways
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Move o2 from the air to pulmonary blood. Filter blood, chemical processing, maintenance and defences (part of first line of defense) Respiration = interchanges of gases between atmosphere and the cells of the body. Ventilation (breathing) = transport of air to and from the lungs. Gas exchange = o2/co2 exchange between the air in the lungs and cells in the body. Cellular respiration = oxidation of cellular molecules that produces co2, water and atp. Ventilation air transported into airways from the atmosphere to the respiratory zone of the lungs. Nasal, oral cavities > pharynx, larynx > trachea > bronchi > bronchioles > alveoli (gas exchange!) Conditioning of the inhaled air: air warmed to core body temp. (prevents temp. shock in the alveoli) Gas humidification: saturation with vapour to prevent dehydration of the respiratory epithelium in alveoli. Filtration cleansing: prevents foreign objects and microorganisms to enter the lungs. Nasal/oral cavities: inner surface: mucous membrane that warms and humidifies air.
