ANSC 3050 Final: Animal Physiology 3080 Final Notes

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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
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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)
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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)
- Follos las of Phsis: flo fo high to lo pessue = depeds o ΔP
Resistance to flow (R): due to friction of air particles with each other
If R↑ ΔP↑ to aitai ai flo
If ΔP↓ R↓
Ventilation Pump (mechanics)
- Compression/epasio of the lugs  espiato usles = otols 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
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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.

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