RESPIRATION

7.2 RESPIRATORY STRUCTURES & BREATHING MECHANISMS IN HUMANS AND ANIMALSRespiratory structures & adaptationsRespiratory structure:The way the different parts of a respiratory system are organized or arranged

Respiratory structures & adaptationsRespiratory surface:Actual exchange of respiratory gases takes placeConsist of a thin & moist membrane where O2 diffuses into the body & CO2 diffuse outCommon characteristics of the respiratory surface:A large surface area to maximized exchange of gasesA moist respiratory surface for gases to dissolve in first before diffusing across the respiratory surfaceA thin respiratory surface for effective diffusion of gasesA network of blood capillaries beneath the respiratory surface (except for protozoa & insects)Breathing Is to maximise the process of gaseous exchangeInvolves pumping movements to ventilate respiratory surfaceDoes not take place in simpler, smaller, organismsRESPIRATORY STRUCTURE OF PROTOZOARespiratory structure of protozoano specific respiratory structureHas high surface area : volume ratio makes diffusion very efficientNo breathing mechanismO2CO2

RESPIRATORY STRUCTURE OF AMPHIBIANSAn amphibian exchanges gases in 3 ways:Cutaneous respirationBuccal respirationPulmonary respirationCutaneous Respiration

Buccal Respiration

Pulmonary Respiration

RESPIRATORY STRUCTURE OF INSECTS

RESPIRATORY STRUCTURE OF FISH

RESPIRATORY STRUCTURE OF HUMANSConsist of:

Nose and nasal cavityPharynxLarynxTracheaBronchi & bronchiolesLungs left & right

Trachea Strengthen by C-shaped cartilage rings which provide structure & keep trachea open

External intercostal musclePull the ribs together, raising the rib cage during inspirationInternal intercostal muscleLower the rib cage during expiration

Mechanism of respirationConsist of:Inhalation Exhalation