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RESPIRATORY SYSTEM - Coggle Diagram
RESPIRATORY SYSTEM
GAS EXCHANGE: is the process of moving CO2 and O2 in opposite directions between environment, bodily fluids and cells
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ATMOSPHERIC PRESSURE: is the pressure exerted by the atmosphere on the body surfaces of animals (mmHg)
- decreases at higher elevations
- gases expand and fewer gas molecules are in a given volume of air
PARTIAL PRESSURE is the pressure exerted by each gas in air
- % gases remain same regardless of altitude, but lower atmospheric pressure results in lower partial pressures
- diffusion is driven by partial pressure gradients
- gases move from regions of high pressure to low pressure
- Rate of Oxygen diffusion into blood islower at higher elevations
SOLUBILITY OF GASES
- gases dissolve in water
- most gases dissolve poorly in water
TYPES OF RESPIRATORY SYSTEMS
- Gas- exchange mechanisms
- across body surface
- gills
- tracheae
- lungs
- VENTILATION is the process of bringing oxygenated water or air into contact with gas-exchange organ
GILLS
- specialised respiratory structures
- EXTERNAL
- uncovered bodily extensions
- large surface area with extensive projections
- limitations
unprotected to damage
energy required to wave gills back and forth
appearance and motion can attract predators
- INTERNAL
- covered by operculum
- Gill arches: main support structure composed of lamellae
- Blood vessels run length of filaments
- countercurrent exchange of water and blood maximises oxygen diffusion into blood
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TRACHEAL SYSTEMS
- found in insects - spiracles on body lead to tracheae that branch into tracheoles
- small amount of fluid/ gas to diffuse
- body muscles draw air in and out
- open circulatory system not used in gas exchange
- oxygen diffuses directly
- efficient
LUNGS
POSITIVE PRESSURE FILLING
- By expanding mouth cavity creating a pressure gradient
- air moves from high pressure atmosphere into lower pressure mouth
- closing mouth raises pressure, forcing air into lungs
NEGATIVE PRESSURE FILLING
- Volume of lungs expand, creating negative pressure, and air is drawn into lungs#
- mammals: external intercostal muscles and diaphragm provide work
- During exercise rate of ventilation increases and helps empty lungs
STEPS IN VENTILATION
- external intercostal muscles contract during inhalation(expands thoracic cavity)
- Diaphragm lowers during inhalation, allows expansion of thoracic cavity
- Air flows in during inhalation, air pressure in lungs lower than outside
- air flows out when muscles relax and thoracic cavity is compressed
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ADAPTIONS FOR GAS EXCHANGE
- moist surfaces for gases to dissolve and diffuse
- high surface area for gas exchange
- extensive blood circulation
- thin, delicate structure
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WATER BREATHING VS. AIR BREATHING
- AQUATIC
- Less available oxygen
- when temps change, oxygen availability fluctuates
- dense water moving over respiratory membranes requires more energy
- water removes heat from gill surface and creates an osmotic movement
STRUCTURE AND FUNCTION OF MAMMALIAN RESPIRATORY SYSTEM
- Nose and mouth
- pharynx
- larynx
- trachea
- bronchi
- bronchioles
- alveoli
ALVEOLI
- type I cells: gases diffuse across
- type II cells : secretory cells
SURFACTANT
- Type II cells produce surfactant
- protein and amphipathic lipids
forms barrier between air and fluid layer inside alveroli
- reduces surface tension
PLEURAL SAC
- Double Layer
- fluid between each layer, acts as lubricant in order to make layers stick to each other
O2 HEMOGLOBIN DISSOCIATION CURVE
- PO2 is high more O2 binds to hemoglobin
- PO2 is low, less O2 binds to hemoglobin
- shape of hemoglobin changes as oxygen loads and unloads