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LU 7: RESPIRATORY SYSTEM FIKRI (50609) RHYNIER (53699) (GAS EXCHANGE IN…
LU 7: RESPIRATORY SYSTEM
FIKRI (50609)
RHYNIER (53699)
RESPIRATION:
process of obtaining oxygen and eliminating carbon dioxide
CELLULAR RESPIRATION:
process of oxidising food molecules to produce energy, carbon dioxide and water.
GAS EXCHANGE IN ANIMALS
ACROSS BODY SURFACE
Phylum Cnidaria
maximize diffusion: thin tissue layer, circulate water across outer surface
Limitation:
: small size
: not involve energy-consuming activities
CUTANEOUS RESPIRATION (skin)
Primary system: Phylum Annelida, many amphibians
Supplementary system for larger animals
To maximize diffusion: thin skin, increase surface area, use of cilia to move water
Limitation:
: cannot get too large
: no energy expensive activities
TRACHEAL TUBE SYSTEM
Phylum Arthropods
tracheal tubes open to outside along body surface
gaseous exchange between tracheoles & body cells.
high metabollic rates
BOOK LUNG
Phylum Arachnid (spiders, scorpions)
hemolymph in lamellae (stakes)
air move in (between lamellae)
gasses exchange occur between haemolymph
quickly runs out of oxygen
GILLS
INTERNAL GILLS
Phylum Chordata
bony fish (class Osteichthyes)
enclosed (water move over gills)
Buccal cavity (mouth), Opercular cavity (gill chamber)
maximise diffusion:
: moist, thin gills
: high surface area
: water pumped constantly
: countercurrent exchange (maximises gradient of gases diffusion)
Limitation:
: not work on land
: less-bouyant air needed
: gas exchange must occue in water (moist surface)
EXTERNAL GILLS
Phylum Chordata
larval fish, amphibians, some salamander
maximise diffusion:
: thin gills
: high surface area (skin as additional respiratory surface)
Limitation:
: constant motion or in water current
: tissue delicate (unprotected)
: small body size
PROCESS IN TERRESTRIAL VERTEBRATES
1) Pulmonary ventilation (breathing)
2) External respiration
3) Transportation of gases
4) Internal Respiration
5) Cellular respiration
CONTROL OF BREATHING
by medulla oblongata (monitors carbon dioxide in blood)
high carbon dioxide: nerve impulse cause diaphragm contraction, air entering lungs
carotid body (arteries): receptors that activated when O2 drop (no increase of C02 production)
PULMONARY GAS EXCHANGE
occur in alveolus
O2 diffuses into blood
O2 distributed to cells, CO2 back to lungs
CO2 in blood diffuses into alveolus
ALVEOLI
-big surface area
moist, thin (one cell thick)
rich of capillaries
diffusion occur
TYPE OF BREATHING & LUNG VENTILATION
Eupnea: normal
Hyperventilation & hypoventilation: rate changes/depth
Hyperpnea: increase of CO2 production
Apnea: absence of breathing
Dyapnea: labored (breathlessness)
Polypnea: increase breathing rate but not beathing depth
TERRESTIAL VERTEBRATES (LUNG)
MAMMALS
enormous surface area
elaborate network of thin air sacs
AMPHIBIANS
frogs and toads
increase surface area (ridges of connective tissues)
REPTILES
simple sacs, folding of wallto increase surface area(not very efficient)
diaphragm absent
Inhalation: ribs move cranially & ventrally, internal pressure control entering of air
passive exhalation: muscle relaxes
SEA TURTLES
uses of muscles
pleural pressure: control by contraction and relaxation of abdominal, pelvic and pectorial muscles
some turtle underwater: gas exchanges in cloaca & oral cavity (hibernation & long dives)
BIRDS
aerodynamic valving
extremlely efficient lungs (parabronchi)
air sacs: allow unidirectional flow (parabronchi)
volume changes: rocking motion (sternum against column) and lateral movement of posterior ribs
mesobronchus: bidirectional air flow
OXYGEN TRANSPORTATION
combine with hemoglobin (oxyhemoglobin
low percentage dissolve in blood plasma (2%)
CARBON DIOXIDE TRANSPORTATION
Modification into bicarbonate ions (60%)
carbaminohemoglobin: small percentage of CO2 bound to protein (30%)
low amount dissolved in blood plasma (10%)
FACTOR AFFECTING OXYGEN BINDING
temperature
pH
Organic Phosphate
others: altitude, free radicals, heavy metals, carbon monoxide
Rate of Respiration
R=D
x
A ▲P/d