gaseous exchange

GASEOUS EXCHANGEGASEOUS EXCHANGE

Respiratory surface

Respiratory System in Human

Control of breathing

Gaseous exchange in Insect

Gaseous exchange in Fish

Gaseous exchange in Plant

Respiratory surfaceRespiratory surface

Small organisms surface volume ratio is large

Larger organism surface volume ratio is small

Characteristics of respiratory Characteristics of respiratory surfacesurface

1. Large surface area

2. Moistened surface

3. Thin and freely permeable to gases

4. With transport system

TypesTypes

Human Respiratory SystemHuman Respiratory System

Lung tissueLung tissue

Mechanism of BreathingMechanism of Breathing

Animation

Treatment to inhaled airTreatment to inhaled air

1. Warmed by capillary in nostrils

2. Moistened by mucus

3. Cleaned and filtered by hair, cilia and mucus

Lung capacitiesLung capacities

Volum

e of air

Control of BreathingControl of Breathing

Respiratory centre

Chemoreceptor

pCO2

chemoreceptorchemoreceptor1. Peripheral chemoreceptor

Detect both Po2 and PCO2

Carotid bodies, aortic bodies

2. Central chemoreceptors

Detect PCO2

Medulla

Effect of PCO2 is larger than Po2

Respiratory centreRespiratory centre

In medulla oblongataReceive impulse from chemoreceptorSend impulse to diaphragm and intercostal muscleChange rate and depth of breathing

Effect to lungEffect to lung

pO2 decrease and pCO2 increase rate and depth of breathing increase

pO2 increase and pCO2 decrease

Rate and depth of breathing decrease

Other effectOther effect

pCO2 increase

Heart : rate increaseBlood vessel: vasodilationIncrease rate and volume of CO2 transport

Partial pressure of COPartial pressure of CO22

pCO2 increase

Detected by chemorecetor

Impulse to respiratory centre

Impulse to intercostal and diaphragm muscle by efferent nerve

Rate and depth of breathing increase pCO2 back to normal

Feedback

Gaseous Exchange in insectsGaseous Exchange in insects

Mechanism

Abdomen movement, fluid movementAbdomen movement, fluid movement

Trachea Trachea

Spiracle Spiracle

During exercise less

fluid

During exerciseDuring exerciseDuring rest more fluid

Breathing in fishBreathing in fish

Gill Gill

Gill photoGill photo

Where is gaseous exchange Where is gaseous exchange taking place?taking place?

Buccal surface

Skin Gill in tapole

Bird Bird

Gaseous Exchange in PlantGaseous Exchange in Plant

No special organ for breathing but some special features in various

organs for increasing surface area

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Stem

Root

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Root HairRoot Hair

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