7.3 & 7.4-a
TRANSCRIPT
7.3 GASEOUS EXCHANGE ACROSS THE RESPIRATORY
SURFACES AND TRANSPORT OF
GASSES IN HUMANS
THE PROCESS OF GASEOUS EXCHANGE ACROSS THE SURFACE OF THE ALVEOLUS & BLOOD
CAPILLARIES
CO2
O2
High partial pressure of O2 Low
partial pressure of CO2
High partial pressure of O2, Low partial pressure of CO2
High partial pressure of CO2, Low partial pressure of O2
THE TRANSPORT OF RESPIRATORY GASES IN HUMANS
Oxygen
Haemoglobin + Oxygen Oxyhaemoglobin
Lungs
Body cells
THE TRANSPORT OF RESPIRATORY GASES IN HUMANS
Transport of CO2
Blood plasma
Carbominohaemoglobin
Biocarbonate ions
7%
23%
70%
THE TRANSPORT OF RESPIRATORY GASES IN HUMANS
Carbon dioxide
CO2 from cell
Blood plasma
Diffuse into
Red blood cell
Diffuse into
Combine with H2O
Form carbonic acid (H2CO3)
H+H2CO3
Diffuse into
Blood plasmaLungs
Blood plasma
Diffuse intoRed blood
cell
Form carbonic acid (H2CO3)
CO2
H2O
Diffuse out of blood
capillaries
AlveoliExpelled during
exhalation
THE EXCHANGE OF RESPIRATORY GASES BETWEEN THE BLOOD AND BODY CELLS
COMPOSITION OF INHALED AND EXHALED AIR
Components of air
Inhaled air Exhaled air
Oxygen 21% 16%
Carbon dioxide 0.03% 4%
Nitrogen 78% 78%
Water vapour Varies More
Dust particles Varies Usually none
Temperature Varies 37OC
7.4 THE REGULATORY MECHANISM IN RESPIRATION
THE RELATIONSHIP BETWEEN THE RATE OF RESPIRATION AND THE OXYGEN AND
CARBON DIOXIDE CONTENTS
Vigorous exercise
Muscle cells need more oxygen & glucose to release energy during cellular respiration
Rate of cellular respiration increases
The oxygen content decreases while carbon dioxide content increases
THE RELATIONSHIP BETWEEN THE RATE OF RESPIRATION AND THE OXYGEN AND
CARBON DIOXIDE CONTENTS
Breathing rate increases
Heartbeat rate increases
More oxygen & glucose can be supplied & more carbon dioxide can be removed from the cells
Rate & depth of breathing increases
THE HUMAN RESPIRATORY RESPONSE AND RATE OF RESPIRATION IN DIFFERENT
SITUATIONS
At rest
Breathing rate
16 – 18 breaths per minute
Heartbeat rate
60 – 70 beats per minute
Ventilation rate
5 dm3 per minute
Vigorous exercise
THE HUMAN RESPIRATORY RESPONSE AND RATE OF RESPIRATION IN DIFFERENT
SITUATIONS
Breathing rate
About 30 breaths per minute
Heartbeat rate
About 120 breaths per minute
Ventilation rate
50 - 60 dm3 per minute
In fear
The breathing & heartbeat rates increase
Rate of respiration is higher to produce more energy
Adrenal glands secrete the hormone adrenaline
Adrenaline increases heartbeat rate & breathing
THE HUMAN RESPIRATORY RESPONSE AND RATE OF RESPIRATION IN DIFFERENT
SITUATIONS
THE REGULATORY MECHANISM OF OXYGEN AND CARBON DIOXIDE
CONTENTS
THE REGULATORY MECHANISM OF OXYGEN AND CARBON DIOXIDE
CONTENTS
Partial pressure of CO2 increase
Vigorous exercise
CO2 + H2O -> carbonic acid
Drop in pH
Central chemoreceptors
Detected by Respiratory centreNerve impulse
Respiratory muscles contrast & relax faster
Increased breathing & ventilation
Excess CO2 removed
Normal CO2 level & pH
THE REGULATORY MECHANISM OF OXYGEN AND CARBON DIOXIDE
CONTENTS
THE REGULATORY MECHANISM OF OXYGEN AND CARBON DIOXIDE
CONTENTS
THE REGULATORY MECHANISM OF OXYGEN AND CARBON DIOXIDE
CONTENTS
Drop in O2 levels
High altitude
Peripheral chemoreceptors
stimulated
Respiratory centre
Nerve impulse Respiratory muscles contrast & relax faster
Increased breathing & ventilation
More O2 inhaled
Normal O2 level