11. Gas Exchange in Humans Flashcards

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1
Q

Function of cartilage and trachea

A

supports trachea and prevents it from closing

without it, the sides would collapse inwards when air pressure inside tube drops

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2
Q

features of efficient gas exchange surfaces in humans (4)

A
  • large SA
  • thin surface = shorter diffusion dist
  • good blood supply
  • good ventilation with air
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3
Q

Explain the differences in composition between inspired and expired air

A

INSPIRED, EXPIRED
Oxygen 21%, 16%
O2 is absorbed into the blood in alveoli; used in respiration - CO2 produced

CO2 0.04%, 4%
released from blood (CO2 produced as a waste product) at alveoli (conc in blood > air)
- diffuses out in lungs before exhaled

Nitrogen 78%, 78%
body doesn’t absorb - too stable

Water Vapour lower, higher
evaporates from moist living alveoli, result of the warmth of the body

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4
Q

Test for carbon dioxide

A

limewater = Ca(OH)2

+ve result/ CO2 present - turns cloudy/milky
-ve - remains colourless

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5
Q

Role of goblet cells (2)

A

found in TRACHEA & BRONCHI

produce mucus into respiratory tract

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6
Q

role of mucus (2)

A
  • produced by goblet cells

- traps bacteria, dust, particles

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7
Q

role of cilia

A

beat and

push the mucus away from the lungs towards the throat

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8
Q

Ventilation of the lungs - in

A

Breathing in (inhalation/inspiration)

  • EXTERNAL INTERCOSTAL MUSCLES CONTRACT, internal - relax
  • ribcage moves up and out
  • DIAPHRAGM CONTRACTS and flattens = pushes abdominal muscles inwards
  • vol of thorax increases
  • PRESSURE inside thorax + conc of air decrease
  • air diffuses into lungs

conc of air in lungs < air

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9
Q

Ventilation of the lungs - out

A

Breathing out (exhalation/exspiration)

  • INTERNAL INTERCOSTAL MUSCLES CONTRACT
  • ribcage moves down and in
  • DIAPHRAGM RELAXES and becomes dome-shaped
  • vol of thorax decreases
  • PRESSURE inside thorax increases
  • air is forced out
    = passive process
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10
Q

Explain the link between physical activity and rate and depth of breathing

A

increased carbon dioxide concentration in the blood, detected by the brain, causing an increased rate of breathing

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