Adaptations in gas exchange Flashcards

1
Q

What are the blood vessels connecting to the alveoli (1)

A
  • to the alveoli - pulmonary artery
  • away from the alveoli - pulmonary vein
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2
Q

State two important structural features of the alveoli (2)

A
  • the alveoli in one cell thick
  • large surface area / highly folded
  • large number of capillaries
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3
Q

Briefly explain how inspiration is brought about (2)

A
  • contraction of intercostal muscles and diaphragm
  • ribcage moves up ant out
  • diaphragm flatter / contract
  • increase volume and decreased pressure so air moves into lungs
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4
Q

Describe three features of fish gills which allow them to achieve efficient fas exchange (3)

A
  • large surface area
  • short diffusion pathway
  • permeable
  • good blood supply
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5
Q

Explain how bony fish have overcome the problems of oxygen uptake in water (4)

A
  • water is forced over the gill by continous sswimming
  • counter current flow of blood and water
  • diffusiongradient is maintaines
  • over the entire gill surface
  • haemoglobin has a high affinity for oxygen
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6
Q

Explain why large mult cellular organisms have evolved special surfaces for gaseous exchange (3)

A
  • metabolic needs
  • large organisms need more oxygen
  • external surfae insufficieint for gas exchange
  • diffusion is proportional to surface area
  • surface area to volume ration is to small
  • diffusion distances are too larfe
  • oxygen cannot diffuse fast enough
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7
Q

Describe and explain how terrestrial mammals are adapated for gas exchange in air (7)

A
  • large number of alveoli to increase surface area
  • internal lungs
  • to reduce heat loss
  • thin walls reduce diffusion ditance
  • gas exchange takes plac in the alveoli
  • kayer of moisture - to allow gases todissolve
  • good blood supply maintain concentration gradient
  • haemoglobin in bloood transports oxygen
  • ventilation mechanism
  • enable continuous exchange of gases
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8
Q

Describe and explain the process of inspiration in a mammal (4)

A
  • intercostal muscles contract aand ribs move up and out
  • diaphragm contract and flattens
  • volume of thorax increases
  • pressure in lungs decreases
  • higher air presure outside draws air into lungs
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9
Q

Explain how counter current flow works in the gills of bony fish (4)

A
  • blood flows across gills in opposite direction to water
  • water always has more oxygen than blood
  • so concentration gradient is maintained
  • oxygen passes from water into blood
  • across entire gas exchange surface
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10
Q

Name the type of flow when percentage saturation with oxygen reaches equilibrium (1)

A

parallel flow

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11
Q

Explain why parallel flow is less efficient than counter current flow (2)

A
  • equilibrium is reached part way across fill lamellae and gradient is not maintained
  • percentage saturation can only reach 50% / equilibrium
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12
Q

Suggest why gill filaments/ gill laemellae would not provide and efficient gas exchange surface on land (2)

A
  • gills dry out
  • prevent oxygen from dissolving on surface of gills
  • gillss may collape decreasing surface area
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13
Q

Describe three properties that all respiratory surfaces must possess and explain why they must have them (3)

A
  • thin - short diffusion pathway
  • large ssurface area - for gas exchange / diffusion
  • moist - allow gases to dissolve
  • permeable - tp allow gases to pass through
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14
Q

Suggest how this frog carries out gas exhcange wihtout lungs (1)

A

Through the skin

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15
Q

How do the conditions in the moutnain stream aid gas exchange (2)

A
  • fast flowing
  • maintains a concentration gradient
  • absorbs more oxygen
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16
Q

Give two reassons why gills do not function effectivley on land (2)

A
  • they dry out
  • they collapse
17
Q

Define counter current flow as seen in the fills of bondy fish and explain why counter current flow makes gas exchange more efficient (3)

A
  • blood flows in opposite direction to water
  • concentration gradient is maintained constantly / equilibrium is never reached
  • a greater concentration of oxygen in the blood is achieved allows more oxygen to diffuse in
18
Q
A