Gas Exchange in Humans Flashcards

1
Q

Explain the functions of the human gas exchange system

A

To allow a large volume of oxygen and carbon dioxide to be exchanged between the blood and the environment. The gases are needed and produced by respiration

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2
Q

Explain why mammals have to absorb large volumes of oxygen and release large volumes of carbon dioxide

A
  • They are large and have a large volume of living cells.
  • They have a high metabolic rate and respiratory rate
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3
Q

Describe the trachea

A

flexible airway supported by cartilage to prevent collapse
walls contain muscle and are lined with ciliated epithelium and goblet cells

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4
Q

Describe the bronchi

A

two divisions in trachea leading to a lung each
produce mucus to trap dirt particles and cilia to move the mucus

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5
Q

Describe bronchioles

A

branching subdivisions of bronchi
muscle in walls to control air flow in and out of alveoli

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6
Q

Describe alveoli

A

air sacs 200 micrometres in diameter at the end of the bronchioles.
collagen and elastic fibres between alveoli.
alveoli lined with epithelium.
the elastic fibres allow the alveoli to stretch and recoil

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7
Q

List (in order) the structures that air passes through on its journey into the lungs

A
  • lungs
  • trachea
  • bronchi
  • bronchioles
  • alveoli
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8
Q

What happens when the external intercostal muscles contract?

A

the contraction leads to inspiration, it causes the ribs to move up and outwards

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9
Q

Describe the process of inspiration

A
  • External intercostal muscles contract, internal intercostal muscles relax
  • the ribs move up and outwards, increasing the volume of the thorax
  • the diaphragm contracts and flattens, increasing the volume of the thorax
  • the pressure in the lungs is reduced
  • atmospheric pressure is greater (than inside the lungs) so air is forced into the lungs
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10
Q

Describe the process of expiration

A
  • internal intercostal contract, external intercostal relax
  • ribs move down and in
  • volume of thorax decreases
  • pressure increases
  • air moves out, moving down pressure gradient
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11
Q

Why do organisms need oxygen?

A

acts as final electron acceptor in aerobic respiration which allows energy to be released in the form of ATP

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12
Q

Give 2 reasons why the lungs are located inside the body

A
  • air is not dense enough to support these structures
  • the body would lose a great deal of water and dry out
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13
Q

What is the purpose of cartilage in the trachea?

A

to prevent the tube from collapsing when air pressure falls

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14
Q

How do cells lining the trachea protect the alveoli from damage?

A
  • cells produce mucus
  • traps dirt, mucus is moved up by cilia
  • if dirt/bacteria entered alveoli, could damage them/cause infection
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15
Q

Which type of inter-costal muscle CONTRACTS to allow for EXPIRATION?

A

internal

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16
Q

Which type of inter-costal muscle CONTRACTS to allow for EXPIRATION?

A

internal

17
Q

How do thin walls in the alveoli allow for rapid diffusion?

A

short diffusion distance/pathway

18
Q

What are 4 features of the alveoli that make them efficient for gas exchange?

A
  • thin walls
  • many of them contained within the lungs
  • covered in lots of capillaries
  • pulmonary capillaries are very narrow
19
Q

What is emphysema?

A

damage to the walls of alveoli, caused by smoking or air pollution. This reduce the surface area for gas exchange

20
Q

What 3 factors impact the rate of gas exchange in lung conditions?

A
  • decreased surface area
  • decrease concentration gradient
  • increased diffusion distance
21
Q

What is vital capacity?

A

maximum amount of air that can be exhaled and inhaled in a single breath

22
Q

What is vital capacity?

A

maximum volume of air that can be inhaled or exhaled in a single breath

23
Q

What is tidal volume?

A

the volume of air we breathe in and out at each breath at rest

24
Q

Why would death of alveolar cells lead to impacted gas exchange?

A
  • increased diffusion distance
  • reduced surface area
  • less gas exchange
25
Q

How would reduced tidal volume impact CO2 in blood?

A
  • less CO2 breathed out
  • smaller concentration gradient
  • less CO2 moves out of blood