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Topic 3A: Exchange and Transport Systems > Gas Exchange in Humans > Flashcards

Gas Exchange in Humans Flashcards

1
Q

Why do humans need to get oxygen into blood?

A

For respiration

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2
Q

What do they need to get rid of made by respiring cells?

A

Carbon dioxide

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3
Q

Where does air enter as soon as you breathe in?

A

Enters into the trachea (windpipe)

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4
Q

What is the trachea spilt into?

A

Bronchi- one bronchus leading to each lung

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5
Q

Where do the bronchioles end in small air sacs called what?

A

Alveoli (gas exchange takes place)

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6
Q

What do the ribcage, intercostal muscle and diaphragm work together to do?

A

Move air in and out

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7
Q

What does ventilation consist of?

A

Inspiration

Expiration

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8
Q

What is an inspiration?

A

Breathing in

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9
Q

What is expiration?

A

Breathing out

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10
Q

What is ventilation controlled by movements of?

A
  • Diaphragm
  • Internal and external intercostal muscles
  • Ribcage
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11
Q

Diagram of inspiration

A
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12
Q

Process of inspiration

A
  • The external and diaphragm muscle contract
  • Cause ribcage to move upwards and outwards causing the diaphragm to flatten
  • Increasing volume of thoracic cavity
  • As volume of thoracic cavitiy increases , pressure decreases (below atmospheric pressure)
  • Air flows from an area of higher pressure to an area of lower pressure (down a pressure gradient)
  • Air flows down the trachea and into the lungs
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13
Q

What type of process is an inspiration?

A

An active process - requires energy

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14
Q

Diagram of expiration

A
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15
Q

Process of expiration

A
  • External intercostal and diaphragm muscle relax
  • Ribcage moves downwards and inwards and diaphragm becomes curved again
  • The volume of the thoracic cavity decreases, causing pressure to increase (above atmospheric pressure)
  • Air is forced to down the pressure gradient (high to low) and out of lungs
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16
Q

What type of process is normal expiration?

A

It is a passive process -it doesn’t require energy

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17
Q

Example of expiration being forced

A

Blowing out candles on your birthday cake

18
Q

Process of forced expiration

A
  • External intercostal muscles relax
  • Internal intercostal muscles contract, pulling ribcage further down and in
  • During this time, the movement of the two sets of intercostal muscles are said to be antagonistic (opposing)
19
Q

What is each alveolus made up of?

A

A single layer of thin, flat cells called alveolar epithelium

20
Q

What is the resting shape of the diagram?

A

Curved - dome position

21
Q

What is the alveoli surrounded by?

A

By a network of capillaries

22
Q

How does oxygen move in humans?

A
  • Oxygen from the air moves down the trachea, bronchi and bronchioles into the alveoli
  • This movement happens down a pressure gradient
  • Once in alveoli, 02 diffuses across the alveolar epithelium and the capillary endothelium into capillary itself
  • Into the haemoglobin in the blood
  • Happens down a diffusion gradient
23
Q

How does c02 move in alveoli?

A

Diffuses into the alveoli from the blood and is breathed out

24
Q

How is alveoli adapted?

A
  • A thin exchange surface: - alveolar epithelium is only one cell thick. There is short diffusion pathway (increase diffusion)
  • Large surface area : Large number of alveoli - large SA for gas exchange
25
Q

How is gas exchange adapted?

A

Steep concentration gradient of oxygen and carbon dioxide between alveoli and capillaries increasing the rate of diffusion

this is constantly maintained by the flow of blood and ventilation

26
Q

Describe two ways in which lungs are adapted for efficient gas exchange

A
  • Lungs contain millions of tiny air sacs called alveoli - creating large surface area for gas exchange
  • Alveolar epithelium is only one cell thick , a short diffusion pathway
  • Alveoli is surrounded by a dense network of capillaries which maintains a steep concentration gradient of oxygen and carbon dioxide between alveoli and blood
27
Q

Does capillaries have thin epithelium?

A

Yes

offering short diffusion pathway

28
Q

What is the ventilation?

A

Bring in air with high concentration of C02 replaces air with low concentration of C02

29
Q

What is circulation?

A

Replaces blood high in oxygen with blood low in 02

30
Q

Why does the volume of oxygen that has to be absorbed and the volume that must be removed are large in mammals?

They have evoled specialised surfaces called lungs for gas exchange between air and blood

A
  • Relatively large organisms with a large volume of living cells
  • Maintain a high body temperature which is related to this having high metabolic and respiratory rates
31
Q

Why are the lungs site of gas exchange inside of the body?

A
  • Air is not dense enough to support and protect these delicate structures
  • Body as a whole would otherwise lose a great deal of water and dry out
32
Q

List in the correct sequence all structures that air passes through on its journey from the gas-exchange surface of the lungs to the nose

A

Alveoli

Bronchioles

Bronchus

Trachea

Nose E

33
Q

How is the cartilage important supporting the trachea?

A

Prevents the trachea collapsing as the air pressure inside falls when breathing in

34
Q

What is the tracheal walls made up of?

A

Muscle lined with ciliated epithelium and goblet cells

35
Q

Advantage of bronchi

A
  • Produce mucus to trap dirt particles and have cilia that move the dirt-laden mucus towards the throat
36
Q

What are the walls of bronchioles made up of?

A

Walls lined with epithelial cells

Muscle allow to constrict so they can control their flow of air in and out of alveoli

37
Q

How has alveoli having collagen and elastic fibres important?

A

Allow alveoli to stretch as they fill with air when breathing in

Spring back during breathing in order to expel the C02

38
Q

Explain how the cells lining the trachea and bronchus protect the alveoli from damage?

A

The cells produce mucus that traps particles of dirt and bacteria in the air breathed

Cilia on these cells move this debris up into the trachea and into the stomach

39
Q

Explain why these figures in table were given per gram of tissue

A

Easier for comparison

Organs differ in size

40
Q

There is a greater percentage reduction in blood flow to the diaphragm than the lungs during dive. Explain the advantage to a diving seal of :

Blood continuing to flow the lungs

A

Some oxygen still in lungs

41
Q

There is a greater percentage reduction in blood flow to the diaphragm than the lungs during dive. Explain the advantage to a diving seal of :

Large reduction in blood flow to the diaphragm

A

There is more blood for other organs to remove C02

42
Q

A mountain climber is climbing at altitiude where there is less oxygen

Suggest how this will affect gas exchange in alveoli

A

Less air - less oxygen would be inhaled in each breath

The concentration gradient of oxygen between alveoli and capillaries are less steep

Slowing rate of diffusion

Topic 3A: Exchange and Transport Systems (9 decks)

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