Gas Exchange

?
  • Created by: Lotto65
  • Created on: 25-03-17 16:27
How do the lungs make up for the fact that alveoli are really small?
They have hundreds of millions of them
1 of 89
What four properties do gas exchange surfaces have?
Permeable to oxygen and carbon dioxide, thin, large SA, moist
2 of 89
Why is it useful that gas exchange surfaces are moist?
To allow oxygen to dissolve
3 of 89
Why is it useful that gas exchange surfaces are thin?
Short diffusion path
4 of 89
What process is going to take place and be improved by a large SA?
Diffusion
5 of 89
How thin are type 1 pneumocytes?
Extremely thin
6 of 89
Are type 1 pneumocytes permeable?
Yes
7 of 89
What are type 1 pneumocytes adapted for?
Efficient gas exchange
8 of 89
Which type of pneumocyte does the alveolus wall consist of mainly?
Type 1 pneumocytes
9 of 89
How many layers of pneumocytes are there in the alveoli?
1
10 of 89
What are the gas concentration levels of the capillaries surrounding alveoli?
High carbon dioxide concentration but low oxygen concentration
11 of 89
Why are the gas concentration levels in the capillaries important?
Maintains steep concentration gradient to allow oxygen to diffuse into the blood from the alveolus and to allow carbon dioxide to diffuse out of the blood
12 of 89
What do type 2 pneumocytes do?
Secrete fluid to keep the inner surface of the alveolus moist
13 of 89
What does the fluid secreted by type 2 pneumocytes contain?
A natural detergent
14 of 89
What is another name for the natural detergent secreted?
Surfactant
15 of 89
What does this natural detergent do?
Reduces surface tension to prevent sizes of the alveoli sticking together
16 of 89
What is the 'diameter' of an alveolus?
100 micrometres
17 of 89
What is epidemiology?
The study of incidence and cause of a disease
18 of 89
Give an example of how epidemiologists might get data
Surveys
19 of 89
Why do epidemiologists use surveys?
To look for correlations between disease rates and factors that could implicate
20 of 89
Does correlation prove causation?
No
21 of 89
How can you see if a factor actually causes a disease?
Careful analysis
22 of 89
Give five causes of lung cancer
Smoking, radon gas, passive smoking, asbestos and silica, air pollution
23 of 89
How does tobacco smoke cause lung cancer?
Contain mutagens that cause tumours to develop
24 of 89
What percentage of lung cancer cases are caused by smoking?
90%
25 of 89
How can passive smoking cause lung cancer?
Inhaling exhaled breath from smokers causes you to inhale carcinogens
26 of 89
How are they reducing the risk of passive smoking causing lung cancer?
Smoking bans
27 of 89
Give examples of air pollution that causes lung cancer
Diesel exhaust fumes, nitrogen oxides from vehicles, smoke from wood and coal fires
28 of 89
Where does radon gas come from?
Leaks out of rocks
29 of 89
Which rock is particularly prone to leak radon gas?
Granite
30 of 89
What about asbestos and silica causes lung cancer?
Dust if deposited in the lungs
31 of 89
What are the symptoms of lung cancer?
Breathing difficulties, chest pain, appetite loss, weight loss, fatigue, persistent coughing, coughing up blood
32 of 89
What is the mortality rate of lung cancer?
High
33 of 89
Why is lung cancer normally fatal?
Usually discovered late when primary tumour is large and secondary tumours have developed elsewhere
34 of 89
What are the two main causes of emphysema?
Smoking and air pollution
35 of 89
What happens to the cilia with emphysema? What is the consequence?
They are damaged and stop working, causing mucus to build up, causing infections
36 of 89
What do cilia do?
Expel mucus
37 of 89
How do toxins affect the ability to fight infection in the lungs?
They damage and inflame white blood cells that fight infections in the lungs
38 of 89
What is the name of the protease that is released by damaged and inflamed white blood cells?
Trypsin
39 of 89
What does the enzyme released by damaged white blood cells do?
Digests elastic fibres in the lungs which breaks down alveoli walls
40 of 89
What happens if the alveoli walls are broken down?
The air sacs get larger with thicker, less permeable walls
41 of 89
If the air sacs get larger, what happens to the surface area of the lungs?
Decreases
42 of 89
If surface area decreases, what happens to the oxygen concentration in the blood?
Decreases
43 of 89
Can you still exercise easily with emphysema?
No
44 of 89
What do we mean by 'shortness of breath'?
Difficulty to exhale
45 of 89
People with emphysema get a shortness of breath. Why?
The lungs have lost their elasticity
46 of 89
What causes emphysema sufferers to cough and wheeze?
Mucus in the lungs
47 of 89
What is the general name for the single layer of cells in the alveoli?
Epithelium
48 of 89
Roughly what is the thickness of type 1 pneumocytes?
0.15 micrometres
49 of 89
How many layers of cells are in the walls of the adjacent capillaries?
1
50 of 89
Is there a large or small distance between the alveolus and the adjacent capillary?
Small
51 of 89
What type of surfactant do type 2 pneumocytes secrete?
Pulmonary surfactant
52 of 89
What is the structure of the surfactant?
Monolayer on the surface of moisture lining in alveoli. Hydrophilic heads facing water and hydrophobic tails facing the air. Reduces surface tension and prevents water causing sides to adhere
53 of 89
What are the functions of the surfactant?
Reduce surface tension, stops alveoli adhering to each other, prevents collapse of the lung
54 of 89
What cause infant respiratory distress syndrome?
Premature babies are born with insufficient surfactant
55 of 89
How can you treat infant respiratory distress syndrome?
Give the baby oxygen and one or more doses of surfactant from animal lungs
56 of 89
What is the structure of the trachea?
Rings of cartilage and smooth muscle in the wall
57 of 89
What is the function of the cartilage in the trachea?
Keeps the trachea open even when air pressure is low or pressure in surrounding tissues is high
58 of 89
Do the bronchi have cartilage?
Yes
59 of 89
What is the structure of the bronchioles?
Smooth muscle fibres
60 of 89
What is the function of the smooth muscle fibres in the bronchioles?
Allows the width of these airways to vary
61 of 89
True/false: Gases will always move from a region of low pressure to high pressure?
No- high pressure to low pressure
62 of 89
What sort of force do muscles exert when they contract?
Pulling force
63 of 89
How are muscles often relaxed or pulled into an elongated state?
Contraction of other muscles
64 of 89
Do muscles exert a pushing force when they relax?
No
65 of 89
Why can muscles only cause movement in one direction?
Muscles cause a pulling action when they contract but do not cause a pushing action when they relax
66 of 89
What do we mean by antagonistic muscles?
One contracts and the opposite relaxes but the second muscle relaxes due to contraction of the first and brings aboutt opposite movement
67 of 89
For inspiration, what does the diaphragm and abdominal muscles do?
Diaphragm contracts, abdominal muscles relax
68 of 89
For expiration, what does the diaphragm and abdominal muscles do?
Diaphragm relaxes and abdominal muscles contract
69 of 89
When the external or internal intercostal muscles relax, what state are they put into?
Elongated state
70 of 89
Why are epidemiological studies mainly observational?
It is rarely possible to investigate causes of disease in human populations by carrying out experiments
71 of 89
Why does correlation not mean causation?
There are normally other confounding factors that have an effect
72 of 89
How can you compensate for confounding factors?
Collect data on many factors, not just the one being investigated
73 of 89
What sort of data is always recorded with epidemiological studies?
Age and sex and sometimes only males, only females or people of a specific age range`
74 of 89
The more cigarettes you smoke a day...
The greater risk of lung cancer
75 of 89
The greater number of years you smoke...
The greater risk of lung cancer
76 of 89
Where can radon gas accumulate?
In badly ventilated buildings
77 of 89
What sort of gas is radon gas?
A radioactive gas
78 of 89
Where is there an increased risk of inhaling asbestos etc?
Quarries, construction sites, mines or factories
79 of 89
What can you do to treat lung cancer if it is detected early enough?
Have all or part of the affected lung surgically removed and then one or more courses of chemotherapy or radiotherapy
80 of 89
What are the consequences of having all or part of your lung surgically removed?
Pain, breathing difficulties, fatigue and anxiety about the disease's return
81 of 89
What happens to the alveoli in emphysema cases?
Less air sacs, larger air sacs and have thicker walls
82 of 89
What does this mean in terms of diffusion?
Smaller SA for gas exchange and a greater diffusion path
83 of 89
Specifically, what protease do phagocytes produce in the alveoli?
Elastase
84 of 89
Which enzyme inhibits elastase and other proteins digesting lung tissue?
Alpha 1-antitrypsin (A1AT)
85 of 89
Are more or less phagocytes produced in the lungs in smokers? What does this mean?
More so more elastase is produced
86 of 89
What else affects the quantity and effectiveness of A1AT in the lungs?
Genetic factors
87 of 89
True/false: Damage to the alveoli is irreversible
True
88 of 89
What are the symptoms of emphysema?
Low oxygen saturation in blood. High carbon dioxide concentration. Lacks energy, shortness of breath even in mild exercise, laboured ventilation, rapid ventilation
89 of 89

Other cards in this set

Card 2

Front

What four properties do gas exchange surfaces have?

Back

Permeable to oxygen and carbon dioxide, thin, large SA, moist

Card 3

Front

Why is it useful that gas exchange surfaces are moist?

Back

Preview of the front of card 3

Card 4

Front

Why is it useful that gas exchange surfaces are thin?

Back

Preview of the front of card 4

Card 5

Front

What process is going to take place and be improved by a large SA?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human Physiology resources »