6.4 Gas Exchange Flashcards
1
Q
What does physiological respiration involve?
A
The transport of oxygen to cells within the tissues
2
Q
What does physiological respiration involve?
A
The transport of oxygen to cells within the tissues
3
Q
What are the three processes in physiological respiration?
A
Ventilation
Gas exchange
Cell respiration
4
Q
What is ventilation?
A
The exchange of air between the atmosphere and the lungs
5
Q
What is gas exchange?
A
The exchange of oxygen and carbon dioxide between the alveoli and bloodstream
6
Q
What is cell respiration?
A
The release of energy from organic molecules?
7
Q
What is needed to maintain a concentration gradient in alveoli?
A
A ventilation system
8
Q
Why is a ventilation system needed to maintain a concentration gradient in alveoli?
A
Because gas exchange is a passive process
9
Q
What is consumed by cells during cell respiration?
A
Oxygen
10
Q
What is a waste product of cellular respiration?
A
Carbon dioxide
11
Q
Where is oxygen being removed from and into where?
A
Removed from the alveoli and into the bloodstream
12
Q
How do the lungs function as a ventilation system?
A
By continually cycling fresh air into the alveoli from the atmosphere
13
Q
What levels stay high in the alveoli?
A
O2 levels
14
Q
What levels stay low in the alveoli?
A
Carbon dioxide
15
Q
What diffuses into the blood?
A
Oxygen
16
Q
What diffuses from the blood?
A
Carbon dioxide
17
Q
How are the lungs structured to increase the overall rate of gas exchange?
A
A very large surface area
18
Q
How does air enter the respiratory system?
A
Through the nose or mouth
19
Q
What does air pass through after entering the nose/mouth?
A
Pharynx to the trachea
20
Q
What does the trachea divide into?
A
Two bronchi
21
Q
What are bronchi connected to?
A
the lungs and the trachea
22
Q
How many lobes is the right lung composed of?
A
Three lobes
23
Q
How many lobes in the left lung?
A
Two
24
Q
Why is the left lung smaller than the right?
A
Due to the position of the heart
25
In each lung, what do the bronchi divide into?
Smaller airways called bronchioles
26
What do bronchioles increase?
Surface area
27
What do each bronchioles terminate with?
A cluster of air sacs called alveoli
28
What occurs in the alveoli?
Gas exchange with the bloodstream
29
What is the function of the alveoli?
The site of gas exchanged
30
What does the thin epithelial layer do?
Minimises diffusion distances for respiratory gases
31
What are alveoli surrounded by?
A rich capillary network
32
What does the rich capillary network around the alveoli increase?
The capacity for gas exchange
33
What is the internal surface of the alveoli covered with?
A layer of fluid
34
Why is there a layer of fluid in the internal surface of the alveoli?
As dissolved gases are better able to diffuse into the bloodstream
35
What are pneumocytes?
The cells that line the alveoli and comprise the majority of the inner surface of the lungs
36
What are the two types of alveolar cells?
Type I pneumocytes and Type II pneumocytes
37
What are type I pneumocytes involved in?
The process of gas exchange between te alveoli and the capillaries
38
What is the shape of the type I pneumocytes?
Squamous and extremely thin
39
Why are type I pneumocytes extremely thin?
To minimise the diffusion distance for respiratory gases
40
How are type I pneumocytes connected?
By occluding junctions
41
What do occluding junctions prevent?
The leakage of tissue fluid into the alveolar air space
42
What are type I pneumocytes unable to do?
Replicate
43
What can type II cells differentiate into?
Type I cells if required
44
What can type II cells differentiate into?
Type I cells if required
45
What are type II pneumocytes responsible for?
The secretion of pulmonary surfactant
46
What does pulmonary surfactant reduce?
Surface tension in the alveoli
47
What is the structure of type II pneumocytes?
Cuboidal and possess many granules
48
What do type II pneumocytes only comprise a fraction of?
The alveolar surface
49
What is the bad thing about the moist lining in alveoli?
It creates a tendency for the alveoli to collapse and resist inflation
50
What is the surface tension?
The elastic force created by a fluid surface that minimises the surface area
51
What happens to the surfactant as an alveoli expands with gas intake?
It becomes more spread out across the moist alveolar lining
52
What slows the rate of expansion?
The increase in surface tension
53
What does the surfactant ensure all alveoli do?
Inflate at roughly the same time
54
What does the surfactant ensure all alveoli do?
Inflate at roughly the same time
55
What is breathing?
The active movement of respiratory muscles that enables the passage of air into and out of the lung
56
What does the contraction of respirator muscles change?
The volume of the thoracic cavity
57
What law does the mechanism of breathing follow?
Boyles law
58
When the volume of the thoracic cavity increases what happens to the pressure in the thorax?
It decreases
59
When the volume of the thoracic cavity decreases what happens to the pressure in the thorax?
It increases
60
In general where will gases move from?
A region of high pressure to a region of lower pressure
61
When will air move into the lungs?
When the pressure in the chest is less than the atmospheric pressure
62
When will the air move out of the lungs?
When the pressure in the chest is greater than the atmospheric pressure
63
What do respiratory muscles contract to change?
The volume of the thoracic cavity and the pressure in the chest
64
What are different groups of muscles required to do because muscles only do work via contraction?
Expand and contract chest volume
65
What does changing chest volume create?
A pressure differential between the chest and the atmosphere
66
What equalises the pressure differential?
Air moving
67
What do muscles that increase the volume of the chest cause?
Inspiration
68
What do muscles that decrease the volume of the chest cause?
Expiration
69
When is atmospheric pressure lower?
At high altitudes
70
Why is it harder to breathe at high altitudes?
As a greater increase in chest volume is required before a pressure differential is formed
71
What are inspiration and expiration controlled by?
Two sets of antagonistic muscle groups
72
What does antagonistic mean?
WOrking oppositely
73
What are the muscles responsible for inspiration?
The diaphragm and external intercostals
74
What happens when the diaphragm muscles contract?
The diaphragm flattens and increase the volume of the thoracic cavity
75
What contracts during inspiration?
Diaphragm and external intercostals
76
What happens when the external intercostals contract?
Ribs are pulled upwards and outwards
77
What also may help pull the ribs up and out?
Additional muscle groups
78
What are the muscles responsible for expiration?
The abdominale muscles and internal intercostals
79
What do the diaphragm muscles do during expiration?
Relax
80
What happens when the diaphragm muscles contract during expiration?
The diaphragm curves upwards and reduces the volume of the thoracic cavity
81
What do the internal intercostals muscles do during expiration?
Contract
82
What happens when the internal intercostal muscles contract?
The ribs are pulled inwards an downwards
83
What happens when the internal intercostal muscles contract?
The ribs are pulled inwards an downwards
84
What do abdominal muscles do during forced exhalation?
Contract and push the diaphragm upwards
85
What else may help pull the ribs downwards?
Additional muscle groups
86
What is lung cancer?
The uncontrolled proliferation of lung cells leading to the abnormal growth of lung tissue
87
What can the abnormal growth of lung tissue impact?
Normal tissue function, leading to a variety of symptoms according to size and location
88
What are the two main reasons lung cancers are the most common cause of cancer related death worldwide?
- lungs are vital and the abrogation of their normal function is detrimental to health
- lungs possess a rich blood supply increasing the likelihood of metastasis
89
What are common causes of lung cancer?
Radiation
Ageing
Pollution
Environment
Diseases
Genetics
Occupation
Asbestos
Tobacco
Smoking
90
What is emphysema?
A lung condition where the walls of the alveoli lose their elasticity due to damage to the alveolar walls
91
What does the loss of elasticity in alveoli result in?
The abnormal enlargement of the alveoli
92
What does the abnormal enlargement of the alveoli lead to?
A lower total surface area for gas exchange
93
What can the degradation of the alveolar walls cause?
Holes to develop and alveoli to merge into huge air spaces
94
What is the major cause of emphysema?
Smoking
95
Why is the major cause of emphysema smoking?
As the chemical irritants in cigarette smoke damage the alveolar walls
96
What does damage to the lung tissue lead to the recruitment of?
Phagocytes to the region
97
In damaged lung tissue what does the recruitment of phagocytes produce?
An enzyme called elastase
98
What does elastase do?
Breaks down the elastic fibres in the alveolar wall
99
What can elastase activity be blocked by?
An enzyme inhibitor but only when elastase concentrations are increased
100
What is a small proportion of emphysema cases caused by?
A hereditary deficiency in the enzyme inhibitor due to a gene mutation
101
When does ventilation in humans change in response to?
Levels of physical activity
102
Why doe ventilation change in response to physical activity?
As the bodys energy demands are increased
103
What does ATP production produce as a waste product?
Carbon dioxide
104
What detects changes in bloodCO2 levels?
Chemosensors in the walls of the arteries
105
Where does chemosensors send signals to?
The brain stem
106
What increases as energy intensity increases?
Demand for gas exchange
107
What are the two ways exercise will influence ventilation?
- increase ventilation rate
- increase tidal volume
108
How does an increased ventilation rate help when exercise intensifies?
A greater frequency of breaths allows for a more continuous exchange of gases
109
How does an increased tidal volume help when exercise intensity is increased?
Increasing the volume of air taken in and out per breath allows for more air in the lungs to be exchanged
110
What are the three ways ventilation in humans can be monitored?
- simple observation
- chest belt and pressure meter
- spirometer
111
How does simple observation work?
Counting the number of breaths per minute
112
How does chest belt and pressure meter work?
Records the rise and fall of the chest
113
What is spirometry?
The measuring o the amount/speed at which air can be inhaled or exhaled
114
What is a spirometer?
A device that detects the changes in ventilation and presents the data on a digital display
115
What is a more simplistic method of a spirometer?
Breathing into a balloon and measuring the volume of air in a single breath
116
How can the volume of air in a balloon be determined?
By submerging the balloon in water and measuring the volume displaced
