Chapter 7 - Exchange Systems And Breathing Flashcards
1
Q
Do single celled organisms have high or low SA:V
A
High
2
Q
What advantage does high SA:V ratio give them
A
allows for the exchange of substances to occur via simple diffusion
o The large surface area allows for maximum absorption of nutrients and gases and secretion of waste products
o The small volume means the diffusion distance to all organelles is short
3
Q
Why is there a need for a specialised system for gas exchanges
A
- supply of oxygen
- removal of C02
4
Q
Why can’t multi-cellular organisms rely on diffusion
A
• The time taken for oxygen to diffuse from the cell-surface membrane to the tissues would be too long
5
Q
What is BMR
A
metabolic rate of an organism when at rest
6
Q
The greater the body mass…
A
higher the metabolic rate
o Therefore, a single rhino consumes more oxygen within a given period of time compared to a single mouse
7
Q
• Effective exchange surfaces in organisms have …
A
o Large surface area
o Short diffusion distance (thin)
o Good blood supply
o Ventilation mechanism
8
Q
Adaptations of root hair cells = effective exchange surface
A
• Root hair cells = increase surface area
9
Q
Adaptations of alveoli - efficient exchange system
A
• One cell thick = short diffusion distance
• Large number of alveoli = increases surfaces area for oxygen + carbon dioxide to diffuse across
• Extensive capillary network
- ventilation
10
Q
How does extensive capillary network effect efficiency of gas exchange in alveoli
A
constant flow of blood through the capillaries means that oxygenated blood is brought away from the alveoli and deoxygenated blood is brought to them
o This maintains the concentration gradient necessary for gas exchange to occur
11
Q
How does ventilation effect efficiency of gas exchange in alveoli
A
maintain gradient = ensure that there is always a higher concentration of oxygen in the alveoli than in the blood
12
Q
Examples of organisms with good blood supply / ventilation
A
Gills / alveolus
13
Q
How do gills have good blood supply / maintain concentration gradient
A
Counter current system
14
Q
What is counter current system
A
extensive capillary system that covers the gills ensures that the blood flow is in the opposite direction to the flow of water
15
Q
Key feature of the counter current system
A
water with the lowest oxygen concentration is found adjacent to the most deoxygenated blood
16
Q
Where does gas exchange take place in humans
A
human thorax
17
Q
What is the human thorax
A
collection of organs and tissues in the chest cavity
18
Q
What is cartilage
A
strong and flexible tissue
19
Q
Where can cartilage be found
A
in rings along the trachea
20
Q
What are these rings of cartilage called
A
Tracheal rings
21
Q
Purpose of tracheal rings
A
help to support the trachea and ensure it stays open while allowing it to move and flex while we breathe
22
Q
What are collated epithelium
A
specialised tissue
23
Q
Where is ciliated epithelium found
A
along the trachea down to the bronchi
24
Q
Purpose or collated epithelium
A
• Each cell has small projections of cilia which sweep mucus, dust and bacteria upwards and away from the lungs and the epithelium itself
25
Where are goblet cells found
scattered throughout the ciliated epithelium in the trachea
26
Function or glo let cells
mucus-producing cells that secrete viscous mucus which traps dust, bacteria and other microorganisms and prevents them from reaching the lungs
27
Where is the mucus swept tk
along by the cilia of the ciliated epithelium upwards and is swallowed
any microorganisms will then be destroyed by the acid in the stomach
28
What is squamous epithelium
Lining of alveoli = forms structure of alveolar walls
29
Features of squamous epithelium
very thin and permeable for the easy diffusion of gases
30
Where is smooth muscle found
throughout the walls of the bronchi and bronchioles
31
Function of smooth muscle
helps to regulate the flow of air into the lungs by dilating when more air is needed and constricting when less air is needed
32
Where are elastic fibres found
all lung tissues
33
Functions of elastic fibres
enable the lung to stretch and recoil = what makes expiration a passive process
34
Purpose of capillary lumen being small = only able to fit one blood cell at a time
ensures that there is sufficient time and opportunity for gas exchange to occur
35
What produces the mucus
Mucous glands in goblet cells
36
Where are elastic fibres actually found
In the squamous epithelium of alveolar walks
37
List the components of the gas exchange system = humans
38
Adaptations of naval cavity
• Large SA with rich blood supply = warms the air
• Hairy lining which secretes mucus to trap dust + bacteria
• Moist surfaces to increase the humidity of incoming air to prevent water loss at the alveoli
39
What is the trachea
channel that allows air to travel to the lungs
40
What shape are tracheal rings
C-shaped
41
Why are they C-shaped
prevent any friction from rubbing with the oesophagus located close behind
42
Adaptations of the trachea
• C-shaped rings of cartilage ensure that this air channel remains open at all times
covering of mucus inside the trachea = prevent bacteria
43
What is the bronchus
• Extensions of the tracheae that split into two for the left + right lung
44
Structure of the bronchus
• Very similar structure to trachea but smaller = thinner walls + smaller diameter
• The cartilage rings in the bronchi are full circles
45
What are the bronchioles
• narrow self-supporting tubes with thin walls
46
Features of the bronchioles
• get smaller as they get closer to the alveoli
47
What do the larger bronchioles have that the smaller ones don’t
smooth muscle
48
Function of this elastic fibres and smooth muscle in the large bronchioles
adjust the size of the airway to increase or decrease airflow = constrict
49
Where is the alveoli found
at the ends of the bronchioles
50
What does the alveoli wall consist of
single layer of epithelium
51
Purpose of single layer of epithelium in alveolus walls
o Elastic fibres are located in the extracellular matrix
o Elastic fibres = cause recoil = helps move air out of alveoli
52
Where does the trachea lead to and from
From mouth and nose to bronchi
53
What is ventilation
mass flow of gases
54
What is ventilation brought about by
pressure differences in the thoracic cavity
55
What is the passage of air
1. Nose / mouth
2. Trachea (windpipe)
3. Bronchi
4. Bronchioles
5. Alveoli
56
What type of process is breathing in = mammals
Active
57
How do mammals breath in
58
Mechanism of breathing out = mammals
59
When we talk about pressure in ventilation = mammals = what should we say
THORACIC PRESSURE
60
What is vital capacity
maximum volume of air that can be breathed in or out in one breath
= maximum amount of air that can be exchanged between maximum inspiration and maximum expiration
61
What is tidal volume
volume of air that is breathed in or out during normal breathing (at rest) = in a single breathe
62
What is breathing rate
number of breaths taken in one minute
63
What counts as one breath
taking air in and breathing it back out again
64
What is oxygen uptake
volume of oxygen used up by someone in a given time
65
What is residual volume
amount of air that remains in the alveoli + airways after forced exhalation
66
Normal breathing rate of humans
12-18 breaths per minute
67
Label this
68
What is the process of using a spirometer
• The person (subject) being examined breathes in and out through the spirometer
• Carbon dioxide is absorbed from the exhaled air by soda lime in order to stop the concentration of carbon dioxide in the re-breathed air from getting too high = can cause respiratory distress
• As the subject breathes through the spirometer, a trace is drawn on a rotating drum of paper or a graph is formed digitally, which can be viewed on a computer
69
How to measure oxygen uptake be measured
o Carbon dioxide is removed from the exhaled air, meaning that the total volume of air available in the spirometer gradually decreases, as oxygen is extracted from it by the subject's breathing
o This change in volume is used as a measure of oxygen uptake
70
Analyse this with the labels
- exercise ends
- exercise begins
- maximum amount of air breathed out
- at rest
- return to rest
- maximum amount of air taken in
- tidal volume
- residual volume
- viral capacity
- total lung capacity
71
From the spirometer data in the image above, calculate the breathing rate during the first minute and then calculate the breathing rate during the second minute.
Step One: Count the number of breaths in the first 60 seconds.
- One breath is shown by the trace going up and then down, so there are 12 breaths in the first 60 seconds.
Step Two: Give appropriate units.
- Breathing rate should be given in breaths min⁻¹ (breaths per minute), so the breathing rate during the first minute = 12 breaths min⁻¹.
Step Three: Count the number of breaths in the second 60 seconds.
- There are 14 breaths in the second 60 seconds.
Step Four: Give appropriate units.
- The breathing rate during the second minute = 14 breaths min⁻¹.
72
Calculate the tidal volume during rest and the peak tidal volume during exercise.
Step One: For the 'at rest' phase of the trace, measure the difference between the top and bottom of the trace in terms of the volume of air in the lungs.
- During rest, the tidal volume = 3 dm³ - 2.6 dm³
- = 0.4 dm³
Step Two: At the peak tidal volume during exercise, measure the difference between the top and bottom of the trace in terms of the volume of air in the lungs.
- The peak tidal volume during exercise occurs right at the end of the exercise period (at around 100 seconds):
- = 4.1 dm³ - 2.3 dm³
- = 1.8 dm³
73
Formula for ventilation rate
Ventilation rate = tidal volume X breathing rate
74
How to calculate vital capacity
inspiratory reserve + expiratory reserve + tidal volume = approx. 4 to 4.5 dm3 = peak to trough
75
How to calculate breathing rate
peak to trough is one breath = count the number of peaks in a minute
76
How to calculate oxygen consumption
air breathed into the spirometer has C02 removed by soda lime = volume of gas decreases = decrease is equivalent to oxygen consumption = LINE GRADIENT IS OXYGEN CONSUMPTION = gradient steeper in exercise
77
What is ficks law
78
How to double rate of diffusion
1. surface area or concentration difference is doubled or
2. thickness of the exchange membrane is halved.
79
Features of the exchange system in insects
- spiracle
- trachea
- tracheoles
80
Why can’t insects just use simple diffusion through skim and why is this an advantage + disadvantage
• rigid exoskeleton with a waxy coating = impermeable to gases
o prevents water loss but also means no gas exchange
81
What is a spiracle
opening in the exoskeleton of an insect which has valves
82
Purpose of spiracle
o allows air to enter the insect and flow into the system of tracheae
83
What are the trachea / tracheoles
tubes within the insect respiratory system which lead to tracheoles (narrower tubes)
84
What di the trachea have in insects
o rigid rings of cartilage / chitin that keep the tracheae open
85
Passage of air in insects
Spiracle = trachea = air sac = tracheoles = muscle cells
86
For smaller insects is this okay
Yes = sufficient oxygen via diffusion
87
How does the oxygen get from tracheoles to muscle cells
• Lactic acid / tracheal fluid– oxygen dissolves into this fluid, where it reaches individual cells to start simple diffusion / gas exchange
88
When inactive, what happens to the fluid
tracheal fluid builds up at the bottom of the tracheoles, causing slower diffusion.
89
When active, what happens to the fluid
muscles draw up tracheal fluid
• Faster diffusion
• Tracheal fluid being drawn up = less pressure = draws air from spiracles
90
What’s the problem with larger insects + how do we fix this
• Need more rapid supply of oxygen = create mass flow of air = ventilation
91
Expiration in insects
• muscles contract & flatten the body
• volume of the tracheal system decreases
• air is forced out
92
Inspiration in insects
• Closing the spiracles
• Using abdominal muscles to create a pumping movement for ventilation
93
Why do fish have a problem with gas exchange
• Oxygen dissolves less readily in water = must pass large volumes of water over their gas exchange systems relative to the volumes of air ventilated by land animals.
94
Why is the gas exchange system effective in fish
very large surface area for gaseous exchange
o gills
2. A short diffusion distance across the gaseous exchange system
o very thin so that blood flowing through them is only a short distance from seawater
3. A high concentration gradient between the blood in the gills and the water passing over them
o Counter-current system
95
Structure of fish gills in bony fish
gills = 4 = on each side of the head
• Each gill arch is attached to two stacks of filament
• On the surface of each filament, there are rows of lamellae
• The lamellae surface consists of a single layer of flattened cells that cover a vast network of capillaries
• lie between the mouth cavity and the opercular flaps
96
What does the capillary system in the Lamellea do
ensures that the blood flow is in the opposite direction to the flow of water = counter-current system
97
Purpose of counter current system
• ensures the concentration gradient is maintained along the whole length of the capillary
• The water with the lowest oxygen concentration is found adjacent to the most deoxygenated blood
98
Describe the ventilation mechanism in fish
• When the fish open their mouth they lower the floor of the buccal cavity.
• causes the volume inside the buccal cavity to increase, which causes a decrease in pressure within the cavity
• The pressure is higher outside the mouth of the fish and so water flows into the buccal cavity
• The fish then raises the floor of the buccal cavity to close its mouth, increasing the pressure within the buccal cavity
• Water flows from the buccal cavity (high pressure) into the gill cavity (low pressure)
• As water enters pressure begins to build up in the gill cavity and causes the operculum (a flap of tissue covering the gills) to be forced open and water to exit the fish
• The operculum is pulled shut when the floor of the buccal cavity is lowered at the start of the next cycle
99
Describe how insects take oxygen into their bodies
• Oxygen from the air diffuses into the insect’s body
• cavity through the spiracles and into long thin tubes
• called tracheae.
• The tracheae branch into smaller tubes called tracheoles that
• have an open ending inside the insect, filled with tracheal fluid.
• Oxygen diffuses into this fluid and into the insect’s cell
