7 - Exchange Surfaces And Breathing 🫁 Flashcards
(107 cards)
1
Q
What do organisms need to exchange?
A
water, minerals, oxygen, fats, proteins, glucose
2
Q
How do Amoeba obtain substances required to survive?
A
diffusion across membrane
3
Q
How do multicellular organisms ensure sufficient materials to survive?
A
transport systems
4
Q
What are the 2 main reasons why diffusion alone is enough to supply the needs of single-celled organisms?
A
- large SA:V ratio
- metabolic activity is low, so resource demands are low too
5
Q
Specialised Exchange Surface
List the 4
A
increased SA, good blood supply, thin layers, ventilation to maintain diffusion gradient
6
Q
Specialised Exchange Surface
How does increased SA help exchange?
A
provides the area for exchange and overcomes limitations of SA:V
7
Q
Specialised Exchange Surface
How do thin layers help?
A
decreases diffusion pathway
8
Q
Specialised Exchange Surface
How does good blood supply help?
A
The steeper the conc gradient, the faster diffusion takes place. So having a good blood supply keeps substances constantly moving
9
Q
Specialised Exchange Surface
How does ventilation to maintain diffusion gradient help?
A
maintains gradient and makes the process more efficient
10
Q
What is the formula for percentage yield?
A
actual yield / theoretical yield X100
11
Q
What is the formula for surface area of a cuboid?
A
2(bh+bl+hl)
12
Q
What is the formula for volume of a cuboid?
A
hbl
13
Q
When can organisms use simple diffusion to exchange gases?
A
When the diffusion pathway is less than 1mm
14
Q
What is Fick’s Law?
A
SA x conc gradient / thickness of membrane
15
Q
What else affects diffusion that isn’t in Fick’s Law?
A
moisture
16
Q
What is a peak flow meter?
A
A simple device that measures the rate at which air can be expelled from the lungs
17
Q
What are vitalographs?
A
More sophisticated versions of peak flow meters
18
Q
How does a vitalograph work?
A
Patient being tested breathes out as quickly as possible through a mouthpiece, and the instrument reproduces a graph of the amount of air they breath out and how fast
19
Q
What is a spirometer?
A
A device that detects changes in ventilation and presents the data on a digital display
20
Q
Why is a nose clip used in spirometry?
A
To stop the patient from exchanging air not in the tank
- this would make the experiment invalid
21
Q
What is the purpose of a soda lime canister in spirometry?
A
To absorb the CO2 so it isn’t breathed in
22
Q
In inspiration, what happens to the graph line in spirometry?
A
- air chamber decreases in volume
- graph line goes down
23
Q
In expiration, what happens to the graph line in spirometry?
A
- air chamber increases in volume
- graph line goes up
24
Q
What is vital capacity?
A
The maximum volume of air that can be breathed in and out in 1 breath
25
What is tidal volume?
The volume of air breathed in and out at rest (normal breathing)
26
What is the breathing rate?
The number of breaths take in 1 minute
27
What is oxygen uptake?
The volume of oxygen used up by someone in a given time
28
How do you calculate pulmonary ventilation?
Tidal volume (dm3) X ventilation rate (min-1)
29
What is the residual volume?
The volume of air that is left in your lungs when you have exhaled as hard as possible
- this can not be measured directly
30
What is inspiration reserve volume?
The maximum volume of air you can great in over and above a normal inhalation
31
What is expiratory reserve volume?
The extra amount of aid you can force out of your lungs over and give the normal tidal volume
32
How do you calculate total lung capacity?
Vital capacity + residual volume
33
What are some control variables when testing lung capacity using a spirometer?
- height
- gender
- medical history
- location eg. higher altitudes
- lifestyle eg. smoker/obese
- oftenest of exercise
34
Why do insects have high oxygen requirements?
They are active, so have a high metabolic demand
35
Why do insects have exoskeletons with a waxy coating?
Acts as a support structure and protection as it is made from chitin
36
Why can’t gas exchange happen across the exoskeleton in insects?
It is impermeable to gases
37
What is the system in insects used to deliver oxygen directly to tissues?
Tracheal system
38
Gas exchange in insects
What are spiracles?
An opening in the exoskeleton of insects to allow air to enter and flow into the tracheae
39
Gas exchange in insects
What is also lost through spiracles and how is this adapted?
Water - spiracles can be opened or closed by sphincters
40
Gas exchange in insects
What do spiracles have around them and how does this help?
Have hairs around them to prevent and trap water vapour
41
Gas exchange in insects
What are trachea?
Largest airways in the system (diameter up to 1mm) leading from spiracles to tracheoles
42
Gas exchange in insects
What are trachea tubes lined with?
Spirals of chitin, which keep them open if they are bent or pressed
43
Gas exchange in insects
What are tracheoles?
Single, elongated cells with no chitin lining so they are freely permeable to gases
44
Gas exchange in insects
How do tracheoles allow most gas exchange to take place?
As they are very small in size (0.6-0.8um) so can run between cells
45
Gas exchange in insects
In most insects, air moves along the tracheae and tracheoles by…
diffusion alone
46
Gas exchange in insects
How do insects increase their SA:V to ensure diffusion?
By having many small tracheoles
47
Gas exchange in insects
What is at the end of tracheoles?
Tracheal fluid, which limits the penetration of air for diffusion
48
Gas exchange in insects
What happens to tracheal fluid when oxygen demands build up (eg. when the insect is flying)?
A lactic acid builds up in the tissues, resulting in water moving out of the tracheoles by osmosis, exposing more SA for gas exchange
49
Gas exchange in insects
How do collapsible enlarged tracheae of air sacs help increase level of gas exchange?
Act as air reservoirs, increasing amount of air moved through the gas exchange system
50
Gas exchange in insects
How does mechanical ventilation of the tracheal system help increase gas exchange?
Air is actively pumped into the system by muscular pumping movements of the thorax/abdomen
These movements change the volume of the body, changing pressure, drawing air in or forcing it out
51
Gas exchange in insects
At rest, what happens to tracheal fluid?
Seeps into tracheoles, decreasing SA as fluid is in the way
52
Why do fish need an exchange system to cope with breathing in water?
- water is 1000x denser than air
- 100x more viscous
- lower oxygen content
53
Gas exchange in bony fish
What is the operculum?
A moveable gill cover that is reinforced with rays of bones and encloses the fill within an operculum cavity
54
Gas exchange in bony fish
What is the gill arch?
Resembles a backbone for the gills
55
Gas exchange in bony fish
What is attached to each gill arch?
Two stacks of filaments (stack is a plate)
56
Gas exchange in bony fish
What is on the surface of each filament?
Many lamellae perpendicular to filaments, consisting on single layer of flattened cells
57
Gas exchange in bony fish
Why are gills good for gas exchange in fish?
- large SA
- good blood supply
- thin layers = short diffusion pathway
58
Gas exchange in bony fish
What do fish need to ensure to allow efficient gas exchange at all times?
To maintain a continuous flow of water over the gills, even when they’re not moving
59
Gas exchange in bony fish
How do fish keep water flowing over gills when they are swimming?
By simply opening their mouth and operculum
60
Gas exchange in bony fish
What is the counter-current system?
The capillary system within the lamellae ensures that the blood flow is in the opposite direction to water flow
61
Gas exchange in bony fish
Why do fish have counter-current mechanisms?
To maintain a conc gradient for maximum diffusion
62
Gas exchange in bony fish
How is a counter-current system achieved?
The water with the lowest oxygen concentration is found adjacent to the most deoxygenated blood
63
Gas exchange in bony fish
Why don’t fish use parallel exchange systems?
Fails to provide a persistent oxygen concentration gradient, so equilibrium is reached and no further gas is exchanged
64
Gas exchange in bony fish
How is ventilation achieved then?
Volume changes in the buccal cavity and opercular cavity creates pressures that are responsible for providing an almost continuous flow of water
65
Gas exchange in bony fish
How does the tips of gill filaments overlapping help gas exchange?
Increases resistance to the flow of water over the gill surfaces, and slows down the movement of water so there is more time for gas exchange
66
Gas exchange in bony fish
How does inspiration happen in a fish?
- muscle contraction lowers the floor of the pharynx
- volume of buccal cavity increases
- this decreases pressure
- water enters the mouth as pressure outside fish is higher than inside mouth
- operculum bulges outwards
- this lowers pressure
- opercular valves are closed
- pressure decreases in cavities
- causing water to flow into opercular cavity
67
Gas exchange in bony fish
How does expiration happen in fish?
- buccal cavity contracts
- floor of pharynx is raised, closing mouth
- pressure increases, forcing water through gill slits
- water moves across gills = pressure rises
- also opercular cavities contract
- pressure increases
- causing opercular calved to open and water to be expelled
68
Gas exchange in bony fish
What is ram ventilation?
Fish swim with their mouths partly open to force water to flow over gill vents continuously
Eg. Mackerel, sharks
69
Mammalian gas exchange
What is ventilation?
A term used to describe air moving in and out of the lungs due to pressure changes in the thorax
70
Mammalian gas exchange
Define the thorax
The chest cavity
71
Mammalian gas exchange
What does the rib cage provide?
A semi-rigid case within which pressure can be lowered
72
Mammalian gas exchange
What is the diaphragm?
A broad, domed sheet of muscle, forming the floor of the thorax
73
Mammalian gas exchange
Where are the intercostal muscles found?
Between the ribs
74
Mammalian gas exchange
What lines the thorax?
Pleural membranes, which surround the lungs
75
Mammalian gas exchange
The spaces between pleural membranes, the pleural cavity, is filled with what?
A thin layer of lubricating fluid so the membranes can easily slide over each other during breathing
76
Mammalian gas exchange
What happens when the pressure in the chest is less than the atmospheric pressure?
Inspiration (active)
77
Mammalian gas exchange
What causes expiration (passive)?
When the pressure in the chest is greater than the atmospheric pressure
78
Mammalian gas exchange
What is the process of inspiration?
- diaphragm contracts
- diaphragm flattens & lowers
- external intercostal muscles contract
- internal intercostal muscles relax
- causing ribs to up and out
- volume of thoracic cavity increases
- so pressure in thorax is reduced
- drawing air in, increasing lung volume
79
Mammalian gas exchange
What is the process of expiration?
- diaphragm muscles relax
- diaphragm moves up and domed
- volume of thoracic cavity decreases
- external intercostal muscles relax
- internal intercostal muscles contract (forced expiration)
- ribs move down and inwards
- elastic fibres in alveoli recoil
- pressure inside thorax is greater than outside, so air moves out
80
Mammalian gas exchange
What happens in forced exhalation?
- intercostal muscles contract
- this pulls ribs down fast and hard
- abdominal muscles contract, forcing diaphragm up to increase pressure in lungs rapidly
81
Mammalian gas exchange
Why do athletes train at altitudes?
To increase EPO = the hormone producing red blood cells
82
What happens to smooth muscle and the bronchioles in an asthma attack?
- cells lining bronchioles release histamines
- stimulates goblet cells to make more muscle
- smooth muscle in bronchiole walls contracts
- causes bronchi to constrict
- can’t breathe
83
Mammalian gas exchange
What is the structure of the lungs?
Right lung has 3 lobes and left lung has 2 lobes (due to heart)
84
Mammalian gas exchange
Order of structures in gas exchange
Nasal cavity
Pharynx (cavity at back of throat)
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
85
Mammalian gas exchange
What features does the nasal cavity have?
- large SA with a good blood supply
- goblet cells and hairy lining
- moist surfaces
86
Mammalian gas exchange
What does the nasal cavity do?
- blood supply warms the air
- mucus traps particulates
- humidifies air to protect more delicate structures in lungs
87
Mammalian gas exchange
What does the trachea do?
A wide tube that carries clean, warm, moist air from the nose down into the chest
88
Mammalian gas exchange
What stops the trachea from collapsing?
Has incomplete rings of cartilage and smooth muscle that divides into the 2 primary bronchi at mid-thorax
89
Mammalian gas exchange
Why is the cartilage in the trachea C-shaped?
So that food can easily pass down the oesophagus, which is behind the trachea
90
Mammalian gas exchange
Why is the trachea lined with ciliated epithelium?
As a source of goblet cells, to secrete mucus onto the lining of the trachea, to trap microorganism and be wafted by cilia to throat to be swallowed
91
Mammalian gas exchange
What is the effects of cigarettes on cilia?
Stops them beating
92
Mammalian gas exchange
What adaptations do bronchi have?
- cartilage and smooth muscle
- lined with ciliated epithelium cells and goblet cells
93
Mammalian gas exchange
What does each bronchus divide into?
Secondary, then tertiary bronchi then bronchioles
94
Mammalian gas exchange
What don’t bronchioles have?
No cartilage rings
95
Mammalian gas exchange
What does smooth muscle in bronchiole walls do?
Smooth muscle contracts, causing bronchioles to constrict
Smooth muscle relaxes, causing bronchioles to dilaye
96
Mammalian gas exchange
What are bronchioles lined with?
A thin layer of squamous epithelium for a short diffusion pathway
97
Mammalian gas exchange
The smallest bronchioles don’t have smooth muscle. What do they have instead?
Elastic fibres
98
Mammalian gas exchange
What occurs at the alveoli?
Exchange of O2 and CO2 by diffusion
99
Mammalian gas exchange
What does each alveolus consist of?
A layer of thin squamous epithelium, collagen, elastic fibres
100
Mammalian gas exchange
How do elastic fibres in alveoli help their function?
Allows alveoli to stretch as air is drawn in, and recoil when air is exhaled
101
Mammalian gas exchange
How big are alveoli?
200-300um
102
Mammalian gas exchange
Why are there so many alveoli?
To create a large SA:V for diffusion
103
Mammalian gas exchange
Why are alveoli made of squamous epithelium?
To provide a thin layer = short diffusion pathway
104
Mammalian gas exchange
Why do alveoli have good blood supply from many capillaries?
To maintain a conc gradient for diffusion
105
Mammalian gas exchange
What makes alveoli moist?
A lung surfactant, allowing the lungs to remain inflated and for oxygen to dissolve in the water before diffusion
106
Mammalian gas exchange
Alveoli
What are type 1 pneumocytes?
- Line alveoli
- are squamous
- can’t replicate
- 95% are type 1
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Mammalian gas exchange
Alveoli
What are type 2 pneumocytes?
- 5% of cells
- secrete surfactant which reduces surface tension and helps gases dissolve
