Flashcards in Exchange Surfaces and Breathing Deck (26)
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1
Why do organisms need exchange surfaces?
The sa:v ratio is too low to allow basic diffusion
2
Why does level of activity affect if an organism needs an exchange surface or not?
More metabolically active organisms will require exchange surfaces so that they can perform more respiration to produce more ATP
3
What are the 3 features of a good exchange system?
Large SA:V ratio
Short diffusion pathway
Good Blood supply
4
Why is a good blood supply important for diffusion?
Provides working areas with Oxygen for respiration
Removes molecules that are being diffused to maintain a steep concentration gradient
5
What are the parts features of the mammalian exchange system?
Mouth
Nose
Trachea
Bronchi
Bronchioles
Alveoli
Lungs
6
What is the role of the intercostals?
Move the lungs up and down during breathing
To work with the diaphragm to create pressure gradients to cause breathing
7
How are the alveoli specialised to perform their function?
Large SA:V ratio
Moist surface, allows gasses to diffuse easier and prevents pneumothorax
Short diffusion pathway (only 1 cell thick)
Good blood supply - transports CO2 to the lungs and O2 away from the lungs
8
What do alveoli's walls contain?
Elastic fibres
Stretch during inspiration and recoil in expiration to push air out
9
How are the airways specialised to perform their function?
Have wide lumen to allow sufficient airflow without obstruction
Are lined with ciliated epithelium and goblet cells. Goblet cells release mucus to trap pathogens , epithelium move this up to the top of the airway where it is swallowed
Supported by rings of cartilage to prevent collapse during inspiration when pressure is low
10
What is the role of smooth muscle and elastic fibres in the airways?
Smooth muscle can contract to restrict airflow, useful if there is something harmful in the air
Cannot relax on its own requires elastic fibres
Smooth muscle may over contract during anaphylaxis
11
What device measures lung volumes?
Spirometer
12
What are the 2 components of lung volume?
Vital capacity
Residual volume
13
What is Vital capacity?
The maximum volume of air expelled from the lungs in one breath
14
What are factors affecting the vital capacity of people?
Age
Gender
Height
How much they exercise
15
What is the residual volume?
The amount of air that cant be expelled and remains in the lungs
16
What is tidal volume?
The volume of air expelled in one breath at rest
17
How does a spirometer measure oxygen uptake?
A person breaths in the oxygen and the body absorbs some of it
They breathe out carbon dioxide which is absorbed by the soda lime
The difference in volume is the amount of oxygen uptake
18
How would you oxygen uptake from a spirometer trace?
Draw a line from one trough to another trough
Measure the gradient of the line
19
How would you measure the breathing rate from a spirometer trace?
Count the number of peaks in a minute
20
Describe the structure of the gaseous exchange system in bony fish
Gills covered by a bony plate called the operculum
Each gill consists of two rows of filaments which are very thin
Gill filament surface is folded into lamellae
Capillaries carry deoxygenated blood close to the surface of lamellae to perform gaseous exchange
21
What is a countercurrent flow in the gills?
Blood flows in the opposite direction as the water
Maintains a steep concentration gradient and allows most oxygen to be removed
22
What is the buccal cavity?
The mouth of the fish
23
How does the buccal-opercular pump work?
Buccal cavity floor moves down drawing water into it
Mouth closes and floor is raised pushing water through the gills
simultaneously the operculum moves outwards to draw water over the gills also
24
What is the name of the fluid circulated around insects?
Haemolymph
25
Describe the gaseous exchange system in insects?
Have a respiratory cavity where gaseous exchange occurs
Air enters through a spiracle
transported via tracheae and tracheoles
The end of the tracheoles contain tracheal fluid where gaseous exchange occurs
26
