Exchange Surfaces and Breathing Flashcards
Why do organisms need exchange surfaces?
The sa:v ratio is too low to allow basic diffusion
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
What are the 3 features of a good exchange system?
Large SA:V ratio
Short diffusion pathway
Good Blood supply
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
What are the parts features of the mammalian exchange system?
Mouth Nose Trachea Bronchi Bronchioles Alveoli Lungs
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
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
What do alveoli’s walls contain?
Elastic fibres
Stretch during inspiration and recoil in expiration to push air out
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
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
What device measures lung volumes?
Spirometer
What are the 2 components of lung volume?
Vital capacity
Residual volume
What is Vital capacity?
The maximum volume of air expelled from the lungs in one breath
What are factors affecting the vital capacity of people?
Age
Gender
Height
How much they exercise
What is the residual volume?
The amount of air that cant be expelled and remains in the lungs
What is tidal volume?
The volume of air expelled in one breath at rest
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
How would you oxygen uptake from a spirometer trace?
Draw a line from one trough to another trough
Measure the gradient of the line
How would you measure the breathing rate from a spirometer trace?
Count the number of peaks in a minute
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
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
What is the buccal cavity?
The mouth of the fish
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
What is the name of the fluid circulated around insects?
Haemolymph
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
Give examples of how different insects may ventilate?
Sections of the tracheal system have flexible walls that can be contracted and relaxed by the flight muscles
Movement of the wings can alter the volume of the thorax causing pressure changes and thus ventilation
Some use valves over spiracles to create a ventilation system where air is drawn in at the front and out at the back
