Exchange surfaces and breathing 3.1 Flashcards
(53 cards)
Why do organisms need a specialised exchange surface?
If they have a small SA:V, high metabolic activity and are multicellular, diffusion cannot provide and remove O2, nutrients and CO2 at a sustainable rate
What are the features of an efficient exchange surface with examples?
- Large SA (root hair cells)
- thin layer/ exchange surface (alveoli)
- good blood supply/ ventilation (gills)
Why is a large SA important to exchange surfaces?
It provides more area for molecules to diffuse through, increasing the rate of diffusion
Why is a thin layer important to exchange surfaces?
To reduce the diffusion distance and to ensure the barrier is permeable to increase rate of diffusion
Why is a good blood supply/ ventilation important to exchange surfaces?
To maintain a conc. gradient so that rate of diffusion is faster
How do you find the SA of a sphere?
4πr2
How do you find the volume of a sphere?
4/3 πr3
What are the mechanisms of inhaling?
- diaphragm contracts downwards
- external intercostals contract
- internal intercostals relax
- ribs raise upwards
- volume of chest cavity increases
- pressure decreases
- air moves into lungs
What are the mechanisms of exhaling?
- diaphragm relaxes upwards
- internal intercostals contract
- external intercostals relax
- ribcage lowers
- volume of chest cavity decreases
- pressure increases
- air moves out of lungs
What are the components of the mammalian gaseous exchange system?
- nose
- trachea
- bronchi
- bronchioles
- alveoli
- lungs
- rib cage
- external/ internal intercostal muscles
- diaphragm
What are the adaptations of the lung
- squamous cells in alveoli
- elastic fibres
What are the adaptations of the trachea and bronchi
- cartilage
- ciliated epithelium cells
- goblet cells
- smooth muscle
What are the adaptations of the bronchioles?
- smooth muscle
- cilliated epthelium cells
- goblet cells
What is the structure and function of cartilage in airways?
- C shaped rings
- allows flexibility and space for food to pass down the oesophagus
- support the airways to prevent collapse during inspiration
What is the structure and function of ciliated epithelium cells?
- cells that have hair like projections called cilia
- waft mucus past cells up the throat to prevent lung infections
What is the function of goblet cells?
Secrete mucus to trap pathogens to reduce risk of infection
What is the function of smooth muscle?
It contracts involuntarily to constrict the airways and reduce the size of the lumen incase there are harmful substances in the air
What is the function of elastic fibres?
They act to dialate airways by deforming when the muscle contracts but then recoiling back to their original size when the muscles relax
What is a spirometer?
A device that can measure the movement of air into and out of the lungs
How do you measure lung volume?
Using a spirometer
How does a spirometer work?
As you breath in the chamber lid lowers and when you breath out it rises and these movements are recorded by a data logger
What happens to the CO2 in a spirometer?
It passes through a soda lime chamber which absorbes CO2
What precautions must be taken when using a spirometer?
- subject should be healthy
- soda lime should be fresh and functioning
- no air leaks in the apparatus
- mouthpeice should be sterilised
- water chamber must not be overfilled
What will increased oxygen uptake be a result of?
- increased breathing rate
- deeper breaths
