Respiratory systems Flashcards
Because of their respiratory system,
- Amphibians are restricted to moist habitats.
- Fish gills only work in water.
How do amphibian and fish respiratory systems work?
- Amphibians have simple lungs, but use their moist, permeable skin to obtain oxygen. The permeable skin makes them susceptible to excessive water loss, which can result in death.
- Fish gills obtain oxygen from water being forced over filaments, so do not work in air.
What happens during inhalation?
In humans, breathing in depends on the contractions of the intercostal muscles (which connect the ribs) and the muscles in the diaphragm. The ribs are moved up and out and the diaphragm is moved downwards, causing the chest volume to increase and the pressure to decrease. The higher outside pressure causes air to enter the lungs.
What happens during exhalation?
To breath out, the intercostal muscles and the diaphragm relax, causing the ribs to move down and inwards and the diaphragm to curve upwards. The chest volume therefore decreases, which increases the pressure, forcing the air out of the lungs.
The total lung capacity consists of;
- Tidal air, which is the amount of air normally breathed in and out while at rest
- Vital capacity, which is the maximum amount of air which can be exchanged
- Residual air, which is the amount of air which cannot be forced out of the lungs
How does exchange of gas take place?
Exchange of gases take place by diffusion between the alveoli and the air in the air sacs. Diffusion occurs because oxygen concentration in the air is higher than in the deoxygenated blood capillaries around the alveoli.
The exchange surfaces are adapted for efficient gas exchange.
- They have a large surface area and a good blood supply.
- They are permeable. moist and only one cell thick
What is asbestosis?
Asbestos is an industrial disease resulting from breathing in asbestos fibres. The fibres cause inflammation and scarring of lung tissue, reducing gaseous exchange.
What happens in cystic fibrosis?
In the inherited condition cystic fibrosis, too much mucus is produced in the bronchioles causing breathing difficulties.
What increases the risk of lung cancer?
The risk of lung cancer is greatly increased by lifestyle factors such as smoking. Lung cells grow rapidly, reducing the surface area available for gaseous exchange
Asthma symptoms
- Wheezing, a tight chest and difficulty in breathing.
- Inhalers can be used to relieve these symptoms
During an asthma attack
The lining of the airways becomes inflamed, mucus and fluid build up in airways and the muscles around the bronchioles contract, narrowing the airways.
Difference between fish and human respiratory systems
The respiratory system in fish allows for a for through flow of water. In humans, air must go in and out of the same structures. This means that chemical particles such as tars from cigarettes and asbestos fibres can become trapped in the air sacs.
