Human Gas Exchange Flashcards
1
Q
How do humans face large organism problems?
A
They reduce water loss by:
- making gas exchange surfaces occur inside the body and air have contact with exchange surfaces inside the body
- having water proof coating on the outside of the body
- having a breathing system to allow a high rate of gas exchange
2
Q
A
3
Q
A
4
Q
What is the function of broncus?
A
they produce mucus to trap dirt and cilia to move this mucus to the throat
5
Q
What supports the broncus?
A
cartilage
6
Q
Describe the structure of a cartilage.
A
- inner wall = layer of glandular and connective tissue, elastic fibres, smooth muscle and blood vessels
- outer wall = ciliated epithelium and goblet cells
7
Q
What are broncheoli?
A
A series of branching subdivisions of the bronchi
8
Q
Describe the structure of broncheoli.
A
They consist of walls made of muscle lined with epithelial cells
9
Q
What is the function of broncheoli?
A
their muscles enable constriction in order to control airflow through the alveoli
10
Q
Describe the alveoli.
A
- Small air sacks
- located at the end of the bronchioles
- Some collagen and elastic fibres are locate between the alveoli
- lined with epithelial cells
- alveolar membrane is the gas exchange surface
- surrounded by capillaries
- one cell thick
11
Q
How are the alveoli adapted for gas exchnage?
A
- the walls of both alveoli and capillaries are very thin and therefore the distance over which diffusion takes place is very short
- alveoli and pulmonary capillaries have a very large total surface area
- constant blood flow through the pulmonary capillaries which maintains a concentration gradient
12
Q
Describe the process of inhalation.
A
- During the process of inspiration, the external intercostal muscles contract, while the internal intercostal muscles relax
- The ribs are pulled upwards and outwards which increase the volume of the thorax
- The diaphragm muscles contract
- The increased volume of the thorax results in the reduction of pressure in the lungs
- Atmospheric pressure is now greater than the pulmonary pressure, so air is forced into the lungs
