1. What are the two parts the compose the human breathing system?
(1) Respiratory tract
(2) other structures that assist breathing
2. List in order the structures of the respiratory tract.
Nasal cavity, trachea, bronchus, bronchiole, air sac, vacuole
3. What are the structures that assist breathing?
Ribs, intercoastal muscles, diaphragm
4. What are the effects of the structures of the nasal cavity on the incoming air?
(1) clean the air
(2) moisten the air
(3) warm the air
5. What is the structure of the inner wall of the nasal cavity?
(1) mucus secreting cells
(2) ciliated epithelial cells
(3) blood capillaries
6. How can the nasal cavity clean the air?
(1) The hair in the nostril can filter larger dust particles from the air
(2) The mucus secreting cells of the inner wall secrete mucus
- sticks onto the dust and pathogens
- moisten the air
(3) the cilia of the ciliated epithelial cells beats to push the mucus together with the substances stuck to it towards the pharynx
7. What is the difference between the location of the pharynx and the larynx?
The pharynx is the junction between the breathing system and the digestive system.
The larynx is located at the trachea, composed of cartilages.
8. With pharynx as the junction point, where can it leads to?
trachea
9. What is the adaptive feature of the trachea that prevent it from collapsing?
C-shaped cartilage
10. Why can the larynx allow humans to produce sound?
When air pass through the vocal cord, it will vibrate to give out sound.
11. What is the difference between the cartilages of the trachea and that of the bronchi?
Trachea – C-shape cartilage Bronchi: ring-shaped cartilage
12. Which structure of the breathing system contains mucus secreting cells and ciliated epithelial cells?
Nasal cavity, trachea and bronchi
13. What is the importance of the ciliated epithelial cells on the trachea and the bronchus?
When the cilia beats, the dust particles trapped in the mucus will be moved upwards towards the pharynx. This prevents harmful substances from entering the lungs.
14. How does gas exchange take place in the air sac? (the mechanism)
Oxygen
(1) human breathes in oxygen
(2) oxygen dissolves into the water film on the inner surface of the air sac
(3) oxygen diffuses into the blood and combines with the haemoglobin of the red blood cells.
Carbon dioxide
(1) carbon dioxide diffuse away from the blood capillaries
(2) to the air sac
(3) human breathes out carbon dioxide
15. What are the adaptive features of the air sac?
(1) There are large amount of air sacs in the lungs (increase the surface area)
(2) The air sac is thin
(3) The inner wall of the air sac is covered with a water film
(4) The air sac is surrounded by a large amount of blood capillaries
(5) The blood capillaries are closely attached to the air sac
16. What structures surround the thoracic cavity?
The rib cage and the diaphragm.
17. What structures is the rib cage composed of? What are their functions?
Sternum, vertebral column and 12 pairs of ribs and intercoastal muscles between ribs
Function:
(1) protect the lungs and the heart
(2) assist breathing/gas exchange
18. What is pleural membrane? What is the function of the membrane?
- There are the inner pleural membrane and the outer pleural membrane.
- The inner pleural membrane is closely attached to the lungs, the outer pleural membrane is closely attached to the diaphragm and the intercoastal muscles.
- The pleural membrane secretes fluid into the pleural cavity between the two membrane.
- The fluid can reduce the friction between the two membranes during breathing.
19. What is the difference between inhaled air and exhaled air?
(1) inhaled air contains more oxygen (20%) (c.f. exhaled air 16%)
(2) inhaled air contains less carbon dioxide (0.03%) (c.f. exhaled air 4%)
(3) inhaled air contains lower humidity (variable). (c.f. exhaled air 100%)
20. What are the adaptive features of the red blood cells in transporting oxygen?
(1) contains large number of haemoglobins which are excellent oxygen carriers.
(2) the red blood cells are biconcave in shape, they can
- increase the surface area to volume ratio
- shorten the distance for oxygen to move into the red blood cells to reach the haemoglobins
(3) mature red blood cells do not have nucleus, it can hold more haemoglobins
(4) no mitochondria, can reduce the consumption of oxygen.
21. What are the major methods of transport of carbon dioxide in blood?
(1) become hydrogencarbonate ion and dissolve into the plasma (Main method)
(2) dissolve directly into water
(3) carried by haemoglobins
22. Describe the mechanism of inhalation.
(1) Intercoastal muscles contract, the rib cage move upwards and outwards; at the same time the diaphragm muscles contract to flatten the diaphragm.
(2) volume of thoracic basket increase, the volume of the lungs increase as a result.
(3) Pressure inside the lungs decrease and becomes lower than the atmospheric pressure
(4) air rushes in
23. Describe the mechanism of exhalation.
(1) intercoastal muscle relax, causing the rib cage to move downwards and inwards.
At the same time, the diaphragm muscles relax. This cause the diaphragm to recoil to it original dome shape.
(2) The volume of the thoracic cavity decrease, and so the lungs volume decreases.
(3) The pressure inside the lungs increases and becomes higher than the atmospheric pressure.
(4) Air is forced out of the lungs.
24. What criterion must be fulfilled before air can leave the lungs?
The pressure inside the lung is higher than the pressure of the atmospheric pressure.
25. What actions can the rib cage model simulates?
Simulate the breathing out and breathing in actions.
It shows that the thoracic cavity is increasing or decreasing in volume.