The human respiratory system

Question 1

What are the features and functions of nostrils?

Answer 1

1. Two openings in the nose; Entrance and exit of the respiratory tract
2. Hairs (only found in nostrils); Filter larger dust in the incoming air (can’t trap bacteria)

Question 2

What are the features and functions of nasal cavity?

Answer 2

1. Mucus-secreting cells; 1.1 Secrete mucus to trap dust and germs 1.2 Moisten (not lubricate) the incoming air
2. Ciliated epithelial cells; possess cilia to sweep the trapped germs and dusts away to the throat for swallowing or coughing
3. Blood capillaries; warm the incoming air
4. Olfactory receptor cells; detect chemical in air (help you to smell)

Question 3

What are the features and functions of pharynx?

Answer 3

Common passage at the back of nose and mouth; allow passage of air

Question 4

What are the features and functions of larynx (the voice box)

Answer 4

1. Made of 5 pieces of cartilage e.g. epiglottis; prevents food from entering the trachea during swallowing
2. Where vocal cord locates; vibrate to produce sound

Question 5

What are the features and functions of trachea?

Answer 5

1. A hollow tube; allow air to pass through
2. Supported by C-shaped cartilages; prevents the trachea from collapsing during breathing
3. Covered with: 1. mucus secreting cell 2. ciliated epithelial cells and blood capillaries; save as the above

Question 6

What are the features and functions of bronchus(i) ?

Answer 6

1. Two branches of the trachea; allow air to pass through
2. Supported by complete rings of cartilages; prevents the bronchi from collapsing during breathing
3. Covered with:1. mucus-secreting cells 2. ciliated epithelial cells and blood capillaries; same as the above

Question 7

What are the features and functions of bronchiole(s)?

Answer 7

1. many smaller branches of the bronchi; air passage to air sacs
2. larger bronchioles also lined with mucus-secreting cells & ciliated epithelial cells * but no mucus-secreting cells in smaller bronchioles (mucus secreted will block the smaller bronchioles)

Question 8

What are the features and functions of lungs (exists in pairs)?

Answer 8

1. Enclosed by ribcage; ribcage protects the lungs
2. Surrounded by two pleural membranes; prevents collapsing of the lungs
3. Pleural membrane secretes pleural fluid; reduces friction during breathing movement
4. Contains about 700 million air sacs (alveoli); provides a large respiratory surface

Question 9

What are the features and functions of ribs?

Answer 9

1. Forms the ribcage; protects the lungs and assist in breathing
2. Intercostal muscle between the ribs; controls ribcaage movement

Question 10

What are the features and functions of diaphragm?

Answer 10

1. Controlled by diaphragm muscle; assist in breathing