chpt 7 respiration

Question 1

What is the passage of air in the body ?

Answer 1

mouth and nostrils -> pharynx -> larynx -> bronchus -> bronchioles -> alveoli

Question 2

What are the features of the nose ?

Answer 2

1. hair and mucus membrane to trap dust and bacteria in air
2. small sensory cells i the mucus membrane that detects harmful chemicals

Question 3

What are the features of the trachea and bronchi ?

Answer 3

1. gland cells that secrete mucus to trap dust and bacteria
2. ciliated cells that have cilia to sweep the trapped dust and bacteria upwards into the pharynx
3. bronchi from lower end of trachea leads to the lungs

Question 4

How does oxygen transport from lungs to tissue ?

Answer 4

1. oxygen dissolves in the moisture lining the alveolar walls and diffuses through the alveolar walls into the capillaries
2. oxygen combines with haemoglobin to form oxyhaemoglobin that is transported away from the lungs
3. when it passes through the tissues, oxyhaemoglobin will release the oxygen
4. oxygen diffuse out of blood capillaries and into tissue cells

Question 5

What are the features of alveoli ?

Answer 5

1. oxygen diffuses from alveolar walls into blood capillaries and co2 diffuses from blood capillaries into alveolar air
2. constant conc gradient is maintained by
   constant breathing, a slow flow of blood through blood capillaries that gives time for gaseous exchange to occur
   a continuous flow of blood in the blood capillaries
3. alveoli have a large SA to vol ratio for more diffusion of oxygen an co2
4. alveoli are only one cell thick ,which allows for shorter diffusion distance between gases
5. a thin film of moisture covers the surface of the alveolus, allowing oxygen to dissolve

Question 6

What happens during inspiration ?

Answer 6

1. external intercostal muscles contract and shorten
2. internal intercostal muscles relax and lengthen
3. ribs and sternum move upwards and outwards
4. diaphragm contracts and flattens
5. air pressure in lung decrease
6. atmospheric pressure higher than pressure in lungs so air flows in passively
7. vol of thorax increases

Question 7

What happens during expiration ?

Answer 7

1. external intercostal muscles relax and lengthen
2. internal intercostal muscles contract and shorten
3. ribs and sternum moves downwards and inwards
4. diaphragm relaxes and arches upwards
5. vol of thorax decreases
6. air pressure in lungs increase
7. atmospheric pressure of air lower than pressure in lungs, therefore air flows out passively