gas exchange in humans

Question 1

fick’s law

Answer 1

rate of diffusion = (surface area x difference in conc)/ diffusion distance

Question 2

lung structure

Answer 2

trachea= tube structure that carries air from mouth to the lungs
bronchi= trachea splits into two bronchi as it enters the lungs which allows air to travel to the left and right lung
bronchioles= divide from the bronchi supply the alveoli with air

Question 3

structure of the alveoli

Answer 3

large surface area
large concentration gradient
1. deoxygenated blood is brought to the lungs by the pulmonary artery from the heart and returns to the heart when oxygenated via the pulmonary vein
2. gases in the alveolar air spaces are separated from the blood by the squamous epithelium and the endothelial wall of the capillary

Question 4

process of inhalation

Answer 4

1. external intercostal muscles contract
2. diaphragm contracts and pulls down
3. thoracic cavity volume increases
4. pressure in lungs is lower than atmospheric pressure
5. air moves into lungs down a pressure gradient

Question 5

process of exhalation

Answer 5

1. external intercostal muscles relax
2. diaphragm relaxes and moves up
3. thoracic cavity volume decreases
4. pressure in lungs greater than atmospheric pressure
5. air moves out of lungs down a pressure gradient

Question 6

diffusion of gases from alveoli to blood

Answer 6

as blood reaches the capillaries the oxygen diffuses into the blood across the squamous epithelial membrane and epithelial wall of the capillary from a high O2 conc to a low O2 conc