Gas Exchange: Lungs and risk factors

Question 1

describe the anatomy of the human respiratory system

Answer 1

• the trachea is a tube-like structure which brings oxygen from the mouth to the lungs
• this branches into two bronchi which supply oxygen to the left and right lungs
• these further branch into bronchioles which at their tips contain air sacs called alveoli
• this is where gas exchange occurs

Question 2

explain ways the alveoli are adapted for rapid gas exchange

Answer 2

1. the structure of the alveoli gives it an extremely large surface area
2. the alveoli have a rich blood suppy which ensures a large concentration gradient
3. the gases in the alveolar air spaces are seperated from the blood by the alveolar epithelium and the endothelium of the capillary
4. the alveolar epithelium is one cell thick which provides a short diffusion distance

Question 3

what is ventilation

Answer 3

the mechanism of breathing air into and out of our lungs

Question 4

explain the process of breathing in (inhalation)

Answer 4

• diaphragm contracts and flattens
• external intercostal muscles contract pulling ribcage up and out
• thoracic cavity volume increases
• pressure in lungs becomes lower than atmospheric pressure
• air moves into the lungs down a pressure gradient

Question 5

explain the process of breathing out (exhalation)

Answer 5

• external intercostal muscles relax
• diaphgram relaxes and curves
• thoracic cavity volume decreases
• pressure in lungs becomes greater than atmospheric pressure
• air moves out of lungs down a pressure gradient

Question 6

what is the equation for pulmonary ventilation rate

Answer 6

pulmonary ventilation rate (dm^3 min^-1) = tidal volume (dm^3) x breathing rate (min^-1)

Question 7

what are risk factors

Answer 7

environmental and genetic factors that can increase the risk of developing a disease

Question 8

correlation does not equal causation

Answer 8

remember that phrase

Question 9

what is the accepted threshold for a true biological effect

Answer 9

probability has to be less than 0.05 or 5%

Question 10

what are the 3 different stastical tests

Answer 10

• T test
• correlation coeffiecient
• chi squared

Question 11

when should you use the T test

Answer 11

when comparing the difference between two means from different groups

Question 12

when should you use correlation coefficient

Answer 12

when assesing the strength of the relationship between two continuous variables