GAS EXCHANGE IN HUMANS

Question 1

Definition of breathing

Answer 1

movement of air into and out of the lungs

Question 2

Definition of ventilation

Answer 2

the scientific word for breathing

Question 3

Definition of respiration

Answer 3

chemical reaction to release energy the form of ATP

Question 4

Definition of gaseous exchange

Answer 4

diffusion of oxygen from the air in the alveoli into the blood and of carbon dioxide from the blood into the air in the alveoli

Question 5

what are the key parts of the human gas exchange system

Answer 5

alveoli
bronchioles
bronchi
trachea
lungs

Question 6

what is the trachea

Answer 6

it is the windpipe and has tough C shaped cartilage rings within it which support and keeps the trachea open

Question 7

what is the bronchi and bronchioles

Answer 7

the trachea branches into two tubes called the bronchi and then the bronchi branches into even smaller tubes called the bronchioles

Question 8

what is the alveoli

Answer 8

at the end of the bronchioles there are air sacs with very thin epithelial cells which are called alveoli

Question 9

what is inspiration

Answer 9

breathing in

Question 10

what is expiration

Answer 10

breathing out

Question 11

The process of inspiration

Answer 11

External intercostal muscles - contract
Internal intercostal muscles - relax
Ribs move - Up and out
Diaphragm - contract
Movement of diaphragm - Flattens
Volume of thoracic activity - Increase
Pressure of thoracic activity - Decrease
Movement of air - Air moves in

Question 12

The process of expiration

Answer 12

External intercostal muscles - relax
Internal intercostal muscles - contract
Ribs move - in and down
Diaphragm - relax
Movement of diaphragm - Up ( doomed position )
Volume of thoracic activity - Decrease
Pressure of thoracic activity - Increase
Movement of air - Air moves out

Question 13

How to calculate the rate pulmonary ventilation

Answer 13

pulmonary ventilation rate ( dm3 min -1) = tidal volume (dm3) x breathing rate (min -1)

Question 14

what happens once the gases are in the alveoli

Answer 14

gas exchanges between the epithelium and the blood

Question 15

how are alveoli adapted for gas exchange

Answer 15

• there are lots of alveoli ( tiny air sacs) which created a very large surface area for gas exchange
• the alveoli epithelium cells are very thin (one cell thick) to minimum diffusion distance
• Each alveolus is surrounded by a network of capillaries to remove exchanges gases , and therefore maintains a concentration gradient

Question 16

Describe the movement of carbon dioxide and oxygen across the alveolar epithelium

Answer 16

oxygen diffuses out of the alveoli, across the alveolar epithelium and the capillary endothelium ( a type of epithelium that forms the capillary wall ),and into the haemoglobin in the blood
carbon dioxide diffuses into the alveoli from the blood , and is breathed out