gas exchange

Question 2

organs involved in gas exchange ? (8)

Answer 2

-trachea
- liquid surfactant
- pleural membrane
- lung
- bronchi
- bronchioles
- alveolus
-diaphragm

Question 3

what is the alveolus the site of ?

Answer 3

it is the site of gas exchange

Question 4

what feature does the trachea have ?

Answer 4

rings of cartilage
- help to keep the trachea open

Question 5

function of the pleural membrane ?

Answer 5

seal + reduces friction

Question 6

function of liquid surfactant ?

Answer 6

reduces surface tension

Question 7

what is the motion of exhaling and inhaling called ?

Answer 7

elastic recoil

Question 8

why is the rate of gas exchange in humans so efficient ?

Answer 8

• because there is around 300 million alveoli in each lung which increase surface area
• each alveolus is surrounded by a network of capillaries to remove exchanged gases, which maintains a conc gradient
• the size of pathway is thin because of the layers squarmous cells which are 1 cell thick so they minimise the diffusion distance

Question 9

what is the definition of breathing ?

Answer 9

the movement of air, in and out of the lungs

Question 10

what is meant by respiration ?

Answer 10

the chemical reaction to release energy in the form of ATP

Question 11

what is ventilation ?

Answer 11

the scientific word for breathing

Question 12

what is meant by gaseous exchange ?

Answer 12

the 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 13

what happens during inhalation ?

Answer 13

-the external intercostal muscles contract
- the internal intercostal muscles relax
- because the 2 muscles are antagonistic
-the diaphragm contracts so thorassic volume increases but the thorassic pressure decreases
- air then moves from high pressure to low pressure into the lungs (diffusion)

Question 14

what does antagonistic mean ?

Answer 14

the muscles do equal and opposite motions

Question 15

what happens during exhalation ?

Answer 15

• the external intercostal muscles relax and the internal intercostal muscles contract
• the diaphragm relaxes so the thorassic volume decreases but thorassic pressure increases
• air moves from high pressure to low pressure out of the lungs (diffusion)

Question 16

when external intercostal muscles contract, what does that lead to ?

Answer 16

inspiration (inhaling)

Question 17

when internal intercostal muscles contract , what does that lead to ?

Answer 17

expiration (exhalation)

Question 18

what are air sacs (alveoli ) surrounded with ?

Answer 18

capillaries

Question 19

why is there a very short diffusion distance between the alveoli and capillaries ?

Answer 19

because the alveolar wall and capillary wall are flattened (single layer of cells) and right next to each other

Question 20

what happens to CO2 and O2 ?

Answer 20

carbon dioxide diffuses out of the blood and into the lungs/ alveoli. and oxygen diffuses out of the alveoli and into red blood cells

Question 21

is the process of inhalation active or passive and why ?

Answer 21

active because it uses ATP

Question 22

is the process of exhalation active or passive and why ?

Answer 22

its passive because it relies on
- gravity
- elastic recoil