gas exchange in humans (topic 11)

Question 1

what are some adaptations of the breathing system

Answer 1

gas exchange surfaces have:
have a large surface area
are thin
have a good blood supply
have good ventilation with air.

Question 2

what are the main structures that compose the breathing system

Answer 2

lungs, diaphragm, ribs, intercostal muscles (internal and external), larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries

Question 3

what is the order of air going into your body for gas exchange?

Answer 3

nose/mouth → larynx → trachea → bronchi → bronchioles → alveoli

Question 4

describe the trachea

Answer 4

A tube made of cartilage that allows ventilation to the lungs from the mouth and nose. they support the airway and help keep it open

Question 5

describe the thorax

Answer 5

The chest cavity that protects some of the main internal organs such as the heart and lungs. Muscle contractions in the thorax allows for ventilation.

Question 6

explain what happens to the thorax when breathing in

Answer 6

the volume of the thorax increases
the pressure inside decreases and becomes less than the pressure outside
air is pushed into the lungs.

Question 7

explain what happens to the thorax when breathing out

Answer 7

the volume of the thorax decreases
the pressure inside increases and becomes more than the pressure outside
air is pushed out of the lungs.

Question 8

what are the changes in the volume of the thorax caused by

Answer 8

contraction and relaxation of the diaphragm
contraction and relaxation of the intercostal muscles resulting in movement of the ribs

Question 9

explain movement of breathing system when breathing in

Answer 9

diaphragm- contracts
internal intercostal muscles relax
external intercostal muscles contract
ribcage moves upwards and outwards

Question 10

explain movement of breathing system when breathing out

Answer 10

diaphragm- relaxes
internal intercostal muscles contract
external intercostal muscles relax
ribcage moves downwards and inwards

Question 11

what are the percentages of gases in inspired air

Answer 11

21%- oxygen
0.04%- carbon dioxide
water vapour- variable
78%-nitrogen

Question 12

what are the percentages of gases in expired air

Answer 12

16%- oxygen
4%- carbon dioxide
water vapour- always high
79%- nitrogen

Question 13

compare the percentage comopositon of gases in expired and inspired air

Answer 13

compared with inspired air, expired air has:
less oxygen- oxygen used by cells for aerobic respiration
more carbon dioxide- a waste product of respiration
more water vapour- moisture evaporates from the cells of the gas exchange surface.

Question 14

how can you test for carbon dioxide

Answer 14

use limewater- turns milky white if present

Question 15

briefly what happens to your rate and depth of breathing when excerising

Answer 15

• rate and depth increases, however after stopping this levels gradually drop

Question 16

explain why the body increases in rate and depth of breathing while exercising

Answer 16

-cells of the body respire more during physical activity, provides energy needed by the muscles.
-increased rate of respiration produces more carbon dioxide, waste product
-increasing concentration of carbon dioxide in blood, detected by brain, triggers body to respond by increasing the rate and depth of breathing to expel the carbon dioxide from body.
-also increases oxygen obtained.

Question 17

why must breathing system have protecting methods as well

Answer 17

because air that you breathe in through your nose or mouth may contain pathogens and other particles

Question 18

how does body protect against possible pathogens and particles in air

Answer 18

as you breathe in through your nose air is moistened warmed and filtered
hairs in nose help filter dust
specialised cells eg. goblet cells and ciliated cells

Question 19

explain role of goblet cells

Answer 19

produce mucus which lines trachea, these pathogens and particles are trapped in mucus

Question 20

explain role of cilliated ells

Answer 20

they line surfaces of nose, trachea, bronchi, bronchioles, specialised cells with very thins structures called cilia, sweep mucus out of breathing system to the throat, carries any trapped pathogens or particles away from the breathing system