Gas exchange in humans Details

Question 1

Features of gas exchange surfaces in humans

Answer 1

-Large surface area(allows for more efficient diffusion)
-Thin surface(short diffusion distance so gas exchange happens quicker)
-Good blood supply(maintains concentration gradient by carrying away substances which have diffused across already)
-Good ventilation with air

Question 2

In the presence of carbon dioxide, the colour of limewater goes from…

Answer 2

colourless to milky

Question 3

Percentage of nitrogen in inhaled air

Answer 3

78%

Question 4

Percentage of nitrogen in exhaled air

Answer 4

78%

Question 5

Percentage of oxygen in inhaled air

Answer 5

21%

Question 6

Percentage of oxygen in exhaled air

Answer 6

16%

Question 7

Percentage of carbon dioxide in inhaled air

Answer 7

0.04%

Question 8

Percentage of carbon dioxide in exhaled air

Answer 8

4%

Question 9

Level of water vapour in inhaled air

Answer 9

Lower than level of water vapour in exhaled air

Question 10

Level of water vapour in exhaled air

Answer 10

Higher than level of water vapour in inhaled air

Question 11

Effect of physical activity on the rate and depth of breathing

Answer 11

Rate and depth of breathing increases

Question 12

Reason why physical activity increases the rate and depth of breathing

Answer 12

-Physical activity causes muscles to increase their rate of respiration
-Greater amount of oxygen needed for increased rate of respiration
-More carbon dioxide is also produced which diffuses into the blood, which causes the acidity of the blood to increase
-Brain detects this and signals for the rate and depth of breathing to increase
-Increased rate of breathing allows the rate of gas exchange to increase(expelling more carbon dioxide while taking in more oxygen)

Question 13

Function of lungs

Answer 13

Contain the surfaces where gas exchange takes place(main organs of the respiratory system)

Question 14

Function of intercostal muscles

Answer 14

External and internal intercostal muscles work antagonistically in pairs to expand and contract the rib cage during breathing

Question 15

Function of ribs

Answer 15

Protect the lungs and heart from physical damage

Question 16

Function of larnyx

Answer 16

Contains the vocal chords

Question 17

Function of trachea

Answer 17

Connects the throat to the bronchi

Question 18

Function of cartilage rings around the trachea

Answer 18

-Provide structural strength
-Keep the trachea open(so that air can pass through it)

Question 19

Function of bronchi

Answer 19

Carry air from the trachea to the lungs(bronchioles)

Question 20

Function of bronchioles

Answer 20

Carry air to the alveoli

Question 21

Function of alveoli

Answer 21

Site of gas exchange(covered by capillary network; oxygen diffuses into the capillaries, while carbon dioxide diffuses out. Waste products are then breathed out)

Question 22

During inhalation, the external intercostal muscles…

Answer 22

contract

Question 23

During inhalation, the internal intercostal muscles…

Answer 23

relax

Question 24

During inhalation, the diaphragm…

Answer 24

lowers/flattens(contracts)

Question 25

During inhalation, the volume of the thorax…

Answer 25

increases

Question 26

During inhalation, air…

Answer 26

diffuses into the lungs

(REMEMBER: IT DOES NOT GET SUCKED IN)

Question 27

Why air diffuses into the lungs during inhalation

Answer 27

When the volume of the chest increases, there is a lower concentration of air in the lungs than outside them, so air diffuses in

Question 28

During exhalation, the internal intercostal muscles…

Answer 28

contract

Question 29

During exhalation, the external intercostal muscles…

Answer 29

relax

Question 30

During exhalation, the volume of the thorax…

Answer 30

decreases

Question 31

During exhalation, the diaphragm…

Answer 31

rises(relaxes)

Question 32

Location of goblet cells

Answer 32

Found in the trachea and bronchi

Question 33

Function of goblet cells

Answer 33

Produce and secrete mucus into the respiratory tract

Question 34

Function of ciliated cells

Answer 34

Move foreign pathogens and particles(which are trapped in the mucus) towards the throat(so that the mucus can be swallowed, and the foreign pathogens and particles can be destroyed in the acidic conditions of the stomach)

Question 35

Function of mucus

Answer 35

Trap foreign particles and pathogens(by sticking to them)