Gas exchange in humans

Question 1

Aerobic Respiration

Answer 1

Glucose + oxygen → water + carbon dioxide + energy

C6H12O6 + 6O2 → 6H2O + 6CO2 + ATP

Question 2

Anaerobic respiration

Answer 2

Glucose → lactic acid + energy

C5H1206 → 2C3H6O3 + ATP

Question 3

Lactic acid

Answer 3

Produced in muscles, builds up during exercise

causes muscle cramps/spasms or sore muscles

Question 4

pathway of oxygen into the bloodstream

Answer 4

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

Question 5

Gas exchange surfaces for efficient gas exchange

alveoli

Answer 5

• has a large surface area
• are thin
• have good blood supply
• have good air ventilation

Question 6

Inspiration

Answer 6

(breathing in) 
diaphragm contracts
internal intercostal muscles relax
external intercostal muscles contract
ribcage and lungs expand

Question 7

Expiration

Answer 7

(breathing out)
diaphragm relaxes
internal intercostal muscles contracts
external intercostal muscles relax
ribcage and lungs contracts

Question 8

Breathing in & out (pressure)

Answer 8

Inspiration - (muscles contracts, lungs expand) pressure decreases lower than pressure outside causing air to move from high pressure to low pressure
Expiration - (muscles relax, lungs contract) volume decreases causing pressure to increase higher than pressure outside causing air to release outward (from high to low pressure)

Question 9

how does physical activity affect breathing

Answer 9

rate of breathing increases

• cells respire more rapidly (since more energy is required to exercise)
• carbon dioxide levels increase (bc its waste of respiration)
• increases heart rate and depth of breathing allows carbon dioxide to be excreted faster & oxygen to get to cells quicker