pathway of air and gaseous exchange at alveoli

Question 1

what is the respiratory system

Answer 1

series of organs responsible for taking in oxygen and expelling carbon dioxide

Question 2

what is the function of the respiratory system

Answer 2

• draw air into the lungs so that oxygen can pass into the blood stream and carbon dioxide can pass out
• once oxygen enters the bloodstream, it can be transported to the working muscles via the heart and blood vessels so that energy can be produced

Question 3

what happens once oxygen enters the bloodstream

Answer 3

once oxygen enters the bloodstream, it can be transported to the working muscles via the heart and blood vessels so that energy can be produced

Question 4

what are the 5 structures

Answer 4

• mouth and nose
• trachea
• bronchi
• bronchioles
• alveoli

Question 5

mouth & nose

Answer 5

first structure through which air passes when we inhale

Question 6

what is gaseous exchange

Answer 6

process by which oxygen diffuses into the bloodstream and carbon dioxide is removed from it

Question 7

trachea

Answer 7

windpipe surrounding by cartilage for protection

Question 8

bronchi

Answer 8

2 branches of the trachea which direct air into the lungs

Question 9

bronchioles

Answer 9

smaller branches of the bronchi which transport air into the alveoli

Question 10

alveoli

Answer 10

millions of air sacs where gaseous exchange takes place

Question 11

what are the features of the alveoli which make for efficient gaseous exchange (6)

Answer 11

• large surface area
• thin walls
• moist lining
• capillary network
• capillary walls one cell thick
• well ventilated

Question 12

moist lining in alveoli

Answer 12

helps gasses diffuse more freely

Question 13

thin walls in alveoli

Answer 13

they are one cell thick which means diffusion distance is short allowing gasses to pass through more quickly

Question 14

large surface area alveoli

Answer 14

specialised shape which maximises contact between gasses and blood, allowing more diffusion

Question 15

capillary network alveoli

Answer 15

surrounded by capillaries which ensures a good blood supply so that gasses can diffuse with ease

Question 16

small capillary walls alveoli

Answer 16

they are one cell thick meaning there is a short diffusion distance so gasses can pass through easily and quickly

Question 17

well ventilated alveoli

Answer 17

air can reach them easily making for a consistant supply of air, and so a speedy removal of CO2