Breathing

Question 1

what does the respiratory (breathing) system do

Answer 1

the respiratory system takes air into and out of the body so that oxygen from the air can diffuse into the bloodstream and carbon dioxide can diffuse out of the bloodstream into the air

Question 2

where are the lungs

Answer 2

the lungs are in the upper part of the body (thorax), protected by the ribcage and separated from the lower part of the body (abdomen) by the diaphragm

Question 3

TO INHALE

Answer 3

• the intercostal muscles contract, pulling the ribcage upwards
• at the same time the diaphragm muscles contract, causing the diaphragm to flatten
• these two movements cause an increase in the volume of the thorax
• the consequent decrease in pressure to below that of the air surrounding the body results in atmospheric air entering the lungs

Question 4

TO EXHALE

Answer 4

• the intercostal muscles relax, allowing the ribcage to move downwards
• at the same time the diaphragm muscles relax, allowing the diaphragm to resume its domed shape
• these two movements cause a reduction in the volume of the thorax
• the consequent increase in pressure results in air leaving the lungs

Question 5

adaptions of the alveoli

Answer 5

the alveoli provide a very large surface area, richly supplied with blood capillaries, so that gases can readily diffuse into and out of the blood

Question 6

why would someone need to be helped to breathe by using a mechanical ventilator

Answer 6

if spontaneous breathing stops due to disease or injury

Question 7

what are the two main types of mechanical ventilators

Answer 7

• negative pressure ventilators, which cause air to be ‘drawn’ into the lungs
• positive pressure ventilators, which force air out of the lungs