What is the significance of performing mouth-to-mouth breaths during CPR?

Exhaled air contains a higher percentage of CO2 than inhaled air, due to it being a waste product of respiration. By breathing excess CO2 into the patient, the blood acidity will decrease and will be detected by the pH receptors in the hypothalamus. This will stimulate the respiratory muscles- the outer intercostal muscles and the diaphragm will contract, causing the chest cavity to be pulled upwards and outwards, decreasing the pressure within the thorax and allowing air to flow inwards. This should help to restore normal breathing in the patient.

PD
Answered by Phoebe D. Biology tutor

2615 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

How are Xerophytes adapted to dry environments?


What is natural selection, and how is it related to changes in allele frequency?


Why does a base substitution in DNA not always result in the formation of non-functional proteins?


What is the difference between competitive and non-competitive enzyme inhibition?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning