Question

When you swim you hold your breath to go under water.

A) What is the effect of breath holding on alveolar and blood gas pressures? [4 marks]

B) What respiratory control mechanisms exist that will eventually cause you to surface and breathe? [5 marks]

Answer 1

Part a

When you hold your breath the ongoing accumulation of carbon dioxide in your cells, in your blood and lungs will eventually irritate and trigger impulses from the respiratory center part of your brain. Rising levels of carbon dioxide signal the body to breathe and ensure our unconscious and autonomous respiration. The body has the ability to detect these C02 levels with great accuracy and relies on them to regulate our respiration, so that we don’t have to.

Beyond the burning in your lungs, the signals your body gets from your brain when your C02 levels are too high, include strong, painful, and involuntary contractions or spasms of the diaphragm and the muscles in between your ribs. At some point the spasms become so frequent and unbearable that you can no longer hold your breath

The alveolar gas pressure of oxygen will reduce significantly and in blood the partial pressure of co2 will increase dramarically

Part b

The chemoreceptors in out body will be triggered by the co2 accumulation in the body that is hypercapnia will trigger the respiratory chemoreceptors in our body and bring an urge to breath