Question

Explain the regulation of forced breathing.  Provide all structures as well as any chemical reactions you would expect to be involved.  

Answer 1

Forced breathing or hyperpnea is a mode of breathing that can occur during that can during exercise and some other activities like breathing.

REGULATION OF FORCED BREATHING AND THE STRUCTURES INVOLVED :

In forced breathing inspiration and expiration both occur due to muscle contractions. In addition to the diaphragm and intercostal muscles other accessory muscles must also contract.

–During forced inspiration, muscles of neck including scalenes, contract and lift the thoracic wall increasing the lung volume .

–Accessory muscles of abdomen including the obliques contract, forcing the abdominal organs to move up against the diaphragm. This helps to push diaphragm further into the thorax, pushing more air out. Accessory muscles also compress the rib cage and reduce the volume of thoracic cavity.

CHEMICAL CHANGES THAT ARE INVOLVED:

chemical changes are detected by central and peripheral chemoreceptors

FORCED INSPIRATION–

—When concerntration of blood CO2 increases the pH of blood also decreases and hydrogen ion concentration is increased. The increased concentration of hydrogen ions triggers the central chemoreceptors to stimulate the respiratory centres to initiate contraction of diaphragm and intercostal muscles.

As a result, the rate and depth of inspiration is increased and CO2 is expelled promoting reduction of blood CO2 levels and hydrogen ion concentration is also reduced.

FORCED EXPIRATION–

Reduced blood carbondioxide levels leads to low levels of hydrogen ions in brain, leading to decrease in rate and depth of pulmonary ventilation, producing slow and shallow breathing

—peripheral chemoreceptors i.e;carotid and aortic arches detects the fluctuations in blood oxygen levels and act accordingly.