Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Cardiac output wikipedia , lookup
High-altitude adaptation in humans wikipedia , lookup
Hemodynamics wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Homeostasis wikipedia , lookup
Biofluid dynamics wikipedia , lookup
Common raven physiology wikipedia , lookup
Circulatory system wikipedia , lookup
Organisms at high altitude wikipedia , lookup
Human vestigiality wikipedia , lookup
Diving response Science Background BIOLOGY Human Physiology Diving response The diving response is a reflex in mammals, which optimizes respiration to allow staying underwater for extended periods of time. The reflex is stronger for aquatic mammals but also exists in other mammals, including humans. Especially in babies up to six months old. The diving response is triggered by cold water contacting the face. Physiological effects Upon initiation of the reflex three physiological effect scan be found in the body. The first response to submerging is the slowing down of the heart (10-25%). The heart rate of aquatic mammals slows down even more dramatic. Slowing the heart rate lessens the need for bloodstream oxygen, leaving more to be used in the other organs. Under high pressure capillaries in the extremities start closing off. First in the toes and fingers, then hands and feet, allowing more blood to flow to the heart and brain. In human about 12% of the total oxygen provision is stored in the muscles. However, in mammals living in aquatic environments, it can be up to 30%, making the muscles remain active for a long time in spite of the fact that the blood flow has been closed. Finally, the blood will shift more towards the vital organs, particularly the lungs. The reflex starts when receptors in the face, that are sensitive to cold, are triggered. Via the cranial nerve the information is transported to the brains after which the autonomic nervous system is activated. As a result, the heart rate is lowered, and the blood is nog longer pumped to the extremities. By means of a cranial nerve, the information is relayed to the brains after which the autonomic nervous system is activated. As a result, the heart rate is lowered, and the blood is no longer pumped to the extremities. In humans, the reflex does not take place when only the legs or arms are submerged in cold water. A lighter reflex can be observed when a test subject only holds his/her breath without being in contact with cold water. The reflex is strengthened when the face is submerged in cold water and the breathing is continued. The reflex becomes stronger as the water temperature decreases. The reflexes are the strongest when the test person holds his/her breath and submerge the face in the same time. Source: The human diving response in a functional and comparative perspective, Erika Schagatay Diving Response – Science Background 1