Concepts Of Lifetime Fitness :: essays research papers

Concepts of Lifetime FitnessHomeostasis is the state of equilibrium in which the internal environment of thehuman automobile trunk remains relatively constant. Two excellent examples of homeostasisare how the body maintains a constant temperature and blood pressure duringstrenuous physical activity or transaction. Although on that point are many otheractivities in the body that display homeostasis, I will only discuss these two. Temperature in the human body is usually kept at approximately 37 degreesCelsius. To maintain such a strict temperature, the body has a few functions tocombat the outside elements. People cannot make themselves arctic as readily asmake themselves hot, however I will mention both homeostasis functions. Whenthe external temperature decreases, a portion of the brain called thehypothalamus detects the drop by means of the blood. To compensate, the brainsends chemical and electrical impulses to the muscles. These impulses tell themuscles to begin to contract and relax at very high intervals. This is commonlyknown as shivering. The business of Adenosine Triphosphate or ATP in themitochondria of the muscles produces heat. If the body temperature does notrise immediately after this, then a second function begins. The brain will type the blood vessels near the skin to constrict or narrow in diameter. Thisoccurs so the heat mystic in the muscles is conserved. Since the vessels are nowsmaller in diameter, less blood is needed to fill them. Since less blood isneeded through the vessels, the heart begins to slow. If the body remains inthis slowed state, hypothermia could result. Hypothermia is the condition inwhich metabolous processes are inhibited. The medical world has taken advantageof this by inducing hypothermia in patients that are undergoing organtransplants.To fight temperatures higher than normal, as in exercise or on hot days, thebody reacts in the opposite way than with cold. Again, the hypothalamus detectsthe change of temperatu re in the blood. The brain signals blood vessels not toconstrict, but to dilate. This increases the diameter of the vessels, andresults in the need for more blood. Since more blood is needed to fill thevessels, the heart pumps faster and that causes respiration to increase. Theincreased respiration will make the body exhale some of the internal heat, likeplacing a fan in a window to cool a room. The blood vessels are dilated so theheat deep in the muscles is easily released. Another commonly known mechanismto fight heat is sweating. Sweat glands found throughout the body arestimulated by the hypothalamus to excrete sweat and when the sweat evaporates,