Ma. Bea Agatha Escueta
Body systems act together to make a point that the body acts efficiently as a whole, with the brain as a command centre. “Homeostasis is derived from the Greek, homeo or ‘constant’; and stasis or ‘stable’ and means remaining stable or remaining the same.” (Wikipedia. 2013) It is the procedure by which the body keeps static surroundings in which cells, tissues, and systems can operate. If there’s an alteration happen, these procedures can stop, decompress or quicken. Homeostatic mechanism controls a lot of activities inside the body such as our heart rate, breathing rate, body temperature and, blood glucose.
“Negative feedback works rather like the central heating system of a building. If the temperature falls below the desired temperature, the thermostat will detect this change and send a message to the boiler to switch on. The heating comes on and the building warms up. When it reached the temperature set by the thermostat, the boiler gets a message to switch off. The heating will switch on again when the temperature drops below the thermostat setting.” (Haworth, et al. 2010 P.206) In order to maintain the interior surrounding at constant, homeostasis relies on feedback like these from the body.
Heart rate is the speed of the heartbeat, specifically the count of heartbeats per unit of time. It is usually expressed as beats per minute (bpm). The normal human heart rate ranges from 60 – 100 bpm. Slow heart rate, defined a below 60 bpm is called bradycardia. Fast heart rate, define as above 100 bpm is called tachycardia. Arrhythmia is when the heart rate is irregular in a regular pattern. These abnormalities sometimes, but not always, indicate disease. Role of internal receptors
Cardiac centre is located in the medulla (also known as medulla oblongata) – the lower half of the brainstem. From the chemoreceptors (also known as chemosensor) – collects information about the level of oxygen or carbon dioxide in the bloodstream – medulla receives signals. They detect the amount of carbon dioxide in the blood. Role of autonomic nervous system
Autonomic nervous system is a part of the peripheral nervous system that works as a control system, operating largely below the level of awareness, and controls visceral functions. It is the one who control the heart. It has two branches –the sympathetic nervous system, general action is to circulate the body’s nervous system fight-or-flight response, and the parasympathetic nervous system, responsible for stimulation of “rest-and-digest” or “feed and breed” activities that happen when the body is at ease, especially after eating. These systems act like an accelerator and a brake on the heart. During muscular work, tension and fear, sympathetic nervous system is active causing the heartbeat to gain strength and heart rate. While during contentment and peace parasympathetic nervous system is active and output that calms the heart. Effects of body temperature
The measurement of the force applied to the inside walls of the blood vessels is the blood pressure. It is the total of the blood being pumped and the width of the blood vessels themselves. When blood vessels expand as a reaction to increased body temperatures, the heart has to pump faster to maintain blood pressure.
Effects of adrenaline
Adrenaline (also known as epinephrine) is a hormone that is released by the adrenal medulla. In situation of tension or fear, it is secreted into the bloodstream and enables a person to adapt the situation by giving a sudden boost of energy and strength. When adrenaline is secreted, one of its effects is increased heart rate. Because of the “fight-or-flight” situation, one decides if he should remain and fight or run for his life. These activities need extra oxygen and energy. The brain will detect this and forward messages to the adrenal glands to release adrenaline into the bloodstream. The heart rate will gain as the body prepare...
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