Hypertension is the term used to describe high blood pressure. Blood pressure is a measurement of the force against the walls of your arteries as your heart pumps blood through your body. Blood pressure readings are usually given as two numbers -- for example, 120 over 80 (written as 120/80 mmHg). One or both of these numbers can be too high. The top number is called the systolic blood pressure, which is the force of blood in the arteries as the heart beats, and the bottom number is called the diastolic blood pressure which is the force of blood in the arteries as the heart relaxes between beats. When you blood pressure is a normal it’s lower than 120/80 mmHg most of the time. High blood pressure (hypertension) which is what you have is when the reading is at least 140/90 or higher. One negative feedback system that helps regulate in blood pressure with negative feedback system( homeostatic imbalance) is when the heart beats faster or harder, blood pressure increases. If a stimulus causes blood pressure to rise the following sequence of events occurs. Baroreceptors (the receptors) pressure-sensitive nerve cells located in the walls of certain blood vessel, detect the higher pressure. The baroreceptors send nerve impulses (input) to the brain (control center). The brain nerve impulses (output) to the heart and blood vessels (the effectors). Heart rate decreases and blood vessels dilate (widen), which cause blood pressure to decrease (response). The organ systems involved are the heart which creates one force as it pumps blood into the arteries and through the circulatory system. The other force comes from the arteries resisting the blood flow. Homeostatic regulation of blood pressure by a negative feedback system the response is fed back into the system, and the system continues to lower blood pressure until there is a return to normal blood pressure (homeostasis). A negative feedback system or loop reverses a change in a controlled
References: 1. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001350/ 2. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001356/ 3. Anatomy and Physiology: From Science to Life Second Edition, copyright 2010, 2007 by Gail Jenkins, Christopher Kemnitz and Biological Sciences Textbooks Inc.