Biology 220 Book Test 1HomeostasisHomeostasisis the basis of control for anatomy and physiology. It is the fundamental idea upon which physiology was developed. Homeostasis is applied to living systems and is based upon normal conditions that our bodies must maintain to remain healthy. Bodies have standards for everything, and in order to maintain them they need a way to stabilize the deviations. External and internal changes occur that will alter our normal values, but our bodies recognize and address the issues, so responses can bemade to get back to the state of normalcy. These unconscious responses are called feedback mechanisms. Anytime a body is not able to address a change, it has a disease or disorder. For example, the normal level of glucosein our blood plasma (the ECM of blood cells) is 90 mg/100mL. This is also called our fasting glucose. Our standard body temperature is 98.6 degrees Fahrenheit. Our standard pH is between 7.35-7.45.Negative Feedback MechanismsAfter eating a Snickers and a Dr. Pepper, there is a digression from the normal level of glucose in our blood. The level goes up, and the beta cells of the Islets of Langerhanssense this. They release insulin, a hormone, which travels into the blood plasma via a capillary. It attaches to a sensor/receptor protein on the outside of the target cell, maybe a fat cell in the hip, and eventually the sugar will get into the cell and out of the blood. Once the sugar is in the cell it can actually be used in cellular respiration for the production of 38 ATP (optimally), water, CO2, andheat.Sugar and O2 are used up on the process. If there is a build-up of sugar in the blood, then he has diabetes. People with Type I (don’t make insulin)diabetes are usually young, and their bodies don’t make insulin. In Type 2, there is so much fat that the target cell cannot recognize insulin. So, they make insulin without a problem, but the receptors on the target cell do not recognize it.The sensors were in over-drive, so they just shut down. Once there is an accumulation of sugar in the blood, it goes to the kidneys and leaves the body in urine.Sugar takes water with it as it leaves the body, so when little kids are always peeing, thirsty, and dehydrated because the sugar isn’t going into their cells and the water is leaving the cells to follow it out of the body, they check for diabetes. Our bodies need sugar to get into our cells to make ATP, so we can do work. But, if sugar cannot get into the cell, then fat will, and the body goes into ketosis. Fat can easily get into the cell because it is hydrophobic and nonpolar like the phospholipid bilayer. When the fat gets broken down in the cell it puts off a lot of bad stuff/junk into the celland it produces an acidic environment.Glycerol will stay in the cell and fatty acid will get into the blood and produce LDL (low density lipoproteins), which hardens arteries.
After not eating for three hours, alpha cells sense this and release the hormone glucagon into the blood through a fenestrated (holy) capillary to tell the cells to release glucose into the blood.