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Unformatted text preview: Chapter 2 Figure 2.4 - Cell membrane consists of a phospholipid bi-layer. - It includes proteins, some with carbohydrates - Receptors identify cells in the body as its own cells and not as foreign ones - The yellow structures shown in the figure are cholesterol o Cholesterol is necessary and stabilizes the membrane by adding strength and rigidity. - HDL is high density lipoprotein and is the good cholesterol (highly desirable cholesterol). - LDL is the low density lipoprotein and is the cholesterol that is bad for the body (least desirable lipoprotein). - It is necessary to have a balance of good and bad cholesterols in the body. The membrane is one of the most important parts of a cell. All cells have one and it is important to understand as a part of our future profession. o In order for a drug to work or a toxin to be harmful, it needs to bind to the membrane or penetrate the membrane. Once it binds to the cell or penetrates the cell, it is able to affect the molecules and do its job. Overdose applies to a controlled substance or a prescribed drug taken without following the directions of the physician. An overdose can occur when a person continues increasing the dose to get the desired effect. The smooth endoplasmic reticulum of liver cells produces enzymes that denature drugs and toxic molecules to protect the body. o Each liver cell has enough smooth ER to deal with what the body is exposed to on a daily basis to maintain a chemical balance. When a foreign material enters the body the person feels the effect because it reaches the brain since the liver can only detoxify some of the material. o As the use of the drug is continued, the liver cells increase the amount of smooth ER in the cell so they can produce more enzymes to deal with the drug. This causes the desired effect to go away after a few times use. o This process is continued as the person keeps increasing the amount of drug when the desired effect goes away. o The higher the dosage, the more smooth ER the liver cells make, and it ends up extending throughout the cell. o At some point the liver cells have no more room or energy to make more smooth ER and cannot detoxify the harmful material. This eventually leads to an overdose. Liver cells do what they can to deal with what they are exposed to; however, they only do so up to a certain limit. The dose that a...
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