Homeostasis
February 11th, 2023
1. Describe your understanding of the homeostasis process by summarizing how the food you have (or have not) eaten today affects your blood glucose level.
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2. Summarize the function of four organelles found in a basic human cell.
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3. Describe how substances move in and out of a cell.
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4. Choose two organs that are found in different body cavities. Describe their location in relation to each other, using at least three positional medical terms.
Answer:
- Homeostasis is the process by which the body maintains a stable and balanced internal environment, despite changes in external conditions. The level of glucose in the blood is an important aspect of homeostasis, as it is the main source of energy for the body’s cells. The food that you have eaten or not eaten today affects your blood glucose level, as the digestion and absorption of carbohydrates in the food results in an increase in blood glucose levels, while the lack of food can cause a decrease in blood glucose levels. In response to these changes, the hormone insulin is secreted by the pancreas to regulate the level of glucose in the blood, by promoting its uptake and storage in cells.
- Four important organelles found in a basic human cell are the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus. The nucleus serves as the control center of the cell and contains the cell’s genetic material, DNA. Mitochondria are the “powerhouses” of the cell, as they produce energy in the form of ATP. The endoplasmic reticulum is involved in protein synthesis and lipid metabolism, and the Golgi apparatus is involved in the modification, sorting, and packaging of proteins and lipids for export from the cell.
- Substances can move in and out of a cell by several mechanisms, including diffusion, osmosis, and active transport. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration, until an equal concentration is reached. Osmosis is the diffusion of water molecules across a selectively permeable membrane, from an area of high concentration to an area of low concentration. Active transport, on the other hand, requires energy input to move substances against their concentration gradient, from an area of low concentration to an area of high concentration.
- Two organs found in different body cavities are the liver and the lungs. The liver is located in the abdominal cavity, while the lungs are located in the thoracic cavity. In relation to each other, the liver is inferior to the lungs, meaning that the liver is located below the lungs. The liver is also medial to the lungs, meaning that it is closer to the midline of the body than the lungs. The lungs are also anterior to the liver, meaning that they are located in front of the liver.