Homeostasis refers to the processes living things use to remain internally stable and survive. The human body maintains steady temperatures and levels of salt, fat, oxygen, sugar, and water to keep optimal function. For example, when the body is overheated, it facilitates sweating to cool itself down. If it needs to retain heat, the body stops sweating and reduces blood circulation to your skin. Homeostasis also refers to mental or psychological stability. Under stress, the mind works with chemical responses to lower anxiety.
Regulating the level of heat in the body is one of the primary aims of homeostasis. Humans are warm-blooded, or endotherms, which means the processes that maintain our internal body temperatures are located inside us, unlike reptiles and amphibians, exotherms whose body temperatures are influenced by the environments. Humans have a normal body temperature of 98.6 degrees Fahrenheit. This temperature helps the organs and bodily systems function properly. Humans must maintain an ideal temperature to surviving. An organism’s size determines the requirements for and responses towards homeostasis. Larger organisms produce more heat, and smaller organisms lose more body heat than they produce, so their bodies have to work harder to reach thermoregulation or normal body temperature.
To maintain homeostasis, the pancreas releases two hormones for regulating blood sugar: insulin and glucagon. Whenever blood sugar levels drop, the pancreas starts storing glycogen in the cells to trigger the body to release insulin later. When the body needs to raise its blood sugar levels, the glycogen converts to glucose and blood sugar rises. Glucose homeostasis regulates blood sugar levels within a narrow range.
A pH score is a measure of the amount of acid in your body. A score below 7 indicates your body and systems are too acidic. Healthy scores range above 7, with the average being about 7.4. Water that is pure has a neutral pH level. The lungs control the amount of acid in our bodies, pushing more or less carbon dioxide, whichever we need, out of the diaphragm when pH levels are unbalanced. When we eat foods that are too acidic or do not have enough alkaline properties, our bodies begin pulling alkaline cells from their own tissues to neutralize the acid and lining the arteries with fat to protect them from corrosion. For some, this is the onset of heart disease.
Blood toxins harm the cells and are inevitable disruptors to homeostasis. The urinary system will try to excrete these toxins, but practices such as smoking can introduce more than the system can handle. Tobacco products contain carbon monoxide and nicotine, and damage blood vessels and increase the risk of stroke and heart attack because they make the heart work harder. These toxins can also have a negative impact on the lungs. Tiny hairs called cilia cover the cells in the trachea and lungs; smoking paralyzes the cilia, leaving them unable to sweep away dirt and debris. Breathing becomes a challenge, and individuals become more vulnerable to infections and lung diseases.
The body takes several safety precautions to maintain healthy blood pressure. For example, the brain sends a signal to the heart to speed up or slow down, to accommodate for the change in your blood pressure. High blood pressure can take a toll, placing stress on the arteries and heart to carry the blood throughout the tissues and organs. Eventually, they may tear, leading to heart attack and stroke.
As with blood sugar, low calcium levels trigger bodily reactions to maintain homeostasis. The body activates calcium-sensing receptors in the parathyroid gland to release the PTH hormone. This response triggers the release of calcium from the bones. By contrast, when calcium levels are too high, calcitonin in the thyroid gland triggers the bones to absorb calcium and lowers these levels. Consumption of acidic food can also adversely affect calcium levels, forcing the body to pull potassium from bones and tissues to compensate. This can result in loss of bone density or osteoporosis.
Both oxygen and carbon dioxide play vital roles in maintaining homeostasis. Oxygen comes into the body as a component of air to be processed by the lungs. The metabolism produces carbon dioxide, a waste product that travels through the bloodstream to the lungs, which exhale it. Oxygen and glucose in the cells get transformed into water, carbon dioxide and energy. Without adequate oxygen, the body does not have enough energy. High levels of carbon dioxide can also create serious issues for overall health. The exchange of these two gases and the process of inhaling and exhaling helps maintain homeostasis.
To keep our bodies in a homeostatic state, we must have the right balance of fluids and water. Fluid intake and the body’s ability to remove fluids as waste determine the quality of internal balance. Balanced fluid levels also help us stay at the appropriate osmotic pressure. Water content cannot be too diluted or too concentrated. The process of maintaining the right fluid balance is called osmoregulation.
The body must respond to three key things to achieve homeostasis. First, the organs and systems must have a clear defining point for homeostasis. This point is not the same for everyone since it depends on body size and how well the organs are functioning. Secondly, an individual or health care provider must be able to tell when the body has deviated away from this defining point. Finally, the body must respond properly to events that set it off balance, including responses to thirst, body temperature changes, hunger, weight fluctuations, and fatigue. Liver and muscle contractions, for example, are physiological responses that generate heat inside the body when the internal temperature drops. If any of these responses are damaged or delayed, homeostasis becomes challenging.
We may also engage in certain behaviors that keep our bodies in a balanced homeostatic state. For example, when the temperature in a room drops and creates a feeling of being cold, we look for additional layers of clothing or move to a warmer spot to stay warm. We may also rub our upper arms to generate more heat. In the meantime, a physiological response such as shivering assists with the process. Both our awareness of cold and our involuntary systems work together to achieve homeostasis.