Homeostasis Gross October 22 & 23

Literal Definition “Homeo”- Unchanging “Stasis”- Standing Translates to a “steady state” or an “unchanging state” Keeping a state of stability no matter what happens from outside factors. Literal Definition

Human Homeostasis

Sneezing is a reflex. When irritants such as germs, dust, pollen, or pollutants, infiltrate the nose lining, the brain sends out a signal to get rid of it. That triggers a deep breath, which gets held in the lungs. Keeps the body stable in response to viral infection. Sneezing

Sweating plays an important role in the body because it helps maintain body temperature by cooling us down. When we're hot and we sweat, that moisture evaporates and cools us off a bit.  Keeps the body stable in warm temperatures Sweating

When you feel cold, tiny sensors in your skin send messages to your brain telling you need to warm up. Your brain sends messages to nerves all over your body telling your muscles to tighten and loosen really fast, which is what we call shivering. It does this because when muscles move they generate heat. Keeps the body stable in colder temperatures Shivering

Blood Vessels Constricting When we are too cold the blood vessels supplying warm blood to the skin become narrow or constrict (vasoconstriction). This reduces the flow of warm blood near the surface of the skin, and reduces heat loss.  Allows the body to remain stable in colder temperatures Blood Vessels Constricting

Allows the body to remain stable in cold temperatures Increasing Activity

Perhaps you have not drunk anything for a while or you have been sweating a lot. Part of the brain, the hypothalamus, detects that there is not enough water in the blood. The hypothalamus sends a message to the pituitary gland which releases ADH. This travels in the blood to your kidneys and affects the tubules so more water is reabsorbed into your blood. As a result you make a smaller volume of more concentrated urine. The level of water in your blood increases until it is back to normal. Body remains stable when there is a lack of water Reabsorption of Water

Animal Homeostasis Hibernation Allows animals to maintain a stable internal environment during winter Animal Homeostasis

Plant Homeostasis Dropping their leaves in excess heat Allows plants to maintain stability in changing external conditions Roots growing towards water Plant Homeostasis