Homeostasis

• Homeostasis is the regulation of constant internal condition for optimum activity of bodily functions.
• Homeostasis can include temperature regulation, water levels and hormone levels.
• If you are too cold, your body may shiver and your skin may become pale.
• If you are too hot, you may sweat and your skin may become red.
• Temperature receptors in the skin detect a change in body temperature. This information is sent via sensory neurones and a response is coordinated by the hypothalamus.
• Vasodilation is where capillaries near the surface of the skin widen to increase blood flow, helping to radiate heat to surroundings and cool down.
• Shivering is when muscles contract rapidly to generate heat.
• Pale skin reflects less light so more heat is lost.
• Vasoconstriction is where blood vessels near the surface of the skin become narrower to decrease blood flow, causing less heat to be radiated to the surroundings therefore maintaining core body temperature.
• Sweat must evaporate in order for the body to cool down - internal thermal energy is used to do this, decreasing the internal thermal energy and therefore body temperature.
• Shivering is increased movement from muscle contraction which generates heat as a bi-product.
• Thermoregulation is under the control of a negative feedback pathway.
• Negative feedback is where mechanisms in the body perform the opposite function as to what is happening in order to help return to a constant state.