B3.3 Maintaining An Internal Environemt Flashcards
What is the optimum temperature for enzymes in your body?
37 degrees Celsius
Define homeostasis
Homeostasis means maintaining a constant internal environment
Why is it important for conditions in your body to be kept steady?
It is important so that all metabolic reactions vital for keeping you alive can continue at an appropriate rate.
What does body need to regulate?
Osmoregulation- you need to keep a balance between the water you gain (in drink, food and respiration) and water you pee, sweat and breathe out.
Thermoregualtion- you need to keep your body temperate steady
Glück regulation- you need to make sure the amount of glucose in your blood doesn’t get too high or too low.
How is your body temperature controlled?
The hypothalamus is your body control body temperature.
It contains receptors that are sensitive to blood temperature in the brain. It also receives electrical impulses from receptors in the skin that provide information about the external temperature.
When the hypothalamus detects a change, it causes a response in the dermis (deep layer of the skin).
When you get too hot…
Erector muscles relax, so body hairs on your skin lie flat.
Sweat glands produce sweat (contains water, salts and urea). As the water in sweat evaporates, energy is transferred by heating from your body to the environment which reduces your temperature.
Blood vessels close to the surface of the skin dilate (widen). This is called vasodilation. It allows more blood to flow near the surface, so it can transfer more energy into the surroundings, which cools you down.
When you get too cold…
Erector muscles contract. Hair stand on the end to trap an insulating layer of air close to the skin, which helps you keep warm.
Sweat glands stop producing sweat
Blood vessels near the surface of the skin constrict (narrow). This is called vasoconstriction. It means less blood flows near the surface, so less energy is transferred to the surroundings.
When you’re cold you shiver so you muscle contract and relax very quickly. This makes your cells respire more quickly, transferring extra energy by heating.
