Staying In Balance Flashcards
What is homeostasis maintained by?
It is maintained by Negative Feedback
What is Negative Feedback?
When changes in the environment trigger a response that counteracts the changers. This means that the internal environment tends to stay around a level at which the cells work best. This only works within certain limits. However if the environment changes too much then it might not be possible to counteract it
What is vasodilation?
It occurs when we’re too hot. The hairs lie flat. Lots of sweat is produced- when sweat evaporates it uses heat from the skin. This transfers heat from the skin to the environment, which cools us down. Blood vessels close to the surface of the skin widen. This allows more blood to flow near the surface, so it can radiate more heat into the surroundings
What is vasoconstriction?
It occurs when we’re too cold. Hairs stand on end to trap an insulating layer of air which helps keep us warm. Very little sweat is produced. Blood vessels near the surface constrict so that less heat can be transferred from the blood to the surroundings. So when we shiver, the movement generates heat in the muscle
What is homeostasis? Give examples
Homeostasis is maintaining constant internal conditions e.g. Water levels, blood sugar levels, ion levels, temperature
What hormone controls blood sugar levels?
Insulin
Changes in blood glucose are monitored and controlled by what?
The pancreas
When blood glucose levels are too high, insulin is added.
Describe the process
Blood sugar rises after a meal. Insulin released from pancreas. Glucose converted to glycogen stored in the liver. Blood sugar falls again. Normal blood sugar range.
Blood sugar falls after exercise. Glucagon released. Glycogen converted back to glucose. Blood sugar rises again. Normal blood sugar range
Why does it take the body longer to respond to a hormone than a nervous impulse?
Because hormones travel in the blood so it can take quite a while for them to get to where they’re needed in the body. However, electrical impulses sent along the nerves travel much faster
What are the two types of diabetes?
Type 1 and type 2
What is type 1 diabetes caused by?
The pancreas produces little or no insulin
How is type 1 diabetes controlled?
It can be partly controlled by having a carefully controlled diet, but also with insulin therapy. This usually involves injecting insulin into the blood several times a day. This makes sure that glucose is removed from the blood quickly once food has been digested. This stops the level of glucose in the blood from getting too high. The amount of insulin needed depends on the person’s diet and how active they are
What causes type 2 diabetes?
When a person resistant to insulin
How can type 2 diabetes be controlled?
Type 2 diabetes is usually just controlled by limiting the intake of foods rich in simple carbohydrates
