Topic 11 - Hormonal Coordination Flashcards
What is the endocrine system?
The endocrine system is made up of glands that secrete chemicals called hormones directly into the blood stream. The blood carries the hormone to its target organ where it produces an effect. The target organ has receptors on the cell membranes that pick up hormone molecules, triggering a cellular response.
What is a hormone?
Hormones are regulatory substances produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action. They are proteins and have a similar receptor-active site system to enzymes.
What does insulin do?
Insulin acts to reduce glucose concentration by increasing glucose absorption from the blood by the liver and muscles; converting excess glucose to glycogen. It can be broken down to glucose when sugar reserves are low.
What does adrenaline do?
It prepares the body for fight or flight by heightening strength, increasing reaction times and transfering glucose to the different parts of the body.
What is the pituitary gland?
The gland control most of the secretion of hormones throughout the body, often referred to as a master gland. It also
-Controls growth in children.
-Stimulates the thyroid gland to make thyroxine and control metabolism.
-In women - stimulates the ovaries to produce and release eggs and make the female sex hormone oestrogen.
-In men - stimulates the testes to make sperm and the male sex hormone testosterone.
What does FSH do?
Follicle Stimulating Hormone stimulates the ovaries to make the female sex hormone oestrogen.
What does TSH do?
Stimulates the thyroid gland to make thyroxine, a hormone that helps control the rate of your metabolism.
What does the pancreatic gland do?
Controls the levels of glucose in the blood.
What does the adrenal gland do?
Prepares the body for stressful situations - by making the body in a hyper state.
What do the ovaries do?
Controls the development of the female secondary sexual characteristics and is involved in the menstrual cycle.
What do the testes do?
Controls the development of the male secondary sexual characteristics and is involved in the production of sperm.
What is glucagon?
When the blood sugar concentration level goes too low, glucagon is secreted which makes the liver break down glycogen, converting it back into glucose. Stored glucose is released back into the blood.
What causes type 2 diabetes?
-The older you get the more likely you are to develop it since metabolism slows.
-It is linked to lack of exercise, excess eating, obesity and more.
-There can also have a genetic tendency to develop type 2 diabetes.
-Your body cells stop responding properly to the insulin you make.
What causes type 1 diabetes and what are the consequences of it?
If your pancreas does not make enough (or any) insulin, your blood glucose concentration is not controlled.
Without insulin your blood glucose levels get very high after you eat.
Eventually your kideneys excrete glucose in your urine. You produce lots of urine and feel thirsty all the time. Without insulin, glucose cannot get into the cells of your body, so you lack energy and feel tired. You break down fat and protein in the body as fuel instead of glucose, losing weight.
How do you treat type 1 diabetes?
You take replacement insulin before meals. Insulin is a protein that would be digested in your stomach, so it usually given as an injection to get into the blood stream.
This injected insulin allows glucose to be taken into your body cells and converted into glycogen in the liver. This stops the concentration of glucose in your blood from getting too high. Then, as the blood glucose levels fall, the glycogen is converted back to glucose. As a result, your blood glucose levels are kept as stable as possible.
If you have type 1 diabetes you need to control the amount of carbohydrate intake and have regular meals. Moreover, exercise requires more planning. Like everyone else, you need to exercise to keep your heart and blood vessels healthy.
How is type 1 diabetes cured?
-Doctors can transplant a pancreas successfully, however, this operation is risky and difficult. Only a few hundred pancreas transplants take place each year. There are not enough pancreas donors to help the 250,000 people with type 1 in the UK.
How do you treat type 2 diabetes?
-Eating a balanced diet with controlled amounts of carbohydrates.
-Losing weight
-Doing regular exercise
There are also drugs that:
-Help insulin work better on the body cells
-Help your pancreas make more insulin
-Reduce the amount of glucose you absorb by the gut.
What is negative feedback?
If a factor in the internal environment increases, changes take place to reduce it and restore the original level.
If a factor in the internal environment decreases, changes take place to increase it and restore the original level.
This is done to keep the level within narrow limits.
How does negative feedback work with thyroxine?
The thyroid gland uses iodine from your diet to produce the hormone thyroxine. This controls the basal metabolic rate of your body. Thyroxine plays an important part in growth and development. In adults, thyroxine levels remain relatively stable. This happens as a result of negative feedback. If thyroxine in the blood begin to fall, it is detected by sensors in the brain. As a result, the amount of TSH released from the pituitary gland increases. TSH stimulates the production of thyroxine by the thyroid gland. As the level of thyroxine increases, it is detected by sensors and in turn the level of TSH released falls.
