Endocrine System Flashcards
What is a hormone?
Its function
Chemical molecule carried in the blood.
Controls activities in the organs
Secreted by glands
Usually have a long lasting effect.
Compare nerves with hormones?
Nerves:
- Faster
- Act for a shorter time
- Act on a precise area
Hormones:
- Slow action
- Act for a longer time
- Act in a more general way.
Pituitary Gland.
Master gland, secretes many hormones. Controls growth in children Stimulates thyroxine production Stimulates ovaries to make eggs and testes to produce sperms. ADH TSH FSH LH
Thyroid
Releases thyroxine which controls metabolic rates by targeting many organs..
Adrenal Gland
Produces adrenaline hormones to prepare the body.
hormone: aldosterone which controls the concentration of salt and water around the body.
Testes
Releases hormone testosterone, increases muscle mass density, and develops secondary sexual features.
Pancreas
Produces hormone INSULIN which controls blood sugar levels.
Makes glucagon involved in regulating blood sugar levels
Targets the liver.
Ovary
Releases OESTROGEN and PROGESTERONE
controls the menstrual cycle
and female sexual characteristics.
Causes of high blood glucose level
- eating too many carbohydrates
- Diabetes
Causes of low blood glucose levels
- Vigorous exercise
- Normal metabolism of cells removes glucose.
Define,
Glucagon
Glycogen
Glucose
Glucagon is a hormone that makes our liver breakdown glycogen and covert it into glucose.
Glycogen is an insoluble sugar used for storage in the liver.
Glucose is a soluble sugar .
What happens when blood glucose levels are too high.
Pancreas detects level too high
secretes insulin
Insulin moves glucose from blood to liver.
Insulin makes liver turn glucose to glycogen so that it can be stored.
Blood glucose levels decrease.
What happens when blood glucose levels are too low.
Pancreas secretes hormone Glucagon
Glucagon makes liver turn glycogen into glucose.
Glucose released back into blood.
Blood glucose levels increase.
How can an excess amount of lipids lead to obesity?
If your muscles are full and the glycogen is stored in the liver, if you regularly consume food that is more than what liver and muscles can store, then all the excess glucose will be stored as lipids.
What is diabetes?
A condition affecting the ability to control blood sugar levels.
Summary of type 1 diabetes.
- When pancreas doesn’t produce enough insulin.
- Treated by Insulin therapy, when insulin is injected into the body to remove the glucose as soon as it is digested.
Why can’t you take insulin as a tablet.
Insulin is a protein ad hormone, the stomach would not digest it before it gets a chance to work if it was a tablet.
Summary of type 2 diabetes.
- Body becomes insulin resistant, our cells stop responding to insulin.
- Treated by a carbohydrate controlled diet and lifestyle choices e.g exercise.
Why do people with Type 1 diabetes urinate and feel thirsty all the time?
Due to lack of insulin, the glucose is excreted through urine, because you urinate more, you feel more thirsty.
Why do people with Type 1 diabetes lose weight?
They lose weight because our cells stop responding and we begin to lack energy. So the body breakdowns fats and protein to use as a fuel instead, so you lose weight.
Curing Type 1 diabetes
- Pancreas transplants, but limited success.
- Turn mouse pancreas cells that normally turn enzymes into insulin producing cells through genetic engineering. Same could be done for humans.
Curing Type 2 diabetes.
- carbohydrate controlled diet
- lose weight
- regular exercise
The role of Kidneys
-Act as filters to clean the blood.
- They make urine by taking waste products.
As substances pass through kidneys, they are filtered out.
Useful substances like glucose are then re-absorbed back through a process called selective reabsorption.
What substances are removed from the body in urine?
- Urea
- Ions
- Water
Urea
Proteins broken into amino acids.
Excess aa converted to fats and carbohydrates.
In liver, the aa are deaminated to form Ammonia.
Ammonia is toxic so its converted back to urea in liver.
Urea goes to kidney, its filtered out and excreted from body as urine.
Ions
Taken in by food and absorbed into the blood.
Having the wrong amount of ion and water content damages cells
Some ions lost through sweat.
Kidney maintains the ion balance.
Re-absorbs the right amount of ions after filtration.
Water
Needs to be constantly balanced.
We lose water from the skin in sweat and from lungs when breathing out.
Kidneys remove excess water through urine.
Role of ADH
ADH controls urine concentration and affects the permeability of tubules.
How does ADH control the conc of urine t
Negative feedback
Well hydrated
Blood water level is high Less ADH is released. Low permeability of tubules. LESS water re-absorbed Dilute and yellowy urine
De hydrated
Blood water level is too low more ADH is released. High permeability of tubules. More water is reabsorbed. Concentrated and dark urine.
