B11 Hormonal Coordination Flashcards
What is the endocrine system?
The endocrine system is composed of glands which secrete chemicals
called hormones directly into the bloodstream. The blood carries the
hormone to a target organ where it produces an effect. Compared to the nervous system the effects are slower but act for longer.
What is the pituitary gland and what does it do?
The pituitary gland in the brain is a ‘master gland’ which secretes
several hormones into the blood in response to body conditions. These
hormones in turn act on other glands to stimulate other hormones to be released to bring about effects.
Identify the following on a diagram of the human body. (Back of card)
- pituitary gland
- pancreas
- thyroid
- adrenal gland
- ovary
- testes.
What do the pancreas monitor?
Blood glucose concentration.
How do the pancreas combat high blood sugar?
If the blood glucose concentration is too high, the pancreas produces
the hormone insulin that causes glucose to move from the blood into the cells. In liver and muscle cells excess glucose is converted to glycogen for storage.
How does Type 1 diabetes function?
Type 1 diabetes is a disorder in which the pancreas fails to produce
sufficient insulin. It is characterised by uncontrolled high blood glucose
levels and is normally treated with insulin injections.
How does Type 2 diabetes function?
In Type 2 diabetes the body cells no longer respond to insulin produced
by the pancreas. A carbohydrate controlled diet and an exercise regime
are common treatments. Obesity is a risk factor for Type 2 diabetes.
How do you treat Type 1 diabetes?
Injections of insulin before mealtimes. This insulin takes glucose to be converted to glycogen in the liver, where if needed it can be converted back into glucose to make blood glucose concentration rise again.
How do you treat Type 2 diabetes?
Sometimes insulin injections, but often normal blood glucose levels can be restored with three simple steps:
- Losing weight
- Regular exercise
- Diet low in carbohydrates.
There are also drugs for Type 2 diabetes which help insulin work better on body cells, increase pancreas insulin production and reduce the amount of glucose absorbed by the intestines.
How do you cure Type 1 diabetes?
Type 1 diabetes can be cured by:
- Pancreas transplant
- Transplanting pancreatic cells from dead to living volunteers.
How do the pancreas combat low blood sugar?
If the blood glucose concentration is too low, the pancreas
produces the hormone glucagon that causes glycogen to be converted
into glucose and released into the blood.
Why is the release of glucagon an example of negative feedback?
Blood sugar is low, so glucagon is high - the opposite occurs.
What does a negative feedback system attempt to accomplish?
Negative feedback systems work to maintain a steady level of a certain substance. If a factor in the internal environment increases/decreases, changes take place to reduce/increase it to its original level.
What are examples of a negative feedback system?
- Release of glucagon
- Release of insulin
- Thyroxine
What does a negative feedback loop look like?
RECEPTORS DETECT CHANGE - RESPONSE LOWERS/RAISES LEVELS - IDEAL LEVEL - LEVELS FALL/RISE - RECEPTORS DETECT CHANGE
The cycle continues in a loop.
What does thyroxine do?
Thyroxine from the thyroid gland stimulates the basal metabolic rate. It
plays an important role in growth and development. Thyroxine levels are controlled by negative feedback. It’s made by iodine from your diet in the thyroid gland.
What does adrenaline do?
Adrenaline is produced by the adrenal glands in times of fear or stress. It increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for ‘flight or fight’.
What is the basal metabolic rate?
How quickly substances are broken down and built up - how much oxygen your tissues use, for example.
What are some osmotic changes in bodily fluids?
Water leaves the body via the lungs during exhalation.
Water, ions and urea are lost from the skin in sweat.
There is no control over water, ion or urea loss by the lungs or skin.
Excess water, ions and urea are removed via the kidneys in the urine.
What happens if osmotic changes are not functioning properly?
If body cells lose or gain too much water by osmosis they do not
function efficiently.
How are amino acids excreted from the body?
The digestion of proteins from the diet results in excess
amino acids which need to be excreted safely. In the liver these amino
acids are DEAMINATED to form ammonia. Ammonia is toxic and so it is
immediately converted to urea for safe excretion.
How do the kidneys function?
The kidneys produce urine by filtration of the blood and SELECTIVE REABSORBTION of useful substances such as glucose, some ions and
water.
How are water levels controlled?
The water level in the body is controlled by the hormone ADH
which acts on the kidney tubules. ADH is released by the pituitary
gland when the blood is too concentrated and it causes more water
to be reabsorbed back into the blood from the kidney tubules. This is
controlled by negative feedback. This process will result in a small amount of very concentrated, dark urine.
How can kidney failure be treated?
People who suffer from kidney failure may be treated by organ transplant or by using kidney dialysis.
