B11 - Hormonal Control (Y11 - Autumn 1) Flashcards
🟢 What Are Hormones
Hormones are chemical messengers used in the body by the endocrine system. They co-ordinate our organs. Hormones are produced by glands
🟢 What Is The Role Of Hormones?
- Hormones travel slower than nerve impulses but have a longer lasting effect.
- They are excreted by the glands and travel in the blood
- Hormones stabilises the body internal environment and also have roles in growth and sexual development
🟢 What Is The Endocrine System And Does It Do?
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. The target organs has receptors on the cell membranes that pick up the hormone molecules, triggering a response in the cell.
Many processes in your body are coordinated by these hormones. Hormones can act very rapidly but, compared to the nervous system, many hormonal effects are slower but long lasting. Hormones that give a rapid response include insulin, which controls your blood glucose, and adrenaline, which prepares your body for fight or flight. Slow-acting hormones with long-term effects include growth hormones and sex hormones.
🟢 What Are The Endocrine Glands
Hormones provide chemical coordination and control for the body and are produced by the endocrine glands. Many endocrine glands around the body are themselves coordinated and controlled by one very small but powerful endocrine gland found in the brain - the pituitary gland.
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.
❌ What Other Hormones Are Released By The Pituary Gland
Some hormones produced by the pituitary in response to changes in the internal enviornment have a direct effect on the body. Examples include ADH, which affects the amount of urine peoduced by the kidney, and growth hornone, which controles the rate of growth in children.
Other hormones released by the pituitary affect specific endocrine glands, stimulating them to release hormones that bring about the required effect on the body. These include:
- Follicle stimulating hormone (FSH), which stimulates the ovaries to make the female sex hormone, oestrogen, and
- TSH, which stimulates the thyroid gland to make thryoxine, a hormone that helps control the rate of your metabolism
Each of the endocrine glands produces hormones that have a major effect on the way your body works. The levels of the hormones vary depending on changes in the internal environment of your body.
🟠 What Are The Endocrine Glands And Where Are They In The Body
- The Pituitary Gland is found located at the base of the brain. The gland is attached to the hypothalamus by nerve fibers and blood vessels
- The Thyroid Gland is at the base of your neck
- The Adrenal Gland is located on top of both kidneys
- The Pancreas is across the back of the belly, behind the stomach
- The Ovary (female) is located on either side of the uterus
- The Testis (male) are behind the penis in a pouch of skin called the scrotum
🟢 How Are Blood Glucose Concentration Levels Monitored
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 Glucagon Help Control Blood Sugar Levels
The control of your blood glucose doesn’t just involve insulin. When your blood glucose concentration falls below the ideal range, the pancreas secretes another hormone called glucagon. Glucagon makes your liver break down glycogen, converting it back into glucose. In this way, the stored glucose is released back into the blood.
By using two hormones and the glycogen store in your liver, your pancreas keeps your blood glucose concentration fairly constant. It does this using negative feedback control, which involves switching between the two hormones.
🟢 What Is Type 1 Diabetes And What Causes It
Type 1 diabetes is a disorder in which the pancreas fails to produce sufficient insulin. Without insulin, glucose cannot get into the cells of your body, so you lack energy and feel tired, while you break down fat and peotein to use as fuel instead, meaning you lose weight. Type 1 diabetes is a disorder that usually starts in young children and teenagers. It is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injections.
🟢 What Is Type 2 Diabetes And What Causes It
In Type 2 diabetes the body cells no longer respond to insulin produced by the pancreas (so insulin is produce, the cells are just immune to it). It gets more common as people get older and is often linked to obesity and lack of exercise. There is also a strong genetic yendancy to develop type 2 diabtetes too. A carbohydrate controlled diet and an exercise regime are common treatments. Obesity is a risk factor for Type 2 diabetes.
🟢 What Happens When Glucose Levels In The Blood Are Too Low?
If the blood glucose concentration is too low (if you haven’t eat for a long time), the pancreas produces the hormone glucagon that causes glycogen to be converted into glucose and released into the blood.
🟢 What Happens When Glucose Levels In The Blood Are Too High?
If the blood glucoses concentration is too high (if you’ve ate a large meal that’s high in glucose levels), the pancreas produces the hormone insulin, that stimulates the formation of glycogen from glucose, which results in lower glucose levels in the blood.
🟢 Type 1 Diabetes overall:
- Cause
- Symptoms
- Prevalence
- Age of Onset
- Treatment
Cause: The pancreas produces little or no isulin
Symptoms: Produce lots of urine and feel thirsty and tiredall of the time
Prevalence: Around 10% of people with diabetes have type 1
Age of Onset: Starts in young children and teenagers
Treatment: Replacement insulin (insulin injections)
🟢 Type 2 Diabetes overall:
- Cause
- Symptoms
- Prevalence
- Age of Onset
- Treatment
Cause: It’s linked to obesity and lack of exercise. It’s also genetic
Symptoms: Obesity and feeling tired due to small insulin production
Prevalence: Around 90% of people with diabetes have type 2
Age of Onset: More common in older people
Treatment: Having a balanced diet, losing weight, and doing regular exercise
🟢 What is Insulin and Where is it Injected?
Insulin is a protein that would be digested in your stomach so it is usually given as an injection to get it into your blood.
🟢 How Can Type 1 Diabetes Be Treated
When you have type 1 diabetes, you will need replacement insulin before meals, which is injected into your blood. The 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 a 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.
To help treat type 1 diabetes, you need to be careful of the levek of carbohydrates you eat, and it’s important to have regular meals. Also, you need to exercise well to keep your heart and blood vessels healthy. However, taking exercise needs careful planning to keep blood glucose levels steady throughout.
🟢 What Cures are there for Type 1 Diabetes
- Replacement Pancreas (you have to take immunosupressants instead of insulin)
- Transplanting Pancreatic Cells
- Genetic Engineering of mouse pancreas cells / Using adult stem cells from patients with disbetes (to make cells that usually make enzymes into insulin-producing cells)
🟢 How can Doctors Cure Type 1 Diabetes (what Operations can they do?)
- Doctors can transplant a pancreas, but operations are very difficult and risky (but it can be done successfully. Only a few hundred transplants take place each year in the UK, but not enough pancreas donors are avaliable. With this treatment, the patient exchanges one medicine (insulin) for another (immunosupressants).
- Transplanting the pancreatic cells that make insulin from both dead and living donors has also been tried, with limited success so far.
- UK scientists dicovered that by using genetic engineering, they turned mouse pancreas cells that normally make enzymes into insulin-producing cells. Other groups are using adult stem cells from patients with diabetes to try the same technique.
🟢 What is Type 2 Diabetes and What Can Cause it?
Type 2 diabetes is linked to obesity, lack of exercise, and old age. Type 2 diabetes is when your body cells no longer respond to insulin made by the pancreas. This can often be treated with needing to inject insulin.
🟢 What 3 things can People with Type 2 Diabetes do to restore their normal blood glucose balance? (+ What 3 things can be done if these measure don’t work)
Many people can also restore their normal blood glucose balance by taking 3 simple steps:
- Eating a balalnced diet with controlled amounts of carbohydrates
- Losing weight
- Doing regular exercise
If these things don’t work, there are drugs that:
- Help insulin work better on body cells
- Help you pancreas make more insulin
- Reduce the amount of glucose you will absorb from your gut.
(Then if these treatments don’t work, the person can take insulin injections)
🟢 What Is The Endocrine System And What Does It Do?
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 Putuitary 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.
❌ 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.
Whatever the initial change, the response is the opposite in negative feedback. (Also, many hormones are involved on negative feedback)
❌ Examples of Hormones That Can Be Involved With Negative Feedback?
Examples include the:
- pituitary gland
- pancreas
- thyroid
- adrenal gland
- ovary
- testes
🟢❌*How Does Negative Feedback Work With Thyroxine
In adults the level of thyroxine in the blood usually remains relatively stable. This happens as a result of a negative feedback control involving the pituitary gland and tbe hormone it produces - thyroxine stimulating hormone or TSH.
If levels of 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. This is a negative feedback system. TSH
stimulates the produce of thyroxine by the thyroid
gland. As a the level of thyroxine goes up, it is
detected by the sensors and in turn, the level of
TSH released fall.
🟢❌*What Can Adrenaline Cause?
Your adrenal glands secrete lots of adrenaline that is carried rapidly around the body in your blood, affecting lots of organs. Adrenaline causes:
- Your heart rate and breathing rate to increase
- Stored glycogen in the liver to be converted to glucose for respriation
- The pupils of your eyes dilate to let in more light
- Your mental awareness to increase
- Blood to be diverted away from your digestive system to the big muscles of the limbs
- It boosts the delivery of oxygen and glucose to your brain and muscles, preparing your body for flight or fight.
❌ What Happens In Puberty?
During puberty reproductive hormones cause secondary sex characteristics to develop.
❌ What Is Oestrogen And What Does It Do?
Oestrogen is the main female reproductive hormone produced in the ovary. Rising oestrogen levels trigger the development of the female secondary characteristics, usually between the ages of 8 and 14 (e.g growth spurt, pubic hair, breasts develop, the brain matures e.c.t). At puberty eggs begin to mature and one is released approximately every 28 days. This is called ovulation.
❌ What Is Testosterone And What Does It Do?
Testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production. As testosterone levels rise, all kinds of changes are triggered and the male secondary characteristics develop. Boys go into the first stages of puberty later than girls (between 9-15) and the main changes include a growth spurts, facual hair, the larynx gets bigger, the voice breaks, and the testes grow (then producing sperm throughout life), the chest and shoulders broaden, and the brain matures.
