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.
❌ What Is The Menstrutal Cycle?
Each month, eggs begin to mature in the ovary. At the same time, the uterus produces a thickened lining ready for a pregnancy. Every 28 days a mature egg is released (called ovulation). If the egg is not fertilised, around 14 days later the lining of the uterus is shed with the egg, which is what makes a period.
❌ What Hormones Are Involved With The Menstrutal Cycle?
Several hormones are involved in the menstrual cycle of a woman:
- Follicle stimulating hormone (FSH) causes maturation of an egg in the ovary.
- Luteinising hormone (LH) stimulates the release of the egg.
- Oestrogen and progesterone are involved in maintaining the uterus lining.
- Progesterone
❌ What do FSH, LH and Oestrogen do/cause in the Menstrutal Cycle
- The pituitary gland in the brain secretes the hormone FSH
- FSH causes the ovaries to produce another hormone called oestrogen.
- Oestrogen then causes the piuitary gland to secrete LH and inhibits further production of FSH
- LH causes an egg to be released from the ovary
❌ FSH (Folicle Stimulating Hormone) Function
- Causes the eggs to mature
- Stimulates the ovary to produce oestrogen
❌ LH (Luteinising Hormone) Function
- Triggers ovulation
❌ Oestrogen Function
- Causes the lining of the uterus to develop
- Inhibits the release of FSH
- Stimulates the release of LH
❌ Progesterone Function
- Maintains the lining of the uterus
- Inhibits the release of both FSH and LH
❌ Acronym to remember what Hormone stimulates/inhibits the next (+where they are secreted)
FOLP
F - FHS (Folicle Stimulating Hormone) (Ovary)
O - Oestrogen (Pituitary Gland)
L - LH (Luteinising Hormone) (Ovary)
P - Progesterone (Pituitary Gland)
❌ How Can Fertility Be Controlled
Fertility can be controlled by a variety of hormonal and non-hormonal methods of contraception. These include:
- oral contraceptives that contain hormones to inhibit FSH production so that no eggs mature
- injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years
- barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg
- intrauterine devices which prevent the implantation of an embryo or release a hormone
- spermicidal agents which kill or disable sperm
- abstaining from intercourse when an egg may be in the oviduct
- surgical methods of male and female sterilisation.
❌ What Chemical Method Prevents Pregnancy
Chemicals that kill or disable sperm are known as spermicides. They are readily avaliabke but are not very effective at preventing pregnancy.
❌ How Do Condoms Work
Barrier methods of contraception prevent the sperm reaching the egg. A condom is a thin latex sheath placed over the penis during intercourse to collect the semen and prevent the egg and speem meeting.
❌ Condoms Advantages and Disadvantages
Pros:
- Have no side affects
- Do not need medical advice
- Protect you from STD’s (like syphilis and HIV/AIDS)
Cons:
- They can get damaged and let sperm through.
❌ How Does A Diaphragm Or Cap Work?
A diaphragm or cap is a thin rubber diaphragm placed over the cervix before sex to pevent the entry of sperm.
❌ Diaphragm/Cap Advantages and Disadvantages
Pros:
- They have no side affects
- (Work better combined with spermicide)
Cons:
- Must be fitted by a doctor initially
- If the cap is not positioned correctly, sperm may get past and reach the egg
❌ How Do Intrauterine Devices (IUD) Work
Intratuterine devices (IUD’s) are small structures inserted into the uterus by a doctor.
❌ Intrauterine Devices (IUD) Advantages and Disadvantages
Pros:
- Last for 3-5 years and can be removed at any time if you want to get pregnant
Cons:
- Have to be inserted by a doctor
- Some IUD’s contain coper and prevent early embryos implanting in the lining of the uterus
❌ How Does Abstinence Work
If people do not have sex, they will not get preganant. Some religious groups do not accept the use of artificial methids of contraception. Abstaining from intercourse around ovulation or when an egg is in the oviduct means sperm cannot fertilise the egg - this is known as the rhythm method. Ovulation indicators make it more effective.
❌ Abstinence Advantages and Disadvantages
Pros:
- The method has no side affects
Cons:
- It’s very unreliable
❌ How Does Surgical Methods In Men (Vasectomy) Work
If people do not want any more children, they can be surgically sterilised. In men, the sperm ducts ate cut and tied, preventing sperm getting into the semen. This is called vasectomy.
❌ How Does Surgical Methods In Women Work
In women, the oviducts are cut or tried to prevent the egg reaching the uterus and the sperm reaching the egg. Although this gives effective, permanent contraception with no risk of human error, women need a general anaesthetic for the surgery.
❌ Surgical Methods Advantages and Disadvantages
Pros:
- There can be no human error
- There is no chance of getting somone/yourself pregnant
Cons:
- Women need a general anaesthetic for their surgery
❌ How Can Lack Of Ovulation Be Countered (In The Form Of A Drug)
Some women want children, but don’t make enough FSH to stimulate the maturation of the eggs in their ovaries. Fortunately, artificial FSH can be used as a fertility drug. It stimulates the eggs in the ovary to mature and also triggers oestrogen production. An artificial form of LH can then be used to trigger ovulation. If a woman who is not ovulating as a result of a lack of her own FSH is treated in this way, she may be able to get pregnant naturally.
❌ What Happens In ‘In Vitro Fertilisation’ Treatment (IVF)
In Vitro Fertilisation (IVF) treatment:
- IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs.
- The eggs are collected from the mother and fertilised by sperm from the father in the laboratory.
- The fertilised eggs develop into embryos under strict conditions in special solutions in a warm environment
- At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb).
❌ What Makes Modern Infertility Treatments More Difficult
Modern infertility treatments (like IVF) rely on advanced microscopy techniques. It takes a high level of manipulative skill and a high magnification to work on single egg cells and sperm, or early embryos without damaging them.
❌ Advantages Of Fertility Treatment (like IVF)
It gives women and men who would otherwise be infertile the chance to have a baby of their own.
❌ Disadvantages Of Fertility Treatment (like IVF)
- IVF is expensive for society, if it is provided by the NHS, and for individuals - as many pay thousands of pounds for repeated cycles of treatment.
- It’s not always successful (the older the parents, the less likely it is that they will have a baby)
- Using donor eggs from younger women or donor sperm from younger men can help the success rate, but then the baby is not biologically the parents’ child
- The use of fertility drugs can have some health risks for the mother. The process of IVF is very emotionally and physically stressful
- The storing of mature eggs produced by a women using fertility drugs raises ethical problems if the woman dies, the relationship breaks up, and e.c.t
❌ What are some of the Downsides to Fertility Treatment
Although fertility treatment gives a woman the chance to have a baby of her own:
- it is very emotionally and physically stressful
- the success rates are not high
- it can lead to multiple births which are a risk to both the babies and the mother.
❌ What Combination Of Hormones Can Allow Eggs To Mature In The Ovary And The Ovulate?
A combination of FSH and LH can be used in fertility treatments to cause eggs to mature in the ovary and to trigger ovulation.
❌ The Stages Of ‘In Vitro Fertilisation Treatment’ (IVF)
- Fertility drugs are used to make lots of eggs mature at the same time for collection.
- The eggs are collected and placed in a special solution in a petri dish.
- A sample of semen is collected.
- The eggs and sperm are mixed together.
- The eggs are checked to make sure they have been fertilised and the early embryos are developing properly.
- When the fertilised eggs have formed tiny balls of cells, one or two are placed in the uterus of the mother. Hopefully, at least one embryo will survive.
🟢 Why are Plants Sensitive?
Plants respond to stimuli to:
- Avoid stress
- Avoid being eaten
- Enhance survival
🟢 What do Plants Produce Plant Hormones For?
Plants produce hormones to coordinate and control growth and responses to light (phototropism) and gravity (gravitropism or geotropism).
🟢 What do Uneven Distribution of Auxin Show
Unequal distributions of auxin cause unequal growth rates in plant roots and shoots.
🟢 Why are Gibberellins Important In Plants
Gibberellins are important in initiating seed germination.
🟢 What does Ethene control in Plants
Ethene controls cell division and ripening of fruits.
🟢 What Direction Do The Roots of Plants Need To Grow and Why
It is very important when the seeds start to grow (germinate) the roots grow downards into the soil, anchoring the seedlings and keeping it stable. They can also take up water and mineral need for healthy growth.
🟢 What Direction Do The Shoots of Plants Need To Grow and Why
The shoots of plants need to grow upwards towards the light so they can photosynthesise as much as possible.
🟢 What are Plant Roots and Plant Shoots Sensitive to
Plant roots are sensitive to gravity and grow down in the direction of the force of gravity.
Plant shoots are sensitive to gravity and light. The shoots grow towards light and against the force of gravity. This means whichever way up the seed lands, the plant always grows the right way up.
🟢 Why do Plant Responses Happen
Plant responses happen as a result of plant hormones that coordinate and control growth. These responses are easy to see in young seedlings, but they also happen in adukt plants. For example, the stems of a houseplant left on a windowsill will soon bend towards the light.
🟢 What are Tropisms/Tropic Responses
These responses of plant roots and shoots to light and gravity are known as tropisms, or tropic responses.
🟢 What is a Phototropism
The response of a plant to light is known as a phototropism.
🟢 What is a Gravitropism
The response of a plant to gravity is called a gravitropism (or a geotropism).
🟢 What are responses of Plants to Light and Gravity Controlled by and why does the Response happen?
The responses of plants to light and gravity are controlled by a hormone called auxin. The respose happens because of an uneven distribution of this hormone in the growing shoot or root. This causes an unequal growth rate. As a result, the root or shoot bends in the right direction.
🟢 What Happens In Phototropism when a young shoot responds to light
Phototropism can clearly ge seen when a young shoot responds to light from one side only. The shoot will bend so it is growing towards the light. Auxin moves from the side of the shoot where light is falling to the unlit side of the shoot. The cells on that side respond to the hormone by growing more - and so the shoot bends towards the light.
Once light falls evenly on the shoot, levels of auxin will be equal on all sides and so the shoot grows straight again.
🟢 What Happens In Gravitoprisms when a young shoot responds to light
Gravitropisms can be seen in roots and shoots. Auxin has different effects in root and shoot cells. High levels of auxin make shoot cells grow more but inhibit growth of root cells. This is why roots and shoots respond differently to gravity.
