B11 - Hormonal Control (Y11 - Autumn 1)

Question 1

🟢 What Are Hormones

Answer 1

Hormones are chemical messengers used in the body by the endocrine system. They co-ordinate our organs. Hormones are produced by glands

Question 2

🟢 What Is The Role Of Hormones?

Answer 2

• 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

Question 3

🟢 What Is The Endocrine System And Does It Do?

Answer 3

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.

Question 4

🟢 What Are The Endocrine Glands

Answer 4

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.

Question 5

❌ What Other Hormones Are Released By The Pituary Gland

Answer 5

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.

Question 6

🟠 What Are The Endocrine Glands And Where Are They In The Body

Answer 6

• 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

Question 7

🟢 How Are Blood Glucose Concentration Levels Monitored

Answer 7

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.

Question 8

🟢 How Does Glucagon Help Control Blood Sugar Levels

Answer 8

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.

Question 9

🟢 What Is Type 1 Diabetes And What Causes It

Answer 9

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.

Question 10

🟢 What Is Type 2 Diabetes And What Causes It

Answer 10

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.

Question 11

🟢 What Happens When Glucose Levels In The Blood Are Too Low?

Answer 11

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.

Question 12

🟢 What Happens When Glucose Levels In The Blood Are Too High?

Answer 12

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.

Question 13

🟢 Type 1 Diabetes overall:

• Cause
• Symptoms
• Prevalence
• Age of Onset
• Treatment

Answer 13

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)

Question 14

🟢 Type 2 Diabetes overall:

• Cause
• Symptoms
• Prevalence
• Age of Onset
• Treatment

Answer 14

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

Question 15

🟢 What is Insulin and Where is it Injected?

Answer 15

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.

Question 16

🟢 How Can Type 1 Diabetes Be Treated

Answer 16

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.

Question 17

🟢 What Cures are there for Type 1 Diabetes

Answer 17

• 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)

Question 18

🟢 How can Doctors Cure Type 1 Diabetes (what Operations can they do?)

Answer 18

• 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.

Question 19

🟢 What is Type 2 Diabetes and What Can Cause it?

Answer 19

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.

Question 20

🟢 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)

Answer 20

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)

Question 21

🟢 What Is The Endocrine System And What Does It Do?

Answer 21

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.

Question 22

🟢 What Is The Putuitary Gland And What Does It Do?

Answer 22

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.

Question 23

❌ What is Negative Feedback?

Answer 23

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)

Question 24

❌ Examples of Hormones That Can Be Involved With Negative Feedback?

Answer 24

Examples include the:

• pituitary gland
• pancreas
• thyroid
• adrenal gland
• ovary
• testes

Question 25

🟢❌*How Does Negative Feedback Work With Thyroxine

Answer 25

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.

Question 26

🟢❌*What Can Adrenaline Cause?

Answer 26

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.

Question 27

❌ What Happens In Puberty?

Answer 27

During puberty reproductive hormones cause secondary sex characteristics to develop.

Question 28

❌ What Is Oestrogen And What Does It Do?

Answer 28

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.

Question 29

❌ What Is Testosterone And What Does It Do?

Answer 29

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.

Question 30

❌ What Is The Menstrutal Cycle?

Answer 30

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.

Question 31

❌ What Hormones Are Involved With The Menstrutal Cycle?

Answer 31

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

Question 32

❌ What do FSH, LH and Oestrogen do/cause in the Menstrutal Cycle

Answer 32

- 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

Question 33

❌ FSH (Folicle Stimulating Hormone) Function

Answer 33

- Causes the eggs to mature | - Stimulates the ovary to produce oestrogen

Question 34

❌ LH (Luteinising Hormone) Function

Answer 34

- Triggers ovulation

Question 35

❌ Oestrogen Function

Answer 35

- Causes the lining of the uterus to develop - Inhibits the release of FSH - Stimulates the release of LH

Question 36

❌ Progesterone Function

Answer 36

- Maintains the lining of the uterus | - Inhibits the release of both FSH and LH

Question 37

❌ Acronym to remember what Hormone stimulates/inhibits the next (+where they are secreted)

Answer 37

FOLP F - FHS (Folicle Stimulating Hormone) (Ovary) O - Oestrogen (Pituitary Gland) L - LH (Luteinising Hormone) (Ovary) P - Progesterone (Pituitary Gland)

Question 38

❌ How Can Fertility Be Controlled

Answer 38

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.

Question 39

❌ What Chemical Method Prevents Pregnancy

Answer 39

Chemicals that kill or disable sperm are known as spermicides. They are readily avaliabke but are not very effective at preventing pregnancy.

Question 40

❌ How Do Condoms Work

Answer 40

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.

Question 41

❌ Condoms Advantages and Disadvantages

Answer 41

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.

Question 42

❌ How Does A Diaphragm Or Cap Work?

Answer 42

A diaphragm or cap is a thin rubber diaphragm placed over the cervix before sex to pevent the entry of sperm.

Question 43

❌ Diaphragm/Cap Advantages and Disadvantages

Answer 43

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

Question 44

❌ How Do Intrauterine Devices (IUD) Work

Answer 44

Intratuterine devices (IUD's) are small structures inserted into the uterus by a doctor.

Question 45

❌ Intrauterine Devices (IUD) Advantages and Disadvantages

Answer 45

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

Question 46

❌ How Does Abstinence Work

Answer 46

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.

Question 47

❌ Abstinence Advantages and Disadvantages

Answer 47

Pros: - The method has no side affects Cons: - It's very unreliable

Question 48

❌ How Does Surgical Methods In Men (Vasectomy) Work

Answer 48

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.

Question 49

❌ How Does Surgical Methods In Women Work

Answer 49

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.

Question 50

❌ Surgical Methods Advantages and Disadvantages

Answer 50

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

Question 51

❌ How Can Lack Of Ovulation Be Countered (In The Form Of A Drug)

Answer 51

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.

Question 52

❌ What Happens In 'In Vitro Fertilisation' Treatment (IVF)

Answer 52

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).

Question 53

❌ What Makes Modern Infertility Treatments More Difficult

Answer 53

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.

Question 54

❌ Advantages Of Fertility Treatment (like IVF)

Answer 54

It gives women and men who would otherwise be infertile the chance to have a baby of their own.

Question 55

❌ Disadvantages Of Fertility Treatment (like IVF)

Answer 55

- 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

Question 56

❌ What are some of the Downsides to Fertility Treatment

Answer 56

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.

Question 57

❌ What Combination Of Hormones Can Allow Eggs To Mature In The Ovary And The Ovulate?

Answer 57

A combination of FSH and LH can be used in fertility treatments to cause eggs to mature in the ovary and to trigger ovulation.

Question 58

❌ The Stages Of 'In Vitro Fertilisation Treatment' (IVF)

Answer 58

1. Fertility drugs are used to make lots of eggs mature at the same time for collection. 2. The eggs are collected and placed in a special solution in a petri dish. 3. A sample of semen is collected. 4. The eggs and sperm are mixed together. 5. The eggs are checked to make sure they have been fertilised and the early embryos are developing properly. 6. 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.

Question 59

🟢 Why are Plants Sensitive?

Answer 59

Plants respond to stimuli to: - Avoid stress - Avoid being eaten - Enhance survival

Question 60

🟢 What do Plants Produce Plant Hormones For?

Answer 60

Plants produce hormones to coordinate and control growth and responses to light (phototropism) and gravity (gravitropism or geotropism).

Question 61

🟢 What do Uneven Distribution of Auxin Show

Answer 61

Unequal distributions of auxin cause unequal growth rates in plant roots and shoots.

Question 62

🟢 Why are Gibberellins Important In Plants

Answer 62

Gibberellins are important in initiating seed germination.

Question 63

🟢 What does Ethene control in Plants

Answer 63

Ethene controls cell division and ripening of fruits.

Question 64

🟢 What Direction Do The Roots of Plants Need To Grow and Why

Answer 64

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.

Question 65

🟢 What Direction Do The Shoots of Plants Need To Grow and Why

Answer 65

The shoots of plants need to grow upwards towards the light so they can photosynthesise as much as possible.

Question 66

🟢 What are Plant Roots and Plant Shoots Sensitive to

Answer 66

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.

Question 67

🟢 Why do Plant Responses Happen

Answer 67

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.

Question 68

🟢 What are Tropisms/Tropic Responses

Answer 68

These responses of plant roots and shoots to light and gravity are known as tropisms, or tropic responses.

Question 69

🟢 What is a Phototropism

Answer 69

The response of a plant to light is known as a phototropism.

Question 70

🟢 What is a Gravitropism

Answer 70

The response of a plant to gravity is called a gravitropism (or a geotropism).

Question 71

🟢 What are responses of Plants to Light and Gravity Controlled by and why does the Response happen?

Answer 71

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.

Question 72

🟢 What Happens In Phototropism when a young shoot responds to light

Answer 72

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.

Question 73

🟢 What Happens In Gravitoprisms when a young shoot responds to light

Answer 73

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.