B11 - Hormonal Coordination Flashcards
What is ADH?
anti-diuretic hormone that helps control the water balance of the body and affects the amount of urine produced by the kidney
What is adrenaline?
Adrenaline is produced by the adrenal glands above the kidneys, it is a hormone that prepares the body for flight or fight
What is contraception?
Methods of preventing pregnancy which usually involves preventing sperm and egg from meeting
What is the endocrine system?
The endocrine system is made up of the glands that produce hormones that control many aspects of the development and metabolism of the body, and the hormones they produce
What is follicle stimulating hormone?
FSH is a hormone that causes the eggs to mature in the ovary
What is glucagon?
Hormone involved in the control of blood sugar levels
What are hormones?
Chemicals produced in one area of the body of an organism that have an effect on the functioning of another area of the body. In animals hormones are produced in glands
What is insulin?
hormone involved in the control of blood sugar levels
What is oestogen?
Female sex hormone that controls the development of secondary sexual characteristics in girls at puberty, and the build-up and maintenance of the uterus lining during the menstrual cycle
What are ovaries?
Female sex organs that produce eggs and sex hormones
What is ovulation?
The release of a mature egg (ovum) from the ovary
What is the pituitary gland?
Endocrine “master gland” found in the brain that secretes a number of different hormones into the blood in response to different conditions to control other endocrine glands in the body
What is testosterone?
The main male sex hormone that controls the male secondary sexual characteristics at puberty and the production of sperm
What is type 1 diabetes?
A disroder where the pancreas fails to produce sufficient insulin
What is type 2 diabetes?
A disorder where the body cells no longer responds to the insulin produced by the pancreas
What happens if a healthy person has low blood sugar levels?
The pancreas secretes glucagon which stimulates glycogen breakdown in the liver, converting it back to glucose. In tis way, the stored glucose is released back into the blood - raising the blood sugar levels
What happens if a healthy person has high blood sugar levels?
The pancreas secretes a hormone called insulin. Insulin stimulates the glucose uptake from the blood by cells, and the formation of glycogen from glucose. In this way, the blood sugar levels are lowered
Explain fully the role of FSH?
Follicle stimulating hormone is secreted by the pituitary gland. It makes eggs mature in their follicles in the ovaries. It also stimulates the ovaries to produce oestogen
Explain fully the role of Oestrogen:
Oestrogen is made and excreted by the ovaries in response to FSH. It stimulates the lining of the uterus to grow again after menstruation in preparation for pregnancy. High levels of oestrogen inhibit the production of more FSH and stimulate the release of LH
Explain fully the role of LH:
Luteinising hormone is secreted by the pituitary gland and stimulates the release of a mature egg from the ovary. Once ovulation has taken place, LH levels fall again. LH inhibits the production of more oestrogen and stimulates the production of progesterone
Explain fully the role of progesterone:
Progesterone is secreted by the empty egg follicle in the ovary after ovulation. It is one of the hormones that helps to maintain a pregnancy if the egg is fertilised. Progesterone inhibits both FSH and LH and it maintains the lining of the uterus in the second half of the cycle, so it is ready to receive a developing embryo if the egg is fertilised. If fertilisation does not happen, then progesterone levels fall and the uterus lining pulls away, causing a new cycle to begin
Why is the endocrine system needed if animals already have a nervous system?
The endocrine system helps long-term changes happen within the body over a longer period of time, over days or even years rather than second to second or minute to minute
Explain how the endocrine system works:
The endocrine system is made up of glands that secrete chemicals called hormones directly into the bloodstream. The blood carries the hormone to its target organ where it produces an effect. The target organ has receptors on the cell membranes that pick up the hormone molecules, triggering a response in the cell
What is the main role of hormones produced by the pituitary gland?
*Controls growth in children
*Stimulates the thyroid gland to made thyroxine to control the rate of metabolism
*Stimulates the sexual organs to produce hormones
What is the main role of hormones produced by the thyroid gland?
Controls the metabolic rate of the body
What is the main role of hormones produced by the pancreas?
Controls the levels of glucose in the blood
What is the main role of hormones produced by the adrenal gland?
Prepares the body for stressful situations - “fight or flight” response
What is the main role of hormones produced by the ovaries?
Controls the development of the female secondary sexual characteristics and is involved in the menstrual cycle
What is the main role of hormones produced by the testes?
Controls the development of the female secondary sexual characteristics and is involved in the production of sperm
Name 6 important endocrine glands:
*Pituitary gland
*Thyroid gland
*Pancreas
*Adrenal gland
*Ovaries
*Testes
Why is control of the blood glucose levels needed?
When you digest a meal, large amounts of glucose pass into your blood. Without a control mechanism, your blood glucose levels would vary significantly. They would range from very high straight after a meal, to very low several hours later - so low that the cells would not have enough glucose to respire. This situation is prevented by your pancreas. IT constantly monitors and controls your blood glucose concentration.
What happens if glucose is converted to glycogen but the liver and muscles are already at maximum glycogen capacity?
The excess glycogen is converted into lipids and stored. If you regularly take in food that results in having more glucose than the liver and muscles can store as glycogen, you will gradually store more and more of it as lipids and may eventually become obese
Explain what type 1 diabetes is:
If your pancreas does not make enough (or any) insulin, your blood glucose concentration is not controlled. This is called type 1 diabetes. Without insulin your blood glucose levels get very high after you eat. Eventually your kidneys excrete glucose in your urine. you produce lots of urine and feel thirsty all the time. Without insulin, glucose cannot get into the cells of your body, so you lack energy and feel tired. You break down fat and protein to use as fuel instead, so you lose weight. Type 1 diabetes is a disorder that usually starts in young children and teenagers. There also seems to be a genetic element to the development of the disease
Explain what type 2 diabetes is:
Type 2 diabetes gets more common as people get older and it is often linked to obesity, lack of exercise, or both. There is also a strong genetic tendency to develop type 2 diabetes. In type 2 diabetes, the pancreas still makes insulin, although it may make less than your body needs. More importantly, your body cells stop responding to the insulin you make. In countries such as the UK and USA, levels of type 2 diabetes are rising rapidly as obesity becomes more common
What would happen if diabetes is not treated?
The person would waste away and fall into a coma before dying
How do you treat type 1 diabetes?
If you have type 1 diabetes, you need replacement insulin before meals. 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. The insulin allows glucose to be taken into your body cells and converted to glycogen in the liver. This stops the concentration of glucose in your blood from getting too high. Then, as blood glucose levels fall, the glycogen is converted back to glucose. As a result, your blood glucose levels are kept as stable as possible.
If you have type 1 diabetes you must also be careful about the levels of carbohydrate that you eat. You need to have regular meals, and exercise to keep your heart and blood vessels healthy. However, taking exercise needs to be carefully planned to keep your blood glucose levels steady. Your cells need enough glucose to respire more rapidly to produce to energy required for your muscles to work
How can you cure type 1 diabetes?
*Doctors can perform a pancreas transplant, however the operations are difficult and risky. Only a few hundred pancreas transplants take place each year in the UK. There are also not enough pancreas donors available. In addition, the patient exchanges one medicine (insulin) for another (immunosuppressants)
*Transplanting the pancreatic cells that make insulin dead and living donors has been tried but with limited success
*Stem cells are also being used to attempt to create insulin-secreting cells
How can you treat type 2 diabetes?
Type 2 diabetes can be cured by restoring their normal blood glucose balance, this can be done by:
*Eating a balanced diet with controlled amount of carbohydrates
*Losing weight
*Doing regular exercise
If this doesn’t help there are drugs which can:
*Help insulin work better on the body cells
*Help your pancreas make more insulin
*Reduce the amount of glucose you absorb from your gut into your bloodstream
If this does not work you will need insulin injections
Explain how negative feedback works:
Negative feedback systems work to maintain a steady state. 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, in negative feedback the response causes the opposite. Many hormones are involved in negative feedback systems, including insulin and glucagon, most female sex hormones, and thyroxine
What happens in a negative feedback system if the level rises above the ideal level?
The receptors will detect the change and then the response lowers the level back to the ideal level
What happens in a negative feedback system if the level falls belowthe ideal level?
The receptors will detect the change and then the response rises the level back to the ideal level
What is thyroxine?
The thyroid gland in your neck uses iodine from your diet to produce the hormone thyroxine. This controls the basal metabolic rate of your body - how quickly substances are broken down and built up, how much oxygen is used by tissues, and how the brain of a growing child develops. Thyroxine plays an important tole in growth and development
How does the level of thyroxine rely on negative feedback?
In adults, the level of thyroxine usually remain stable. This happens as a result of a negative feedback control involving the pituitary gland and the hormone it produces - thyroid stimulating hormone (TSH). If the levels of thyroxine in the blood begin to fall, it is detected by the 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 production of thyroxine by the thyroid gland. As the level of thyroxine goes up, it is detected by the sensors and in turn the level of TSH released falls
What is thyroid stimulating hormone?
TSH is secreted by the pituitary gland and it stimulates the production of thyroxine by the thyroid gland
What does adrenaline cause?
*Your heart rate and breathing rate to increase
*Stored glycogen in the liver to be converted to glucose for respiration
*The pupils of your eyes to dilate and let more light in
*Your mental awareness to increase
*Blood to be diverted away from your digestive system to the big muscles of the limbs to provide extra glucose and oxygen
Name a hormone controlled by negative feedback:
Thyroxine
Is adrenaline controlled by negative feedback?
No.
What are the primary sexual characteristics?
The sexual characteristics that you are born with, testes in boys and ovaries in girls.
What hormone triggers the development of female secondary characteristics?
Oestrogen
How long is the menstrual cycle?
28 days
Explain female fertility over a lifetime:
The ovaries of a baby girl contain all the eggs she will ever have. After puberty, eggs mature and are released every month, for an average of 35-40 years, except if she is pregnant. Eventually the supply of eggs runs out and the woman goes through the menopause - she can no longer have children. Approaching the menopause, a woman is less fertile and has a higher risk of having a baby with genetic problems.
What hormone triggers the development of male secondary characteristics?
Testosterone
Explain the menstrual cycle:
The average length of the menstrual cycle is about 28 days. Each month the lining of the uterus (womb) thickens to support a developing baby. At the same time, eggs start maturing in the follicles of the ovary. About 14 days after the eggs start maturing, one is released from the ovary in ovulation. The lining of the uterus stays thick for several days after the egg has been released. If the egg is fertilised by a sperm cell, then pregnancy may take place. The lining of the uterus provides protection and food for the developing embryo. If the egg is not fertilised, about 14 days after ovulation the lining of the uterus and the egg are shed from the body in the monthly period.
What 4 hormones control the menstrual cycle?
FSH, Oestrogen, LH, Progesterone
Describe how hormones control the menstrual cycle:
Between days 1-5 the levels of FSH being secreted by the pituitary gland are increasing, the uterus wall is also thinnest at this point as it has recently been shed during a period. At around day 5 the levels of FSH peak. FSH causes the eggs to mature in the follicles in the ovaries. The FSH stimulates the production of Oestrogen in the ovaries. The oestrogen then inhibits the production of FSH, causing FSH levels to fall. The oestrogen production increases until around day 12 where it peaks, during this time the oestrogen stimulates the lining of the uterus to grow. The uterus lining is thickest at around day 14. The oestrogen also stimulates the secretion of LH in the pituitary gland. The LH produced then inhibits the production of oestrogen, causing the levels of oestrogen to fall. The LH levels increase from day 12 before peaking at day 14. The LH stimulates the release of a mature egg from the ovary. LH stimulates the production of progesterone from the empty egg follicle in the ovary. The progesterone then inhibits the production of LH, causing LH levels to fall. Progesterone levels increase from day 14 before peaking at day 21. The progesterone helps to maintain the lining of the uterus so it is ready to receive a developing embryo if the egg is fertilised. If an egg is not fertilised, progesterone levels fall at about day 28, causing a new cycle to begin and the uterus lining to pull away (a period).
Name the different hormones:
Light blue = FSH
Dark blue = LH
Green = Oestrogen
Orange = Progesterone
At what day does FSH levels peak?
5-7
At what day does LH levels peak?
14
At what day does oestrogen levels peak?
12
At what day does progesterone levels peak?
21
At what day is the uterus lining the thinnest?
5
At what day is the uterus lining the thickest?
14
What is oestrogen stimulated by, what does it inhibit, and what does it stimulate?
Oestrogens is stimulated by FSH, It inhibits the production of FSH, and it stimulates LH
What is LH stimulated by, what does it inhibit, and what does it stimulate?
LH is stimulated by oestrogen, it inhibits the production of oestrogen, and it stimulates progesterone
What is progesterone stimulated by and what does it inhibit?
Progesterone is stimulated by LH, and it inhibits the release of FSH and LH
What does FSH stimulate the production of?
Oestrogen
Explain how a lack of ovulation can be treated:
Some women do not 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. The woman can then get pregnant naturally. The doses of the hormones must be carefully controlled as to reduce the risk of multiple births which can be dangerous for some people
What is IVF treatment?
IVF stands for “In Vitro Fertilisation”. In vitro fertilisation is a process of fertilisation where an egg is combined with sperm in vitro (outside the organism)
Explain the process of IVF treatment:
The mother is given FSH to stimulate the maturation of a number of eggs at the same time, followed by LH to bring the eggs to the point of ovulation. The doctors collect the eggs from the ovary of the mother and place them in a special solution in a petri dish. A sample of semen from the father is mixed with the eggs in the petri dish, this allows the sperm to fertilise the eggs. The fertilised eggs are kept in special solutions in a warm environment to develop into embryos. At the stage when they are minute balls of cells, one or two of the embryos are inserted back into the uterus of the mother. In this way they bypass the faulty tubes
When would IVF treatment be used?
If the oviducts have been damaged or blocked by infection
What are the pros of IVF?
*It overcomes the issue of infertility, it gives men and women who would otherwise be infertile the chance to have a baby of their own.
*The mature eggs produced by a woman using fertility drugs may be collected and stored, or fertilised and stored, until she wants to get pregnant later
What are the disadvantages of IVF?
*IVF is expensive for both society (as taxes pay for the NHS), and for individuals - many people end up paying thousands of pounds for repeated cycles of treatment
*It will not always successful, the older the parent the less likely the chances of success are. Using donor eggs or sperm from younger donors can help the success rate, but then the baby is no longer biologically the parents child
*IVF treatment can be physically and mentally stressful
*It can increase the number of multiple births, increasing the risk to both mother and child. Multiple births can also lead to premature births which need a lot of specialist care in hospital and can be expensive
*There are ethical issues if the mature eggs or embryos of a woman are stored for future use.
Name 6 types of fertility control:
*Hormone-based control
*Chemical methods
*Barrier Methods
*Intrauterine Devices
*Abstinence
*Surgical Methods
Explain how Hormone based control contraception works:
Hormones can be used in the form of oral contraceptives, an implant, or a patch. They use female hormones to prevent pregancy. It contains low doess of oestrogen and progesterone which inhibit the production and release of FSH by the pituitary gland, affecting the ovaries, so no eggs mature, preventing pregancy. The hormones also prevent the uterus lining developing, therefore preventing implantation. They also make thick mucus in the cervix to prevent sperm getting through
Explain how chemical methods can be used as a control of fertility:
Chemicals that kill or disable sperm are known as spermicides. They are readily available, but are not very effective at preventing pregnancy
Explain how barrier methods can be used as a control of fertility:
Barrier methods prevent the sperm reaching teh egg. A condom is a thin latex sheath palced over the penis during intercourse to collect the semen and prevent the egg and sperm meeting. They also pretect against STD’s
Explain how intrauterine devices can be used as a control of fertility:
intrauterine devices are small structures inserted into the uterus by a doctor. They last for 3-5 years but can be removed at any time. Some contain copper and prevent any embryos implanting in the uterus lining. Others contain progesterone, slowly releasing it to prevent the build-up of the uterus lining
Explain how abstinence can be used to control pregnancy
If people fo not have sex they will not get pregnant. Some religious groups do not accept the use of artificial methods. Abstaining from intercourse during ovulation means the sperm cannot fertilise the egg
Explain how surgical methods can be used to control pregnancy
If people never want to have children, they can be surgically sterilised. For men they can have a vasectomy, this is when the sperm ducts are cut and tied preventing any sperm getting into the semen. For women the oviducts can be cut or tied to prevent the egg reaching the uterus
Explain the pros and cons of hormone based control of fertility:
Pros:
*Easy to use and effective
*Often longer term
Cons:
*Person may forget to sue it
*Slight risk of raised blood pressure, thrombosis, breast cancer
Explain the pros and cons of chemical control of fertility:
Pros:
*Easy to obtain
Cons:
*Not very effective
Explain the pros and cons of barrier based control of fertility:
Pros:
*Effective
*Protects against STD’s
*No side effects
Cons:
*May break and allow sperm into the vagina
Explain the pros and cons of intrauterine device control of fertility:
Pros:
*very effective
Cons:
*Must be inserted by a doctor
*Can cause period problems or infections
Explain the pros and cons of abstinence control of fertility:
Pros:
*100% effective
Cons:
*Unreliable if ryhtm method is used
Explain the pros and cons of surgical based control of fertility:
Pros:
*Permanent
*Extremely effective
Cons:
*Not reversible
*Women needs a gerneal anaesthetic
Where are the adrenal glands located?
Above the kidneys
Where is the thyroid gland located?
In the neck
Where is adrenaline released and what is its target organ?
*Adrenal gland
*Heart
Where are glucagon and insulin released and what is their target hormone?
*Pancreas
*Liver
What is auxin?
A plant hormone that controls the responses of plants to light (phototropism) and gravity (gravitropism)
What are gibberellins?
Plants hormones that are important in initiating seed germination, stem growth, and flowering
What is gravitropism (geotropism)?
The response of a plant to gravity
What is phototropism?
The response of plants to light
What is tropism?
The responses of plant roots and shoots to environmental stimuli such as light or gravity
Are plant hormones local or circulating hormones and why?
They are local, they do not flow around the entire organism
Where are auxins produced and what happens after they are produced?
The auxins are produced in the tips of the roots and shoots, they then dissolve in the solution of the cells and diffuse backwards along the shoot or the root to stimulate the cell growth just behind the tips
Do auxins stimulate or inhibit growth in the shoots?
Stimulate
Do auxins stimulate or inhibit growth in the roots?
inhibit
Where do auxins accumulate?
The shaded and lower side
Describe what is meant when the shoots are described as positively phototropic but negatively geotropic:
*They grow towards the light
*They grow away from the ground
Describe what is meant when the roots are described as negatively phototropic but positively geotropic:
*They grow away from the light
*They grow towards to ground
Describe the process of phototropism in the shoots:
If the distribution of light is the same all around the shoot, the distribution of auxin is equal and all the cells grow at the same rate, therefore the shoot grows straight up
If light falls on one side of the shoot, the auxin will accumulate on the shaded side, this causes there to be an uneven distribution of auxin and therefore unequal growth. The auxin stimulates growth and causes the cells on the unlit side to increase in length more and grow faster than those on the lit side, this causes the shoot to bend towards the light
Describe the process of gravitropism in the shoots:
If the shoot is growing straight up, the distribution of auxin is equal and all the cells grow at the same rate, therefore the shoot continues to grow straight up.
If a shoot is growing sideways, the auxin will accumulate on the lower side, this causes there to be an uneven distribution of auxin and therefore unequal growth. The auxin stimulates growth and causes the cells on the lower side to increase in length more and grow faster than those on the upper side, this causes the shoot to bend away from the ground
Describe the process of phototropism in the roots:
If the distribution of light is the same all around the root, the distribution of auxin is equal and all the cells grow at the same rate, therefore the root grows straight down
If light falls on one side of the root, the auxin will accumulate on the shaded side, this causes there to be an uneven distribution of auxin and therefore unequal growth. The auxin inhibits growth and causes the cells on the unlit side to increase in length less and grow slower than those on the lower side, this causes the shoot to bend towards the ground
Describe the process of gravitropism in the roots:
If the root is growing straight down, the distribution of auxin is equal and all the cells grow at the same rate, therefore the root continues to grow straight down
If a root is growing sideways, the auxin will accumulate on the lower side, this causes there to be an uneven distribution of auxin and therefore unequal growth. The auxin inhibits growth and causes the cells on the lower side to increase in length less and grow slower than those on the upper side, this causes the root to bend towards the ground.
What does the plant hormone ethene do?
Controls cell division and ripening of fruits
What does unequal distributions of auxin cause?
Unequal growth rates, this results in bending of the shoot or root
What happens if the tip of a shoot of a plant is cut off?
No auxin is available so the shoot may stop growing
