This page contains the GCSE AQA Biology Hormonal Coordination Questions and their answers for revision and understanding Hormonal Coordination.
1 (a)
hormone is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behavior.
(b)
Endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct.
2
Nervous control is very rapid and integral for immediate action, coordination and control, and receiving and interpreting messages from your environment. The rapid control is achieved via a network of neurons in the central and peripheral nervous systems (CNS and PNS).
To understand rapid control you must understand how the neurons function. The neurons connect onto each other and a rapid electrical impulse is transmitted from one to the other (the basis of which is ion channels opening and closing and changing the potential difference across the membrane of the neuron relative to its surroundings).
These events occur speedily and efficiently- going from sensory neurons in your skin (all part of the PNS) or sense organs straight to the CNS (brain and spinal cord). There the information is processed, and sent back along motor neurons (also in the PNS) to the effectors (usually muscles, but can be glands or organs) in order to elicit a response from them. This occurs in a matter of milliseconds.
On the other hand, the endocrine system controls functions which take much longer to come into effect. This includes growth and development, homeostasis (which is keeping the systems balanced in the body), and signalling for longer term responses. You do not grow all at once, or reach puberty in a millisecond.
The way in which the endocrine system controls functions over a long period pf time is via the release of specific hormones from specific glands and organs which target the cells or organs for which the effect is meant.
The types of functions controlled by the endocrine system include maturation of an individual during puberty, milk production and release in female mammals, blood glucose and sodium levels, and growth of all tissues approaching, during, and after puberty.
3
The pituitary controls the function of most other endocrine glands and is therefore sometimes called the master gland. In turn, the pituitary is controlled in large part by the hypothalamus, a region of the brain that lies just above the pituitary. By detecting the levels of hormones produced by glands under the pituitary’s control (target glands), the hypothalamus or the pituitary can determine how much stimulation the target glands need.
4(a)
pituitary gland doesn’t produce enough growth hormone, growth can slow. A lack of growth hormone causes growth hormone deficiency. This can cause a child to be very short to have very low bone density and muscle strength.
(b)
In adults, excessive growth hormone for a long period of time produces a condition known as acromegaly, in which patients have swelling of the hands and feet and altered facial features. These patients also have organ enlargement and serious functional disorders such as high blood pressure, diabetes and heart disease. Over 99% of cases are due to benign tumors of the pituitary gland, which produce growth hormone. This condition is more common after middle-age when growth is complete so affected individuals do not get any taller.
(a)
hormone produced in the pancreas by the islets of Langerhans, which regulates the amount of glucose in the blood. The lack of insulin causes a form of diabetes.
(b)
a disease in which the body’s ability to produce or respond to the hormone insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood
(c)
Polysaccharide that is the chief carbohydrate storage material in animals, being converted to glucose by depolymerization; it is formed by and largely stored in the liver, and to a lesser extent in muscles, and is liberated as needed.
2(a)
In response to an increase in blood glucose level above the normal level, the pancreas produces a hormone called insulin which is released into the bloodstream. Insulin causes glucose to move from the blood into cells, where it is either used for respiration or stored in liver and muscle cells as glycogen.
(b)
When blood sugar drops too low, the level of insulin declines and other cells in the pancreas release glucagon, which causes the liver to turn stored glycogen back into glucose and release it into the blood.
(c)
Many people who live with diabetes don’t feel any particular symptoms, unless they are experiencing hyperglycemia (glucose level is too high) or hypoglycemia (glucose level is too low). Hyperglycemia can cause significant damage to some organs, which then leads to complications of diabetes. These include:
To avoid the complications of diabetes, you must control your blood glucose very well to minimize the risk of hyperglycemia. This will allow you to prevent the complications of diabetes.
3
| differences between type 1 and type 2 diabetes | |
| Type 1 Diabetes | Type 2 Diabetes |
| Often diagnosed in childhood | Usually diagnosed in over 30 year olds |
| Not associated with excess body weight | Often associated with excess body weight |
| Often associated with higher than normal ketone levels at diagnosis | Often associated with high blood pressure and/or cholesterol levels at diagnosis |
| Treated with insulin injections or insulin pump | Is usually treated initially without medication or with tablets |
| Cannot be controlled without taking insulin | Sometimes possible to come off diabetes medication |
4
Insulin and glucagon have both similarities and differences. Both are hormones secreted by the pancreas but they are made from different types of cells in the pancreas. Both help manage the blood glucose levels in the body but they have opposite effects. Both respond to blood glucose levels but they have opposite effects.
During digestion, foods that contain carbohydrates are converted into glucose. Most of this glucose is sent into your bloodstream, causing a rise in blood glucose levels. This increase in blood glucose signals your pancreas to produce insulin.
The insulin tells cells throughout your body to take in glucose from your bloodstream. As the glucose moves into your cells, your blood glucose levels go down. Some cells use the glucose as energy. Other cells, such as in your liver and muscles, store any excess glucose as a substance called glycogen. Your body uses glycogen for fuel between meals.
Glucagon works to counterbalance the actions of insulin.
About four to six hours after you eat, the glucose levels in your blood decrease, triggering your pancreas to produce glucagon. This hormone signals your liver and muscle cells to change the stored glycogen back into glucose. These cells then release the glucose into your bloodstream so your other cells can use it for energy.
This whole feedback loop with insulin and glucagon is constantly in motion. It keeps your blood sugar levels from dipping too low, ensuring that your body has a steady supply of energy.
1
| Differences between type 1 and type 2 diabetes | |
| Type 1 diabetes | Type 2 diabetes |
| Symptoms usually start in childhood or young adulthood. People often seek medical help, because they are seriously ill from sudden symptoms of high blood sugar. | The person may not have symptoms before diagnosis. Usually the disease is discovered in adulthood, but an increasing number of children are being diagnosed with the disease. |
| Episodes of low blood sugar level (hypoglycemia) are common. | There are no episodes of low blood sugar level, unless the person is taking insulin or certain diabetes medicines. |
| It cannot be prevented. | It can be prevented or delayed with a healthy lifestyle, including maintaining a healthy weight, eating sensibly, and exercising regularly. |
2 (a)
For type 1 diabetes, insulin has long been the essential treatment method. Blood glucose monitoring, frequent insulin injections, even insulin pumps are used to help diabetics control their glucose levels and avoid dangerous spikes and dips in their blood sugar. it is found that transplanting purified human pancreatic islet cells into type 1 diabetics can lead to nearly normal glycemic control and no longer being reliant on insulin.
(b)
People with type 2 diabetes don’t respond normally to insulin anymore, so glucose stays in the bloodstream and doesn’t get into the cells. This causes blood glucose levels to go too high.
4
High blood sugar levels can make teens with type 2 diabetes feel sick, so their treatment plan involves keeping their blood sugar levels within a healthy range while making sure they grow and develop normally. To do that, they need to:
The good news is that sticking to the plan can help people feel healthy and avoid diabetes problems later.
1
Negative feedback is a regulatory mechanism in which a ‘stimulus’ causes an opposite ‘output’ in order to maintain an ideal level of whatever is being regulated.
There are many negative feedback pathways in biological systems, including:
2
Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. Thyroid hormones play vital roles in regulating the body’s metabolic rate, heart and digestive functions, muscle control, brain development and maintenance of bones.
This hormone production system is regulated by a negative feedback loop so that when the levels of the thyroid hormones, thyroxine and triiodothyronine increase, they prevent the release of both thyrotropin-releasing hormone and thyroid stimulating hormone. This system allows the body to maintain a constant level of thyroid hormones in the body.
3
4 (b)
Adrenaline is a hormone released from the adrenal glands and its major action, together with noradrenaline, is to prepare the body for ‘fight or flight’.
Adrenaline is released mainly through the activation of nerves connected to the adrenal glands, which trigger the secretion of adrenaline and thus increase the levels of adrenaline in the blood. This process happens relatively quickly, within 2 to 3 minutes of the stressful event being encountered. When the stressful situation ends, the nerve impulses to the adrenal glands are lowered, meaning that the adrenal glands stop producing adrenaline.
1
Hormones are the drivers of human reproduction, responsible
For secondary sexual development (puberty)
controlling the menstrual cycle.
Oestrogen in female produced by ovary. Testosterone in male produced by testes and stimulates sperm production
2
Differences between boys and girls at puberty
The physical changes for females during puberty experience are marked by the following features of growth:
The physical changes during puberty for males that occur are different in a number of ways. The developments that a boy undergoes during adolescence are:
3.
The menstrual cycle is an approximately 28-day cycle which results in the release of a mature egg from the ovary. This egg may then go on to become fertilized or may be released, unfertilized, along with the lining of the uterus. The latter may take place with monthly bleeding called menstruation — day 1 of the 28-day cycle. This delicate cycle results from a complicated interplay among several hormones.
Follicle-Stimulating Hormone (FSH)
This hormone stimulates the development of new follicles as well as the production of the hormone estrogen. During this phase, called the follicular phase of the menstrual cycle, an increase in FSH occurs. This increase stimulates the growth and development of new follicles, one of which will develop into the ovulated egg.
Estrogen
Estrogen is responsible for the continuing development of follicles within the ovaries. However, the effects of estrogen are not limited to within the ovaries. In the uterus, the rising levels of this hormone play an important role in thickening the endometrium — a layer of the uterus. It also causes the mucus within the cervix to become thicker. Finally, estrogen release acts as a suppressor of its own release — called a negative feedback loop. It also acts to suppress the production of LH, until just before ovulation. Afterward, estrogen actually stimulates the release of large amounts of LH in what is called the mid-cycle LH surge.
Luteinizing Hormone (LH)
LH peaks in the middle of the 28-day cycle. This is typically called the LH surge and serves as a signal that ovulation — the release of the mature egg from one of the two ovaries — is about to occur. During this peak of LH release, concentration of this hormone becomes ten times higher than usual. Ovulation generally occurs within 9 hours of the LH surge. The egg releases from the ovary, able to be fertilized for about 1-2 days after it releases. If it does not become fertilized, it begins to disintegrate or releases along with the inner lining of the uterus as part of the monthly menstruation cycle.
Progesterone
Once ovulation has occurred, the hormone progesterone releases from a structure called corpus luteum. Progesterone makes the mucus around the entrance of the uterus thick and sticky, preparing for a potential pregnancy. If the released egg becomes fertilized, it will become implanted in the wall of the uterus and the fetus will begin to grow.
b
Size
Egg: One of the largest cells in the female body.
Sperm: One of the smallest cells in the female body.
Produced in
Egg: Produced in the ovary of a female.
Sperm: Produced in the Testicles of a male.
Appearance
Egg: Round shaped and consists of a large amount of cytoplasm before conception.
Sperm: Oval head on the top and has a rigid middle with a slimly tail in the back to allow it to swim.
Amount
Egg: Only a single egg cell is produced during once menstruation cycle.
Sperm: Millions of cells are released during a single ejaculation.
Temperature
Egg: Requires warm body temperature for sustenance.
Sperm: Requires approximately two degrees lesser than body temperature.
Life-Span
Egg: Have a short life span 12-24 hours.
Sperm: Longer life span surviving for 3-5 days.
Storability
Egg: Cannot be stored.
Sperm: Can be frozen and stored.
1
The four hormone that control the menstrual cycle are:
FSH:
LH:
OESTROGEN:
PROGESTERONE:
b
The interaction of four hormones control the maturing and release of an egg from the ovary and the buildup of lining of the uterus in the menstrual cycle
2 (a)
On 28th day women have menstrual cycle
(b)
LH and FSH are the hormones that encourage ovulation. Both LH and FSH are secreted by the pituitary gland in the brain. At the beginning of the cycle, LH and FSH levels usually range between about 5-20 mlU/ml. Most women have about equal amounts of LH and FSH during the early part of their cycle. However, there is a LH surge in which the amount of LH increases to about 25-40 mlU/ml 24 hours before ovulation occurs. Once the egg is released by the ovary, the LH levels goes back down.
(c)
Oestrogen hormone control the buildup of lining of uterus
3
The menstrual cycle is a recurring process which takes around 28 days. During the process, the lining of the uterus is prepared for pregnancy. If pregnancy does not happen, the lining is then shed. This is known as menstruation.
The length of menstrual cycle has been assumed to be 28 days (which is the average among women). The entire duration of a Menstrual cycle can be divided into four main phases:
Menstrual phase (day 1-5)
Menstrual phase begins on the first day of menstruation and lasts till the 5th day of the menstrual cycle. The following events occur during this phase:
Follicular phase (day 1-13)
This phase also begins on the first day of menstruation, but it lasts till the 13th day of the menstrual cycle. The following events occur during this phase:
On the 14th day of the cycle, the pituitary gland secretes a hormone that causes the ovary to release the matured egg cell. The released egg cell is swept into the fallopian tube by the cilia of the fimbriae. Fimbriae are finger like projections located at the end of the fallopian tube close to the ovaries and cilia are slender hair like projections on each Fimbria.
Luteal phase (day 15-28)
This phase begins on the 15th day and lasts till the end of the cycle. The following events occur during this phase:
Several hormones control this cycle – for example, they are involved in controlling the release of an egg each month from an ovary, and changing the thickness of the uterus lining.
| Hormone | Produced | Role |
| FSH (follicle stimulating hormone) | Pituitary gland | Causes an egg to mature in an ovary. Stimulates the ovaries to release oestrogen |
| Oestrogen | Ovaries | Stops FSH being produced (so that only one egg matures in a cycle). Repairs and thickens the uterus lining. Stimulates the pituitary gland to release LH. |
| LH (luteinising hormone) | Pituitary gland | Triggers ovulation (the release of a mature egg) |
| Progesterone | Ovaries | Maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy. |
1
Contraception (birth control) prevents pregnancy by interfering with the normal process of ovulation, fertilization, and implantation. There are different kinds of birth control that act at different points in the process.
2 (a)
All the form of contraceptive uses the progesterone.
(b)
The pill uses hormones to prevent pregnancy. The combination pill contains estrogen and progestin. Birth control pills prevent pregnancy by stopping your ovaries from releasing an egg each month. The hormones thicken the cervical mucus, which makes it harder for sperm to swim to the egg. The hormones also alter the lining of the uterus, so that if an egg does get fertilized, it will be unable to implant in the uterus.
Contraceptive
The patch contains the same hormones as the pill, estrogen and progestin. The patch works just like the pill. The hormones prevent an egg from being released and change both the cervical mucus and uterine lining..
The implant is made of medical plastic that is sterile and soft. This contraceptive rod is 40mm (1.5 inches) long and 2mm (0.08 inches) in diameter. The implant, once inserted, is effective for a maximum of three years. Once the birth control implant is inserted, it begins releasing small doses of the synthetic progesterone. it is released slowly and steadily over the course of the three year period.
(c)
Contraceptive implant is most effective of all of these because the contraceptive implant can last up to three years. A tiny tube is inserted under the skin by the doctor and slowly release progesterone. This 99.95% effective
3
Birth Control Methods Comparison Charts
Barrier method:
Abstinence
Surgical method:
Surgical “irreversible” methods of contraception.
These include:
1
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm outside the body, in vitro (“in glass”). The process involves monitoring and stimulating a woman’s ovulatory process, removing an ovum or ova (egg or eggs) from the woman’s ovaries and letting sperm fertilise them in a liquid in a laboratory. The fertilised egg (zygote) undergoes embryo culture for 2–6 days, and is then transferred to the same or another woman’s uterus, with the intention of establishing a successful pregnancy.
2
(a)
Artificial hormone can be used to help people overcome infertility and conceive naturally.artificial FSH can be used as a fertility drug . it stimulate the eggs in the ovary to mature and also triggers oestrogen production. An artificial LH can then be used to triggers ovulation. If women 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.
(b)
Fertility drugs are also used in IVF (In vitro fertilisation).
IVF is a form of fertility treatment used if the oviducts have been damaged or blocked by infection, if a donor egg has to be used, or if there is no obvious cause for long-term infertility.
4
Advantage of artificial hormone to control the fertility:
Risks and disadvantages
1 (a)
Phototropism: the orientation of a plant or other organism in response to light, either towards the source of light ( positive phototropism ) or away from it ( negative phototropism ).
(b)
Gravitropism: Gravitropism (also known as geotropism) is a turning or growth movement by a plant or fungus in response to gravity. It is a general feature of all higher and many lower plants as well as other organisms
2
A ‘tropism’ is a growth in response to a stimulus. Plants grow towards sources of water and light, which they need to survive and grow.Auxin is a plant hormone produced in the stem tips and roots, which controls the direction of growth.
Tropisms are directional movement responses that occur in response to a directional stimulus. Plants are not able to relocated if they happen to start growing where conditions are suboptimal. However, plants can alter their growth so they can grow into more favorable conditions, To do so requires the ability to detect where the conditions are better and then alter their growth so they can “move” in the appropriate direction. One of the most commonly observed tropic responses in plants is phototropism, in which plant stems grow towards light. As anyone who has grown plants near a window knows, the plants tend to lean towards the window where the light is usually stronger than inside the room. Another commonly observed tropic responses is gravitropism, where a plant will grow so that it stays oriented relative to the source of gravity (the earth). Thus, if a plant is knocked down the shoot will grow faster on the lower side until the shoot is more-or-less standing up again.
Tropic responses result from differential growth. Phototropism is a blue-light-dependent response controlled by the action of specific blue light photoreceptors called phototropins. Gravitropism is dependent on the presence of starch-filled plastids (amyloplasts) in specialized cells. When the orientation of the cells changes, the mass of the starch-filled plastids causes them to sink to the lower end of the cell. The tumbling of the amyloplasts triggers, through unknown mechanisms, differential growth that causes curvature to develop.
1 (a)
Plant hormones (also known as phytohormones) are chemicals that regulate plant growth. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, moved to other locations, in other functional parts of the plant
(b)
Rooting hormone acts as a catalyst for the new roots and protects the cuttings from fungus and disease that may have been introduced during the cutting process. A rooting hormone is used in plant propagation to grow new roots on cuttings.
2
Auxin can be used to make effective weed killers. If auxin solution spray on to the leaves of plant, the hormone is absorbed. The extra auxin can send the plant into rapid uncontrolled growth, killing them. Selective weedkillers kill some plants but not others. This can be useful for getting rid of dandelions in a lawn without killing the grass, or getting rid of thistles in a field without killing the wheat plants. The selective weedkiller contains growth hormone that causes the weeds to grow too quickly. The weedkiller is absorbed in larger quantities by the weeds than the beneficial plants.