B11-Hormonal Coordination

Question 1

What is a hormone?

Answer 1

Chemical messenger produced in glands and carried by the blood to specific organs in the body.

Question 2

What is a negative feedback mechanism?

Answer 2

Mechanism to lower raised levels of something, and to raise reduced levels of something.

Question 3

What is homeostasis?

Answer 3

The maintenance of steady conditions. The ability of the body to maintain a constant internal environment, eg temperature and blood glucose concentration.

Question 4

What is the endocrine system?

Answer 4

The endocrine system is a complex network of glands and organs. It uses hormones to control and coordinate your body’s metabolism, energy level, reproduction, growth and development, and response to injury, stress, and mood.

Question 5

What are the main endocrine organs?

Answer 5

hypothalamus, pineal gland, pituitary gland, thyroid gland, parathyroid glands, thymus, adrenal glands, and pancreas.Also includes ovaries and testes

Question 6

Hormones vs Nervous system

Answer 6

hormones:
* chemicals that control the processes of the body,
* released from glands into blood,
* some act quickly but many act more slowly,
* all are slower than nervous control

nervous system:
* electrical impulses passed from receptors to brain,
* transmitted along neurones,
* can be very fast (especially reflexes),
* transmission from one neurone to another involves chemical
substances

Question 7

Why is the pituitary gland called the master gland?

Answer 7

Pituitary gland is small endocrine gland in brain that controls many
different body processes as well as controlling secretions of many other
endocrine glands in the body.

It produces a number of different hormones that give it this control.

Question 8

What is Insulin?

Answer 8

Insulin is a hormone made in the pancreas that allows your body to use glucose from carbohydrates in the food that you eat for energy or to store glucose for future use. Insulin helps keep your blood sugar level from getting too high.

Question 9

What happens when sugar is too high or too low?

Answer 9

Too High:
Insulin: When blood glucose levels are high e.g.,after a meal, insulin is released by the pancreas. Insulin enables cells to take up glucose from the blood, and it also stimulates the liver and muscles to store glucose as glycogen. This lowers blood glucose levels.

Too Low:
Glucagon: When blood glucose levels are low e.g. ,during fasting or exercise, glucagon is released by the pancreas. Glucagon stimulates the liver to break down glycogen into glucose and release it into the blood, increasing blood glucose levels.

Question 10

What is diabetes?

Answer 10

Condition under which pancreas cannot make enough insulin to control blood sugar or body cells stop responding to insulin made by pancreas.

Question 11

What is the difference between type 1 and type 2?

Answer 11

Type 1 diabetes is a disorder in which the pancreas fails to produce enough insulin. Type 1 is controlled by injection of insulin.

In type 2 diabetes the person’s body cells no longer respond to insulin produced by the pancreas. Type 2 is controlled by diet and exercise.

Question 12

What is glucagon?

Answer 12

Glucagon is a hormone secreted by the pancreas that causes glycogen in the liver to break down back into glucose to prevent glucose levels from dropping.

Question 13

What does the hormone Thyroxine do?

Answer 13

Hormone produced by the thyroid gland that stimulates the basal metabolic rate. Your Basal Metabolic Rate (BMR) is the number of calories you burn as your body performs basic (basal) life-sustaining function.

Question 14

How does the negative feedback work with thyroxine and TSH?

Answer 14

Low thyroxine levels in the bloodstream stimulate the hypothalamus to release Thyrotropin-releasing hormone (TRH) and this causes the pituitary to release Thyroid-stimulating hormone (TSH) so the thyroid releases more thyroxine. So blood levels return to normal.

Normal thyroxine levels in the bloodstream inhibit TRH release from the hypothalamus and this inhibits the release of TSH from the pituitary, so normal blood levels are maintained.

Question 15

What is the hormone Adrenaline and its function?

Answer 15

Adrenaline, also known as epinephrine, is a hormone and neurotransmitter. Its main purpose is to prepare the body for “fight or flight” responses in stressful or dangerous situations. It increases heart rate, blood pressure, and glycogen conversion rate, pupil dilation and increases brain alertness.

Question 16

What do testosterone and oestrogen do?

Answer 16

Testosterone– controls the development of male secondary sexual characteristics

Oestrogen– controls the development of female secondary sexual characteristics

both released during puberty

Question 17

What is FSH?

Answer 17

Follicle Stimulating Hormone. It stimulates oestrogen production and the growth of follicles (egg-sacs) in the ovary. It is secreted by the pituitary gland.It stimulates Oestrogen

Question 18

What is LH?

Answer 18

Luteinising Hormone, secreted by the pituitary gland, which stimulates ovulation

Question 19

What is oestrogen?

Answer 19

A female sex hormone produced in the ovaries, which is responsible for puberty in girls and the regulation of the menstrual cycle.It stimulates LH and inhibits FSH

Question 20

What is progesterone?

Answer 20

A hormone produced by the ovaries and maintains the uterus lining.It inhibits FSH and LH

Question 21

Describe the relationship between hormones in the 28 days of the Menstrual cycle?

Answer 21

Days 1 to 12 – oestrogen gradually increases and peaks approximately on the 12th day. Progesterone, LH and FSH stay approximately at the same levels and begin to increase slightly from around day 12.

FSH and LH patterns are very similar and peak during ovulation at approximately 14 days during this cycle. They drop sharply on day 15 and stay constant until day 28.

Oestrogen drops during days 13 and 14, and progesterone continues to gradually increase until about day 21, when it slowly begins to decrease again. Oestrogen mirrors this shape and also has a second lower peak at about day 21.

Question 22

What is menstruation?

Answer 22

Shedding of uterus lining.

Question 23

What is contraception?

Answer 23

control of fertility to prevent pregnancy by preventing egg and sperm
meeting or preventing implantation of fertilised egg in uterus

Question 24

Compare effectiveness of 3 types of contraception;

Answer 24

hormone‑based: relatively effective (0–10% failure rate per Figure 2),
open to human error
barrier: less effective (12–18% failure rate per Figure 2), open to human
error or damage
surgical: very effective, not open to human error following successful
surgery

Question 25

What does the pill contain?

Answer 25

The oral contraceptive, which is known as the pill, contains oestrogen or progesterone . These hormones inhibit the production of FSH , and eggs cannot mature

Question 26

What is In vitro fertilisation.

Answer 26

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 a dish in the laboratory. The fertilised eggs develop into embryos. At the stage when they are tiny balls of cells one or two embryos are inserted into the mother's uterus (womb)

Question 27

How do fertility drugs work?

Answer 27

Some women have difficulty becoming pregnant because they don't produce enough FSH to allow their eggs to mature. Fertility drugs contain FSH and LH, which stimulate eggs to mature in the ovary.

Question 28

Advantages and Disadvantages of IVF?

Answer 28

Advantages of IVF It allows people to have babies of their own, who otherwise can't due to a variety of reasons. It has a safe track record and has been used since 1978. The embryos can be screened for genetic diseases, which is important for families that already have an affected child. Only unaffected embryos are used. Unused eggs can be used for research or donated to other couples. Disadvantages of IVF There are side effects form the drugs used, such as hot flushes and severe headaches. There is a possibility of multiple births, which is dangerous for mother and babies. Ovarian hyper-stimulation syndrome (OHS), when too many eggs develop in the ovaries. It is very emotionally and physically stressful. The success rates are not high.

Question 29

What are positive and negative tropisms in plants?

Answer 29

positive tropisms – the plant grows towards the stimulus negative tropisms – the plant grows away from the stimulus

Question 30

What is phototropism and geotropism?

Answer 30

Phototropism is a response to the stimulus of light. Geotropism/Gravitropism is a response to the stimulus of gravity

Question 31

What is the plant hormone auxins?

Answer 31

Plant hormones that control cell elongation.

Question 32

What do auxins do?

Answer 32

They are mostly made in the tips of the growing stems and roots, which are known as apical meristems, and can diffuse to other parts of the stems or roots. Auxins control the growth of plants by promoting cell division and causing elongation in plant cells (the cells get longer). Stems and roots respond differently to high concentrations of auxins: cells in stems grow more cells in roots grow less

Question 33

How do auxins work in roots and shoots?

Answer 33

In a stem, the shaded side contains more auxin and grows longer, which causes the stem to grow towards the light. Auxins have the opposite effect on root cells. In a root, the shaded side contains more auxin and grows less - causing the root to bend away from the light.

Question 34

What are gibberellins used for?

Answer 34

end seed dormancy promote flowering increase fruit size

Question 35

What is ethene used for?

Answer 35

Ethene is a hydrocarbon gas which speeds up ripening in fruit. It also controls cell division during plant growth. In the food industry fruit is often picked unripe and then transported. This prevents fruit from over-ripening on the journey. It is ripened during storage by adding ethene and then taken to the shops.

Question 36

What are auxins used for in horticulture?

Answer 36

as weed killers as rooting powders for promoting growth in tissue culture

Question 37

How are auxins used as weed killers?

Answer 37

Weedkillers A dandelion. 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 weeds that compete with crops such as wheat. The selective weedkiller contains a growth hormone that causes the weeds to grow too quickly and die. Because most weeds have broader leaves than grass or wheat, the weedkiller is absorbed in larger quantities by the weeds. A plant cutting being dipped into rooting powder. Selective weedkillers kill plants that some species of animals rely on as a food source. This can result in a reduction of biodiversity.

Question 38

How are auxins used as Rooting powders?

Answer 38

Plant cuttings can be dipped in hormone rooting powder before planting. Synthetic plant hormones are used to control plant growth. For example, rooting powder contains growth hormones that make stem cuttings develop roots quickly.