B3.2 -Endocrine System Flashcards

Question

describe stages of a negative feedback loop (in terms of thyroxine)

Answer 1

- hypothalamus detects cells need more energy - pituitary gland releases TSH - thyroid produces thyroxine - hypothalamus detects cells have enough energy - pituitary gland stops producing TSH - thyroid stops producing thyroxine Low thyroxine levels in the bloodstream stimulate the hypothalamus to release TRH (Thyrotropin releasing hormone) and this causes the pituitary to release TSH so the thyroid releases more thyroxine. So blood levels return to normal.

Answer 2

When stress is removed, the brains signals to the adrenal glands stop —> the glands stop producing adrenaline —> the affected body systems return to their previous state

Answer 3

- FSH (follicle stimulating hormone) - Oestrogen - Luteinising Hormone (LH) - Progesterone

Answer 4

- Follicle stimulating hormone - secreted by the pituitary gland - travels to the ovaries where it causes an egg to mature - also stimulates production of oestrogen

Answer 5

- made and secreted by ovaries - causes lining of the uterus to build up - as oestrogen levels rise, they inhibit the production of FSH — usually prevents more than one egg maturing - also stimulates the pituitary gland to release luteinising hormone

Answer 6

- Luteinising Hormone - when LH levels reach a peak in the middle of the cycle, ovulation is triggered (egg released, approx 14 days after it starts to mature in one of the ovaries)

Answer 7

- produced in ovaries after ovulation - maintains lining of the uterus during days 14-28 - levels remain high throughout pregnancy - inhibits the release of LH and FSH.

Answer 8

- triggers the breakdown of the lining | - marks day 1 of the next menstrual cycle.

Answer 9

- uterus lining breaks down, resulting in period

Answer 10

-uterus lining starts to build up again into a thick, spongy layer full of blood vessels.

Answer 11

- Ovulation | - an egg is released from one of the ovaries

Answer 12

- uterus lining is maintained, ready for the arrival of a fertilised egg - if egg not fertilised, uterus lining breaks down, cycle restarts

Answer 13

- thickens mucus in cervix, stopping sperm from reaching an ovum - also thins lining of uterus, preventing implantation - and can prevent ovulation - taken around same time every day Allegedly: - fewer side effects than combined pill (but as effective)

Answer 14

- Contains both oestrogen and progesterone. - (oestrogen builds up in the body - stop FSH, no eggs mature - ) prevents ovulation - thickens mucus in cervix, stopping sperm from reaching an ovum - prevents implantation of a fertilised egg into the uterus wall - taken daily for 21 days of menstrual cycle

Answer 15

- non-hormonal - barrier methods that prevent a sperm contacting the egg or physical devices that’s release chemical compounds, which kill sperm cells (spermicides) or prevent the implantation of fertilised eggs. - hormonal - disrupt the normal female reproductive cycle

Answer 16

- place over penis, or inside vagina - prevents sperm entering vagina - can also prevent the spread of STIs

Answer 17

- nonhormonal - inserted into vagina to cover the cervix - prevents sperm cells from entering the uterus - removed after 6 or more hrs following sexual intercourse - not effective unless used in combination with a spermicide

Answer 18

- nonhormal - inserted into uterus - releases copper, which prevents sperm surviving in the uterus and fallopian tubes - can also prevent implantation of fertilised ovum - remains effective for 5 TO 10 YEARS

Answer 19

- hormonal - inserted into uterus Same effect on the body as progesterone only pill: - thickens mucus in cervix, stopping sperm from reaching an ovum - also thins lining of uterus, preventing implantation - and can prevent ovulation - remains effective for 3to5 years

Answer 20

usually hormonal

Answer 21

as the sperm would not be able to meet the egg

Answer 22

- blocked sperm ducts - not enough sperm being produced in testes - lack of mature eggs produced in the ovaries - failure of the ovaries to release an egg

Answer 23

1) Fertility (FSH - also LH so many collected) drugs are uses 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 and the sperm and eggs are mixed in the Petri dish 4) The eggs are checked to make sure they have been fertilised and that the early embryos are developing properly 5) When the fertilised eggs gave formed tiny balls of cells, 1 or 2 of the tiny embryos are placed in the womb of the mother. Then, if all goes well, at least one baby will grow and develop successfully

Answer 24

- not a natural process - many result in multiple births - can be dangerous for both mother and unborn babies - embryo may not develop properly (dies) - expensive NOT reliable, may result in - no pregnancy - multiple pregnancies == can be distressing for those undergoing treatment

Answer 25

- allows homosexual couples to have children - allows older couples to have children - allows younger women to focus on their careers (and choose to have a baby later in life)

Answer 26

a response to stimuli which involves growth in a particular direction

Answer 27

a part of a plant growing towards light

Answer 28

growing in the same direction as gravity | growing downwards

Answer 29

phototropism + gravitropism

Answer 30

plant hormones that enable plants to grow towards or away from a stimulus

Answer 31

- uneven distribution of auxin - unequal growth rate - shorts or root to bend (grow more on one side)

Answer 32

stimulates them to grow more

Answer 33

inhibits the growth of root cells

Answer 34

- light hits one side of shoot tip - auxin moves to the other side of the shoot - concentration of auxin increases on unlit side of the shoot - increases the length of this side - shoot bends towards light

Answer 35

in roots, plants grow more to areas with least auxin (elongate less in areas with more auxin, inhibits growth of root cells), in stems, plants grow more on areas with most auxin / stimulates growth of shoot cells

Answer 36

at the tip (meristems)

Answer 37

- Fruit production + Ripening - Growth - Move towards the light - Leaves falling - Disease resistance

Answer 38

- stimulates growth by causing cell elongation | - also help to regulate fruit development - fruits too small without auxin

Answer 39

- causes plant fruits to ripen by stimulating the conversion of starch into sugar - > this is why a ripe fruit taste sweeter than an unripe one - only plant hormone that EXISTS AS a GAS

Answer 40

- promotes growth, particularly stem elongation) | - also can end the dormancy period of seeds + buds —> leads to shoots + flowers opening

Answer 41

- contain auxin - selective herbicides (only kill broad-leaved plants, and not narrow-leaved, such as grass - Auxin weed killer makes weeds grow too fast - this rapid uncontrolled growth kills the plant

Answer 42

- contains auxin - auxin used to produce identical plants, clones, from cuttings - cut off a plant shoot, dip it into rooting powder and plant it - after a few days, new roots develop from the cut stem - the new roots anchor into the soil and take up water and minerals

Answer 43

- Auxin is sprayed on fruit trees to delay ripening | - this allows a harvester to be collected all at the same time, and can prevent fruit from dropping off trees early

Answer 44

- Ethene is sprayed on fruit trees and plants so that their fruits ripen quicker - this allows fruit to be ready earlier in the growing season

Answer 45

- use auxins - (Seeds produced after plant is pollinated by insects or the wind ) - if auxins are applied to unpollinated flowers, the plant produces seedless fruit

Answer 46

- seeds remain dormant until conditions are ideal for growth - this normally prevents them germinating at the end of the summer so they survive the winter - commercial growers trigger seeds to germinate in the winter by spraying them with gibberellins or auxins in the greenhouse

Answer 47

2 - In the root, more auxin gathers on the lower side - in the shoot, more auxin gathers on the lower side 3 - The root grows more on the side with the least auxin, making it bend and grow down towards the force of gravity. When it has grown down, the auxin becomes evenly spread again. - The shoot grows more on the side with the most auxin, making it bend and grow up away from the force of gravity. When it has grown up, the auxin becomes evenly spread again.

Answer 48

- To stimulate one of the eggs in the ovary to mature / oestrogen to be produced

Answer 49

- Hormones bind to specific receptors for that hormone (found on the membranes or in the cytoplasm of target cells) - Once bound to their receptors the hormones stimulate the target cells to produce a response.

Answer 50

- pituitary gland to releases thyroid-stimulating hormone - TSH stimulates the thyroid gland to release thyroxine. - This increases the metabolic rate, allowing cells to transfer additional energy. - When cells are being supplied with the required amount of energy, the hypothalamus inhibits the production of TSH. - The thyroid gland therefore stops releasing thyroxine (negative feedback).

Answer 51

To allow a response to changes in the environment

Answer 52

for homeostasis (keeps internal conditions constant)

Answer 53

When a stem grows towards tree light, the plant can photosynthesise more, so more food is produced for the plant, so it can grow faster, which increases the plant’s chances of survival

Answer 54

Barrier methods that prevent a sperm contacting the egg or physical devices that release chemical compounds

Answer 55

Use of hormones to disrupt the normal female reproductive cycle

Answer 56

Roots growing downwards: Growing deeper into soil provides anchorage, and normally takes roots nearer to water. Especially Important for germinating seeds which often land the wrong way up, so ensures that grow correctly.

Answer 57

fetus develops here

Answer 58

Eggs mature here

Answer 59

Entrance to uterus

Answer 60

Receives sperm from the penis during sexual intercourse

Answer 61

``` Fallopian tube (oviduct) - where the egg is fertilised before travelling along the tube to the uterus. ```

Answer 62

- when the women takes this drug it stimulates eggs to mature in her ovaries - it also triggers oestrogen production - this significantly increases her chance of getting pregnant, as it increases the likelihood of one or more eggs being released

Answer 63

Advantages of IVF include: 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 include: there are side effects from 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 Ethical concerns Some people worry about the ethical implications of IVF. They are concerned that couples may want 'designer babies' with 'desirable' qualities, so may only want certain fertilised eggs. For example, they may want a girl if they have lots of boys in the family. Also, the embryos that are not used may be destroyed. Some people might view these as new lives, so may consider destroying them to be unethical.

Answer 64

They are produced by cells in one area of the plant, and then transported to a different area to produce a response

Answer 65

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 beings to decrease again. Oestrogen mirrors this shape and also has a second lower peak at about day 21.

Answer 66

Changes occur at puberty because of the hormones: testosterone - produced by the testes - controls the development of male secondary sexual characteristics oestrogen - produced by the ovaries - controls the development of female secondary sexual characteristics

Answer 67

- voice breaks - hair grows on face and body - body becomes more muscular - testes start to produce sperm cells

Answer 68

- pubic hair grows - underarm hair grows - sexual organs grow and develop

Answer 69

- voice deepens gradually - hips get widen - breasts develop - ovaries start to release egg cells - menstruation starts

B3.2 -Endocrine System Flashcards

(93 cards)