B11 Flashcards Preview

GCSE Biology > B11 > Flashcards

Flashcards in B11 Deck (69)
Loading flashcards...
1
Q

What are hormones

A

Chemical molecules released directly into the blood . They are carried in the blood to other parts of the body , but only effect particular cells , in particular organisms called target organs.

2
Q

What do hormones control?

A

Things in cells that need constant adjustment

3
Q

Where are hormones produced and secreted?

A

Various glands called endocrine glands. These glands make up the endocrine system

4
Q

What effect does hormones have?

A

Long lasting effects

5
Q

What is the pituitary gland?

A

Produces many hormones that regulate body conditions. It is sometimes called the ‘master gland’ because these hormones act on other glands , directing them to release hormones that bring about change

6
Q

What is the thyroid gland?

A

Produces thyroxine, which is involved in regulating things like the rate of metabolism , heart rate and temperature

7
Q

What are the ovaries?

A

Produce oestrogen , which is involved in the menstrual cycle

8
Q

What are testes?

A

Produce testosterone which controls puberty and sperm production in maled

9
Q

What is the pancreas?

A

Produces insulin which is used to regulate the blood glucose level

10
Q

Difference between a nerve and a hormone?

A

Nerves a fast , hormones are slow. Nerves act for a short time , hormones act for a long time. Nerves act in a precise area and hormones act more generally

11
Q

What is the endocrine system composed off?

A

Glands that secrete chemicals called hormones directly into the blood stream. Travels to target organs and produces an effect.

12
Q

What happens when one hormone is released?

A

Stimulates others to bring about an effect

13
Q

What monitors and controls blood glucose?

A

Pancreas

14
Q

What food increases blood glucose?

A

Carbohydrates

15
Q

What happens to glucose normally when consume

A

Removes glucose from the blood and vigorous exercise removes even more .

16
Q

What happens if there is excess glucose?

A

Can be stored as glycogen in the liver and in the muscles

17
Q

What must the level of glucose in the blood be?

A

Kept steady . Changes are monitored and controlled by the pancreas , using the hormones insulin and glucagon.

18
Q

What happens if blood glucose concentration is too high?

A

The pancreas produces the hormone insulin that causes glucose to move from the blood into the cells . In the liver and muscle cells excess glucose is converted to glycogen for storage.

19
Q

What happens if blood glucose concentration is too low?

A

The pancreas produces the hormone glucagon that causes glycogen to he converted into glucose and released into the blood.

20
Q

What is type 1 diabetes?

A

A disorder in which the pancreas fails to produce sufficient insulin . It is characteristics by uncontrolled high blood glucose levels and is normally treated with insulin injections.

21
Q

What is type two diabetes?

A

The body cells no longer respond to insulin produced by the pancreas . A carbohydrate controlled diet and an exercise regime are common treatments. Obesity is a risk factor for type 2 diabetes.

22
Q

Features of type 1 diabetes?

A
  • inherited genetically
  • potentially fatal
  • inject insulin, to stop high blood glucose levels
  • diagnosed at birth
  • symptoms-increased thirst, frequent urination, extreme hunger, fatigue , weakness , weight loss , blurred vision
  • treatments-injection insulin , food counting m blood sugar monitoring , healthy food , regular exercise
23
Q

Features of type 2 diabetes?

A
  • caused by unhealthy lifestyle , body cells no longer respond to insulin
  • risks : heart disease/stroke, nerve damage , sores /infections, vision loss , kidney problems
  • symptoms- thirsty all the time , tired all the time , fatigue , blurred vision, itching, cuts take longer to heal
  • treatments-taking medication , regular exercise , eating healthier
  • can be cured
24
Q

What happens in the endocrine system during puberty?

A

Bodys starts releasing sex hormones that trigger sexual characteristics(such as development of facial hair in men and breasts for women)all causes egg to mature in the woman.

25
Q

What is the main reproductive hormone in men?

A

Testosterone . It is produced by the testes and stimulates sperm production

26
Q

What is the main reproductive hormone in women?

A

Oestrogen. Produced by the ovaries , as well as bringing about physical changes , oestrogen is also involved in the menstrual cycle.

27
Q

Stage 1 of the menstrual cycle ?

A

Menstruation starts- the uterus lining breaks down for about four days

28
Q

Stage 2 of the menstrual cycle ?

A

Uterus lining builds up again- from day 4 - 14 , into a thick spongy layer full of blood vessels , ready to receive a fertilised egg.

29
Q

Stage 3 of the menstrual cycle ?

A

An egg develops and is released from the ovary at day 14 , this is called ovulation

30
Q

Stage 4 of the menstrual cycle ?

A

The wall is then maintained for about 14 days until day 28. If no fertilised egg has landed on the uterus by day 28, the spongy lining starts to break down and the whole cycle starts again.

31
Q

What hormones control the menstrual cycle?

A

Follicle stimulating hormone
Oestrogen
Luteinising hormone
Progesterone

32
Q

Follicle stimulating hormones role in the menstrual cycle?

A
  • produced by the pituitary gland
  • causes an egg to mature in one of the ovaries in a structure called a follicle
  • stimulates the ovaries to produce oestrogen
33
Q

Oestrogens role in the menstrual cycle?

A
  • produced in the ovaries
  • causes the lining if the uterus to grow
  • stimulates the release of Luteinising hormone and inhibits the release of FSH
34
Q

Luteinising hormones role in the menstrual cycle?

A
  • produced in the pituitary gland
  • stimulates the release of an egg at day 14 (ovulation )
  • inhibits oestrogen
35
Q

Progesterones role in the menstrual cycle ?

A
  • produced in the ovaries by the remains of the follicle after ovulation
  • maintains the lining of the uterus during the second half of the cycle and during a potential pregnancy . When the levels of progesterone falls, the lining breaks down .
  • inhibits release of LH and FSH
36
Q

What can oestrogen be used for ?

A

Used to prevent the release pf an egg so can be a method of contraception. If oestrogen is taken everyday to keep the level permanently high , it inhibits the production of FSH and after a while egg development and production stop and stayed stopped

37
Q

What other uses does progesterone have?

A

Reduces fertility , by stimulating the production of a mucus , which prevents any sperm getting through and reaching an egg

38
Q

What is the pill?

A

An oral contraceptive containing oestrogen and progesterone . Its over 99% effective at preventing pregnancy, but it can cause side effects like headaches and it doesn’t protect against STDs

39
Q

What are the alternatives to a pill?

A

Progesterone only pill which has fewer side effects

40
Q

What is the contraceptive patch?

A

Contains oestrogen and progesterone. Its small patch that is stick to the skin. Each patch lasts one week

41
Q

What is the contraceptive implant?

A

Inserted under the skin of the arm. It releases continuous amount of progesterone, which stops the ovaries releasing eggs, makes it hard for sperm to swim to the egg, and stops any fertilised egg implanting in the uterus. Can last 3 years

42
Q

What is a contraceptive injection?

A

Contains progesterone. Each does lasts for 2-3months

43
Q

What is an IUD ?

A

T shaped device that is inserted into the uterus to kill sperm and prevent implantation of the fertilised egg. There are two main types- plastics IUDs that release progesterone and copper IUDs that prevent sperm surviving the uterus

44
Q

What are non hormonal forms of contraception ?

A

Designed to stop sperm from reaching egg without effecting the hormones

45
Q

What are condoms?

A

Worn of penis during intercourse to prevent the sperm entering the vagina . There are also femidoms that are worn in the vagina. Condoms are the only form of contraception that will protect against stds

46
Q

What is a diaphragm?

A

A shallow plastic cup that fits over the cervix(entrance of the uterus ) to form a barrier . It has to be used with spermicide ( a substance that disables or kills sperm)

47
Q

Can spermicide be used alone?

A

Yes , but is not very effective 70-80%

48
Q

What is sterilisation?

A

Involves cutting pr tying the fallopian tubes(which connect the ovaries to the uterus)in a female , or the sperm duct ( the tube between the testes and penis) in a male. This is a permanent procedure . Hoverer there is a very small chance that the tubes can rejoin

49
Q

What are natural methods of contraception?

A

Pregnancy may be avoided by finding out when the woman’s cycle is most fertile and avoiding sexual intercourse .

50
Q

What is abstinence?

A

Only way to be completely sure is to not have intercourse

51
Q

What do some women have so they cant get pregnant?

A

Have Levels of FSH that are too low to cause egg to mature. No eggs are released and the women cant get pregenant

52
Q

What hormones are given to women in fertility drugs to stimulate ovulation?

A

FSH and LH

53
Q

Advantages of using hormones to increase fertility?

A

Helps a lot of women to get pregnant when previously they couldn’t

54
Q

Disadvantages of using hormones for fertility treatment ?

A
  • doesn’t always work - some women may have to do it many times which can be expensive
  • too many eggs could stimulate , resulting in multiple unexpected pregnancies
55
Q

What is IVF?

A

1)Involves collecting eggs from the womans ovaries and fertilising them in a lab using the mans sperm
2)

56
Q

What is intra-cytoplasmic sperm injection?

A

Can be used during IVF. It is where the sperm is injected directly into an egg. Its useful if the man has a very low sperm count

57
Q

Where are fertilised eggs grown?

A

Grown into embryos in a laboratory

58
Q

What happens when the embryos are grown in IVF?

A

Transferred to the woman uterus to improve the chance of pregnancy. lH and FSH are given before egg collection to stimulate several eggs to mature.

59
Q

Advantages of IVF?

A

Can give an infertile couple a child

60
Q

Cons of IVF?

A
  • multiple births can happen if more than one embryo grows into a baby, risky for mothers and babies.
  • success rate of IVF is low , average success rate in the uk is about 26% . This makes the proceeds stressful and upsetting , especially if it ends in failure
  • emotionally stressful, physically stressful . Strong reaction to hormones , vomiting , abdominal pain , dehydration
61
Q

What has helped IVF?

A
  • advances in microscope techniques
  • development of time lapse imaging (to check that healthy into an incubator )means growth of embryos can be continuous, to help identify those that are more likely to result in a successful pregnancy
62
Q

Why are people against IVF?

A
  • often results in unused embryos that are eventually destroyed, some see this as unethical
  • genetic testing of embryos before implantation also raises ethical issues , as some could lead to a selection of preferred characterisitics
63
Q

Where is adrenaline released?

A

The adrenal glands, just above the kidneys

64
Q

What is adrenaline ?

A

Released into response to stressful or scary situations . Brain detects fear or stress and sends nervous impulse to the adrenal glands, which secrete adrenaline

65
Q

What does adrenaline help the body do?

A

Get ready for fight or flight. By triggering mechanisms that increase the supply of oxygen and glucose to cells in the brain and muscles. Adrenaline increases the heart rate

66
Q

What is a negative feedback system?

A

A way the body can control the levels of hormones in the blood. If the body detects the level of the substance has gone above or below the normal level a response is triggered

67
Q

How does thyroxine regulate the metabolism?

A
  • thyroxine released by thyroid gland ,which is in the neck.
  • regulates basal metabolic rate, the speed chemical reactions take place while the body is at rest . Also important for processes in the body such as stimulating protein synthesis for growth and devleopment.
68
Q

What is thyroxine released in response too?

A

Thyroid stimulating hormone

69
Q

How does a negative feedback system keep the amount of thyroxine in the blood at the right level ?

A

Tsh will be secreted if it goes too high for the pituitary gland. Reduces amount or thyroxine released from the thyroid gland , so levels fall back to homeostatic levels