Hormones (B9.4)

Question 1

what is the endocrine system?

Answer 1

uses hormones to respond to changes in the environment or changes inside the body, made up of endocrine glands

Question 2

what is the differences between the nervous system and endocrine system?

Answer 2

nervous system is very fast, short and very precise to the area of action. The endocrine system is slow, long and more general to the area of action.

Question 3

what is thyroxine?

Answer 3

it is released from thyroid gland and regulates the basal metabolic rate- the speed that chemical reactions take place in the body while it is at rest.

Question 4

the release of thyroxine is controlled baby what other hormone?

Answer 4

thyroid stimulating hormone (TSH) released from the pituitary gland. This keeps the level of thyroxine in the blood within a normal range

Question 5

what gland monitors the level of thyroxine in the blood?

Answer 5

hypothalamus

Question 6

what happens when thyroxine in the blood is higher than normal range?

Answer 6

-the release of TSH by the pituitary gland is inhibited
-Less thyroxine is released from the thyroid gland
-The level of thyroxine in the blood falls to within the normal range

Question 7

what happens when thyroxine in the blood is lower than normal range?

Answer 7

-TSH is released by the pituitary gland
-The thyroid gland is stimulated to release more thyroxine
-The level of thyroxine in the blood rises to within the normal range

Question 8

what is the role of adrenaline?

Answer 8

Adrenaline is released by the adrenal glands in response to stressful or scary situations. It prepares the body for the ‘fight or flight’ response and has many target structures.

Question 9

what is the main female reproductive organ produces in the ovaries?

Answer 9

Oestrogen

Question 10

what is the main male reproductive organ?

Answer 10

Testosterone, produced by the testes and it stimulates sperm production.

Question 11

what occurs during ovulation?

Answer 11

At puberty, eggs (ova) begin to mature and one is released approximately every 28 days, around day 14, of the menstrual cycle.

Question 12

what hormones are involved in the menstural cycle?

Answer 12

-FSH: follicle stimulating hormone
-oestrogen
-LH: luteinising hormone
-progesterone

Question 13

FSH function and where is it produced?

Answer 13

-produced in pituitary gland and targets ovaries
FSH stimulates an ovary:
- to develop a follicle containing an egg (ovum maturation)
- to produce oestrogen.

Question 14

Oestrogen function and where is it produced?

Answer 14

Oestrogen is produced by the ovaries
- stimulates the uterus lining to thicken.

Question 15

LH function and where is it produced?

Answer 15

-produced in pituitary gland and targets the ovaries
- stimulates the mature follicle to release the egg/ovum (ovulation) in the middle of the cycle (around day 14).

Question 16

Progesterone function and where is it produced?

Answer 16

Progesterone is secreted by the empty follicle in the ovary (the yellow body or corpus luteum)
- maintains the lining of the uterus during the second half of the cycle so that a fertilised egg may implant.

Question 17

oestrogen and progesterone inhibits the production of what?

Answer 17

LH and FSH

Question 18

what does decreasing progesterone levels cause?

Answer 18

thickened uterus lining to break down and be discharged (menstruation).

Question 19

how can the menstural cycle be controlled artificially?

Answer 19

the administration of the hormones oestrogen and progesterone

Question 20

how can be oestrogen and progesterone be used as contraception?

Answer 20

-Oestrogen and progesterone prevent ovulation.
-These hormones, taken every day, keeps their blood levels high.
-High levels of oestrogen and progesterone inhibit FSH production and egg/ovum maturation.
-Ovulation cannot take place.

Question 21

what does progesterone stimulate?

Answer 21

the production of thick cervical mucus so that sperm are unable to enter the uterus to fertilise an egg

Question 22

what are the two types of oral pill (hormonal) contraception?

Answer 22

-combined oestrogen and progesterone
-progesterone only.

Question 23

what are the problems with the combined oral contraceptive pill?

Answer 23

-not 100% effective
-side effects are possible (mainly due to oestrogen) – headaches, nausea, irregular menstrual bleeding, fluid retention
-no protection from sexually transmitted diseases (STDs)
-relies on remembering to take it daily.

Question 24

describe the skin patch, hormonal method of contraception?

Answer 24

• contains oestrogen and progesterone (same as the combined pill)
• a small patch stuck to the skin – changed each week.

Question 25

describe the implant, hormonal method of contraception?

Answer 25

• inserted under the skin of the arm
• releases a continuous amount of progesterone
• lasts for up to three years.

Question 26

describe the injection, hormonal method of contraception?

Answer 26

• contains progesterone
• each dose lasts 2 to 3 months.

Question 27

describe the intrauterine devices, hormonal method of contraception?

Answer 27

T-shaped devices inserted into the uterus that prevent the implantation of an embryo
- plastic IUDs – release progesterone.

Question 28

what are the barrier methods of contraception (non-hormonal)?

Answer 28

• condoms – worn over the penis to prevent sperm from entering the vagina – the only contraceptive device that protects against sexually transmitted diseases
• diaphragm – a shallow plastic cup that fits over the cervix and is used with a spermicide
• spermicide – a substance introduced into the vagina to kill sperm or make them inactive – more effective when used with a diaphragm.

Question 29

what are the intrauterine device methods of contraception (non-hormonal)?

Answer 29

T-shaped devices inserted into the uterus that prevent the implantation of an embryo
- copper IUDs – prevent sperm from surviving in the uterus.

Question 30

what are the surgical methods of contraception (non-hormonal)?

Answer 30

permanent sterilisation
cutting or tying structures involved in human reproduction:
- female: oviducts that connect the ovaries to the uterus
- male: sperm duct between the testis and the penis
- very small chance of the structures reconnecting.

Question 31

what are the natural methods of contraception (non-hormonal)?

Answer 31

• avoiding sexual intercourse when an egg may be in the oviduct (most fertile time) – not very effective
• abstinence – no sexual intercourse – 100% effective.