b11- hormonal coordination

anki exported for the eoy cram

what is puberty?

stage where reproductive organs mature + secondary sexual characteristics develop due to hormones

what are primary sexual characteristics?

reproductive organs present at birth (ovaries + testes)

what are secondary sexual characteristics?

physical changes during puberty caused by hormones

which hormone is the main female reproductive hormone?

oestrogen

where is oestrogen produced?

the ovaries

which hormone is the main male reproductive hormone?

testosterone

where is testosterone produced?

the testes

what is the menstrual cycle?

hormone-controlled cycle preparing uterus for pregnancy

how long is the average menstrual cycle?

approximately 28 days

what is ovulation?

release of a mature egg from ovary into oviduct

what does fsh stand for and what does it do?

follicle stimulating hormone

what does lh stand for?

luteinising hormone

what do oestrogen and progesterone do?

they stimulate the build-up and maintenance of the uterus lining.

what is negative feedback in the menstrual cycle?

high oestrogen inhibits fsh

how does oestrogen affect fsh and why is it important?

high oestrogen inhibits fsh → prevents multiple eggs maturing

how does oestrogen affect lh?

high oestrogen stimulates lh release before ovulation

what hormone maintains the uterus lining after ovulation?

progesterone

how does progesterone affect fsh and lh and why is it important?

progesterone inhibits fsh + lh → prevents another egg maturing

what happens to progesterone if pregnancy does not occur?

progesterone falls → uterus lining sheds (menstruation)

what do the testes produce after puberty?

sperm (throughout life)

what does testosterone stimulate?

male secondary sexual characteristics + sperm production

how are hormones transported

in the bloodstream

what does the blood transport the hormone to

a target organ where it has an effect

hormones vs electrical nervous system impulses

hormones are slower but longer lasting

what is the pituitary gland known as

the master gland

when hormones are released from pituitary what can they do in relation to other glands

stimulate other glands to release hormones

key endocrine glands

pituitary, thyroid, pancreas, adrenal glands, ovaries and testes

what is negative feedback

a mechanism that restores conditions to normal levels by reversing a change

blood glucose concentration is monitored and controlled by what

pancreas

what does the pancreas produce

insulin and glucagon

what is insulin + purpose

a hormone that allows glucose to move from the blood into the cells and to be stored as glycogen in the liver and muscles. lowers blood glucose levels.

what is glucagon + purpose

a hormone that allows glycogen to be converted into glucose and released into the blood

negative feedback loop example in control of blood glucose levels

when glucagon interacts with insulin in a negative feedback cycle

does glucagon increase or decrease blood glucose levels

increases blood glucose levels

does insulin increase or decrease blood glucose levels

decreases

what happens in people with type 1 diabetes 

blood glucose can increase to fatally high levels

why does type 1 diabetes mean excess sugar in body

as the pancreas does not secrete enough insulin

what happens in type 2 diabetes

the body stops responding to its own insulin

in the liver and muscle cells what happens to the glucose

its is converted to glycogen for storage

what is glycogen

how extra glucose is stored

how is fat formed

if glycogen stores are full, the extra is converted into fat and stored in the body

is glycogen a long term or short term energy store

short term

is fat a long or short term energy store

long term

risk factor for type 2 diabetes

obesity

how can type 1 diabetes be treated

daily insulin injections + monitoring blood glucose levels

type 2 diabetes treatment

exercise regiment and carbohydrate controlled diet

what is thyroxineand what does it stimulate

a hormone that determines the basal metabolic rate

what is the basic metabolic rate

the minimum energy (calories) required to maintain vital bodily functions WHILE AT REST

what does thyroxine play an important role in

growth and development

what is adrenaline

a hormone that prepares the body for fight or flight

where is adrenaline secreted from

the adrenal glands

where are the adrenal glands in the body in relation to other organs

above the kidneys

how does adrenaline prepare the body for fight or flight

increases heartrate, boosts oxygen delivery and glucose to the brain and muscles.

where is thyroxine secreted from

the thyroid gland

what are thyroxine levels controlled by

negative feedback loop with TSH

explain the negative feedback loop with thyroxine, TSH and TRH for low thyroxine

low thyroxine ---> TRH which stimulates TSH which stimulates thyroxine

where is TRH secreted from

hypothalamus

where is TSH secreted from

the pituitary glan

what does fsh stand for?

follicle stimulating hormone

what does fsh do?

stimulates egg maturation in ovary + stimulates oestrogen production

what does lh do?

stimulates ovulation

what does oestrogen do?

builds up uterus lining

what does progesterone do?

maintains uterus lining

name all contraceptive methods

combined pill, mini pill, implant, injection, patch, spermicides, condom, diaphragm, iud (copper), iud (hormonal), surgery, abstaining from sex near ovulation

what is a vasectomy?

sperm ducts cut and tied to prevent sperm entering semen

how does the combined pill work?

contains oestrogen + progesterone → inhibits fsh + lh → prevents ovulation

how does the mini pill work?

contains progesterone → thickens cervical mucus + inhibits ovulation

how does a condom work?

barrier preventing sperm reaching egg

how does a diaphragm work?

barrier covering cervix to stop sperm entering uterus

how do spermicides work?

kill sperm

how does an iud (copper) work?

releases copper ions toxic to sperm

how does an iud (hormonal) work?

releases progesterone → thickens mucus + thins uterus lining

which contraceptive protects against stis?

condom

advantage of hormonal contraception

highly effective

disadvantage of hormonal contraception

side effects (e.g. headaches, mood changes)

advantage of barrier methods

no hormones

disadvantage of barrier methods

less effective than hormonal methods

what is ivf?

fertilisation outside the body in a lab

how is ivf carried out?

fsh + lh stimulate eggs → eggs collected → fertilised → embryo inserted into uterus

advantage of ivf

allows infertile couples to have children

disadvantage of ivf

low success rate, expensive, ethical issues

what hormones control the menstrual cycle

FSH, LH, progesterone and oestrogen

explain the negative feedback loop of the menstrual cycle

when oestrogen drops, fsh increases, oestrogen increases, increasing lh. lh increases progesterone. progesterone stops another egg from maturing.

where is FSH secreted from

the pituitary

where is progesterone secreted from

empty follicle post ovulation

where is oestrogen secreted from

ovaries

where is lh secreted from

the pituitary gland

progesterone role

maintains the uterus lining

fsh role

stimulates follicle maturation and oestrogen release

oestrogen role

builds up uterus lining, inhibits fsh and lh

lh role

triggers ovulation

how often do eggs mature

28 days

ovulation

the release of a mature egg

what does testosterone cause

stimulates sperm production

how can infertility be cured (women)

fertility drugs and IVF

how can infertility in men be cured

IVF or sperm donor

what do fertility drugs contain

FSH and LH

how do fertility drugs work

increasing FSH and LH means the woman can get pregnant in a normal way

how does IVF work

giving the mother a fertility drug then collecting the eggs and taking sperm from father and making them meet in tje lab. when cell division occurs and it is a ball of cells it is inserted into mother's uterus.

why does the woman get given fertility drugs in IVF

as then several eggs mature leading to higher success rate