B11 Flashcards
What is the endocrine system
The endocrine system (hormonal) is made up of glands that releases chemicals called hormones directly into the bloodstream.
Thyroid
Controls metabolic rate of the body
Pancreas
Controls blood glucose levels
Pituitary
Controls growth in children
Adrenal gland
Prepares the ‘floght or fight’ response
What does insulin do
allows glucose to move from the blood into the cells and to be stored as glycogen in the liver and muscles.
WhT does glucagon do
glycogen to be converted back into glucose and released into the blood.
Glucose
The sugar used in respiration
Glycogen
A storage carbohydrate found in the liver and muscles
Glucagon
A hormone that stimulates the liver to break down glycogen to glucose
When there is high blood glucose…
Insulin released from pancreas
Glucose moves from blood into liver and muscle cells
Insulin makes liver turn glucose into glycogen for storage
Testes
Produces testostrone which controls sperm production and puberty
Ovaries
Produces oestrogen which is involved in menstrual cycle
Dif between nerves and hormones
Hormones have slow action and act for a long time in a more general way
Nerves have fast action and act for a short time in a precise area
When there is too little glucose….
Glucagon is released by pancreas
Glucose released into blood by liver
Glucagon makes liver turn glycogen into glucose
Explain type 1 diabetes
Where the pancreas produces little or no insulin - menas too much glucose
Treatment - insulin injections, diet (less carbs), regular exercise
Explain type 2 diabetes
Where a person becomes resistant to their own insulin - causes glucose levels to rise too high
Treatment - carb controlled diet and regular exercise
Risk factor - OBESITY
Four stages of menstrual cycle
Day 1-4 lining of uterus breaks down
Day 4-14 lining of the uterus builds up
Day 14 egg released
Day 14-28 lining of uterus is maintained
Four hormones that control the menstrual cycle (and where they’re produced from)
FSH - pituitary gland
LH - pituitary gland
Oestrogen - ovaries
Progesterone - ovaries by the remains of the follicle after ovulation (day 14)
FSH
Causes an egg to mature in one of the ovaries in a follicle
Stimulates ovaries to make oestrogen
LH
Stimulates release of egg
Oestrogen
Causes lining of uterus to grow
Stimulates release of LH
And inhibits release of FSH
Progesterone
Maintains the lining of the uterus during the SECOND HALF
When progesterone falls, lining breaks down
Inhibits the release of FSH and LH
How can oestrogen reduce fertility
If its taken everyday to keep the level of it permanently high it inhibits the production of FSH and after a while egg development and production will stop .
How does progesterone reduce fertility
Produces thick mucus to stop the sperm reaching the egg
Name two forms of contraception of reduce fertility by releasing oestrogen
Contraceptive pill
Patch
What is the role of FSH and LH during IVF
They stimulate several eggs to mature
Give one drawback to using hormones to inc fertility
Doesn’t always work
Expensive
Unexpected multiple pregnancies, as too many eggs can be stimulated
IVF
Collecting eggs from woman’s ovaries and fertilising them in a lab using the man’s sperm
Pros and cons of IVF
Success rate is low and it’s seen as unethical
Fertility treatment can give an infertile couple a child
Describe the response if the level of thyroxine in the blood gets too high
Secretion of TSH is stopped (pituitary gland)
Reduces the amount of thyroxine released from the thyroid, therefore lowering the level of thyroxine in the blood
Explain what causes plant shoots to grow towards light
More auxin accumulates on the shaded side
Causes it to elongate faster
So shoot bends towards the light
Give one way gibberellin can be used commercially
To stimulate seed germination
To control dormancy - grow all year round
To stimulate flowering - flower without any change in env
To grow larger fruit
Give one way auxin can be used commercially
Killing weeds - disrupts their growing pattern - leaves grass
Growing from cuttings with rooting powder
Growing cells in tissue culture - stimulates cells to divide to form roots and shoots
Which plant hormone is responsible for fruit ripening
Ethene - stimulates enzymes that cause fruit to ripen
