B5 - Infection and Response 2 Flashcards
What happens when blood glucose levels are too high ( 4 marks)
Insulin secreted by pancreas - causes glucose to move from the blood into liver and muscle cells - blood glucose reduced - insulin makes liver turn glucose into glycogen
What happens when blood glucose levels are too low (4 marks)
Glucagon secreted by pancreas - glucose released into blood by liver - blood glucose increased - glucagon makes liver turn glycogen into glucose
What is type 1 diabetes and how is it treated
Disorder in which the pancreas fails to produce sufficient insulin. Results in uncontrolled high blood glucose levels and is normally treated with insulin injections.
What is type 2 diabetes
Where a person becomes resistant to their own insulin.
Describe the first and second stage of the menstrual cycle
stage 1 (Day 1-4):
Uterus lining breaks down for four days
Stage 2 (Day 4-14):
Uterus lining builds up again into a thick spongy layer full of blood vessels, ready to receive a fertilised egg
Describe the third and fourth stage of the menstrual cycle
stage 3 (Day 14):
An egg develops and is released from ovary at day 14
stage 4 (Day 14-28):
The wall is then maintained for 14 days until day 28. If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down and the cycle starts again
Describe the function of the 4 hormones that control the menstrual cycle
(First 2)
FSH: produced in the pituitary gland
Causes egg to mature in one of the ovaries in a follicle
Stimulates the ovaries to produce Oestrogen
Oestrogen: produced in ovaries
Causes the lining of the uterus to grow
Stimulates the release of LH inhibits release of FSH
Describe the function of the 4 hormones that control the menstrual cycle
(Last 2)
LH: produced by pituitary gland
Stimulates the release of an egg at day 14(ovulation)
Progesterone: 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. When the level of progesterone falls, the lining breaks down
Inhibits the release of LH and FSH
Describe how oral contraceptives, injections and barrier methods prevent fertilisation (3 marks)
oral contraceptives that contain hormones to inhibit FSH
production so that no eggs mature
* injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years
* barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg
Describe 4 abnormal ways of contraception
- intrauterine devices which prevent the implantation of an
embryo or release a hormone - spermicidal agents which kill or disable sperm
- abstaining from intercourse when an egg may be in the
oviduct - surgical methods of male and female sterilisation.
Describe 3 drastic ways to avoid pregnancy
Sterilisation - cutting/typing the fallopian tubes or the sperm duct
Natural methods - Finding out when in the menstrual cycle the woman is most fertile and avoiding sexual intercourse
Abstinence - Don’t have intercouse.
Pros/Cons of using hormones that can be used to increase fertility
Pros: helps a lot of women to get pregnant
Cons: doesn’t always work - some women may have to do it many times which can be expensive
Too many eggs could be stimulated, resulting in unexpected multiple pregnancies - risk to both mother and babies
Describe the different steps in IVF(4 marks)
IVF involves giving a mother FSH and LH to stimulate the
maturation of several eggs.
* The eggs are collected from the mother and fertilised by
sperm from the father in the laboratory.
* The fertilised eggs develop into embryos.
* At the stage when they are tiny balls of cells, one or two
embryos are inserted into the mother’s uterus (womb).
Pros/Cons of IVF ( 4 marks)
Pros: fertility treatment can give an infertile couple a child
Cons: multiple births can happen if more than one embryo grows into a baby
Success rate of IVF is low - makes procedures incredibly stressful and often upsetting
Both emotionally stressful and physically stressful for a woman - abdominal pain, vomiting, dehydration
Why would some people be against IVF (3 marks)
Process of IVF often results in unused embryos that are eventually destroyed - potential human life destroyed
Genetic testing of embryos before implantation - could lead to the selection of preferred phenotypes
