Control Systems Flashcards
What are the functions of the kidneys
Remove urea from the blood
Adjust ion levels in the blood
Adjust water content in the blood
They filter stuff out of the blood under high pressure then reabsorb thing that the body needs
What is ultrafiltration
A high pressure is build up which squeezes glucose, urea, water and ions into the Bowman’s capsule
The glomerulus and the Bowman’s capsule act like filters so big molecules like proteins and blood cells stay in the blood
What is reabsorption in the nephrons
As the liquid flows along the nephron the useful substances are reabsorbed against the concentration gradient
The ADH levels control how much water is reabsorbed
Reabsorption happens in the convoluted tubules and the loop of henlé
What happens to urea and excess water in the nephron
Urea and excess water are not reabsorbed and go to the bladder as urine
How is water content controlled
Water loss Brain detects Pituitary gland releases ADH ADH makes kidney reabsorb more water Hydrated Brain detects Pituitary gland releases less ADH Lack of ADH makes kidney reabsorb less water Hydrated
This is negative feedback
What happens in dialalysis
A machine used to filter blood
It has to be done regularly
Dialysis fluid has the same concentration of salts and glucose as the blood so these aren’t removed from the blood
The barrier is permeable to ions, waste substances and excess water
So they can move across into the dialysis fluid and get taken away
What is a kidney transplant
When the kidney is given from the donor to the recipient usually when the donor dies and is carrying a donor card or is registered as an organ donor
What precautions must be taken for kidney transplants
The donor must have a tissue type that closely matches the recipients
The patients are given drugs to suppress a weaken the immune system
What are the specialised features of an egg cell
Contains nutrients in the cytoplasm to feed the embryo
Straight after fertilisation the membrane changes its structure so no more sperm cells can get in
Contains a haploid nucleus
What are the specialised features of a sperm cell
Small
Long tail so it can swim far to the egg
Lots of mitochondria to provide energy to swim
Acrosome where they store the enzymes needed to get through the membrane of the egg
Haploid nucleus
What is stage one of the menstrual cycle
The bleeding
Day 1-4
What is stage 2 of the menstrual cycle
Day 4-14
The lining of the uterus builds up again into s thick spongy layer of blood vessels ready for the fertilised egg
What is stage 3 of the menstrual cycle
Day 14
An egg is released from the ovaries
This is called ovulation
What is stage 4 of the menstrual cycle
Day 15-28
The lining is maintained for 14 days if no fertilised egg has landed of the uterus wall by day 28 then the lining starts to break down again
What is the purpose of FSH
Follicle stimulating hormone
Causes a follicle to mature in one of the ovaries
Stimulates oestrogen production
What is the purpose of oestrogen
Causes the lining of the uterus to thicken and grow
A high level stimulates a surge in LH
What is the purpose of LH
Surge stimulates ovulation when the follicle ruptures and the egg is released
Stimulates the remaining follicle to form a corpus Leuteum which secretes progesterone
What is the purpose of progesterone
Maintains the lining of the uterus
Inhibits production of FSH and LH
When the level of progesterone falls and the oestrogen level is low the uterus lining breaks down
Low progesterone allows FSH to increase
What happens when a woman becomes pregnant
The egg implants in the uterus and progesterone levels stay high
The spongy uterus lining allows the placenta to grow
How is the FSH level controlled
By negative feedback
Pituitary gland -> FSH -> ovary -> oestrogen
How are hormones used to increase fertility
FSH and LH can be given to the woman to stimulate the production of eggs in the ovaries
What are the pros and cons of hormones used to increase fertility
Pros-
Helps lots of women to get pregnant
Cons-
Doesn’t always work and can be expensive
Too many eggs could be stimulated resulting in multiple pregnancies
What is ivf
Taking a mans egg and sperm and fertilising them in a lab
They’re grown into embryos
Some of them are put into the woman’s womb to increase the chance of the getting pregnant
What are the pros of ivf
Can give an infertile couple a child
With an egg donor a woman who can’t produce eggs can have a baby and it prevents the risk of a genetic disorder being passed on
What are the cons of ivf
Some women have a reaction to the hormones
Some reports say the hormone treatments increase the risk of cancer
Multiple births are more likely and carry more risks
With donated eggs it is emotionally difficult for the family knowing the baby doesn’t have the mothers genes
What is a surrogate mother
When a woman carries a baby for another couple
Ivf is done to produce and embryo then it is implanted into the surrogate mothers womb
After giving birth the surrogate gives the baby to the parents
What are the pros and cons of surrogacy
Pros-
It allows couples to give birth is father risk would be big or the mother couldn’t
Cons-
The surrogate mother is legally the mother until the child is adopted by the intended couple so she has the right to keep the child
What chromosomes do men have
X and y
Y chromosome cause male characteristics
What chromosomes do all women have
X and X
The combination allows female characteristics to form
What are sex linked genetic disorders
Colour blindness and haemophilia can only be seen in men because the allele can only be found in the X chromosome so the Y chromosome can’t correct the defect
What experiment did Louis Pasteur do
He heated broth in two flasks in one the microbes could get in and they went into the broth and in the other the microbes couldn’t get in so they settled in the tube then duplicated this proved that microbes exist
What did Louis Pasteur invent
Pasteurisation
When you heat something up to about 70c then cool it
This kills most germs
It is an antiseptic technique
It is used to treat raw milk to make it safe to drink
What is resazurin
A Dye that is sensitive to oxygen
As the concentration of oxygen decreases it changes blue to mauve then pink then colourless
Microorganisms use up oxygen when the respire so the more microorganisms the less oxygen
How do white blood cells respond to bacteria
Every pathogen has unique molecules on the surface of its cells called antigens
When a B lymphocyte comes across an antigen they start to produce proteins called antibodies
Which kill the invading cells, the specific antibodies can only work one one antigen
Antibodies are then produced rapidly and flow around the body to kill, the antigens
How do memory lymphocytes work
When a pathogen enters the body for the first time the response is slow
After being exposed to the antigen memory lymphocytes are produced they remain in the body for a long time and remember the antibody
The person is now immune to that particular pathogen
What is immunisation
Injecting dead or inactive microorganisms into the body they carry antigens so even though they’re harmless the body makes antibodies to attack them
The antigens still cause memory lymphocytes to be made
What did Edward Jenner do
Invented the first vaccine
He saw people who got cowpox wouldn’t get smallpox
Cowpox was much safer than small pox so he took a scab from a girl with cowpox and put it into a cut on a boys arm the boy got cow pox but then recovered then he exposed the boy to small pox but he didn’t get ill
Small pox and cowpox are similar so the same antibodies will work
What are the pros of immunisation
Prevents big outbreaks of disease
If people are immunised then the people who aren’t are less likely to catch the disease but if a big number of people aren’t immunised then the disease will spread
Some diseases have been virtually wiped out by immunisation
What are the cons of immunisation
It doesn’t always work
Sometimes people can get bad reactions
What are monoclonal antibodies
B lymphocytes contain antibodies but don’t reproduce fast cancer cells reproduce really fast but don’t have antibodies
You can fuse a b lymphocyte with a cancer cell to create a hybridoma
They reproduce really quickly with identical antibodies
How are monoclonal antibodies used in pregnancy tests
The stick you wee in has antibodies to the pregnancy hormone with blue heads attached
The test strip has some more antibodies for the hormone stuck to it so it can’t move
The hormone binds to the antibodies on the blue beads the urine moves up the stick carrying the beads and the hormone they bind to the antibodies stick to the strip
so the blue beads stick to the strip making it blue
If your not pregnant then the blue beads aren’t taken up the strip so no blue line
What does photoperiodic mean
Respond to changes in day length
Some plants only germinate flower or grow when there is a certain amount of light or dark
What are the examples of photoperiodic responses
Seeds of some arctic plants only germinate when the days are really long so that they grow in the warmest conditions
Some plant buds wait until the days are starting to increase in length to sprout so they’re not killed by frost
Long day plants e.g. Spinach only flower when the days are longest
Short day plants only flower when the days are less than a certain length e.g. Early spring or autumn
What are circadian rhythms
Biological processes that follow a 24 hour rhythm
E.g. Chemical patterns
Physiological patterns
And patterns of behaviour
Animals plants and microorganisms all have them
What are examples or circadian rhythms in humans
Sleep
The body clock gets informs from the light intensity when it’s dark melatonin production increases so we sleep
Urine
The body clock controls ADH production at night ADH levels increase so that urine production is reduced
What are examples of circadian rhythms in plants
Stomata opening
Responding to light levels in the day they open so co2 and o2 can go in and out at night they close to reduce water loss
Flower opening
The flowers only need to be open at the time when the creatures that pollinate them are active
