Topics 1, 2 And 3 Flashcards
Name two things that are reabsorbed by kidneys
1) glucose
2) sufficient water (osmoregulation)
What is osmoregulation?
The process of maintaining the right water content in the body
How does a dialysis machine work? Which substance does it remove from the blood?
Mechanically filters the blood
1) urea 2) excess ions 3) excess water
What are the advantages and disadvantages of a kidney transplant over dialysis?
Disadvantages: kidneys can be rejected by the patients immune system
Advantages: only cure for kidney disease
What is ultrafiltration?
1) When high pressure squeezes water, urea, ions and glucose out of the blood and into the Bowmans capsule
2) The glomerulus and the Bowmans capsule act like filters, so big molecules like proteins and blood cells are not squeezed out. They stay in the blood
Urea and excess water are not reabsorbed. What happens to them?
They continue out of the nephron, into the ureter and down to the bladder as urine.
Where is urine released from?
Through the urethra
Describe two ways that sperm cells are specialised for their role in reproduction
1) small with long tails so they can swim to the egg
2) lots of mitochondria in their middle section to provide the energy they need to swim the distance
Describe two ways eggs are specialised for reproduction
1) contains nutrients in he cytoplasm to feed the embryo
2) straight after fertilisation the eggs membrane changes it’s structure to stop any more sperm getting in ensuring offspring end up with right amount of DNA
Briefly describe what happens in each of the four stages of the menstrual cycle
Stage 1) uterus lining breaks down and is released
Stage 2) lining builds up again
Stage 3) egg is released from the ovary (ovulation)
Stage 4) uterus lining is maintained for 14 days until day 28. If there’s not fertilised egg the spongy lining breaks down again
And the cycle starts over
Which four hormones control the menstrual cycle? What exactly do they do?
1) FSH (follicle stimulating hormone) causes a follicle to mature in one of the ovaries - stimulates oestrogen production
2) oestrogen - causes the lining of the uterus to thicken and grow - a high level stimulates an LH surge
3) LH (luteinising hormone) stimulates ovulation - stimulates the remains of the follicle to develop into a corpus luteum - which secrets progesterone
4) progesterone - maintains uterus lining - prevents the production of FSH and LH - when the progesterone levels fall the uterus lining breaks down - a low progesterone level allows FSH to increase and the cycle starts again
Give one example of how the menstrual cycle is controlled by negative feedback
1) the levels of different hormones in the blood
- FSH stimulates the ovary to release oestrogen
Name the three fertility treatments
1) inject hormones into ovaries ( FSH LH)
2) IVF (in vitriol fertilisation)
3) surrogate mother
Describe how hormones increase fertility give one pro and one con
If levels of FSH are too low eggs won’t mature - no eggs released - can’t get pregnant. FSH and LH are injected to stimulate egg release
1) pro - it helps women get pregnant
2) con - doesn’t always work, too many eggs could be stimulated resulting in unexpected multiple pregnancies (twins triplets)
Describe IVF give a pro and con
Involves collecting eggs from woman’s ovaries and fertilising them in a lab. These are then grown into embryos. Then transferred to the womb. FSH And LH are given before hand to stimulate egg production
1) pro - can give an infertile couple a child
2) con - hormones can cause vomiting, increase risk of cancer, multiple births
