Reproduction Flashcards
When are eggs released from the ovary?
Day 14
What is it called when eggs are released from the ovary?
Ovulation
How often does the cycle repeat itself?
Every 28 days
From which days does menstruation occur
the first 5-7 days
What is menstruation?
Breakdown/shedding of the uterus lining
Describe oestrogen levels and when they peak
They rise from day 1 to peak just before day 14
What is the purpose of oestrogen?
Causes uterus lining to thicken/stimulates uterus to develop a lining (for implantation)
Inhibits FSH production (stops another egg being matured)
Stimulates LH production
Describe levels of progesterone
Stays low from day 1-14 and starts to rise once ovulation has occured (after day 14)
What is the purpose of progesterone?
Maintains uterus lining.
Inhibits LH and FSH production (so no more eggs are released or matured)
What is menstruation triggered by (refer to a hormone) ?
Drop in progesterone, progesterone maintains the uterus lining.
What is FSH released by?
Pituitary gland.
What is LH released by?
Pituitary gland
What is the purpose of FSH?
Stimulates a follicle (egg) to mature in the ovary.
Stimulates release of oestrogen
What is the purpose of LH?
Causes ovulation to occur (egg released from oviduct)
Stimulates progesterone production
Where is oestrogen produced?
Ovary.
Where is progesterone produced?
Ovary.
Mnemonic for remembering order of hormones
FOLP (FSH, Oestrogen, LH and Progesterone)
What nutrients are passed from the mother’s blood to the foetus?
Glucose, amino acids, fatty acids, water, oxygen, minerals, vitamins
Waste products absorbed by the mother’s blood from the foetus’s blood
Carbon dioxide and Urea
Why are pregnant women advised not to smoke?
Nictoine can pass across the placenta. Not all toxin molecules are stopped by the placenta.
Adaptations of the placenta
Difference in concentration gradient
Large surface area, many villi
Short diffusion distance, foetus’s blood vessels are close to mother’s blood supply
Explain process of mitosis
DNA replicates to form chromatids (2 copies of each chromosome). Nuclear membrane breaks down. Spindle fibres attach to chromatids and they move to the equator of the cell. Spindle fibres shorten, chromatids pulled apart by their centromeres. The now chromosomes move to opposite ends of the cell. Cell begins to divide, nuclear membrane forms again, cell constricts and chromosomes become less distinct. 2 daughter cells are formed.
Differences between mitosis and meiosis
Mitosis produces genetically identical daughter cells. Meiosis produces genetically non-identical daughter cells.
Mitosis: 2 cells produced. Meiosis: 4 cells produced.
Mitosis: divides once. Meiosis: divides twice
Mitosis: produces diploid cells. Meiosis: produces haploid cells
Mitosis: Same number of chromosomes. Meiosis: Half number of chromosomes.
Use of mitosis
Growth, repair, asexual reproduction
Use of meiosis
To produce gametes for sexual reproduction
How is the developing embryo protected by amniotic fluid?
Amniotic fluid surrounds the embryo. Acts as a cushion absorbing shocks and protecting the embryo from external impacts.
