Chapter 15 Flashcards
Spermatogenesis
A process of sperm production that takes place in the seminiferous tubules.
Oogenesis
Process of secondary oocyte or female gamete production.
Where spermatogenesis take place?
Testis
Where oogenesis take place?
Ovary
What hormones are produced by pituitary gland?
FSH and LH
What hormones are produced by ovary?
Oestrogen and Progesterone
Function of FSH
-stimulate follicle growth in ovary
-stimulate release of oestrogen
Function of LH
-stimulate ovulation
-formation of corpus luteum
-stimulate release of progesterone
Function of oestrogen
-Repairs and stimulate thickening of endometrium
-Stimulate follicle growth until mature
Function of progesterone
-Stops the release of FSH and LH to prevent follicle growth and ovulation
-stimulate thickening of endometrium,rich in blood vessel and thick for embryo implantation
Hormone produced by placenta during pregnancy?
HCG (human chorionic gonadotropin)
Umbilical vein
-carries blood rich in oxygen and nutrients
-from placenta to the foetus
Umbilical arteries
-carry deoxygenated blood and nitrogenous waste
-from foetus to placenta
Deoxygenated blood rich in?
Carbon dioxide
Nitrogenous waste example?
Urea
Difference between identical twins and fraternal twins (placenta)
Identical-one placenta shared by two foetus
Fraternal-each foetus has own placenta
How are identical twins formed?
-Product of fertilisation of one ovum and one sperm forming one zygote
-Zygote then divides into 2
How are fraternal twins formed?
-Product of fertilisation of two sperms and two ova forming 2 zygote
-Embryo does not divide
Causes of male impotency
-hormonal imbalance
-low sperm count
-erectile dysfunction
Causes of female impotency
-hormonal imbalance
-ovaries do not produce secondary oocyte
-blocked fallopian tubes
Meaning of growth in organisms ?
An irreversible, permanent process that involves the increase in the number of cells , size , volume and weight of the organisms’s body.
Dry weight ?
-weight of an organism after all the fluid in the body is removed
Fresh weight ?
-can be taken whenever and organisms do not need to be killed
What the two types of growth insects go through ?
-complete metamorphosis
-incomplete metamorphosis
How frequently does ecdysis occur ?
-occurs multiple times until the insect reaches adulthood
Meaning of ecdysis ?
The moulting process of the exoskeleton that allows growth and development of insects.
Exoskeleton are made up of…..
chitin
How does ecdysis happen ?
-a new exoskeleton forms underneath old exoskeleton
-before new exoskeleton hardens, insect will increase its volume by sucking air to expand its body
-this action breaks the old exoskeleton and the insect with new exoskeleton will emerge
-insect will expand its body again before new exoskeleton hardens
Growth phases in sigmoid growth curves of humans and animals ?
-lag phase
-exponential phase
-stationary phase
-maturation phase
-senescence phase
-death phase
Spermatogonium (diploid) produces……
Four sperms (haploid) after meiosis
Oogonium (diploid) produces……
-One functional secondary oocyte (haploid)
-Three non-functioning polar bodies
-After meiosis
