This summary Human Biology includes books, slides and lecture notes. Titles are clearly marked in color, and expressed figures are all included. The text is written in English. Good luck, it worked for me ;-)!
One sperm fertilizes the egg
Only one sperm can succeed : 2nd stage of meiosis is only completed when a sperm makes contact => Then,
secondary oocyte is surrounded by a protective covering ‘ZONA PELLUCIDA’ and a layer of granulosa cells from
the follice ‘CORONA RADIATA’.
When sperm encounters egg, tip of its head ‘ACROSOME’ releases enzymes=> digest path between granulosa cells
of corona radiata, thru zona pellicuda to the oocyte plasma membrane => When first one makes contact, special
protein “keys” of sperm recognize receptor protein “locks” in oocyte plasma membrane => plasma membranes of
egg & sperm fuse => sperm nucleus can enter the egg = begin of FERTILIZATION => triggers 2nd meiosis & formation
of haploid OVUM (= mature egg).
Fertilization is complete when both haploid nuclei form a SINGLE diploid cell or zygote with 46 chroms.
The cytoplasm of the egg must support 2-weeks of cell division until the ‘pre-embryo’ makes contact with the
uterine lining and begins to receive nutrients from the mother.
PAGINA 559 GROTE FIGUUR en FIGIIR 56O en 567
Twins may be fraternal or identical (changes 1/90)
Fraternal: ovulation of more than one oocyte
Identical : from one zyogte => up to 8-cell stage, all cells of pre-embryo are identical. Ball of cells breaks before
differentation has begun.
Development : Cleavage, morphogenesis, differentiation & growth
Cleavage : cell divisions (no growth or differentiation). First 4 days => Ball of identical cells with same size as original
zyogte. Only energy is stored in cytoplasm + little glycogen in oviduct.
Morphogenesis : changes in form & shape
Differentiation : cells take specialized form & functions (= primary cause of morphogenesis)
Growth : starts when embedded in endometrial lining of uterus (nutrients from mother)
Pre-embryonic development : The first 2 weeks
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller IsoldeLas. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.27. You're not tied to anything after your purchase.
