57.1 - Fertilisation and Implantation
Time between fertilisation and implantation
8 days
Causes of sperm hyperactivation in the oviducts
Acrosomal glycosylation
Luteal phase of menstrual cycle
After ovulation, progesterone maintains the endometrial lining until hCG takes over in pregnancy
Which layer of cells surrounds the oocyte and protects it during ovulation? (Syncytiotrophoblast, Colloid, Corona radiata, Granulosa layer or Zona pellucida)
Corona radiata
Which hormone is important for maturation of the foetal lungs before parturition? (Aldosterone, Cortisol, Oestrogen, Progesterone, Tesosterone)
Cortisol
Receptor activating acrosome
Egg ZP3
Role of the cortical reaction
Ensure a diploid zygote is formed, as opposed to polyploid
Characteristic hormone of the follicular phase
Estrogens
What is the hormone that acts on Sertoli cells to initiate and maintain spermatogenesis? (estrogen, FSH, LH, progesterone, testosterone)
FSH
Decidual reaction
Flooding of endometrium with spiral arterial blood and oedematous fluid to promote secretions and develop into placenta
Cortical reaction
Granules of the ZP are released when ZP2Rs are stimulated by sperm, leading to cortical granules spreading across the ZP to induce coagulation and hardening that prevents entry of further sperm
Role of syncytiotrophoblast
Invade basal lamina to embed conceptus further, protect the fetus
Role of trophoblastic cells
Invade the endometrium and adhere to heparin sulfate sites
What is the hormone that stimulates testosterone production by Leydig cells? (estrogen, FSH, LH, oxytocin, progesterone)
LH
Stage of meiosis the egg is arrested in prior to fertilisation
Metaphase II
What is the hormone released by the pituitary gland that stimulates uterine contraction? (estrogen, FSH, LH, oxytocin, progesterone)
Oxytocin
Follicular phase of menstrual cycle
Preparatory phase of lining - endometrium thickens by epithelial hypertrophy, and spiral arteries develop
What is the hormone secreted by the corpus lute that causes the development of the endometrial layer of the uterus? (estrogen, FSH, human chorionic gonadotrophin, oxytocin, progesterone)
Progesterone
Which hormone has a relaxant effect on uterine smooth muscle during pregnancy? (Aldosterone, Human chorionic gonadotrophin, Oestrogen, Progesterone, Tesosterone)
Progesterone
What is the phospholipid-derived hormone present in seminal fluid? (FSH, human chorionic gonadotrophin, LH, prostaglandin, testosterone)
Prostaglandin
Action of acrosome
Release of lytic enzymes to degrade zona pellucida
Role of endometrial glands
Secrete glycogen-containing fluids to support an early conceptus
Which tissue invades the maternal endometrium? (Corona radiata, Decidua, Syncytiotrophoblast, Thecal tissue, Zona Pellucida)
Syncytiotrophoblast
Preparation of the uterus for implantation results from stimulation by
The hormone progesterone, which is secreted into your blood stream by the burst follicle (now called the corpus luteum) prepares the uterus for the egg to implant
thecal tissue
Thecal cells are required for the production of androgens to provide a structural scaffold, and they form the network of cells that support the vascular system, and after ovulation, thecal cells luteinize and form cells of the corpus luteum.
Stages of Fertilisation in Humans
Zona Pellucida binding, acrosome reaction; cortical reaction.
What is a blastocyst?
a hollow ball of cells with a cluster of cells inside known as the inner cell mass (day 5)
Which hormone increases gap junction proteins in uterine smooth muscle cells to ensure contractions are in synchrony in childbirth? (aldosterone, cortisol, oestradiol, progesterone, testosterone)
oestradiol
granulosa
the layer of small cells that forms the wall of a follicle (During the follicular phase, these cells secrete estrogen. (follicular cells that synthesize estrogen from testosterone))
decidua
the thick layer of modified mucous membrane that lines the uterus during pregnancy and is shed with the afterbirth. (the endometrium of the uterus during pregnancy)
how does implantation occur?
the zona pellucida degenerates, and the trophoblast attaches itself to the uterine endometrium. The trophoblast (in the blastocyst) secretes enzymes that enable it to burrow into the endometrium until the entire blastocyst is covered.
Acrosome reaction
when sperm releases contents of acrosome when it binds to zona pellucida proteins (When the contents of the acrosome are released and proteases digest a route for the sperm.)
