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.)