Fertilisation And Implantation Flashcards
(62 cards)
What is the first hurdle in fertilisation?
Survival of spermatozoa in the vagina
Sperm must survive the vaginal environment to reach the cervix.
What are the factors involved in spermatozoa maturation?
- 100 fold concentration of sperm (oestrogen-dependent)
- Completion of sperm modelling
- Changes in metabolism
- Acquisition of forward motion
- Changes in membrane surface proteins, charge, and fluidity
- Coating of sperm plasma membrane with glycoproteins
Adequate stimulation of the epididymis by androgens is essential.
What mediates coitus in both males and females?
- Sympathetic activity (hypogastric nerve)
- Parasympathetic activity (pelvic nerve)
- Somatic outflow (pudendal nerve)
These activities coordinate the physiological responses involved in sexual intercourse.
What is the role of lactobacillus spp. in the vagina?
They produce lactic acid, maintain an acidic pH (<5), and prevent pathogenic bacterial colonisation
This helps create a protective environment for sperm.
What is capacitation in spermatozoa?
It is a process required for sperm to reach full fertilisation capacity
Capacitation involves loss of glycoproteins coat, revealing binding sites and receptors.
What happens during the acrosome reaction?
Exocytosis of acrosome enzymes occurs, allowing sperm to penetrate the zona pellucida
Enzymes like acrosin and hyaluronidases are involved.
What is the significance of the cumulus oophorus in fertilisation?
It surrounds the ovulated oocyte and aids in its collection by fimbria
This structure is crucial for guiding sperm to the oocyte.
Fill in the blank: Sperm fusion with the oocyte membrane triggers the release of _______ from internal stores in the oocyte.
Ca2+
What are the stages of preimplantation development?
- Zygote (24 hours post-fertilisation)
- Morula (80-96 hours post-fertilisation)
- Blastocyst (120-150 hours post-fertilisation)
Each stage represents significant developmental milestones leading to implantation.
What occurs during the maternal recognition phase?
It involves the embryo signaling its presence to the mother to prevent menstruation
This is crucial for successful implantation.
True or False: The journey of spermatozoa through the uterus is solely dependent on self-propulsion.
False
Other factors like ciliated cells and myometrial contractions also play a role.
What is the role of progesterone during the luteal phase regarding cervical mucus?
It decreases cervical mucus secretion and hydration, making it impermeable to sperm and pathogens
This protects the potential fertilized embryo.
What triggers spermatozoa hyperactivation?
An increase in intracellular Ca2+
This results in ‘whiplashing’ tail beats, enhancing motility.
What is the role of the tetraspanin network in fertilisation?
It facilitates sperm fusion with the egg membrane
Components like CD9 and CD81 are involved.
What are the two main types of receptors involved in sperm attraction to the oocyte?
- Odorant receptors
- Specific receptors responding to chemo-attractive substances
These receptors help direct sperm towards the oocyte in the uterine tube.
What does the term ‘chemotaxis’ refer to in the context of sperm movement?
The movement of sperm towards chemo-attractive substances
This is essential for sperm locating the oocyte.
Fill in the blank: The outer rim of the blastocyst is called _______.
trophoblast
What factors can neutralise the acidic vaginal environment?
- Alkaline seminal fluid
- Immunosuppressive compounds in seminal fluid
These factors help sperm survive the vaginal environment.
What is the significance of the fimbria during ovulation?
They collect the ovulated oocyte from the peritoneal cavity
This is crucial for the oocyte’s journey to the fallopian tube.
What is the rim of trophoblast cells that form a precursor to extra-embryonic support tissue?
Trophectoderm
The trophectoderm is crucial for the formation of the placenta.
What is the fluid-filled cavity within the blastocyst called?
Blastocoel
The blastocoel is essential for the development of the embryo.
What is the first hurdle that spermatozoa must overcome?
Survival of spermatozoa in the vagina
What is the second hurdle that spermatozoa must penetrate?
Penetration through the cervix
What is the third hurdle in the journey of spermatozoa?
Journey through the uterus
