Fertilization and Embryo Development Flashcards
What species have sperm deposition in the uterus?
Rodents, dog, pig, horse
What species have sperm deposition in the cervix?
Cat and pig
What species have sperm deposition in the vagina?
Cat, rabbit, sheep, cattle, human
What is the shift of pH in the upper vagina once sperm is deposited?
4.3-> 7.2 in 10 seconds
What is deposited in the upper vagina during copulation?
Seminal fluid
What is the purpose of seminal fluid?
Its composition and buffering capability protect spermatozoa from the acidity of the upper vagina
How long does the buffering effect last in the reproductive tract, and what is its significance?
The buffering effect lasts only a few minutes, which is enough for sperm to approach the cervix in a pH range of 6 to 6.5, optimal for sperm motility.
What role does the cervix play in spermatozoal transport?
The cervix is a major barrier to spermatozoal transport and serves as a spermatozoal reservoir.
What happens to mucus production in the cervix during estrus?
Copious mucus is produced under the influence of estrogen, regulating the transport of spermatozoa.
How does the composition and viscosity of cervical mucus change?
It varies throughout the menstrual cycle; during days 9-16, its water content increases, facilitating sperm passage at ovulation.
3 functions of the cervix
a) it is receptive to sperm penetration and inhibits sperm migration during other phases of estrus cycle
b) It protects sperm from hostile environment in the vagina
c) it filters defective and immotile spermatozoa
What are the two types of sperm transport?
Rapid transport
Slow release and transport
What occurs immediately after insemination/ejaculation regarding sperm transport?
Spermatozoa penetrate the cervical mucus and some are quickly transported through the cervical canal to the uterine tubes within one hour of ejaculation
What facilitates the rapid transport of spermatozoa?
Muscular movements of the female reproductive tract.
Is it clear whether the first spermatozoa entering the oviduct participate in fertilization?
It is still unclear whether the first spermatozoa entering the oviduct participate in the fertilization of the ovum.
What is the swimming speed of spermatozoa through cervical mucus?
Spermatozoa swim through cervical mucus at a rate of 2-3 mm/hr.
How are spermatozoa stored and released in the cervix?
They are stored in cervical crypts and released sequentially for a prolonged period, allowing passage through the cervical canal for as long as 3-4 days after ejaculation.
What is the significance of slow sperm release from the cervix?
It ensures the continued availability of spermatozoa for entry into the oviduct to effect fertilization.
What is the role of anatomical and physiological barriers in the female reproductive tract?
They help prevent polyspermy
Where does fertilization usually occur?
Ampullary part of the uterine tube
What is fertilization?
Series of processes beginning with the spermatozoa penetrating the corona radiata and ending with the intermingling of maternal and paternal chromosomes after the spermatozoon entered the egg
How many spermatozoa typically surround the corona radiata?
12
What enzyme from the sperm head might assist in penetrating the corona radiata?
Hyaluronidase, emanating from the acrosome of the sperm head.
What role does sperm motility play in relation to the corona radiata?
Major role in penetration of the corona radiata
What is the primary function of the zona pellucida regarding sperm entry?
It allows only sperm of the same species to enter the egg.
What happens to sperm entry after fertilization?
The zona pellucida prevents any other spermatozoon from entering the egg.