BY5.2 - Human Reproduction Flashcards
What is the function of the testes?
Contains seminiferous tubules where spermatogenesis occurs
What does hCG stand for?
Human Chorionic Gonadotropin
What is the function of the epididymis?
Spermatozoa mature
What is the function of the Vas Deferens?
Connects epididymis to the urethra
What is the function of the Seminal vesicles?
Produces a secretion that aids spermatozoa motility
What is the function of the Prostate Gland?
Produces a secretion that neutralises the acid conditions of the vagina
What is the function of the urethra?
Carries urine and spermatozoa out of the body
What is the function of the Ovary?
Oogenisis occurs in the ovary
What is the function of the Oviduct?
Site of fertilisation,
carries the zygote down to the uterus
What is the function of the uterus?
Embryo implants into the endometrium of the uterus and develops there in its thick, muscular walls
What is the Endometrium?
a mucus membrane lining the uterus where embryo implantation occurs
shed during menstruation
What is the name of the opening to the cervix
vagina
What is spermatogenesis?
the process by which spermatozoa are produced
Where does spermatogenesis occur?
Germinal epithelium of the seminiferous tubules
Describe the process of Spermatogenesis
1) Diploid spermatogonia divide many times by mitosis - produces primary spermatocytes
2) First meiotic division - stops at metaphase 1
3) Haploid (n) secondary spermatocytes form
4) Second meiotic division
5) Spermatids form
6) Differentiation -> Mature spermatozoa
7) Sertoli cells secrete fluid which nourishes spermatozoa and protects them from the immune system
What is the function of the mid piece of spermatozoa?
-Has many mitochondria to carry out aerobic respiration to produce ATP for flagellum contraction (movement)
What is Oogenesis?
the process by which ova are produced in the ovaries
Describe the processes of Oogenesis that occur before puberty
1) Oogonia (formed before birth) -mitosis-> Primary oocytes (2n)
2) Primary Oocytes undergo meiosis - stop at prophase I
4) Germinal epithelium divides = follicle cells
5) Follicle cell surrounds primary oocytes
6) result = primary follicles
Describe the processes of oogenesis that occur at and after puberty
1) primary oocyte completes 1st meiotic division -> haploid secondary oocyte and small polar body form
2) hormones stimulate the follicles to develop
3) every month one follicle matures into a fully developed graafian follicle
4) Graafian follicle migrates to the surface of the ovary and bursts
5) Secondary oocyte is released into the oviduct - ovulation
6) remaining follicle cells form the Corpus luteum (endocrine gland which secretes hCG) - maintains endometrium if implantation is successful
7) secondary Oocyte begins second meiotic division - stops at metaphase - unless fertilisation takes place
Describe the process of fertilisation:
1) Enzymes in the uterus cause the ovum to undergo capacitation - proteins and glycoproteins are removed
2) sperm contacts the corona radiata
3) the sperms acrosome ruptures and releases protease enzymes - digest oocyte’s zona pellucida
4) Inversion of one sperms acrosome - acrosome reaction - needle-like filament pierces softened oocyte membrane
5) head of same sperm penetrates secondary oocyte
6) Zona pellucida thickens -> fertilisation membrane - prevents polyspermy
7) entry of head stimulates completion of second meiotic division of oocyte nucleus
8) sperm and ovum nuclei fuse to form a diploid nucleus - zygote
Describe the completion of Oogenesis upon fertilisation:
1) upon fertilisation, division is completed to form a large ovum and a second polar body
2) after division, the ovum nucleus fuses with a sperm nucleus to form a zygote
3) result = embryo
What is A blastocyst?
A hollow ball of cells (3 day old)
What is Implantation?
3 day old blastocyst embedding in the endometrium
What is the function of the placenta?
Supplying blood to the embryo
Describe the process of the formation of the placenta:
1) Trophoblast(outer blastocyst layer) develops into 2 membranes: -Amnion&Chorion
2) Chorion grows chorionic villi -> increase S.A. for absorption of Nutrients from the wall of the uterus
3) Chorion also secretes human chorionic gonadotrophin (hormone) -> prevents degeneration of corpus luteum, which secretes progesterone -> maintains endometrium
4) chorionic villi form part of the placenta which is attached to the foetus via the umbilical cord
What is female infertility?
The complete inability to conceive a child
What are the causes of female infertility?
1) failure to ovulate - no/irregular menstrual cycles - treated with clomiphene
2) blockage of Fallopian tubes -> prevents movement of ovum to uterus - can be caused by infection - treated with microsurgery
What biological compound do most pregnancy testing kits use, and what do they detect?
Monoclonal Antibodies
- antibodies that bind to only one foreign antigen
- is specific
- binds to hCG
How do pregnancy testing kits work?
1) hCG is produced in high quantities by the placenta in early pregnancy - present in mothers urine
2) Monoclonal antibodies are embedded in coloured latex beads (immobilised) at the end of a dipstick
3) dipstick is placed in urine - hCG binds to antibodies
4) hCG - antibody complexes form
5) thousands of hCG molecules bind together
6) colour change in beads, visible in test window
