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154 Cards in this Set
- Front
- Back
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what is gametogenesis?
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production of gametes in the gonads
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what is spermatogenesis?
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production of sperm in the testes
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oogenesis?
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formation of eggs/ ova in ovary
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1st stage of spermatogenesis? where are the S.? found? |
Spermatogonium (2n) are found at or near the basement membrane
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2? what do the spermatogium have and why
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have a high rate of cell division (by mitosis) to produce spermatogonia
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3? what do the spermatogium do?
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spermatognium grow to form Primary Spermatocytes which have completed S phase
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4? what do the primary spermatocytyes do?
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separate the homologous pairs of chromosomes in meiosis 1 to produce (reduction division) to form diploid/haploid Secondary spermatocytes
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what then happens to the secondary spermatocytes?
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form haploid spermatids after the separation of the sister chromatids in meiosis II
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where are the spermatids found?
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in association with the Sertoli cells
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what do the sertoli cells do?
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nourish the spermatids as they differentiate into Spermatozoa and protects them from male immune system |
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what is the rate of formation of spermatozoa like throughout the life of a sexually mature male?
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high and continuous
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what is the average number of spermatozoa in ejaculated semen?
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32 x10 ^6 ml-1
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1st stage of Oogenesis?
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Oogonium (2n) divide by mitosis to produce many oogonia
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whn does this occur in the lifecycle of a female?
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before birth
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where do the oogonia grow?
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within the follicle of cells
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what happens next?
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meiosis begins |
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but?
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stops in prophase (I)
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where are the oogonia found?
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within the primary follicles
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how are these primary follicles formed?
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from the germinal epithelium
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how many primary follicles are there in the ovary before puberty?
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about 400,000
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what may happen to primary follicles (prophase I)?
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develop to secondary follicles (metaphase (II) |
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how?
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under the influence of FSH
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what happens during puberty?
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primary oocytes undergo first meiotic division to form haploid secondary oocytes |
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what happens to the first polar body (haploid chromosomes)?
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doesn't progress beyond metaphase II
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what happens to the secondary oocyte?
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begins secondary meiotic division but doesn't progress to end of meiosis unless fertilisation takes place |
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oogenesis flow chart explain
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spermatogenesis flow diagram explain
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what is the acrosome?
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thin cap over nucleus of the sperm
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function of acrosome?
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acrosome vesicle contains hydrolytic enzymes to digest through ovum wall
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nuclei- strcutre?! and function?
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23 chromosomes- haploid nuclei contains paternal chromosome set |
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what does the mid section of the sperm contain?
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many mitocondria
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why?
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synthesis of ATP to provide energy needed to move tails structure- swim
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what do the protein fibres do?
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add longitudinal rigidity and provide a mechanism of propulsion |
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explain sperm diagram
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structure of nuclei and stage of meisosis?
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haploid nuclei (23 chromosmes) arrested at metaphase II |
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where situated?
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inside a cell with a large volume of cytoplasm (yolk)
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where is the 1st polar body situated?
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outside plasma membrane
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how is it formed?
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during follicle development of cell, unequal division of cell during meiosis 1 produce 1st polar body
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what happens to the 1st polar body?
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does not develop
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what surrounds these structures?
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the zona pellucida
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what is the zona pellucida composed of?
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glycoproteins
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what will they be involved with and with what else? at fertilisation?
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with cortical granules will be involved with acrosome reaction
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whats around the outside?
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follicular cells
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explain mature egg diagram
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width of ovary?
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3-4cm
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function of ovary?
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female sex organs which produce the female gametes (secondary oocytes) and secrete hormones oestrogen and progesterone |
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function of fallopian tube (oviduct)
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connect ovary to uterus each tube ends in finger like projections which collect oocyte following ovulation |
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structure of uterus?
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compact muscular organ, made up of muscle!! endometrium and myometrium |
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function of uterues?
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nourishes and protects growing foetus
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where does the embryo become impanted?
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in endometrium
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what happens if no embryo?
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internal surface of endometrium shed each month...
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situation of cervix?
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neck of uterus
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function?
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a muscular ring which closes entrance to uterus dilates during birth |
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structure and function of vagina?
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muscular tube leads to outside of body |
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function and strcutre of urethra?
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connects to bladder allows passage of urine |
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A=germinal epithelial cells B= Graafin follicle C= D= primary oocytes in primary follicles |
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E=Antrum F=granulosa cells G=Haploid nucleus H=Secondary oocyte |
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when are oogonia formed?
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before birth |
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what happens to these oogonia next? |
undergo mitosis to form primary oocytes |
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what do these primary oocytes start to do? |
but stop at Prohphase I |
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what are the primary oocytes surrounded by?
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primary follicle cells, forming primary follicles |
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what happens at puberty? |
FSH from pituitary gland stimulates some of primary follicles to develop into secondary follicles |
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what does the primary oocyte do? |
completes first meiotic division to form a secondary haploid oocyte and a smaller poar body |
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where is the secondary oocyte? |
in the graafin follicle |
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what happens next to the secondary oocyte?
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begins meioises II but stops at metaphase |
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what does the graafin follicle now do? whats this called |
burts projecting secondary oocyte into fallopian tube called ovulation |
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when is meiosis comlpeted (only
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if fertilisation takes place |
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what is formed?
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an ovum |
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when can spermatozoa only fertilise an ovum? |
after a process called capacitation |
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where does capacitation of the sperm take place?
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as sperm move through fluid in the uterus |
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what does capacitiation do? |
so increasing the chance of binding of the sperm to the secondary oocyte |
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how long does capacitation approximately take? |
7 hours |
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what do enzymes In the uterus cause? |
and plasma proteins from seminal fluid removal of cholesterol - which weakens cell membrane |
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what does this cause the membrane to be?
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more permeable to calcium ions |
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how does this affect the sperm?
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and starts acrosome reaction |
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sperm released from epididymis travel along the vas deferens out of penis through urethra |
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female |
spermatozoa are deposited at top of vagina swim through cervix along lining of the uterus into oviduct where meet secondary oocyte |
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what does contact with the outer jelly coat cause? |
releasing hydrolytic protease enzymes |
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what do these enzymes digest? |
and zona pelluicda |
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what does entry of the head stimulate? |
completion of meiosis II |
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what do cortical granules in the ovum do? |
produce the fertilisation membrane, which prevents entry of any further sperm |
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what happens next to form a diploid zygote?
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nucleus of ovum fuses with nucleus of sperm |
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what is the ovum known as following fertilisation?
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zygote |
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what does the zygote do next? |
divides by mitosis to form a hollow ball of undifferentiated cells known as the blastocyst |
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what is the division of the zygote known as? |
cleavage |
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how long? |
blastocyst reaches uterus and is embedded into endometrium this is implantation |
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what is the outer layer of the blastocyst called? |
the chorion |
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function of chorion layer? |
which remains corpus luteum hroughout pregnancy |
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how is hCG linked with pregnancy testing?
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hCG forms basis of pregnancy testing kit
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pregnancy testing: 1: what does the developing embryo release? |
human Chorionic Gonadotrophin |
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where does the hCG move to how? |
moves to ovaries via blood stream |
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what does the hCG do? |
maintains corpus luteum |
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what does the corpus luteum do? |
oestrogen and progesterone which maintains pregnancy |
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what happens after 2 months? |
placenta develops |
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was can the placenta do? |
produce these hormones |
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what does hCG (where)? provie the basis of?
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pregnancy esting kit |
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what is pregnancy testing dpendent on? |
the use of monoclonal antibodies
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why? |
specific to hormone hCG |
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how to use pregnancy testing kit: 1- wht do you do first? |
dip the absorbent tip in a sample of early morning urine
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2? what is the structure of the absorbent strip like?
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embedded with anitbodies specific to hCG (hCG is the antigen) |
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what is the antibody also bound to?
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a coloured latex bead |
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what will form if pregnant?
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hCG will form a HCG-antibody complex
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what is the HCG-antibody complex like -movement wise? |
mobile |
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so what will the HCG-antibody complex do?
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move up the stick to the large window |
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what is there in the large window? |
a strip of immobilised antibodies which are complementary to the HCG-antibody complex |
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What happens as the complex binds to the second antibody? |
a coloured line builds up |
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pregnancy test |
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How can I be sure the test has worked?
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if pregnant both coloured bands appear if not pregnant coloured band in second window appears but no first coloured band |
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why may the pregnancy test not work?
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if test carried out too early on in pregnancy as not enough HCG hormone produced to form complex and produce visible coloured line` |
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what is one of the major causes of female infertility?
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blocked fallopian tubes
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what does the blockage prevent?
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or zygote moving down fallopian tube |
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what may cause blocked fallopian tubes?
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or endometriosis |
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what treatment is available? |
IVF |
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what is IVF? |
then zygote implanted into uterus |
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treatment using IVF step 1? |
Ovulation is stimulated |
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how? |
using hormones at a specific dose to cause several follicles to develop at the same time |
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what is collected?
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oocytes |
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how? |
using a tube inserted through the vagina |
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how are the follicles located?
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using ultrasound |
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how many sperm are placed in a petri dish per oocyte? |
100,00 |
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what happens after 3 days? |
any fertilised zygotes can be reintroduced into the uterus
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A=seminal vesicle B= Vas deferens C= Prostate gland D= Urethra E= epididymis F= Seminiferous tubule |
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what is the scrotum? |
an external sac which holds the testes outside the body |
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function?
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gives optimum temperature of sperm production of 35 degrees |
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function of testes? |
produce male gametes- spermatozoa |
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what is the urethra? |
a tube that connects the bladder to the outside, passes through the penis |
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function?
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transfers urine and semen to outside |
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function of penis? |
is an organ that is used to pass semen into reproductive system |
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function of vas deferens |
tube that takes sperm from testis to urethra during ejaculation
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epididymis?
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sperm collect and mature here |
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where are the seminiferous tubules found? |
in testis |
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function? |
site of sperm production |
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where is the prostate gland found? |
at base of bladder |
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function? |
produces an alkaline secretion that neutralises any urine left in urethra and aids in sperm motility |
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function of seminal vesicle
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gland that produces a mucus secretion that helps sperm motility
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structure of sf |
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spermatagonesis
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what is spermatogenesis?
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production of haploid (n) spermatozoa from diploid (2n) spermatagonia.
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where does it occur?
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in seminiferous tubules of testes
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name 4 stages?
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Multiplication Growth Maturation Differentiation |
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what happens in multiplication?
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multiplication of many diplod spermatagonia via mitosis from a germinal epithelium on the outer layer of the seminiferous tubule |
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growth? what happens to these spermatagonia?
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grow into diploid primary spermatocytes and DNA replication synapsis and tetrad formation occurs |
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maturation?
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primary spermatocytes undergo meioisis I to produce secondary spermatocytes (still 2n)
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then what happens to these diploid secondary spermatocytes?
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undergo meioisis II to produce haploid (n) spermatids
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explain differentiation, what happens next?
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haploid spermatids differentiate into spermatazoa form mid-piece and tails |
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how do they obtain their nutrients throughout this process?
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via sertolli cells
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Germinal epithelium cells Spermatagoniium Primary spermatocytes Secondary Spermatocytes Spermatids Spermatazoa Sertolli cells |
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what do sertoli cells do?
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nourish and protect spermatozoa once formed
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sperm formation diagram
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structure of a sperm
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