Term
| Which autonomic nervous system deals with ejaculation? |
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Definition
| Sympathetic nervous system |
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Term
| Which autonomic nervous system deals with erection? |
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Definition
| Parasympathetic nervous system |
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Term
| What are the three criterion for male sterility? |
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Definition
1. Less than 20 million/ml
2. Less than 30% motile at 24 hr
3. Greater than 20% abnormal (tails or heads)
3. |
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Term
| How long does it take for sperm to mature in the epidydymus? |
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Definition
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Term
| What is capacitation? Where does it occur? |
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Definition
Capacitation is the change of the membrane of sperm to render them competent for fertilization.
Occurs in the female reproductive tract |
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Term
| Where does normal fertilization occur? |
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Definition
| In the ampulla of the uterus |
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Term
| How long after ejaculation does it typically take sperm to reach the ampulla of the uterus? |
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Definition
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Term
| What is the corona radiata? |
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Definition
| Outer layer of cells of an ovum. Composed of follicle cells |
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Term
| What are the methods employed by the ovum to prevent polyspermy? |
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Definition
Fast block: a change of charge across the ovum after the fusion of the first sperm
Cortical/zona reaction: change in the zona pellucida after a sperm unites with the plasma membrane of the ovum |
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Term
| Why is it important to block polyspermy? |
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Definition
| If polyspermy occurs then this will cause a partial hydatidiform mole to appear (root cause is polyploidy) |
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Term
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Definition
| genetic abnormality that yields greater than 2 multiples of haploid chromosomes |
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Term
| What are the three ways a partial hydatidiform mole can form? |
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Definition
1. 2 sperm fertilize 1 egg
2. 1 sperm fertilizes an egg that did not separate from its polar body
3. 1 DIPLOID sperm fertilizes a haploid egg |
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Term
| How does a hydatidiform mole form? |
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Definition
| Fertilization of an enucleated egg. Results in a fluid filled placenta with no embryo |
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Term
| What are the two mechanisms by which a complete hydatidiform mole form? |
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Definition
2 haploid sperm enter a enucleated egg, known as Dispermic (only XX or XY)
1 Sperm enters a enucleated egg and undergoes mitosis. Known as monospermic (XX only) |
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Term
| Why does a YY hydatidiform mole never form? |
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Definition
| X chromosome essential for life |
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Term
| Why is are the XY or XX dispermic hydatidiform moles not viable? |
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Definition
| Maternal X chromosome necessary for proper development |
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Term
| What is the most common Hydatidiform mole? |
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Definition
| XX of the monospermic variety |
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Term
| What are the clincal signs of a hydatidiform mole? |
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Definition
| Spotting and high hCG levels. These mole must be treated if not a choriocarcinoma can occur |
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Term
| What is the definition of totipotency? |
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Definition
| Ability of a cell to divide and produce all the differentiated cells of an organism |
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Term
| What is the definition of pluripotency? |
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Definition
| Pluripotent cells can develop into any fetal or adult cell type but cannot form the critically important extraembryonic tissue |
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Term
| In early embryonic development, at what stage do cells lose totipotency and become pluripotent? |
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Definition
| The cells of a developing embryo are totipotent until after the morula stage. Oncy it is a blastocyte the cells become pluripotent |
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Term
| What is indicative of the start of the blastocyte phase of early embryonic development? |
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Definition
| development of a cavity and unilaminar disc in the mass of cells is indicative of change from the morula stage to the blastocyte stage |
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Term
| What are the two layers of the blastocyte? |
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Definition
| Outer layer is called the trophoblast and the inner layer is called the inner cell mass |
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Term
| What is the chain of X deactivation in females? |
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Definition
Remember inactivation starts when cells lose totipotency (after morula stage)
Once the embryo becomes a blastocyte the trophoblastic cells are the first to have X chromosome deactivated (parental).
Once the embryo develops germ layers then all either maternal or paternal X chromosome gets silenced
both are active during oogenesis |
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Term
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Definition
| Barr Bodies are inactivated X chromosomes in females |
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Term
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Definition
| XIC is the gene code from which XIST is transcribed |
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Term
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Definition
| XIST is the transcript that translates into a RNA that coats the X chromosome and deactivates it |
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Term
| Where does the ovum go after ovulation? |
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Definition
| Firstly into the peritoneal cavity where it is picked up by the fimbriae of the uterine tube and travels to the ampulla to await fertilization |
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Term
| What has to break down so that implantation can occur, post fertilization? |
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Definition
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Term
| What is an Ectopic Pregnancy? |
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Definition
| Abnormal site of implantation |
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Term
| What do the trophoblasts do during implantation? |
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Definition
| Trophoblasts differentiate into cytotrophoblasts which then fuse to make syncytiotrophoblasts. Syncytiotrophoblasts help with implantation and hormonal signalling |
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Term
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Definition
| Endometriosis is when endometrial tissue travels up and out the uterine tubes and collects somewhere in the peritoneal cavity. Fertilized eggs can also do this is in a form of Ectopic Pregnancy (typically implanting in the recto-uterine pouch) |
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Term
| What is a chimera and how does it form? |
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Definition
A chimera is an organism that is composed of two or more different populations of genetically distinct cells.
In humans chimeras form by the early deterioration of the Zona Pellucida resulting in the mixing of two blastocytes |
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Term
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Definition
| Parthogenesis is the creation of an embryo with no fertilization. Typically results from nuclear fusion with a polar body |
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Term
| What is Superfecundation? |
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Definition
| Fertilization of oocytes at different coupling events. Double pregnancy |
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