Term
| Where does gonad formation occur and how do the germ cells get there? |
|
Definition
| gonad formation occurs at the genital ridge (kidneys also develop here). Germs cells migrate from the yolk sac |
|
|
Term
| What happens if germ cells migrate to the wrong region? |
|
Definition
|
|
Term
| What are the gametes in the genital ridge of males? |
|
Definition
|
|
Term
| When a type A spermatagonia undergoes mitosis, what are the by products? |
|
Definition
| A type A spermatagonia and a type B spermatagonia |
|
|
Term
| What is the difference betweeen type A and type B spermatogonia |
|
Definition
Type A: stem cells that continually undergo mitosis
Type B: gametes that differentiate via meiosis into sperm cells |
|
|
Term
| Which gene is responsible for early gonadal development? |
|
Definition
|
|
Term
| Which gene is responsible for ovary formation? |
|
Definition
| Dax-1, an X-chromosome linked gene |
|
|
Term
| Which gene is the testis determining factor and what gene does it silence? |
|
Definition
| Sry gene. Y linked gene that silences Dax-1 |
|
|
Term
| What happens when the Sry gene translocates away from the sex chromosomes? |
|
Definition
| If Sry gene exists to silence Dax-1 then ambiguous genitalia will form |
|
|
Term
| Does the Sry gene need to be present to develop male genetalia? |
|
Definition
| No. While it would logically seem to be the case their do exist a population of 46 XX with no detectable Sry gene who develope male genetalia. The genetic mechanism is still unclear |
|
|
Term
| What is the name of the process in which a spermatid develops into a spermatazoon (full, normal sperm) |
|
Definition
|
|
Term
| What is the function of Leydig cells, and where are they located? |
|
Definition
| Leydig cells have LH receptors and secrete testosterone. They are located adjacent to the seminiferous tubules (not in the lumen!) |
|
|
Term
| What is the function of Sertoli cells, and where are they located? |
|
Definition
| Sertoli cells make up part of the seminiferous tubules. They function to nurse the sperm cells through the stages of spermatogenesis. They also have finger like projections that form up and create the blood-testis barrier. Finally they have FSH receptors and secrete androgen biding proteins to help with transport |
|
|
Term
| What is Androgen Insensitivity Syndrome and why does it arise? |
|
Definition
Androgen insensitivity syndrome is when a chromosomally male patient has all of the outward appearances of being a female.
This condition arises from a hormonal inbalance in which Sertoli cells have either limited FSH receptors or limited production of Androgen binding protein |
|
|
Term
[image]
What is the name of the gamete cell and its ploidy? |
|
Definition
1.Spermatagonium B, Diploid 2n
2.Primary Spermatocyte, Diploid 4n
3.Secondary Spermatocyte, Haploid 2n
4.Spermatid, Haploid 1n
5.Spermatozoon, Haploid 1n |
|
|
Term
|
Definition
| polar bodies are the result of asymmetrical cell division during oogenesis. These smaller cells (1 made at first meiotic division [Haploid 2n] and 3 made at second meiotic division [Haploid 1n]) are insufficient to support fetal development |
|
|
Term
| Ovulation occurs after which stage of oogenesis? |
|
Definition
| after the primary meiotic division. The gametes travel as secondary oocytes |
|
|
Term
| How do you know that a follicle has progessed from primary to the secondary stage? |
|
Definition
| presence of a cavity within the follicle. This cavity is called the antrum |
|
|
Term
| When do primordial follicles develope? |
|
Definition
| Before or at birth. After birth all follicles are primary until puberty and the beginning of the menstrual cycle. |
|
|
Term
| Where is the membrane granulosa, what is it composed of, and what is its function? |
|
Definition
| The membrane granulosa is the outer layer of follicular cells. Its function is to provide a blood-follicle layer |
|
|
Term
| What is the Zona Pellucida? |
|
Definition
| The Zona Pellucida is the membrane between the follicle cells and the ovum. |
|
|
Term
| What is the cumulus oophorus? |
|
Definition
| The cumulus oophorus is the layer of follicle cells that wrap around the ovum in the cavity (Antrum) |
|
|
Term
| When do the theca folliculi (internal and external theca cells) appear? |
|
Definition
| The begin to form as the follicles become tertiary follicles |
|
|
Term
| What is the Theca interna, and what is its function? |
|
Definition
| The theca interna is the internal layer of the Theca Cells. It has LH receptors and releases testosterone into the granulosa |
|
|
Term
|
Definition
| Aromatase is an enzyme that converts testosterone into estrogen |
|
|
Term
| What cell produces aromatase? |
|
Definition
| Granulosa cells. These cells have FSH receptors |
|
|
Term
| As the oocyte develops, how do the granulosa cells change and why is this important? |
|
Definition
| As the oocyte develops the granulosa cells add LH receptors and differentiate the ability to produce progesterone. Progesterone secreted by the corpus luteum is necessary in the early development of the embryo |
|
|
Term
| What are the two phases of the ovary during the menstrual cycle and what event marks the change? |
|
Definition
| follicular and luteal. These are marked by ovulation |
|
|
Term
| What are the two phases of the endometrium during the menstrual cycle? |
|
Definition
The two phases of the endometrium are the proliferative phase and the secretory phase
proliferative: heavy growth of endometrium
secretory phase: sectretion of glycogens to help cellular growth |
|
|
Term
| What does FSH do in oogenesis? |
|
Definition
| Stimulate follicle development |
|
|
Term
| What does LH do in oogenesis? |
|
Definition
| LH drives ovulation and steroid synthesis |
|
|
Term
| What is the clincal significance of the series of LH spikes for ovulation? |
|
Definition
| The spacing of the spikes are important, could cause infertility by not driving ovulation |
|
|
Term
| What is the effect of estrogen levels on the gonadotropins (LH and FSH)? |
|
Definition
High estrogen levels have a negative effect on FSH and a positive effect on LH.
Estrogen will initially stimulate FSH but as the levels of Estrogen climb it will begin to inhibit FSH |
|
|
Term
| What is the relationship between Progesterone and LH? |
|
Definition
| High levels of progesterone inhibit LH through GRH intermediary |
|
|
Term
| What is the corpus luteum? What important function does it serve? |
|
Definition
| The corpus luteum is the follicle cells after ovulation. The function of the corpus luteum is to secrete much needed progesterone (through the now differentiated granulosa cells) to support fetal developement |
|
|
Term
| If the corpus luteum needs LH and secrets progesterone and progesterone has an inhibitory effect on LH, how does the Corpus Luteum survive? |
|
Definition
| Placenta creates an LH like factor that is not inhibited by progesterone, this sustains the corpus luteum until it is no longer necessary |
|
|
Term
| How does the morning after pill work? |
|
Definition
| The morning after pill works by pumping the body with high levels of a progesterone analog which prevents ovulation |
|
|
Term
| How does mifepristone work? |
|
Definition
| Binds on progesterone receptors. Progesterone is necessary to maintain the embryo |
|
|
Term
| What are the drugs in IVF trying to do? |
|
Definition
| All the IVF drugs try to increase levels of FSH |
|
|
Term
[image]
Identify the structures and, if applicable, the ploidy. |
|
Definition
1.Oogonia, Diploid 2n
2.Primary Oocyte, Diploid 4n
3.Secondary Oocyte, Haploid 2n
4.Ovum, Haploid 1n
5. Polar Bodies |
|
|
