Repro Exam 3

What are stages of the lifespan of a corpus luteum?

Corpus hemorrhagicum and corpus albicans

What cells are part of the process of luteinization? What hormone is important for this transformation to take place?

Theca cells and granulosa cells; LH

Small luteal cells derive from what cells? Do they multiply?

Theca cells; YES

What are the general actions of progesterone?

Reduces GnRH pulse frequency, prevents behavioral estrus, stimulates the secretion of endometrial glands, and reduces myometrial tone.

Luteolysis entails the maintenance of the corpus luteum?

FALSE

The site of production of the luteolytic product(s) is the same in all species.

FALSE

What is the main luteolytic product?

PGF2 alpha

What is the role of oxytocin and its receptors in luteolysis?

Stimulate PGF2 alpha

If you perform a total uterectomy in a ewe after ovulation, how does it affect the lifespan of the CL?

Prolongs the lifespan

The primordial germ cells are the progenitors of what cells?

Gametes

Are PCGs mitotic or meiotic cells? Are they totipotent?

Mitotic; YES

What is the longest phase of female meiosis?

Prophase I

When mammalian females are born at what stage of meiosis are the oocytes arrested?

Prophase I

Are the oocytes smaller, similar or larger than most cells?

Larger

Name two molecular components that are present in the yolk of oocytes

Proteins and lipids (carbohydrates)

An example of the egg coat is the zona pellucida. Name two functions of it.

Egg and embryo protection, species specific fertilization

Besides the ZP name two typical organelles of eggs

Cortical granules, ER clusters, cytoplasmic lattices

Where are GDF9 and BMP15 produced? What are the target cells for these factors?

Oocyte; Granulosa cells

What is AMH? Is its role in folliculogenesis to promote follicular activation or maintain a balance between activated follicles and those remaining in the resting pool?

Anti-Mullerian hormone; maintain a balance

What is an antrum in an antral follicle?

Fluid accumulation

In the antral and Graafian follicles, what granulosa cells are next to the oocyte?

Cumulus

Connexin 43 is expressed between what cells? Connexin 37?

Granulosa cells; cumulus cells and oocytes

What follicular cells produce cyclic guanosine monophosphate?

Mural granulosa

What hormone increase stops cGMP production and induces the resumption of meiosis and oocyte maturation?

LH

Is MPF activity important for oocyte maturation? Is it necessary for MII arrest? Is Emi2 required to maintain or deactivate MPF activity?

YES; YES; maintain

One gamete is produced per meiosis in males or females?

Females

Differentiation of the gamete occurs while diploid in the meiotic prophase in males or females?

Females

Meiosis and differentiation proceed without arrests in males or females?

Males

Give the sequential order from more immature to mature forms in the cells that are part of spermatogenesis

1. Spermatogonia A1

2. Intermediary spermatogonia

3. Spermatogonia B

4. Primary spermatocyte

5. Secondary spermatocyte

6. Spermatid

7. Mature spermatozoa

What cells of the group are the last to undergo mitosis?

Spermatogonia B

Is spermiogenesis the transformation of spermatids into spermatozoa?

YES

Is spermiation the release of mature sperm into the seminferous tubule lumen?

YES

What structure in mature sperm derives from the Golgi?

Acrosome

Protamine proteins replace what other proteins in the sperm nucleus?

Histones

List two hormones produced by sertoli cells

AMH; inhibin; ABP

What hormone do the leydig cells produce? Are they inside or outside the seminiferous tubules?

Testosterone; outside

What type of cellular junctions create the compartmental organization of the seminiferous tubulus?

Tight

What are the main functions of the epididymis?

Store, transport mature sperm

List 3 functional changes that occur in the sperm in the epididymis and are related to fertilization?

Fertilizing capacity, loss of cytoplasm droplets, progressive motility

List 2 changes the epididymal fluid experiences during transit in the epididymis?

Viscosity, lower pH

Name 2 proteins that are part of the axoneme

Microtubules, dynein

Where does capacitation happen in the female tract?

Oviduct

Hyperactivation involves changes in what region of the sperm?

The tail

What is the step of fertilization for which hyperactivation is required?

Zona pellucida penetration

The acrosome reaction involves the fusion of membranes in the sperm head. Name 2 membranes

Plasma membrane, outer acrosome membrane

There are 2 types of sperm transport in the female tract. Which one is most important for fertilization and fertility?

Sustained transport

Name a barrier to sperm transport in the female tract

Cervix, UTJ

What hormone triggers ovulation?

LH

Is the expression of the progesterone receptor important for ovulation? What receptor is important for follicular rupture?

YES; PGR

Does cumulus expansion occur before or after ovulation? List 1 molecule involved in this process.

Before; hyaluronidase

What are the possible mechanisms the sperm may use to cross the zona pellucida?

Mechanic and enzymatic

List 4 events of egg activation

1. Ca release

2. CG excocytosis

3. Resumption of meiosis

4. PN formation

List 2 molecules involved in sperm-egg fusion. 1 from the sperm and 1 from the egg.

Juno and izumo

The IP3R1 receptor is important for release of?

Calcium

The uterus produces PGF2a that enters the venous drainage at high concentrations. PGF2a diffuses from the ? into the ?

Uterine lumen; vein

Name an enzyme present in the cortical granules

Ovastacin

After fertilization, what sperm proteins associated with DNA are replaced by oocyte proteins? Name both types

Protamines and histones

What structure dissolves to initiate meiotic maturation?

Germinal vesicle membrane

What is the function of cortical granules during fertilization?

Preventing polyspermy

What is unique about the progression from Meiosis I to Meiosis II in oocyte maturation?

There is no intervening prophase II stage

What is the DNA content of an oocyte in the diplotene stage of the first meiotic prophase?

4 times the haploid DNA

What is the DNA content of an unfertilized egg arrested at metaphase II?

2 times the haploid DNA

What structure isolates the follicle from neighboring tissues during early differentiation?

Basal lamina

What is the approximate duration of spermatogenesis in humans?

74 days

What happens to the sex cords at puberty?

They hollow out

What are the three main regions of the epididymis?

Caput, corpus, and cauda

What is the microtubule arrangement found in sperm axonemes?

9 + 2

Where are the mitochondria located in a sperm cell?

Midpiece

How long can spermatozoa survive in the cauda during sexual rest?

More than 3 weeks

What is the storage capacity of the epididymis in terms of ejaculates?

More than 10

What hormone stimulates myometrial contractions during the follicular phase?

Estradiol

Where should semen be deposited in a cow during AI to minimize loss?

Uterus

What percentage of sperm is in the stallion's first 3-4 squirts?

80%

Which fluid pushes the dog's sperm-rich fraction into the uterus?

Prostatic fluid

Which cervical mucus has low viscosity?

Sialomucin

What is the thinnest part of the follicular wall where rupture occurs?

Stigma

Approximately how many human sperm reach the site of fertilization?

200

What is egg activation without sperm called?

Parthenogenic activation

At what point does a zygote become an embryo?

After syngamy

What are the cellular divisions occurring at regular intervals in early development called?

Cleavages

Order the stages of early embryo development:

1. Cleavage stage

2. Blastocyst stage

3. Embryo stage

4. Fetus stage

What is the typical duration of mammalian cleavages?

12-24 hours

What term describes the rotational cleavage patterns in mammals?

Meridional and equatorial

In the transition from morula to blastocyst, what is pumped into intercellular spaces to drive water movement?

Sodium

What type of cell junctions form between the outer cells of the morula?

Tight junctions

What type of cell junctions form between the inner cells of the morula?

Gap junctions

Which two separate cellular components emerge in the early blastocyst?

Inner cell mass (IM) and Trophoblast

What is the fluid-filled cavity in a blastocyst called?

Blastocoele

At what cell stage does a cow embryo typically enter the uterus?

16-cell

In humans, how many days after ovulation does the blastocyst stage typically occur?

5 days

What molecules might neighboring cells use to restrict cell fate?

Morphogens

What controls the very first cell divisions in an embryo?

Maternal transcripts

What is the term for the transition from maternal to embryonic control of development?

Maternal-zygotic transition

At what stage does the 'Beginning of transcription' occur in human embryos?

4-8 cell

What is development initiated without the contribution of the male genome called?

Parthenogenetic development

What is the primary DNA modification involved in epigenesis?

Methylation

In placental mammals, what is imprinting tightly linked to?

Evolution of the placenta

Which processes are regulated by imprinted genes in Eutherians?

Growth, placental development, and nutrient transfer

In flowering plants, where is imprinting mostly found?

Endosperm

What is the specific term for parthenogenesis mentioned for lizards and Komodo dragons?

Thelytoky