Exam 3

Although sheep and horses breed at different times of the year. the pathway that senses season and results in cyclicality is the same UNTIL which step?

At kiss neurons

Regarding sexual differentiation of the brain in the male, ___ enters the brain tissue and is converted to ___ which causes the brain to be “defemivnized.” In females, this process is prevented by ___. As a result, the ___ will develop in the female, but not in the male.

Testosterone, estradiol, alpha fetoprotein, tonic center of the hypothalamus

The portion of the hypothalamus that receives the light/dark information from the eye is the:

Suprachiasmatic nucleus

The blastocoel forms as a result of ___ junctions forming between outer cells of the mould and ___ junctions forming between inner cells. The process requires ___ to be pumped into the intercellular spaces.

Tight, gap, sodium

The cells of which embryo is the last to be considered totipotent?

16 cell stage

Syngamy is the

Pronucleus/pronuclei fusion

When the sperm tail has ATP available, which of the following is the correct sequence of event that will happen to cause sperm tail movement?

Dynein arm detaches and shortens, dynein arm tilts elongates and attaches at a lower site, dynein arm shortens and returns to horizontal rigor

During oogenesis, the meiosis of the oocyte is arrested twice. What is the 2nd event that causes the meiosis to restart?

Fertilization

We discussed 2 different sugars that sperm can use as an energy substrate. Which of those sugars is naturally provided in the seminal plasma?

Fructose

For the male, the postcopulatory refractory period is affected by all of the following except:

All of the above affect the refractory period

During a semen evaluation, which of the following is not typically measured or observed?

All of the above are typically measured or observed

Regarding seasonal breeders during long day length, at what point in the signaling process is an excitatory signal exciting an inhibitory neuron?

Superior Cervical Ganglion

The 9+9+2 arrangement in sperm refers to the:

Axoneme

Concerning the capacitation of sperm, which is true?

It is defined as the set of changes in the sperm plasma membrane that enables a cell to acquire fertilizing potential and undergo the acrosome reaction

Upon entering the oocyte, the sperm nucleus must decondense. This means that there must be a reductio in?

Disulfide cross links

Polyspermy is due to?

Supernumerary sperm

During erection ___ is converted to ___ by the enzyme ___. This enzyme is activated by ___

GTP, cGMP, guanylate cyclase, nitric oxide

The purpose of the acrosome reaction is to?

Enable the sperm to penetrate the zona pellucida and modify the equatorial segment so that it can later fuse with the plasma membrane of the oocyte

The stages of female reproductive behavior that we discussed in class are?

Attractively, perceptivity, and receptivity

In pigs, the signal for maternal recognition of pregnancy is produced by the ___ and is called ___. This hormone modifies the direction of ___ secretions to prevent CL regression

Trophoblast, estrogen, prostaglandin F2a

T or F: One of the functions of the oviductal sperm reservoir is to maintain sperm and allow a trickle-like delivery of high quality sperm to the site of fertilization

True

T or F: Immune cells in the uterus can between bacteria and spermatozoa and only kill bacteria after insemination

False

T or F: ZP3 is the zona protein that binds to a receptor on the sperm plasma membrane and induces the acrosome reaction

True

T or F: Chemotaxis and thermotaxis are 2 methods by which the sperm and the oocyte recognize each other

True

T or F: A secondary follicle does not have an antrium, contains a primary oocyte and is the stage at which cortical granules are formed

True

T or F: Maternal recognition of pregnancy in the cow involves a protein that increases oxytocin receptor synthesis in the endometrium

False

T or F: Penile erection and protrusion occurs during the precopulatory stage of the male reproductive behavior

True

T or F: At the time of ovulation, the oocyte is 2n

True

T or F: The hormone in the brain promoting reproductive behavior of the male is testosterone

False

T or F: The nasopalatine ducts are accessory olfactory organs that allow examination of less volatile material

False

T or F: The vitelline block to polyspermy is considered the fast block

True

T or F: The cumulus cells surrounding the oocyte are removed from the oocyte as it exits the follicle during ovulation

False

T or F: In the cow, there are 2 types of mucous in the cervix. These are sulfomucin secreted by basal cells of crypts and sialomucin secreted by the apical portion of the crypts

False

T or F: Intromission is defined as the entrance of the penis into the vagina

True

T or F: Some sperm are delivered to the oviduct within minutes of copulation. This is called the rapid transport phase, but pertains to that sperm that are non viable and incapable of fertilization

True

T or F: Only hyperactivated sperm can detach from the oviductal sperm reservoir

True

T or F: Sperm from all of the farm species look the same and cannot be distinguished from each other by simply looking at them under a microscope

False

T or F: Maternal recognition of pregnancy in the 4 farm species is categorized as luteotropic

False

T or F: The zygote is a 1-cell embryo in which the pronuclei have combined

False

T or F: When conducting a semen eval, if there are high proportion of sperm with a cytoplasmic droplet this finding suggests that something is interfering with sperm maturation in the epididymis

True

T or F: The annulus is the juncture between middle piece and principal piece of the sperm tail

True

T or F: An embryo is usually at a 4-cell stage of development when it enters the uterus

False

T or F: Cleavage is the process of mitotic cellular division without growth

True

T or F: After fertilization, if you observe the ootid under the microscope, it would be normal to see either 2 or 3 polar bodies

True

T or F: During fertilization, when the sperm reaches the perivitelline space it settles into a bed of cilia

False

T or F: Uniquely shaped mitochondria are found in the oocyte, these are called lock and key mitochondria

False

T or F: The primary oocyte is arrested in meiotic prophase I. The specific stage at which it is arrested is dictylate

True

T or F: The mare begins to cycle in the fall, and the ewe begins to cycle in the spring

False

T or F: As darkness increases, melatonin also increases

True

T or F: In the spring, Kiss 10 concentrations would be high in sheep

False