Reproduction Exam 1 Review

Which of the following species has the longest gestation period or the longest length of pregnancy?

• Mare

• Cow

In the cow, if the uterine horn ipsilateral to the corpus luteum is removed, which of the following will happen?

• the lifespan of the corpus luteum is extended

True or False: From a reproductive perspective, as well as a variety of other functions, the hypothalamus is considered the "Master Control Center" of the body.

• True

The type of epithelium present in the mucosa of the posterior (caudal) vagina is:

• stratified squamous

• pseudostratified columnar

The site of fertilization in the ewe is the:

• ampullar-isthmic junction

True or False: During steroid synthesis, the first conversion of cholesterol to pregnenolone occurs in the smooth endoplasmic reticulum of the cell.

• False

Match the enzyme with the appropriate action

__ 3 beta hydroxysteroid dehydrogenase (3B-HSD)

__ P450 aromatase enzyme (P450arom)

__ Adenylyl Cyclase

__ Protein kinase A

__ P450 side chain cleavage enzyme (P450scc)

__ Phospholipase C

1.	Converts pregnenolone to progesterone
2.	Cleaves ATP to cAMP
3.	Cleaves phospholipids to DAG and IP3
4.	Converts cholesterol to pregnenolone
5.	Converts testosterone to estradiol
6.	Responsible for the phosphorylation of histone proteins in the nucleus

• 3β-hydroxysteroid dehydrogenase (3β-HSD) → 1. Converts pregnenolone to progesterone

• P450 aromatase (P450arom) → 5. Converts testosterone to estradiol

• Adenylyl cyclase → 2. Cleaves ATP to cAMP

• Protein kinase A (PKA) → 6. Responsible for the phosphorylation of histone proteins in the nucleus

• P450 side-chain cleavage enzyme (P450scc) → 4. Converts cholesterol to pregnenolone

• Phospholipase C → 3. Cleaves phospholipids to DAG and IP₃

True or False: In quaternary structure of protein hormones such as FSH and LH, it is the beta subunit/chain that confers specificity to the molecule and distinguishes it during hormone-receptor interactions.

• True

Which of the following contribute to anestrus in animals through insufficient GnRH secretion?

• stress

During a follicular wave in the cow, primary reason(s) for the decline in systemic FSH secretion once a follicle from the cohort has become selected and dominant is because:

• the dominant follicle secretes estradiol

• the dominant follicle secretes inhibin

  • why: one a dominant follicle is selected, it produces estradoil and inhibin, both of which exert negative feedback on the anterior pituitary to suppress FSH secretion

True or False: The pituitary gland is essentially comprised of two different types of tissues.

• True

True or False: Steroid hormones, such as estradiol, have effects on target cells only through nuclear receptors.

• False

Which of the following components is (are) not considered part of the Ca2+ second messenger pathway?

• Cyclooxygenase

At what stage(s) of follicular growth is the follicle clearly not dependent upon gonadotropin stimulation?

• primordial

  • early follicular development from primordial → primary is considered largely gonadotropin independent and is regulated mostly by local ovarian

True or False: The cells within the anterior pituitary gland that respond to GnRH stimulation by secreting FSH and/or LH do so via the cyclic AMP (cAMP) second messenger system.

• False

True or False: The fornix of the vagina is the area along side of the internal cervical os.

• false

Which of the following hormone(s) stimulate the Ca2+ second messenger pathway in its target tissue? Select all possible answers.

• GnRH

• Oxytocin

  • both GnRh and oxytocin act through G protein coupled receptors (Gq) that activate the Ca2+ second messenger pathway

True or False: Of the two major hormones produced in the female, estradiol and progesterone, estradiol is produced in higher concentrations circulating throughout the body.

• True

True or False: Releasing hormones such as GnRH originate from nuclei in the hypothalamus and make their way to the anterior pituitary via the hypophyseal artery.

• False

match letter to structure

• Vulva → H

• Uterine Body → E

• Oviduct → A

• Uterine Horn → D

• Ovary → B

• Vestibule → G

• Cervix → C

• Vagina → F

True or False: The typical bovine ovary is 5-6cm in length.

• True

Infertility in an aging female is a common occurrence because the number and quality of oocytes declines at a rapid rate.  Which of the following ovarian events explains best the major cause of oocyte depletion over time?

• atresia

  • the major cause of oocyte depletion over time is follicular atresia, which is the degeneration and loss of follicles at all stages of development. The vast majority of oocytes are lost this way - not through ovulation

Match the letter to structure

• Secondary follicle → B

• Tertiary follicle → C

• Primary follicle → D

• Corpus luteum → A

• Atretic follicle → E

True or False: The bovine uterus is considered "bicornuate", which means it has two moderately developed uterine horns.

• True

Which of the following is (are) not a chemical property of the hypothalamic hormone, GnRH? Select all possible answers.

• is 30,000 MW

• has quaternary structure

• is a glycoprotein

  • Gonadotropin releasing hormone (GnRH) is a small decapeptide (10 amino acids) with a molecular weight of 1,200 Da. It does not have have quaternary structure and is not a glycoprotein

True or False: The mucosa of the vagina consists of columnar epithelium in the anterior vagina, and stratified squamous epithelium in the posterior vagina.

• false

True or False: Atresia of follicles can occur at any time during the estrous cycle or menstrual cycle of the female.

• True

Steroids can be orally consumed and remain biologically active (e.g., birth control pills), whereas protein hormones can not.  This is because:

• steroids are hydrophobic, but proteins are hydrophilic

  • steroid hormones are lipid soluble (hydrophobic), so they can survive the digestive tract and pass through cell membranes intact

  • protein hormones, on the other hand are hydrophilic and get broken down by digestive enzymes in the gastrointestinal tract

As reviewed in class, which of the following cell types utilizes the cAMP second messenger system in response to hormone stimulation?  Select all possible answers.

• theca cells

• granulosa cells

• luteal cells

  • These ovarian cell types response to gonadotropins (LH/FSH) via Gs protein - couples receptors, activating the cAMP second messenger pathway

    • Theca cells → LH -cAMP → androgen production

    • Granulosa cells → FSH → cAMP → estrogen production

    • Luteal cells → LH → cAMP → progesterone production

Starting from the outside of the cow and moving inward, properly order the following secondary sex structures that the penis and sperm of the bull might encounter during copulation and sperm transport toward the oocyte/ovum.

• 5 → Uterine body

• 1 → Vestibule

• 3 → Fornix

• 2 → Anterior vagina

• 6 → Uterine horn

• 8 → Ampulla

• 4 → Internal cervical os

• 7 → Isthmus

As reviewed in class, which of the following cell types utilize the Ca2+ second messenger pathway in response to hormone stimulation? Select all that apply.

• uterine smooth muscle cells

  • uterine smooth muscle cells respond to hormones like oxytocin via Gq protein - couples receptors, activating the Ca2+ (IP3/DAG) signaling pathway, which leads to muscle contraction

The pituitary hormone ______ triggers rupture of the follicle at ovulation.

• luteinizing hormone (LH)

  • a surge in LH from the anterior pituitary triggers the final maturation of the follicle and leads to follicular rupture (ovulation)

The organelle of the cell known as the  _______ is responsible for storing and releasing calcium (Ca2+) when a cell is stimulated by a hormone.

• smooth endoplasmic reticulum

In the female reproductive cycle, the _________ is considered the most consistent phase in length in women who have irregularly short or long cycles.

• Luteal phase

  • The luteal phase (post ovulation) is relatively constant in length (about 14 days)

The 3 segments of the broad ligament that support the female reproductive tract include the ________, which supports the uterus, the ______, which supports the ovary, and the ______, which supports the oviduct.

• mesometrium → supports the uterus

• mesoovarium → supports the ovary

• mesosalpinx → supports the oviduct

The steroid ______ is the primary hormone produced by growing, tertiary follicles. 

• estradiol (estrogen)

  • growing tertiary (antral) follicles primarily produce estradiol, which is synthesized by granulosa cells

Using short answers, describe two (of four) functions of the uterus that were discussed in class.

• site of implantation: the uterus provides the environment where the embryo implants into the endometrium and begins development

• support of fetal development: it nourishes and protects the develop fetus throughout pregnancy, including forming part of the placenta and supplying nutrients.

In 2-3 sentences, describe the two ovarian cell types and the two gonadotropic hormones involved in the "2-cell, 2-gonadotropin model" of estradiol synthesis in the female.

• The two cell, two gonadotropin model involves theca cells and granulosa cells, regulated by LH and FSH

• LH stimulates theca cells to produce androgens, which diffuse into granulosa cells

• FSH induces aromatase to convert those androgens into estradiol

In 1 to 2 sentences, briefly describe the two majors functions of the primary sex organ of the female.

• the primary sex organ of the female, the ovary, has two major functions: it produces oocytes (eggs) and secretes reproductive hormones such as estrogen and progesterone

Follicles that have grown and matured to the point of having a fluid-filled cavity called an _______ are called tertiary or Graafian follicles.

• antrum

The hormone ______ is directly responsible for maintaining pregnancy in the female cow.

• progesterone

In 2-3 sentences, provide an answer for the following case study: A cow is diagnosed as having cystic ovarian structures. One large ovary was removed and it was determined that the cystic structures within it immuno-stained strongly for inhibin and anti-Mullerian hormone (AMH).  What does detection of inhibin and AMH indicate about the type of cystic structures present? What are the roles of inhibin and AMH?4

• Strong staining for inhibin and AMH indicates that cysts are follicular (granulosa cell derived),

• since both hormones are produced by granulosa cells rather than luteal tissue

• Inhibin suppresses FSH secretion from the anterior pituitary

• while AMH helps regulate follicular recruitment by inhibiting early follicle development and reducing sensitivity to FSH