Lecture 26 3/19/24

Question 1

What are the characteristics of the cervix?

Answer 1

-thick-walled and rigid
-physical barrier from exterior
-secretes mucus during pregnancy to isolate uterus (cervical seal)
-produces mucus during estrus to lubricate vagina and flush material

Question 2

How does the cervix respond to hormones?

Answer 2

-open and relaxed in response to estrogen
-closed and rigid in response to progesterone

Question 3

What is the utero-tubal junction?

Answer 3

the connection between the uterine horn and the oviduct

Question 4

What is the main ligament supporting the uterus?

Answer 4

broad ligament

Question 5

What are the characteristics of a bicornuate uterus?

Answer 5

-two uterine horns
-small uterine body
-length of horns depends on degree of fusion between paramesonephric ducts

Question 6

What influence does progesterone have on the uterus?

Answer 6

-lumen secretes uterine milk
-induces uterine quiescence/low contractility

Question 7

What influence does estradiol have on the uterus?

Answer 7

-enhanced immune system response
-increased uterine contractility

Question 8

What are the layers of tissue of the uterus?

Answer 8

-serosa (outer)
-muscularis
-endometrium (inner)

Question 9

Why is it important that the muscularis allows the uterus to contract?

Answer 9

-transport of secretory products and gametes
-expulsion of fetus and fetal membranes during parturition

Question 10

What is the importance of the endometrial folds?

Answer 10

provide the uterine surface for development of the placenta

Question 11

What is the function of the infundibulum?

Answer 11

to capture the newly ovulated oocyte

Question 12

What is the function of the muscularis of the oviduct?

Answer 12

transport newly ovulated oocytes and spermatozoa to the site of fertilization

Question 13

What is important about the substances secreted by the oviduct mucosa?

Answer 13

-provides optimum environment for free floating, unfertilized oocyte
-sustains spermatozoal function until oocyte arrives after ovulation
-provides suitable environment for early embryo

Question 14

What occurs in a complete ovarian cycle?

Answer 14

-ovulation occurs
-antral follicles transform into corpus luteum and produce progesterone
-corpus luteum is destroyed
-new follicles develop and produce large amounts of estrogen
-ovulation occurs again; new cycle

Question 15

Where is the population of oocytes housed?

Answer 15

cortex of ovary

Question 16

What is found in the ovarian medulla?

Answer 16

vasculature, nerves, and lymphatics

Question 17

What are the three layers of an antral follicle?

Answer 17

-theca externa
-theca interna
-granulosa cell layer

Question 18

What is the theca externa?

Answer 18

loose connective tissue that surrounds and supports the follicle

Question 19

What is the theca interna?

Answer 19

layer responsible for production of androgens under the influence of LH

Question 20

What are the products of the granulosa cell layer?

Answer 20

-estrogen
-inhibin
-follicular fluid

Question 21

What is the 2-cell, 2-gonadotropin model?

Answer 21

-binding of LH to its receptors on theca interna cells leads to conversion of cholesterol into testosterone
-binding of FSH to its receptors on granulosa cells leads to conversion of testosterone into estradiol

Question 22

What is the important step in preparation of the follicle for ovulation?

Answer 22

synthesis of LH receptors by granulosa cells

Question 23

Which conditions must be met for the final stages of maturation to occur during folliculogenesis?

Answer 23

-animal must have undergone puberty
-must be appropriate season for animals with seasonal repro. patterns
-minimal body condition score must be met
-proper hormonal environment/absence of progesterone from previous corpus luteum

Question 24

What are the characteristics of oocyte division in the prenatal stages?

Answer 24

-germ cells divide through mitosis
-generate large number of oocytes to form ovarian reserve
-divide into oogonia/primary oocytes
-oocytes enter first meiotic prophase after last mitotic division
-cells arrest in meiotic prophase until after puberty

Question 25

What are the characteristics of oocyte division post-puberty?

Answer 25

-meiosis resumes
-primary oocyte becomes secondary oocyte
-typically complete first meiotic division at the time of ovulation
-second meiotic division occurs at fertilization

Question 26

What is the key characteristic of a prepubertal female?

Answer 26

lack of gonadal estradiol to stimulate the surge center

Question 27

When is puberty initiated in the female?

Answer 27

when GnRH neurons can respond completely to positive and negative feedback

Question 28

Which factors impact the development of hypothalamic GnRH neurons in the female?

Answer 28

-threshold body size and/or composition
-exposure to certain environmental or social cues

Question 29

What is ovarian senescence?

Answer 29

depletion of primordial follicles in a female, at which point repro. cyclicity stops

Question 30

What are the main effects of ovarian senescence?

Answer 30

-decrease in reproductive efficiency
-prolonged and irregular estrous cycles
-eventual cessation of estrous cycles
-net decline in blood estrogen levels
-increases in FSH due to lack of inhibin
-decline in progesterone

Question 31

What is the main difference between the preantral and antral stages?

Answer 31

there are much higher levels of FSH and LH during the antral stages since the inhibition of GnRH by progesterone is no longer occurring

Question 32

Which type of follicle is able to enter a follicular wave?

Answer 32

antral follicles

Question 33

What must occur in order for a follicular wave to result in ovulation?

Answer 33

breakdown of the previous CL and removal of progesterone

Question 34

How does folliculogenesis differ from follicular waves?

Answer 34

-folliculogenesis is the complete process of development and maturation of oocytes/follicles
-follicular waves are the last few days of folliculogenesis

Question 35

What is follicular atresia?

Answer 35

degeneration of antral follicles

Question 36

What is the main trigger for follicular atresia?

Answer 36

the follicle not being exposed to the right concentration of gonadotropin

Question 37

What is ultrasonography?

Answer 37

use of high-frequency sound waves to generate an image

Question 38

What are the four types of reflection on ultrasound?

Answer 38

-fluid: anechoic/black appearance
-soft tissue: hypoechoic/grayish appearance
-bone: hyperechoic/bright white appearance
-air: dispersion/acoustic shadow/no image