Microanatomy Lecture 2

Question 1

Primordial follicle

Answer 1

central oocyte with simple squamous epithelium

Question 2

Unilaminar primary follicle

Answer 2

central oocyte with simple cuboidal epithelium

Question 3

Multilaminar primary follicle

Answer 3

central oocyte with stratified cuboidal epithelium

Question 4

Secondary follicle

Answer 4

central or acentral oocyte with stratified cuboidal epithelium and one or more fluid-filled spaces

Question 5

Mature follicle

Answer 5

the dominant secondary follicle that produces a visible bulge from the surface of the ovary

Question 6

Large atretic follicle

Answer 6

stratified cuboidal epithelium and one or more fluid-filled spaces, with cells with pyknotic nuclei sloughed into the spaces. oocyte may or may not be present

Question 7

What are the four histological layers of the ovary?

Answer 7

1. germinal epithelium (simple, cuboidal)
2. tunica albuginea (dense, irregular connective tissue)
3. cortex (follicles, stroma, endocrine glandular tissue)
4. medulla (loose connective tissue - contains blood vessels and nerves)

Question 8

What is a follicle, and what cell types make up an ovarian follicle?

Answer 8

follicles: house germ cells and synthesize estrogen
cell types: follicular epithelium surrounding a single oocyte

avascular with a basement membrane

Question 9

What hormone initiates follicle growth?

Answer 9

follicle stimulating hormone (FSH)
(promotes follicular cells to produce aromatase which converts precurosor steroids into estrogen which drives follicular cell mitosis)

Question 10

What hormone sustains follicle growth by promoting follicular cell/granulosa cell proliferation?

Answer 10

Luteinizing hormone LH

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Question 11

What structure separates the primary oocyte from the granulosa? What is the function of this structure? How do the primary oocyte and granulosa cells communicate across this structure?

Answer 11

Zona pellucida - functions to promote sperm association and activation during fertilization

communicate by filopodia from granulosa cells that penetrate the zona pellucida to contact oocyte microvilli - gap junctions on these allow for transport and signaling

Question 12

What histological features distinguish a large, viable follicle from a large, atretic follicle?

Answer 12

the follicle of an atretic follicle will collapse and their basement membrane thickens into a collagenous scar called the corpus fibrosum

Question 13

What cell(s) produce estrogen?

Answer 13

granulosa cells (formally the follicular epithelium) 
also by corpus luteum (arises from ruptured follicle after ovulation)

Question 14

What are the histological feature of luteinized granulosa cells? What do these features indicate about the functions of these cells?

Answer 14

large, pale, eosinophilic cells with foamy-appearing cytoplasm - lots of smooth ER, large mitochondria, numerous lipid droplets

why? undergoing hypertrophy (cell growth no division) and differentiation into steroid hormone-producing cells

Question 15

Name at least three steroid hormone-producing structures that can be found in the ovary (not always present at the same time) How would you distinguish these in a histological section?

Answer 15

luteinized granulosa cells (corpus luteum)
luteinized theca cells (corpus luteum)
theca interna (mature follicle)

Question 16

The corpus luteum and corpus albicans can sometimes be mistaken for each other in histological sections. What histological features are similar between them? What histological features can be used to distinguish them?

Answer 16

corpus luteum: from ruptured follicle - has leuteinized granulosa and luteinized theca cells (smaller and darker than granulosa, thin outer border while granulosa is bulk to corpus luteum wall)
corpus albicans: large connective tissue scar that remains after luteolysis (apoptosis of corpus luteum in absence of pregnancy) - dense collagen fibers - appear as large, mostly acellular eosinophilic area

Question 17

How do the histological features of the oviduct mucosal epithelium relate to its functions?

Answer 17

simple columnar ciliated with ciliated cells (to sweep the oocyte towards the uterus) and secretory cells (secretions nourish and protect gamete and capacitate sperm activatioN)

Question 18

What are three ways in which the oviduct aids in transporting the oocyte complex or fertilized embryo to the uterus?

Answer 18

has ciliated cells to sweep
secretory cells to release secretions to nourish and protect gamete and capacitate sperm activation
smooth muscle in the lamina propria to move the fimbriae

Question 19

Why is an ectopic pregnancy life-threatening for the mother?

Answer 19

developing placenta erodes large blood vessels and growing embryo ruptures the oviduct causing hemorrhaging

Question 20

What does the endocrine glandular tissue include?

Answer 20

theca interna, corpus luteum, interstitial glands ***