Histology

Question 1

What are the 2 main roles of the ovary?

Answer 1

Produce gametes (oogenesis in females)

Produce steroids, mainly oestrogens and progestogens

Question 2

What are the 2 main layers of the ovarian structure?

Answer 2

A medulla and a cortex

Question 3

What does the ovarian medulla contain?

Answer 3

loose connective tissue
tortuous  vessels (arteries, veins and lymphatics)

Question 4

What does the cortex of the ovary contain?

Answer 4

• scattered ovarian follicles
• highly cellular connective tissue stroma.
• outer ‘shell’ of the cortex = dense connective tissue layer called the tunica albuginea

Question 5

What is the name given to the single layer of cuboidal cells covering the outside of the tunica albuginea?

Answer 5

germinal epithelium

Question 6

What is the clinical relevance of the germinal epithelium?

Answer 6

Many ovarian cancers arise from this small layer

Question 7

What is the blood supply to the ovary?

Answer 7

Helicine arteries

- these enter the hilum from the broad ligament and supply blood to the ovary

Question 8

Germ cells migrate from the yolk sac to the ovaries to become what type of cells?

Answer 8

Oogonia

Question 9

How are oocytes formed?

Answer 9

Meiosis division of oogonia (oogenesis)

Question 10

What is meant by folliculogenesis?

Answer 10

growth of the follicle which consists of the oocyte and any associated support cells.

Question 11

When are most oogonia (precusors to oocytes) present in a females ovaries?

Answer 11

7 months in utero

Question 12

Where in meiosis do the oocytes halt and why?

Answer 12

Prophase I

further development is only required if that oocyte becomes the dominant one (i.e. for ovulation)
=> many will remain in this state for several decades

Question 13

Describe the different types of follicle found during follicle development

Answer 13

Primordial
Primary (early/late)
Secondary
Mature Graafian follicle

Question 14

Why is it important for an oocyte to associate with the flat cells surrounding it during its development?

Answer 14

If it does not associate with Pregranulosa cells it will die

• these cells become cuboidal upon the oocyte entering the growth phase

Question 15

What layer of extracellular matrix between the oocyte and granulosa cells is visible in a primary follicle?

Answer 15

Zona Pellucida

Question 16

In a late primary follicle, what layers begin to form outside of the granulosa cell layer?

Answer 16

theca interna - goes on to secrete oestrogen precursors, converted to oestrogen by the granulosa cells (GC).

Theca Externa = outer layer, fibroblast-like

Question 17

What can be seen in a secondary follicle?

Answer 17

Antrum (new space) becomes filled with follicular fluid
- forms and enlarges in the granulosa cell layer
=> forming a secondary follicle

Question 18

Explain how meiosis progresses in the dominant follicle for ovulation

Answer 18

• oocyte in the largest Graafian follicle will complete meiosis 1
• produce one cell called a secondary oocyte, similar in size to primary oocyte
• also produces a tiny polar body that carries the second nucleus away to degenerate.

Question 19

What is the follicular stigma?

Answer 19

• pressurised area of ovary where tunica albuginea is parted aside
  => indicating imminent rupture of the follicle.
• This will release the oocyte and the granulosa cells that surround it

Question 20

How does pregnancy prevent the degeneration of the corpus luteum?

Answer 20

If implantation occurs, the placenta secretes HCG which prevents degeneration of the corpus luteum

=> CL maintains progesterone levels, which maintains the pregnancy

Question 21

Describe the epithelium in the fallopian tubes and how this is useful?

Answer 21

• ciliated epithelium
• Secretory cells in the epithelium secrete nutrients.
  => egg can be given nutrients and moved down the tube by cilia towards the uterus

Question 22

Describe the histological appearance of the ampulla of the uterine tube

Answer 22

• mucosa is highly folded
• lined by simple columnar epithelium
• ciliated cells and secretory cells
• surrounded by smooth muscle

Question 23

What are the 3 layers of the uterus?

Answer 23

Endometrium (glandular tissue and stroma)

Myometrium (3 layers of smooth muscle
with collagen and elastin)

Perimetrium (loose connective tissue covered by mesothelium)

Question 24

What are the two layers of the endometrium and what are their functions?

Answer 24

Stratum Functionalis (F)  which undergoes monthly growth, degeneration and loss.
- arteries in this tissue constrict to allow for shedding

Stratum Basalis (B) which is a reserve tissue that regenerates the functionalis. 
- arteries in this tissue do not constrict, but help to regenerate the above tissue

Question 25

Describe the appearance of uterine glands in the secretory phase?

Answer 25

coiled with a corkscrew appearance and secrete glycogen

Question 26

Describe the change of epithelium in the cervical canal and what the clinical relevance of this site is

Answer 26

Changes from simple columnar epithelium to stratified squamous epithelium towards the outside of the body This transition zone is a common site of dysplasia, and neoplastic changes leading to cervical cancer

Question 27

What type of fluid is secreted by the endocervical glands?

Answer 27

- thin and watery in the proliferative phase (allowing the passage of sperm) - thick and viscous following ovulation (preventing the passage of sperm, or microorganisms)

Question 28

A blockage of the endocervical glands can cause what?

Answer 28

Nabothian cyst

Question 29

What are the four histological layers in the vaginal walls?

Answer 29

- Non-keratinized stratified squamous epithelium (appear clear due to glycogen accumulation) - Lamina propria: connective tissue rich in elastic fibres - Fibromuscular layer: inner circular and outer longitudinal smooth muscle. - Adventitia

Question 30

How are the vaginal walls lubricated if there are no glands in the vaginal wall?

Answer 30

- lubricated by mucous from the cervical glands AND fluid from the thin walled blood vessels of the lamina propria

Question 31

How does the accumulation of glycogen in the vaginal walls contribute to preventing infection?

Answer 31

Commensal bacteria metabolize the glycogen to lactic acid which inhibits the growth of pathogenic bacteria.

Question 32

Describe the hair follicles found in the mons pubis

Answer 32

- highly oblique hair follicles => produce coarse, very curly hair - overly fat pad which itself overlies the pubic symphysis

Question 33

What type of glands are found on the labia majora?

Answer 33

apocrine sweat glands and sebaceous glands

Question 34

Describe the histological make up of the clitoris?

Answer 34

- two tubes of erectile vascular tissue | - covered by a fibrocollagenous sheath

Question 35

Describe the differences between the labia majora and minora

Answer 35

lack subcutaneous fat and hair follicles | BUT are rich in vasculature and sebaceous glands