Repro

Question 1

When does gonadal development begin?

Answer 1

4th embryonic (or 6th menstrual) week

Question 2

What are primordial germ cells?

Answer 2

The primary undifferentiated stem cell type that will differentiate towards gametes: spermatozoa or oocyte

Question 3

What will happen to an embryo in the absence of the Y chromosome?

Answer 3

The embryo will develop in to a female phenotype

Question 4

What part of the y chromosome is responsible for determining the male sex?

Answer 4

The sex-determining region of the Y chromosome

SRY

Without this a fetus will develop along the default or female phenotypic pathway

Question 5

Are all of the genes necessary for the male phenotype on the Y chromosome?

Answer 5

No, many of the genes that control testicular development are on other chromosomes - but a gene in the SRY region is needed to activate them.

Question 6

Where are primordial germ cells made? What from?

Answer 6

Yolk sac

From the endoderm that lines it

Question 7

1) What is the first step of gonadal development?

Answer 7

Migration of undifferentiated primordial germ cells - they detach from the lining of the yolk sac, and migrate dorsally along the yolk stalk, midgut and dorsal mesentery to reach the genital ridges.

Question 8

Where are the ‘genital ridges’?

Answer 8

Medial to mesonephric ridge

Urogenital ridge: Region of intermediate mesoderm giving rise to both the embryonic kidney and the gonad

Question 9

2) What happens after primordial germ cells have migrated to the genital bridge?

Answer 9

Mitosis. Much mitosis forming many precursor gametes.

Question 10

What can lead to complete failure of gonadal formation?

Answer 10

A failure of the primordial germ cells to develop and populate the genital ridges

Question 11

3) What happens when germ cells reach the coelomic epithelium that lines the genital ridge?

Answer 11

Cellular contact causes coelomic epithelia to differentiate into primitive germinal epithelium. During this process, the germ cells become embedded in the epithelium.

This combination of cells is now the sex cords.
At this point, they are still connected to the coelomic wall.

Question 12

What forms the sex cords?

Answer 12

The combination of germ cells and primitive germinal epithelia that is formed when the germ cells make contact with the coelomic epithelium.

Question 13

E4) What happens to the sex cords in the presence of a Y chromosome?

Answer 13

They enlarge, split and begin to form the primitive testis

Question 14

In a male embryo, what happens after the sex cords begin to form the primitive testis (hint: at this point, they are still connected to the coelomic (gonadal) wall.

Answer 14

Subepithelial mesenchyme arises between the germinal epithelium and sex chords - cutting them off from the gonadal surface.

The sex cords are now housed within the testicular medulla (the inner portion of the gonad).

Question 15

E5) In a male embryo, what happens to:

(a) the primordial germ cells
(b) the supporting sex cord cells

…once the sex cords have been housed within the testicular medulla?

Answer 15

(a) The primordial germ cells within them begin to differentiate in to immature sperm cells called spermatogonia.
(b) The supporting sex cells form precursor Sertoli cells.

Question 16

What is sexual differentiation dependent on once the undifferentiated gonad has begun to develop?

Answer 16

Secretions from the testis

In their absence, female phenotype

Question 17

Pelvis

Answer 17

Lower limit of abdo cavity

Routes of exit for génito-urinaire dsahjdhaskjfhsfhaio

Question 18

Significance of pelvic outlet

Answer 18

Genitourinal and gastro outlet

Band of muscles holds in place

Question 19

How is the pelvic floor similar to a teacup on a saucer?

Answer 19

Cup = levator ani (iliococcygeus and two others)
Pelvic side wall: obturator internus and piriformis
Saucer = perineal group

Cup and saucer has potential space in between

Question 20

Muscles of pelvic side walls

Answer 20

Obturator internus and piriformis

Question 21

Muscles of the pelvic diaphragm

Answer 21

Levator ani is the cup in cup and saucer analogy

All run from either ilium or pubis to coccyx

Iliococcygeus
Puborectalis
Pubococcygeus
(Ischio)Coccygeus

Question 22

Muscles of the perineum (both layers)

Answer 22

Deep layer

Superficial layer

Question 23

Urogenital triangle

Answer 23

J

Question 24

What do the. Perineal muscles do?

Answer 24

Contributes to continence
External anal sphincter - v superficial
External urethral sphincter - a little bit deeper to ^

Question 25

Ischioanal fossa

Answer 25

Space between levator ani and perineal group - space that fluid abscess can form

Has. Anterior and. Posterior recesses
Posterior recesses communicate but anterior dont - like horseshoe rather than doughnut

Question 26

Perineal body

Answer 26

Fibrous insertion
Most muscles attach here - interesting because most muscles attach to bone
Makes sure pelvic floor can do what it needs to do but
Is vulnerable to damage i,e. Tearing and stretching

Question 27

Neurovascular supply to pelvic floor

Answer 27

Posterior trunk iliac nerve

Pudendal nerve - roots S2, S3, S4 keep your guts off the floor

Question 28

Functions of pelvic floor

Answer 28

Pelvic organ support - maintain appropriate position

Contributes to continence

Question 29

Puborectalis - how does it contribute to faecal continence?

Answer 29

critical role in maintaining anorectal flexure

Combined with external anal sphincter important in faecal continence

Question 30

How can the pelvic floor be damage?

Answer 30

Childbirth:

• mechanical i.e. Muscles stretched/nerve damage
• iatrogenic i.e. Episiotomy

Question 31

Pelvic floor dysfunction

Answer 31

Pelvic organ prolapse - i.e. Pelvic viscera not in right place

Incontinence

Question 32

Lymphatic drainage of uterus

Answer 32

Remember uterus develops as two separate tubes
They are going to run from the posterior wall where the kidneys are and it’s going to drop

Hence we will have iliac nodes and sacral nodes

Para-aortic nodes imp in fundus due to point of origin of some ligament

Fundus also drains to superficial inguinal node because of the round ligament of the uterus

Question 33

Body of uterus - lymphatic node

Answer 33

External and internal iliac

Question 34

Most common causes of unpredictable, irregular upper genital tract bleeding?

Answer 34

Anovulation - this is a menstrual cycle problem

Pregnancy shouldn’t have bleeding

Question 35

With what feature is increased progesterone production in the post-ovulatoire (luteal) phase f the ovarian cycle associated?

Answer 35

Basal temp rise of 0.5 c to 1 c

Question 36

What does oestrogen and progesterone do the endometrium?

Answer 36

Oestrogen grows and increase progesterone receptors on endometrium

Progesterone specialises the cells

Question 37

What stimulates the ovaries

Answer 37

Gonadotropin hormones

Question 38

What happens if no fertilised egg?

Answer 38

No HCG hence corpus leuteum dies
Lose oestrogen and progesterone
Loss of those hormones cuts blood supply due to spasms
Shedding

Question 39

PID - Pelvic inflammatory disease

Answer 39

Infection leading to inflammation

Typically STI, ascends from endocervix to upper genital tract –> may go up to peritoneum in which case peritonitis

Question 40

What happens if PID is left untreated?

Answer 40

Inflammation and adhesions can lead to délicate tubes being blocked - infertility

Also Tuboovarian abscess - potentially life threatening because can rupture and cause sepsis

Question 41

Symptoms of PID

Answer 41

Lower abdo and Deep dyspareunia - pain during sex
Fever
Abnormal discharge/bleeding

Question 42

PID suspected - what questions do you ask? I.e. Risk factors

Answer 42

Sexual partner number
Condoms?
Previous history of STI
IUD