Female Reproduction System, Including Menstrural Cycle And Oogenesis

Question 1

Outline an overview of the female reproductive system

Answer 1

External genitalia is known collectively as the vulva

Internal reproductive organs: the vagina, the uterus, two uterine tubes and two ovaries

Question 2

Describe the moms pubis/veneris

Answer 2

Rounded pad of fat lying anterior to the symphysis pubis

Question 3

Describe the labia majora

Answer 3

Two folds of fat and areolar tissue, covered with skin and pubic hair on the outer surface and have a smooth inner surface

Question 4

Describe the labia minora

Answer 4

Two small subcutaneous folds that lie between the labia majora. The upper layer passes above the clitoris to form the prepuce, which overhangs the clitoris. The lower layer passes below the clitoris to form the frenulum of the clitoris.

Question 5

Describe the prepuse

Answer 5

Retractable piece of skin, formed by the labia minora, which surrounds and protects the clitoris

Question 6

Describe the fourchette

Answer 6

Labia minora fuse posteriorly to produce the fourchette

Question 7

Describe the vestibule

Answer 7

The area enclosed by the labia minora in which the openings of the urethra and the vagina are situated

Question 8

Describe the urethral orifice

Answer 8

Immediately in front of the vaginal orifice. On either side lie the openings of the Skene’s ducts, two small blind-ended tubules 0.5 cm long running within the urethral wall

Question 9

Describe the vaginal orifice

Answer 9

Aka the introitus of the vagina. The orifice is partially closed by the hymen, a thin membrane that tears before or during penetrative sexual intercourse

Question 10

Describe the greater vestibular glands

Answer 10

Baratholin’s glands: two small glands that open on either side of the vaginal orifice. They secrete mucus, which lubricates the vaginal opening

Question 11

Describe the clitoris

Answer 11

External part: clitoral glans. Densely filled with nerve ending.

Internal part: extremely vascular, erectile tissue

The erectile bodies: paired bulbs and paired corpora, which are continuous with the crura

Question 12

Describe the blood supply and nerves in the vulva

Answer 12

Blood supply: internal and external pudendal arteries and corresponding veins

Lymphatic drainage: inguinal glands

Nerve supply: branches of the pudendal nerve

Question 13

Define vagina

Answer 13

A canal from vestibule to the cervix, passing upwards and backwards into the pelvis along the line of the pelvic brim

Question 14

Outline the function of a vagina

Answer 14

Passage and escape of menstrual flow

Receives the penis and ejaculate during inter course

Provides exit of fetus during birth

Question 15

Name 4 other names for vagina, with reference to different anatomical locations

Answer 15

Anterior: bladder

Posterior: rectum

Superior: uterus

Inferior: external genitalia

Question 16

Describe the structure of the vagina

Answer 16

Posterior wall-10 cm long
Anterior wall- 7.5cm because cervix projects at right angles into upper part
Upper end- vault

Cervix projects into the vault forming fornices
Posterior fornix- largest because vagina is attached to uterus at a higher level behind
Lateral fornices- lie either side
Anterior fornix- in front of the cervix

Question 17

Describe the layers of the vagina

Answer 17

Lining: squamous epithelium, arranged in rugae. Kept moist by cervical secretions pH 4.9-3.5-acidic due to presence of Doderlein’s bacilli

Muscle layer: weaker inner circular fibres and stronger outer longitudinal fibres

Pelvic fascia: connective tissue surrounding the vagina

Question 18

Describe the uterus

Answer 18

Hollow, pear-shaped muscular organ located in the true pelvis between the bladder and the rectum

Position of the uterus within the true pelvis is one of anteversion and anteflexion

Anteversion means that the uterus leans forward and anteflexion means that it bends forwards upon itself

The non-pregnant uterus is 7.5cm long, 5cm wide and 2.5cm in depth, each wall being 1.25cm thick, and weighs 60 grams

Question 19

Describe the fungus

Answer 19

Doomed upper wall between the insertions of the uterine tube

Question 20

Describe the cornuae

Answer 20

Upper outer angles of the uterus where the uterine tubes join

Question 21

Describe the body/corpus

Answer 21

Makes up the upper two-thirds of the uterus

Question 22

Describe the cavity

Answer 22

Within the body of the uterus, triangular in shape

Question 23

Describe the isthmus

Answer 23

7mm long situated at the junction of the body and cervix

Question 24

Describe the layers of the uterus

Answer 24

1. Perimetrium: layer of peritoneum draped over the uterus and uterine tubes
2. Myometrium: muscle layer
   Inner layer- circular fibres around the cornua and cervix
   Middle layer- interlacing spiral fibres- the upper part of the body
   Outer longitudinal fibres- from the cervix anteriorly over the fundus to the cervix posteriorly
3. Endometrium
   Functional layer- which thickens and is shed during menstrual cycle
   Basal layer- from which functional layer regenerates every cycle

Question 25

Describe the blood and nerve supply in the uterus

Answer 25

Blood supply:
Uterine and ovarian arteries- branches of internal iliac artery
Venous drainage- corresponding veins

Lymphatic drainage:
Lumbar and hypogastric nodes

Nerve supply:
11th, 12th thoracic and 1st lumbar nerve cervix by sacral nerves 2, 3 and 4

Question 26

Describe the cervix

Answer 26

Part of the uterus
The lower part sits within the vagina, and upper part sits above the vagina
The cervical canal is made up of columnar epithelium that secretes mucus (known as compound racemose glands)
The muscle fibres are embedded in collagen enabling it to stretch in labour
The internal os is a narrow opening between he isthmus and cervix
The external os is a small round opening at the lower end of the cervix

Question 27

Define the uterine tubes

Answer 27

Two tubes, each leading from an ovary into the uterus

Question 28

What is the function of the uterine tube?

Answer 28

Propels the ovum towards the uterus, receives the spermatozoa as they travel upwards and provides a site for fertilisation

Question 29

Where is the position of uterine tubes?

Answer 29

Extend laterally from the cornua of the uterus towards the side walls of the pelvis. They arch over the ovaries, the fringed ends hovering near the ovaries in order to receive the ovum. Hold in place by their attachment to the uterus and the peritoneum.

Question 30

Describe the interstitial portion

Answer 30

It is 1.25cm long and lies within the wall of the uterus. It’s lumen is 1mm wide

Question 31

Describe the isthmus

Answer 31

Another narrow part that extends for 2.5 cm from the uterus

Question 32

Describe the ampulla

Answer 32

The wider portion, where fertilisation usually occurs. 5cm long.

Question 33

Describe the infundibulum

Answer 33

The funnel-shaped fringed end that is composed of many processes known as fimbriae. One fimbria is elongated to form the ovarian fimbria, which is attached to the ovary.

Question 34

Describe the structure of the uterine tube

Answer 34

Longitudinal and circular muscle
Lining of ciliated columnar epithelium:
-wafts ovum from infundibulum towards the uterus
-contains foods or plicae
-contains goblet-shaped cells which produce secretions to nourish the ova

Question 35

Describe the blood and nerve supply in the uterine tubes

Answer 35

Blood supply:
Ovarian and uterine arteries- branches of the internal iliac artery and corresponding veins

Lymphatic drainage: lumbar glands

Nerve supply: ovarian plexus and the parasympathetic system

Question 36

Describe the function of the ovaries

Answer 36

The ovaries produce oocytes and the hormones, oestrogen and progesterone

Question 37

What is the position of the ovaries?

Answer 37

They are attached to the uterus by the ovarian ligaments. 3cm x 2cm x 1cm, almond shaped

The ovary is comprised of the medulla and the cortex

Question 38

Describe the medulla

Answer 38

It is the supporting framework, which is made of fibrous tissue; the ovarian blood vessels, lymphatics and nerves travel through it. The hilum is where these vessels enter the ovary (known as the mesovarium)

Question 39

Describe the cortex

Answer 39

It is the functioning part of the ovary. It contains the ovarian follicles in different stages of development, surrounded by stoma (unique type of connective tissue)

Question 40

What is puberty?

Answer 40

The age at which the internal reproductive organs reach maturity, usually between the ages of 12 and 14 (though it is correlated with body mass)

Question 41

What is the hormonal trigger for puberty?

Answer 41

Hypothalamus releases luteinising hormone releasing hormone (LHRH)
LHRH acts on the anterior pituitary gland, causing it to release follicle stimulating hormone (FSH) and luteinising hormone (LH)
FSH and LH cause the ovaries to secrete oestrogens
Oestrogens are responsible for secondary sex characteristics

Question 42

Name 6 secondary sex characteristics in females

Answer 42

Maturation of the uterus, uterine tubes and ovaries
Development and enlargement of the breasts
Growth of pubic and axillary hair
Increase in height
Widening of the pelvis
Increased fat deposition in the subcutaneous tissue, especially at the hips and breasts

Question 43

Define menarche

Answer 43

Onset of menstruation

Question 44

Define menopause

Answer 44

Ceasing of menstruation

Question 45

Define menstruation

Answer 45

A ‘period’ of vaginal bleeding as the lining of the uterus sheds and is passed through the vagina

Question 46

Define reproductive cycle

Answer 46

Aka the menstrual cycle

A series of events, occurring regularly in females every 26-30 days throughout the childbearing period between menarche and menopause

The cycle consists of a series of changes taking place concurrently in the ovaries and uterine lining, stimulated by changes in hormones

Question 47

Describe what happens in the ovary during the reproductive (menstrual) cycle

Answer 47

Oogenesis: maturation of ova

In utero:
By 20 weeks gestational age: primary ova are formed in the developing ovaries of the fetus. Over 1 million are present at the time of birth
These follicles are immature; their development is halted until menarche

During each cycle, one or so follicles mature. Maturation is controlled by the hypothalamus secretes luteinising hormone releasing hormone (LHRH) and the anterior pituitary gland, which releases gonadotropins (follicle stimulation hormone FSH) and luteinising hormone (LH), both of which act on the ovary

Hormones:
The developing follicle is a source of hormones
During first half of cycle, while ovum is developing within the follicles, the follicle secretes increasing amounts of oestrogen
However, after ovulation, the corpus luteum secretes primarily progesterone, with some oestrogen and inhibin

Question 48

Describe the stages of development of one ovarian follicle

Answer 48

Before ovulation:
The follicle develops from an immature (primordial) follicle to a mature (Graafian) follicle. The follicle is filled with follicular fluid, which increases. The Graafian follicle migrates from the cortex to the surface of the ovary.

Ovulation:
On day 14 of the cycle, the follicle ruptures, releasing the ovum into the peritoneal cavity. It is ‘caught’ by the fimbriae at the end of the uterine tube. It is propelled by cilia, along the uterine tube towards the uterus. Body temp rises by 1 degree Celsius

After ovulation:
Corpus luteum develops, which secretes progesterone (and oestrogen and inhibin). Progesterone causes LH and FSH to fall. If the ovum is not fertilised, falling LH levels lead to degeneration and death of the corpus luteum. If the ovum is fertilised, the corpus luteum continues to secrete hormones for 3-4 months.

Question 49

Describe what happens in the uterus during the reproductive (menstrual) cycle

Answer 49

Menstrual: days 1-4
Progesterone and oestrogen levels therefore fall, and the functional layer of the endometrium is shed in menstruation as the myometrium contracts.

Proliferative: days 5-14
The maturing ovarian follicle stimulates the thickening (regrowth) of the functional layer of the endometrium in preparation for the reception for the fertilised ovum. The endometrium thickens, becoming very vascular and rich in mucus-secreting glands. This stand ends at ovulation.

Secretory: days 15-28
Progesterone from the corpus luteum stimulates the endometrium to become oedematous and the secretary glands produce increased amounts of watery mucus. This assist the motile spermatozoa through the uterus to the uterine tubes, whee the ovum is usually fertilised. This stage begins at ovulation.