- anatomy of the female reproductive system
- physiology of the female reproductive system with particular
reference to the role of specific hormones
- changes that takes place from puberty to menopause
- common pathologies of the female reproductive system
The female reproductive system consists of the following
- 1 vulva
- 1 vagina
- 1 uterus
- 2 uterine (fallopian) tubes
- 2 ovaries
- 2 mammary glands
- Mons pubis (veneris): an elevation of adipose tissue, covered with course pubic hair. Situated over the symphysis pubis. Anterior to the vaginal and urethral opening
- Labia majora: 2 folds of skin. Fat and adipose tissue which forms the boundary of the vulva. Contains many sebaceous glands
- Labia minora: 2 smaller folds of skin between the labia majora. The cleft between the folds is called the vestibule into which the vagina, urethra and ducts of the greater vestibular glands open
- Clitoris: contains sensory nerve endings and erectile tissue
- Hymen: thin layer of erectile tissue which partially occludes the vaginal opening
- Greater vestibular glands (Bartholin’s glands): located on each side of the vaginal opening. Secrete mucous to keep the hymen moist
- A fibromuscular tube which connects the internal and external reproductive organs.
- Situated between the urinary bladder and rectum
- Sperm enter the vagina during their journey to meet an ovum
- The vagina is a passageway for menstruation and childbirth
There are 3 layers of tissue:
- Mucous membrane: continuous with that of the uterus Stratified squamous epithelial and connective tissue which lies in a series of transverse folds called rugae
- Muscular layer: smooth muscle which can stretch considerably
- Adventitia: areolar tissue
- Size and shape: pear-shaped, 7.5cm long, 5cm wide, 2.5cm thick
- Relations: anterior – bladder , posterior – rectum , laterally – uterine tubes, inferior – continuous with the vagina
Main parts of the uterus:
- Fundus: dome shaped superior portion of the uterus
- Body (Corpus): major tapering central portion tapers into the cervix inferiorly
- Cervix: narrow, necklike passage at the lower end of the uterus
- Isthmus: situated between the body of the uterus and cervix, approx 1 cm long
The uterus is comprised of 3 layers:
Perimetrium: consists of peritoneum
- Anteriorly it extends over the fundus and body then reflected on to the bladder – the vesicouterine pouch
- Posteriorly it extends over the fundus, body and cervix and is reflected on to the rectum to form the retrouterine pouch
- Laterally covers just the fundus and then becomes the broad ligament
Myometrium: thickest layer. Consists of a mass of smooth muscle fibres, interlaced with fibrous tissue, blood vessels and nerves
Endometrium: simple columnar epithelium. Large numbers of mucus secreting cells. Thickness changes with menstrual cycle
The ligaments of the uterus
The uterus is supported by several ligaments:
- The cardinal ligaments – pass from each side of the uterus to the lateral walls of the pelvis
- The round ligaments – attached to the uterus just below the uterine tubes. Run to the lateral walls of the pelvis
- The broad and uterosacral ligaments – 2 folds of peritoneum that are attached to the bladder and rectum respectively
Nerve supply to the uterus
Sympathetic nerve fibres of the uterus arise from the uterovaginal plexus. This largely comprises the anterior and intermediate parts of the inferior hypogastric plexus.
Parasympathetic fibres of the uterus are derived from the pelvic splanchnic nerves (S2-S4).
The cervix is largely innervated by the inferior nerve fibres of the uterovaginal plexus.
The afferent fibres mostly ascend through the inferior hypogastric plexus to enter the spinal cord via T10-T12 and L1 nerve fibres
Uterine (fallopian) tubes:
- 10 cm long, extend from the sides of the uterus between the body and the fundus
- The lateral end opens out into the peritoneal cavity close to the ovary
- Situated in the upper free border of the broad ligament
- The end of each tube is expanded and has finger like projections called fimbriae
- They convey the ovum from the ovary to the uterus, mucous secreted forms the ideal environment for the movement of spermatozoa and ova
- Fertilisation occurs here and the zygote moves to the uterus
- Located in the upper pelvic cavity and lie in a shallow depression, the ovarian fossa, either side of the uterus
- Attached to the upper part of the uterus by the ovarian ligament
- Attached to the back of the broad ligament by a band of tissue called the mesovarium. It is through this that blood and nerve vessels reach the ovary
- The ovary consists of a central portion – the medulla made up of fibrous tissue and blood vessels
- It is surrounded by the cortex – a framework of connective tissue or stroma covered by germinal epithelium
- It contains ovarian follicles at various stages of maturity, each containing an ovum
- Each month during childbearing years, one ovarian follicle (Graafian follicle) matures, ruptures and releases an ovum into the peritoneal cavity – ovulation
- Maturation of the follicle is stimulated by FSH
- While maturing the follicle produces oestrogen
- After ovulation the follicle lining cells develop into the corpus luteum (yellow body) and the influence of LH to produce progesterone
- If fertilisation occurs the ovum embeds itself into the wall of the uterus and produces human chorionic gonadotrophin which stimulates the corpus luteum to produce progesterone for the first 3 months of pregnancy
- If the ovum is not fertilised the corpus luteum degenerates and a new cycle begins with menstruation
- At the site of the corpus luteum a mass of fibrous tissue forms called the corpus albican
- ovarian arteries, branch of the A.A. just below the renal arteries
- Into a plexus of veins behind the pelvis then to ovarian veins. The rights opens into the IVC , the left into the left renal vein
- Lateral and pre – aortic lymph nodes
- The differentiation of the ovum
- a growth process in which the ovum becomes a mature ovum
- In any one human generation, the egg’s development starts before the female that carries it is even born
- 8 to 20 weeks after the fetus has started to grow, cells that are to become mature ova have been multiplying, and by the time that the female is born, all of the egg cells that the ovaries will release during the active reproductive years of the female are already present in the ovaries
- These cells, known as the primary ova, number around 400,000
- The primary ova remain dormant until just prior to ovulation, when an egg is released from the ovary
- Some egg cells may not mature for 40 years; others degenerate and never mature
The Menstrual Cycle
- The menstrual cycle begins when a female reaches the age of puberty.
- It is the reproductive cycle that produces ovum for fertilisation
- During the menstrual cycle the endometrium of the uterus prepares itself for implantation of a fertilised ovum, if this does not occur the uterus lining is shed from the body;
- this is known as menstruation or a “period“
- On average the menstrual cycle lasts between 28-35 days
- Day 1 of the cycle begins on is the first day of bleeding (bleeding can last for 3-7 days) and the cycle ends just before the next menstrual period
- The menstrual cycle is carefully regulated by several hormones:
- Luteinizing Hormone (LH)
- Follicle-stimulating Hormone (FSH)
- The female sex hormones Oestrogen and Progesterone
- The ovarian cycle consists of the follicular phase, ovulation, and the luteal phase
- The uterine cycle consists of menstruation (menses), proliferative phase, and secretory phase
The ovarian cycle
The ovarian cycle can be divided into three phases:
- follicular (before the egg is released)
- ovulatory (egg is released)
- luteal (after release of the egg)
1. Follicular Phase -Before the egg
- This phase begins on the first day of bleeding
- The key aspect of this phase is the development of follicles in the ovaries
- At the start of the follicular phase, the lining of the uterus is thick with fluids and nutrients intended to nourish an embryo (fertilised egg)
- If no embryo is present, oestrogen and progesterone levels are low
- This causes the uterus lining to shed and menstrual bleeding occurs
- The pituitary gland (found in the brain) increases its’ production of follicle stimulating hormone (FSH)
- This hormone stimulates the growth of several follicles (each contains an egg) to develop in the ovaries
- The levels of FSH hormone decreases and the follicles begin to secrete oestrogen
- The follicle that develops first (the dominant follicle) secretes the most amount of oestrogen, and this secretion subsequently suppresses the development of the other follicles
- The follicular phase roughly lasts about 13 or 14 days. The phase ends when the level of luteinizing hormone (LH) surges dramatically
2. Ovulatory Phase -Egg is released
- This phase begins with the luteinizing hormone surge (LH surge)
- The level of FSH increases to a lesser extent
- LH stimulates enzymes in the dominant follicle and along with the increased pressure causes the follicle to rupture and release the egg (ovulation)
- The egg travels into the fallopian tube, ready for fertilisation
- The egg can survive for 12 to 24 hours after ovulation
- The LH surge can be used as a measurement to determine when a woman is fertile
- Around 12 to 24 hours after the egg is released, the LH surge can be
detected by measuring the level of this hormone in urine
- The ovulatory phase usually lasts 16 to 32 hours and ends when the egg is released
3. Luteal Phase -After release of the egg
- This phase begins after ovulation
- It lasts about 14 days and ends just before a menstrual period, unless of course fertilisation occurs
- In this phase the egg travels along the fallopian tube by wave like motions caused by the finger-like projections in the walls of the fallopian tube
- The remainder of the ruptured follicle in the ovary closes after releasing the egg and forms a structure called a corpus luteum
- The corpus luteum secretes large quantities of progesterone and oestrogen and prepares the uterus for fertilisation
- Progesterone causes the endometrium to thicken, filling with fluids and nutrients to nourish the potential embryo it also causes the mucus in the cervix to thicken, so that sperm and bacteria are less likely to enter the uterus
- Progesterone also causes body temperature to increase slightly during the luteal phase and remain elevated until a menstrual period begins
- This increase in temperature can be used to estimate whether ovulation has occurred
- LH and FSH levels fall back to low and steady levels
- Oestrogen levels fall a little after the LH/FSH surge, but rise due to continued secretion of oestrogen and progesterone by the corpus luteum
- The increase in oestrogen and progesterone levels causes milk ducts in the breasts to dilate
- In turn the breasts sometimes swell and become tender
- If the egg is not fertilised, the corpus luteum shrinks and begins to degenerate
- After 14 days (the corpus luteum is designed to die after 14 days)
- The unfertilised egg also dies and passes out of the uterus with the menstrual bleeding
- Oestrogen and progesterone levels fall, bleeding starts and the uterine lining is shed
- A new menstrual cycle begins
- If the egg is fertilised the cells around the developing embryo begin to produce a hormone called human chorionic gonadotropin (hCG)
- This hormone rescues the corpus luteum and allows it to continue secreting progesterone and oestrogen, until the growing foetus can produce its’ own hormones
- Note: Pregnancy tests are based on detecting an increase in the
human chorionic gonadotropin level
- The uterine cycle is the monthly series of changes that the female’s uterus, or uterine tissue, undergoes in preparation for the implantation of a fertilized egg
Menstruation (menses) – days 1-5
- Approx. 4 days
- Endometrium shed down to basal layer
Proliferative – days 6-15
- Developing follicle to ovulation
- Endometrium thickens, oestrogen from Graafian follicle
Secretory – days 16-18
- After ovulation to fertilisation
- Endometrial lining becomes more vascular
- Glands in endometrium secrete nutritive substances
- a small sac, embedded in the ovary, that encloses an ovum
- About every 28 days between puberty and the onset of menopause, one of the follicles develops to maturity, or ripens, into a graafian follicle
- As it ripens, it gets larger. The ovum within becomes larger, the follicular wall becomes thicker, and fluid collects in the follicle and surrounds the ovum
The menarche (first menstruation)
Menarche begins when the hypothalamus in the brain is sensitised to begin producing Gonadotropin-releasing hormone (GnRH) at around the age of 12 to 15 years.
But evidence suggests that GnRH may begin at an earlier age in girls who are well nourished and exposed to sexual motivating factors, such as watching sexual films and talking about sex.
In malnourished girls, who have little exposure to sexual motivating factors, menarche may be delayed until the age of 17 to 20 years.
Disease conditions that affect the hypothalamus and pituitary gland, or the ovaries and uterus, can also affect the age of first menarche.
Around the age of the menarche, the female sex hormones, oestrogen and progesterone, are responsible for the development of secondary sexual characteristics in the female.
- the development of the breasts
- the broadening of the pelvis
- increased activity of sweat glands and sebaceous glands (oil glands in the skin)
- the growth of pubic and armpit hair
Together with the menarche, the appearance of the secondary sexual characteristics marks the period known as puberty — the period of life (typically between the ages of 10 to15 years) during which the reproductive organs grow to adult size and become functional.
The secondary sexual characteristics are termed ‘secondary’ because they develop after the primary sexual characteristics, which distinguish females from males.
Menopause is an event that typically (but not always) occurs in women in midlife, during their late 40s or early 50s, and it signals the end of the fertile phase of a woman’s life.
However rather than being defined by the state of the uterus and the absence of menstrual flow, menopause is more accurately defined as
“the permanent cessation of the primary functions of the ovaries”
Primary Functions: The ripening and release of ova and the release of hormones that cause both the creation of the uterine lining, and the subsequent shedding of the uterine lining.
Pelvic inflammatory disease
A bacterial infection of the female upper genital tract, including the uterus, fallopian tubes and ovaries.
It is a common disease and around 1 in 50 sexually active women in the UK are diagnosed with PID every year.
Many more women with PID experience few or no symptoms. PID mostly affects sexually active women between the ages of 15 and 24.
Toxic shock syndrome
It occurs when the bacteria responsible – Staphylococcus aureus and Streptococcus pyogenes, which normally live harmlessly on the skin – invade the body’s bloodstream and release poisonous toxins.
These toxins cause a sudden high fever and a massive drop in blood pressure (shock)
Cancer of the cervix. Relatively uncommon, almost all cases of cervical cancer are caused by the human papillomavirus (HPV).
An inflammation or irritation of the lining of the uterus (the endometrium).
Endometriosis is a female health disorder that occurs when cells from the lining of the uterus grow in other areas of the body. This can lead to pain, irregular bleeding, and infertility.
Leiomyoma (fibroid myoma/fibroids)
Benign soft tissue neoplasms that arise from smooth muscle.
When a fertilised egg implants itself outside of the uterus, usually in one of the fallopian tubes.
Polycystic ovary disease
An imbalance of a female sex hormones. This may lead to menstrual cycle changes, cysts in the ovaries, infertility and other health changes.
Ovarian cancer occurs when a cancerous tumour forms in a woman’s ovary. In most cases, there are no known causes.
Symptoms are often vague, but common ovarian cancer symptoms include ongoing pain or cramps in the stomach or back, increased abdominal girth, and nausea and bloating.