Repro Flashcards
Give one disadvantage of the migration of the primordial germ cells.
If they don’t make it can increase risk of later gonadal tumours
The reproductive system arises from which embryological tissue?
Intermediate mesoderm - indifferent gonad
Yolk sac - germ cells
How does the indifferent gonad differentiate into male or female genitalia?
SRY gene expression from Y chromosome - male
Absence of SRY - female
What hormone does the female gonad secrete during development of the internal genitalia?
Oestrogen
What hormones does the male gonad secrete during development of the internal genitalia? From which cells?
Testosterone - leydig cells
Mullerian inhibitory substance (MIS) - sertolli cells
What is the action of oestrogen in the developing female internal genitalia?
Destruction of wolfian duct
Formation of genitalia
What is the action of testosterone in the developing male reproductive tract?
Growth of wolfian duct
Formation of genitalia
What is the action of MIS in the developing male reproductive tract?
Destruction of the Müllerian duct
Describe the development of the ovarian follicle at puberty.
FSH and LH lead to the development of an Antrum (fluid filled space). This leaves it capable of rupture to release an oocyte.
Describe days 1-12 of the menstrual cycle.
Day 1 bleeding.
Then Follicular/proliferation stage
Gamete waits in the follicle and lining proliferates
When in the menstrual cycle does ovulation occur?
Day 12-14
Which hormones are produced by the corpus luteum and what are their effects on the menstrual cycle?
Oestrogen and progesterone
Maintain endothelium
Inhibin
prevent FSH stimulation of ovulation
When can spermatogonia begin meiosis?
After puberty
What happens to the testis at puberty?
Seminiferous tubules hollow out and testes migrate through the inguinal canal
Describe the mechanism that allows so many sperm to produced at a time?
Spermatogonia undergo mitosis. One cell is used for proliferation. The other becomes an A1 spermatogonia which undergoes mitosis to for a a whole chain of 64 identical diploid cells. These undergo meiosis to produce 256 haploid cells each - spermatids. These mature to spermatozoa
What hormone is produced by the hypothalamus to stimulate the HPGonadal axis?
Gonadotropin releasing hormone
GnRH
Which two gonadotrophs are released from the anterior pituitary in response to GnRH to stimulate the gonads?
FSH and LH
Follicle stimulating hormone and luteinising hormone
What is the action of inhibin?
Negative feedback onto FSH
Give two functions of testosterone in the male.
Irreversible - eg secondary sexual characteristics
Regulatory - eg negative feedback regulation of spermatogenesis
How often is GnRH released?
Regular pulses every 90 minutes
Describe the levels of FSH, LH, oestrogen, inhibin and progesterone in the follicular phase of the menstrual cycle.
Small follicle means low inhibin, oestrogen
No corpus luteum so low progesterone
Therefore no feedback and FSH and LH increase
FSH more than LH because it is used to having double inhibition
Describe the levels of FSH, LH, oestrogen, inhibin and progesterone in the ovulation phase of the menstrual cycle.
Follicle fully developed and oestrogen reaches peak
Oestrogen so high it flips to positive feedback onto GnRH, overpowering the high inhibin
LH (and FSH) surges
Describe the levels of FSH, LH, oestrogen, inhibin and progesterone in the luteal phase of the menstrual cycle.
Corpus luteum secretes oestrogen and progesterone
Together with inhibin they inhibit FSH and LH
For 14 days these levels are constant till the corpus luteum dies and triggers a bleed
On what gonadotroph does inhibin act?
FSH only
What is triggered by the LH surge?
Ovulation
When does oestrogen switch to providing positive feedback to the gonadotrophs?
When it is at a high enough concentration. This triggers the LH surge and ovulation
Where do the germ cells migrate through the body?
From mesonephric ridge - dorsal mesentery - inguinal canal - testis/ovar
As the germ cells complete their migration to the testis, the spermatic cord picks up 3 layers of fascia. What are they and where do they originate?
External fascia - external oblique
Cremasteric fascia - internal oblique
Internal fascia -Transversalis fascia
What type of neoplasm is most common in the testis? Does it tend to be malignant or benign?
Germ cell neoplasm - seminoma or teratoma (malignant)
Not leydig or sertolli
What hormones stimulate and are secreted by sertolli cells? Where are they found?
Stimulated by:
FSH
Secrete:
Inhibin
Müllerian inhibitory substance
Inside the testis
What hormones stimulate and are secreted by leydig cells? Where are they found?
Stimulated by:
LH
Secrete:
Testosterone
Surrounding the testis
What is the rete testis?
Where the seminiferous tubules converge inside the testis.
Where is semen produced?
85% in the seminal vesicle
Some from the prostate
Some from the bulbourethral gland
How are sperm moved along the tract from testis to penis?
Stereocilia on the epithelia
Gradually more and more smooth muscle along the tract
What is significant about the zones of the prostate?
BPH - transition zone. Surrounds the urethra so can affect urination.
Cancer - peripheral zone. Few symptoms so present late. More likely Palpable on PR exam.
What passes out through the superficial inguinal ring?
Vas deferens
Lymphatics
Genitofemoral nerve
What is the embryological derivative of the broad ligament (female)?
The paramesonehpric (Müllerian) ducts fuse. Form a double layer of peritoneum.
What is enclosed by the broad ligament (female)?
Uterus, ovaries and the neuro vascular supply.
What are the name of the glands in the vestibule of the labia minora?
Bartholin glands
What is the ostium of the Fallopian tube?
Where it opens into the peritoneum - risk of peritonitis from pelvic inflammatory disease or sti
Describe the three areas of the cervix. Where are neoplasms most likely in the cervix?
Endo cervix - simple columnar and goblet
Ecto cervix - stratified squamous non keratinised
Squamocolumnar junction - location of neoplasm
Describe the layers of the uterus.
Endometrium -stratum functionalis - stratum compactum
- stratum spongiosum
- stratum basalis
Myometrium
Which layer of the uterus grows during the proliferative period? Describe two processes that occur.
Stratum functionalis of the endometrium
Remodelling of spiral arteries
Hyperplasia of endothelium
What type of secretion occurs in the breast?
Apocrine
What types of cell are found in the follicle?
Granulosa - inside
Theca - outer shell
Where is the pouch of Douglas?
Rectouterine
What is the difference between an sti and an std?
Sti includes asymptomatic
Std is symptomatic only
Define amenorrhea.
Absence of periods.
Primary - never
Secondary - stopped
Define menorrhagia
Heavy periods
Define Dysmenorrhea
Painful periods
Define oligomenorrhea.
Long delays/ irregular
What types of cause would you look for menstrual dysfunction with the following hormone results:
Low FSH and low oestrogen
HPG axis
Primary - kallmann syndrome, prolactinoma
Secondary - exercise, stress, low bmi, thyrotoxicosis
What types of cause would you look for menstrual dysfunction with the following hormone results:
High FSH, low oestrogen
Ovarian
Primary - Turner syndrome
Secondary - pregnant, menopause, pcos, tumour
What types of cause would you look for menstrual dysfunction with the following hormone results:
Normal FSH, normal oestrogen
Outflow tract
Primary - Müllerian agenesis, imperforate hymen
Secondary - asherman’s syndrome (endometrial fibrosis)
Describe the pathway that leads to erection.
Parasympathetic nervous stimulation, ip3 pathway, nitric oxide, cGMP, decrease Ca, vasodilation of pampiniform venous plexus.
Describe the pathway involved in ejaculation.
Sympathetic stimulation, smooth muscle, sphincter of bladder, bulbospongiosus and ischiocavernosus contract
Describe the process of fertilisation - 3 points.
- Capacitation - sperm matures in the female
- Acrosome enzymes digest the zona pellucida
- Cortical reaction - 1 sperm enters and cortical granules block the gap in the zona pellucida
By what three mechanisms do hormonal contraceptives prevent pregnancy?
Decrease ovulation - combined
Increase cervical mucus - mini
Decrease endometrium - combined
How does Viagra work?
Inhibits cGMP breakdown, decrease in cellular Ca, increase in vasodilation.
What percentage of sperm should be swimming?
More than 60
Less than 30 is abnormal
What produces hcg? What does it indicate?
Syncitiotrophoblast cells. Indicates pregnancy.
What is the function of hcg? (2 things)
- Mimics LH to maintain the corpus luteum and therefore the pregnancy.
- Immunosuppressant to prevent rejection
Name 2 functions of the hormone hpL during pregnancy.
- Increases insulin resistance
- Increases lipolysis
Both to free up more glucose for the foetus. The mother relies more on fatty acids.
What causes gestational diabetes? What is an important sign? Name 4 risks.
It is an extreme version of a normal physiological process. HpL increases blood sugar to provide more for the foetus but this can go a bit too far.
Abdo circumference > head
Risk of still birth, genetic defects, large baby, neonatal diabetes
Name 2 factors that raise the risk of acidosis in pregnancy.
- HpL increases lipolysis, so increase use of fatty acids, increase in ketones
- Kidneys are excreting extra bicarbonate to balance out respiratory alkalosis. This gets rid of the buffer so harder to self regulate if goes acidotic.
Give a factor that raises the risk of alkalosis in pregnancy.
Physiological hyperventilation
Name 3 physiological effects of progesterone during pregnancy and their potential complications.
- Decreased GI motility - constipation, gall stones, pancreatitis
- Dilates ureters - increased stasis leads to uti
- Reduces BP - postural hypotension
What are the symptoms of pre eclampsia?
Vasoconstriction - high bp Pitting Oedema Proteinuria Liver failure ( all because Inadequate placenta)
How does the placenta develop?
- High Progesterone causes decidualisation - remodelling of spiral arteries in the endometrium to increase flow
Pre decidual cells prevent too much invasion - Implantion
- Primary, secondary and tertiary villi
Describe the primary secondary and tertiary villi of the placenta?
- First projections of the trophoblast
- Invasion of mesenchyme
- Fetal vessels invade the mesenchyme and the membrane thins to one cell thick of syncitiotrophoblast
Name 3 metabolic functions of the placenta.
- Glycogenesis
- Lipolysis
- Cholesterol synthesis - for making oestrogen and progesterone
Name 2 endocrine functions of the placenta.
- Hcg and hpL
2. Oestrogen and progesterone
Name 3 active, 4 passive, 1 facilitated passive and 1 RME transport functions of the placenta.
- Active - iron, amino acids, vitamins
- Passive - water, electrolytes, gases, urea
- Facilitated passive - glucose
- Receptor mediated endocytosis - immunoglobulin
Which infections cross the placenta?
Toxoplasmosis O Rubella CMV Herpes
What is the difference between asymmetrical and symmetrical growth restriction?
Assymmetrical - caused by decreased growth support, growth prioritises the brain so that head circumference is normal but abdo circumference is reduced
(Or opposite in gestational diabetes)
Symmetrical - caused by decreased growth potential so that both circumferences are reduced.
Where is GnRH released from?
Hypothalamus
Where are FSH and LH released from?
Anterior pituitary
Why does only a small amount of FSH and LH have a large effect?
Released into the hypophyseal portal system where there is a small volume of blood so only a small volume of hormone will change the concentration a lot.
Which cells release oestrogen?
Theca cells release androgens which are converted and released by granulosa