Theme 2 - Reproductive system, fetal development and birth Flashcards
8 effects of testosterone
Increased aggression and libido* Enlargement of the larynx Male pattern pubic hair Maturation of genitalia Muscle development Sperm production Bone growth* Acne
8 effects of oestrogen and progesterone
Bone Growth Female psyche Fair complexion Breast Development Widening of the pelvis Maturation of genitalia Female pattern pubic hair Subcutaneous fat deposition
Draw a graph to show changes in hormone levels throughout menstrual cycle
Start on day of bleeding Increase oestrogen and FSH Drop in FSH then oestrogen LH surge (ovulation) Increase in progesterone and oestrogen then both drop off
What acts of legislation governs conscientious objections and regarding reproduction and fertility what are the key points?
Abortion Act 1967
Human Fertilisation and Embryology Act 1990
no person shall be under any duty, whether by contract or by any statutory or other legal requirement, to participate in any treatment authorised by this Act to which he has a conscientious objection
Nothing in subsection (1) of this section shall affect any duty to participate in treatment which is necessary to save the life or to prevent grave permanent injury to the physical or mental health of a pregnant woman
What is the time limit on embryo research, and why?
14 days – before possibility of twinning. Justification is that prior to this stage, the embryo isn’t part of a continuum for an identifiable future person.
What is the Warnock position on moral importance and at what stage of development?
there is no particular part of the developmental process that is more important than another; all are part of a continuous process
What 3 things to female oral contraceptives do to prevent conception?
Prevent ovulation
Thicken cervical mucus
Hostile endometrium
What effect does the progesterone only contraceptive pill have on the menstrual cycle and how does it prevent conception?
inhibit ovulation by suppression of LH surge, thicken cervical mucus and render the endometrium ‘hostile’.
3 examples of progesterone only contraceptive
norethisterone, levonorgestrel, desogestrel
Adverse affects of progesterone only oral contraception (up to 7)
Menstrual irregularity, nausea, vomiting, headache. Breast discomfort, weight changes, changes in libido.
Potential male contraceptive hormone mechanism of action?
Injection of testosterone agonist to generate negative feedback and progesterone to suppress LH. The aim is to halt spermatogenesis.
Adverse affects of male hormone contraception
The most common adverse events were acne, injection site pain, increased libido, and mood disorders
What 2 types of neuron stimulate GnRH
Kisspeptin and the KNDy
What des FSH act upon and what does this produce?
Primary follicle in granulosa cells
To produce oestrogen and inhibin
FSH leads to an increase of what type of receptor in the graulosa cells?
LH
Oestrogen and inhibin usually inhibit FSH by negative feedback, but when is this not the case and what does this cause?
When oestrogen reaches critically high levels they positively act on the Kisspeptin and KNDy neurones which stimulate the production of GnRH which in turn produces LH (due to increased frequency and amplitude of the pulse from GnRH). Triggers ovulation
How can ovulation be diagnosed?
Day 21 progesterone blood test
Urinary LH detection kit
Trans vaginal pelvic ultrasound
Causes of ovulation problems in the hypothalamus?
Hypothalamus (lack of GnRH)
- Kiss1 gene deficiency- rare
- GnRH gene deficiency - rare
- weight loss/stress related/excessive exercise
- anorexia/bulimia
Causes of ovulation problems in the pituitary?
Pituitary (lack of FSH and LH)
- pituitary tumours (prolactinoma/other tumours)
- post pituitary surgery /radiotherapy
Causes of ovulation problems in the ovary?
Ovary (lack of oestrogen/progesterone)
- Premature ovarian insufficiency
- Developmental or genetic causes eg Turner’s syndrome
- Autoimmune damage and destruction of ovaries
- Cytotoxic and radiotherapy
- Surgery
Polycystic Ovarian Syndrome: commonest cause
Amenorrhoea definition
lack of period for more than 6 months. Primary - never. Secondary -have stopped.
Oligomenorrhoea definition
irregular periods. Usually occurring more than 6 weeks apart.
Polymenorrhoea definition
periods occurring less than 3 weeks apart
Hirsuitism definition
Androgen dependent - in male distribution
3 Clinical features of PCOS
Hyperandrogenism -Hirsutism, acne Chronic oligomenorrhoea / amenorrhoea - 9 periods / year -Subfertility Obesity (but 25% of women with PCOS are “lean”)
How does PCOS affect LH and FSH levels?
Exaggerated pulsatile release of GnRH causes an increase of circulating LH an an increase in the ratio of LH:FSH.
How does the increase in LH:FSH ratio in PCOS affect androgen levels?
Ovarian theca cells respond to LH by increasing conversion of cholesterol to androgen. The realtive lack of FSH prevents this from being converted to oestrogen.
How does hyperandrogenism in PCOS account for its associated symptoms?
Increased androgen causes local follicular arrest and therefore amenorrhea/oligoamenorrhea.
Stimulation of sex-responsive hair follicles causes hirsuitism and acne.
What happens to insulin resistance in pats with PCOS?
Insulin resistance increases
How does insulin resistance in pts with PCOS relate to hyperandrogenism?
Insulin synergises with LH to increase androgen production by theca cells.
Inhibits hepatic production of SHBG and therefore increases the amount of free androgen.
Are the cysts in PCOS?
Actually small follicles
What are the effects of testosterone and oestrogen on SHBG?
SHBG increased by oestrogens
SHBG decreased by testosterone thus releasing more free testosterone
What is the most common cause of anovulation?
PCOS
What are the 3 reproductive affects of PCOS?
Reduction in fertility (to a varying degree)
Increased risk if miscarriage
Increased risk of gestational diabetes
How does PCOS relate to risk of endometrial cancer and why?
Increased risk due to the lack of progesterone.
Endometrial cancer also associated with T2 diabetes and obesity
Best treatment for PCOS
Lifestyle modification - diet and exercise
How would the COCP help treat PCOS? (3)
increases SHBG and thus decreases free testosterone
decreases FSH & LH and therefore ovarian stimulation
regulates cycle & decreases endometrial hyperplasia
What are the risks with using the COCP to help treat PCOS?
Increase weight gain may exacerbate metabolic sydrome
What medication could be used in combination with the COCP to treat PCOS? 2 examples
Anti androges
-Spironolactone - anti mineralocorticoid and anti androgen properties
-Cyproterone Acetate (oral tablet)
inhibits binding of testosterone & 5 alpha dihydrotestosterone to androgen receptors
What drug could be used to help treat the insulin resistance in women with PCOS?
Metformin
Definition of Premature ovarian failure/primary ovarian insufficiency
Cessation of menses before age 40 in absence of genetic abnormalities.
How may POF/POI present?
Primary or secondary amenorrhea . Possibly with hot flashes.
Aetiology of POF/POI?
Autoimmune
Iatrogenic - surgery/radiotherapy
Genetic - Turners syndrome
Genetic predisposition
What is Turner’s syndrome?
Absence of second sex chromosome
XO 50%
rest mosaicism or partial
How may Turner’s syndrome present?
Women Primary/secondary amenorrhea Short stature webbed neck shield chest
Conditions associated with Turner’s?
CV system -Coarctation of aorta -Aortic dissection -Hypertension (adults) Renal Congenital abnormalities Metabolic syndrome Hypothyroidism Ears / hearing problems
Most common causes of hirsuitism?
PCOS or idiopathic hirsuitism (95%)
When would hirsuitism be a cause for concern?
Sudden onset of severe symptoms Virilisation Frontal balding Deepening of voice Male-type muscle mass Clitoromegaly Possible Cushing’s syndrome
Least common causes of hirsuitism?
Cushings
Ovarian tumor
Non-classical congenital adrenal hyperplasia (CAH)
What is the causes the majority (95%) of cases of congenital adrenal hyperplasia?
21-hydroxylase deficiency
How will CAH present in children and what type of CAH is this known as?
Classic/severe -Salt wasting Hypovolaemia, shock -Virilisation Ambiguous genitalia in girls Early virilisation in boys Precocious puberty -Abnormal growth Accelerated early Premature fusion
How will CAH present in adults and what type of CAH is this known as?
non-classic/mild Hirsutism Oligo / amenorrhoea Acne Subfertility
Similar to ‘PCOS’ presentation
Where in the testes does spermatogenesis occur?
seminiferous tubules
Which cells produce testosterone?
Leydig cells
Following production in the Leydig cells, where is testosterone distributed to? 3
majority into blood stream
some into lymphatic system
some into the Sertoli cells within seminiferous tubules to facilitate spermatogeneis
What cells in the testes are stimulated by LH and what is the affect of this?
Leydig cells - to produce androgen
What cells in the testes are stimulated by FSH and what is the affect of this?
Sertoli cells - for spermatogenesis
What are the 3 elements of spermatogenesis?
Mitotic proliferation to produce lots of cells
Meiotic division to generate genetic diversity
Cell modelling to package chromosomes for delivery to the oocyte
In what part of the semiferous tubule does mitosis od the prospermatogonia occur?
Basal
What is the name of the cells that emerge from the first round of mitosis during spermatogenesis?
A1 spermatogonia
What is the name of the cells that emerge from the final round of mitosis during spermatogenesis?
primary spermatocytes
Where does meiosis of sperm primary spermatocytes take place?
adluminal compartment
What is the name of the cells that emerge from the first division of mieosis during spermatogenesis?
Secondary spermatocytes
What is the name of the cells that emerge from the second division of mieosis during spermatogenesis?
spermatid
Draw and label a sperm - 5 points
5: Tail for forward propulsion
4: Midpiece with mitochondria for energy
3: Nucleus with packaged chromosomes
2: Cap region forms for sperm-oocyte fusion
1: Acrosome
What is the interval between subsequent sperm production?
16 days
Time for completion of spermatogenesis?
64 days
What’s in jiz and whats the point of it? 4 points
Nutrition (fructose, sorbitol)
Buffer (to protect against vaginal acidity)
Antioxidants (ascorbic acid, hypotaurine
In the endocervix, what hormones make the mucus watery/inhibit secretory activity?
Oestrogen - watery
Porgesterone - inhibit production