SHIT IDK YET Flashcards
process of steroidogenesis
Cholesterol is the main component, it has three 6 sided rings and one 5 sided ring. There are carbons numbered 20 to 27 on the 5 sided ring.
Progestogens are made through carbon 22 to 27 being removed. There are only 21 carbons.
Androgens are made by removing carbons 20 to 27. There are only 19 carbons.
Oestrogens are made by removing carbon 19 to 27. There are only 19 carbons.
congenital adrenal hyperplasia
- enzyme 21-hydroxylase is not functioning
- progestogens are not converted so they increase
- progestogens are converted into testosterone
- testosterone causes the wolffian ducts to develop producing male external genitalia
- as cortisol is not produced there is no negative feedback so ACTH increases which stimulates the adrenals
- more progestogens increase so more testosterone is made
- XX female with CAH has no AMH, high levels of testosterone therefore male and female internal genitalia will develop
- DHT is present, producing male external genitalia
gonadal dysgenesis
This is where sexual differentiation is incomplete so the genitalia does not develop properly.
Happens due to:
- missing SRY in male
- partial and complete deletion of second X in female
e.g. AIS, 5-α-reductase deficiency, Turner syndrome and congenital adrenal hyperplasia
5-α-reductase deficiency
- type of gonadal dysgenesis
- testosterone is made but not DHT due to absence of enzyme
- autosomal recessive disorder and can depend on inter-related marriage
features: - testes form, AMH acts, testosterone acts
- internal structures form but external do not
Extent of features depends on degree of enzyme block.
Assessment has to happen at puberty as high testosterone at the adrenarche and puberty can induce virillisation.
structure of gonadotrophins
- heterodimeric peptides
- FSH and LH have N-linked carbohydrate chains
- hCG has O-linked side chains
what hormones does the anterior pituitary gland release
- FSH
- LH
- TSH
- ACTH
- GH
- PRL
Outline the menstrual cycle, starting from the death of the CL and thus the fall in Progesterone
- Decreased Progesterone
- Leads to decreased negative feedback and the intercycle rise in FSH
- FSH causes maturation of antral follicles
- Antral follicles produce E2
- Increased E2 causes negative feedback and a fall in FSH leading to the death of all but the dominant follicle
- The dominant follicle produces high consistent E2 which becomes +Ve feedback
- LH surge
- Ovulation
- High progesterone from the CL
- Negative feedback slowly reduces gonadotrophs and P falls as the CL die
Tanner stage IV
Coarse hair across pubis (not thighs)
Increase penis width/glans
Breasts enlarge, raised areolar
Tanner stage III
Coarsening of pubic hair
Increase penis size
Enlarged breasts, mound forms
What is a non-invasive method of testing tubal patency?
Hystero Salpingo-contrast Sonogrpahy (HyCoSy)
How are spermatozoa formed in waves?
The cells remains connected to one and other by cytoplasmic bridges forming a syncytium allowing synchronous development
What are the 2 types of postcoital pills? What are their failure rates?
Levonelle - Levonorgestrel - Failure rate of 1.7%
ellaOne - ulipristal acetate - Failure rate 1.2%
What are the progesterones used in COCP?
Older (2nd gen) - Norethisterone & Levonorgestrel
Newer (3rd gen) - Desogestrel, Gestodene & Norgestamine
Latest - Drospirenone (derived from spironolactone
Outline some contraindications of the COCP
Breast cancer, Undiagnosed genital bleeding, pregnancy, <3 wks post partum, Breast feeding, HTN, migraine with aura, SLE etc…
When is the emergency contraceptive pill indicated?
Any day of the natural cycle: >21 days after pregnancy or >5 days after abortion, miscarriage, evaluation of trophoblastic disease
Any day of the cycle where contraception was compromised.
The contact of the sperm and what initiates the acrosomal reaction?
Sperm and the zona-cumulus complex
What is the corona radiata?
Innermost layers of cumulus cells in contact with the ZP
Made by granulosa cells adhering to the oocyte as it leads the follicle