Physiology Flashcards
(29 cards)
What is the function of 5 alpha reductase?
application drug?
Converts testosterone to dihydrotestosterone (DHT)
Finasteride is an inhibitor of this enzyme
- used to treat BPH
- hair loss
What is the function of DHT?
Formation of external male genitalia
Enlargement of prostate at puberty and beyond
Anterolateral recession of hairline
What is the function of aromatase?
Conversion of androgens to oestrogen (in adipose tissue)
What enzyme is deficiennt in congenital renal hyperplasia?
21 beta-hydroxylase
Lead to decreased cortisol production. Hence ACTH increases leading to hyperplasia.
Also, increase in androgen production.
Treatment :large doses of cortisol
What is the effects of CAH on boys and girls?
Boys-Precocious puberty. Short stature due to early closure of epiphyseal plates
Girls-masculinisation of genitalia
The ferning pattern of cervical mucous is seen in which phase?
Follicular phase
(oestrogen)
in luteal phase the secretion is thick and forms cervical mucus plug that inhibits the ferning effect
The basal body temperature increases in which phase?
Luteal phase because progesterone is thermogenic
What is the MOA of mifepristone?
Blocks the binding of progesterone with its receptor and hence causes abortion.
Progesterone’s has anti oestrogens effect on myometrium:
- decreases excitability
- decreases the sensitivity to oxytocin
What is the pattern of release of gonadotropin releasing hormone (GnRH) from the hypothalamus?
Pulsatile Circhoral rhythm (every 30 to 60 minutes)
To suppress ovarian production of oestrogen, a drug should be given by In infusion or hourly iv injection?
IV infusion to downregulate GnRH receptors on anterior pituitary, causing a decreased response of anterior pituitary gonadotrophs to GnRH. This decreases LH and FSH secretion and decreases gonadal activity.
(the normal body mechanism is by circhoral rhythm to prevent this downregulation)
A manis suffering from Kallmann;s syndrome. What is it and wht is the treatment?
Hypogonadotrophic hypogonadism
To simulate testicular function, a drug with GnRH activity should be given as an hourly I.V. injection as it follows the body’s natural circhoral rhythm.
What is the criteria for the diagnosis of preeclampsia?
Hypertension >140/90
>20 weeks pregnant
protenuria
oedema
Also HELLP
Haemolytic anemia
Elevated liver enzymes
Low platelet count
What makes preeclampsia eclampsia?
If associated with a seizure
What is the function of human placental lactogen?
It is structurally related to GH and prolactin. Also known as human chorionic somatomammotropin (HCS).
It alters maternal glucose metabolism by making glucose more readily available to the foetus by antagonising insulin, glucose transport into maternal cells in decreased, raising the blood glucose concentration of the mother.
Foetal growth is promoted not by GH but by hPL.
The transportation of LDL and IgG across the placenta is mediated by what mechanism?
Receptor-mediated endocytosis
What is:
placenta accreta
placenta percereta
placenta increta
placenta accreta: due to abnormal adhesion between the chorionic villi and the uterine wall
placenta percereta: the chorionic villi penetrate the myometrium al the way through to the peritoneum
placenta increta: placenta penetrated into the myometrium
What is velamentous attachment of the umbilical cord?
Normally, the umbilical cord inserts into the middle of the placenta as it develops. In velamentous cord insertion, the umbilical cord inserts into the fetal membranes (choriamniotic membranes), then travels within the membranes to the placenta (between the amnion and the chorion). The exposed vessels are not protected by Wharton’s jelly and hence are vulnerable to rupture.
What is Battledore placenta?
A placenta in which the umbilical cord is attached at the placental margin; so called because of the fancied resemblance to the racquet (racket) used in battledore, a precursor to badminton.
Which part of the fetal membrane, the chorion or the amnion is in contact with the endometrium?
The chorion
hCG is produced by what cells?
Trophoblast cells
What is the function of hCG?
- Prevents luteolysis and stimulate progesterone production
- For the development of fetal adrenal and gonad during the first trimester
What pathology produce hCG?
Choriocarcinoma
Hydatiform mole
What is progesterone’s effect on prostaglandin?
Progesterone blocks the myometrial prostaglandin production hence reduces uterine contactility.
How is placental oestrogen produced?
The oestrogen precursor DHEA-sulfate comes from fetal adrenal gland and is converted by placental sulfatase to free DHEA.
DHEA-S needs to be obtained from the foetus as the placenta lacks 17alpha dehydroxylase enzyme which converts pregnenolone to progesterone.
Oestrogen deficiency may cause foetal anaencephaly but is not mandatory for the maintanence of the pregnancy iitself.
