ER 20+21

Question 1

importance of the mesonephric duct?

urogenital sinus?

Answer 1

Mesonephric duct is important for development of the male reproductive system

female vagina is partially formed from the urogenital sinus

Question 2

gonadal ridges?

Answer 2

appear during week 5 on the medial aspect of the mesonephros

male and female are indistinguishable before week 7

Question 3

important of primordial cells?

Answer 3

migrate from the umbilical vesicle to the gonadal ridges to initiate development of gonads

Question 4

how are genders differentiated when is it done?

SRY gene?

Answer 4

sex determination is done by week 12

female: ovaries develop by regression of medulla
male: testes develop from regression of the cortex and differentiation of medulla

testis determining factor encoded by SRY gene leads to male development (testis)

Question 5

congenital inguinal hernia?

Answer 5

the connecting portion of the process vaginalis does not obliterate

leaves a patency where intestines may herniate through

Question 6

hydrocele

Answer 6

the process vaginalis contains a small amount of fluid before it obliterates

the fluid is usually reabsorbed

if not.. hydrocele

identified by transillumination

Question 7

cryptorchidism and ectopic testis

Answer 7

cyto:
testes do not descend
lead to infertility and high risk for germ cell cancer

ectopic:
testes are in an abnormal place

Question 8

Role of testosterone and AMH?

mesonephric ducts?

Answer 8

testosterone: stimulates in mesonephric ducts to transition into male genital ducts (from the leydig cells)

AMH: development of the paramesonephric ducts into female genital ducts is inhibited by AMH from sertoli cells

mesonephric ducts give rise to epididymis, ductus deferens, seminal vesicles

Question 9

how is the prostate developed?

Answer 9

Endodermal outgrowths from the prostatic urethra differentiate into glandular tissue

Question 10

development of the uterus

endo and myometrium?

Answer 10

the cranial portion of the paramesonephric duct becomes the uterine tubes

the caudal portion fuses together- from the uterine canal to give rise to the uterus.

endo and myometrium is formed from the splanchnic mesenchyme

Question 11

double uterus?

bicornuate uterus?

unicornuate?

Bicornuate uterus with rudimentary horn?

Answer 11

double:
no or minimal fusion of the paramesonephric ducts

bicornuate:
if incomplete fusion is only superior

unicornuate:
incomplete development of one of the mesonephric duct

Bicornuate with:
One paramesonephric duct is inhibited and
this duct does not fuse with the second duct

Question 12

vaginal agenesis

Answer 12

failure of the sinovaginal bulbs to develop and form the vaginal plate

the absence of the vagina is usually accompanied by no uterus
the development of the uterus induces the formation of the sinovaginal bulbs

Question 13

vaginal atresia

Answer 13

failure of the canalization of the vaginal plate

Question 14

imperforate hymen

Answer 14

failure of the inferior end of the vaginal plate to perforate

Question 15

canal of nuck

Answer 15

the process vaginalis remains patent

this is subject to both herniation and hydrocele

females

Question 16

targeted screening and population screening

Answer 16

target: screening of populations known to be at risk
Ex: affected person in family or high risk ethnic groups

population:
screening all members of a population regardless of family history (breast exam)

Question 17

purpose of prenatal screening?

Answer 17

usually used to detect 3 abnormalities:

trisomy 21 and 18 ]

neural tube defects

Question 18

alpha fetal protein?

Answer 18

synthesized in yolk sac, fetal GI and fetal liver

detectable at 6 weeks
peak at 12-14 weeks

can be used as a screening marker

Question 19

first trimester test? date ?

second trimester test? date?

Answer 19

first:
11-14 weeks + 1 day

look for pregnancy associated plasma protein A
human chorionic gonadotropin

second: 14 weeks + 2days to 20 weeks

triple test:
AFP, estriol, and HCG

Quad test:
inhibin A

Question 20

Low serum AFP,
low estriol
low PAPP-A
high β-hCG and high Inhibin A

Answer 20

trisomy 21

Question 21

Low serum AFP, estriol, PAPP-A and β-hCG

Answer 21

trisomy 18 (edward syndrome)

Question 22

first trimester test often shows reduced PAPP-A and β-hCG

second trimester doesn’t help with this diagnosis

Answer 22

trisomy 13 (patau syndrom)

Question 23

cell- free DNA (non-invasive prenatal screening)

Answer 23

used to detect aneuploidy (trisomy)
may be used to detect mutation

challenges:
young maternal age
twins
previous pregnancy

Question 24

neural tube effects can be best diagnosed by?

Answer 24

best diagnosed at 18 weeks with ultrasound and increased AFP

Question 25

Enlarged nuchal translucency 11-14 weeks

Answer 25

associated with trisomy

Question 26

chorionic villus sample

Answer 26

10-14 weeks

involves the removal of fetal cells by aspiration from the inner surface of placenta

direct chromosomal analysis by FISH

Question 27

amniocentesis

Answer 27

15-18 weeks

amniotic fluid is aspirated with the help of ultrasound

fetal cells are pelleted and used for chromosome analysis

supernatant can be used for AFP testing

Question 28

Percutaneous umbilical blood sampling (PUBS)

Answer 28

usually done after 18 weeks

Performed when there is a delayed suspicion of a
chromosomal abnormality usually detected by
ultrasound in 2nd trimester

Question 29

PKU screening

Answer 29

First to be screened by using quantitative mass spectrometry or tandem MS

elevated levels of Phe in the blood

treated by Phe restriction

Question 30

sickle cell detection and treatment

Answer 30

hemoglobin electro 
DNA test (PCR-RFLP) 

treatment:
prevention of sickling crisis by blood transfusions and use of hydroxyurea

Question 31

detecting thalassemia?

Answer 31

mean corpuscular hemoglobin and hemoglobin electrophoresis

Question 32

cystic fibrosis detection and management

Answer 32

sweat test
DNA test
IRT test

manage:
Antibiotics to combat respiratory infections, gene therapy, management of associated malabsorption

Question 33

SCID detection and management

Answer 33

RT-qPCR can detect

manage: bone marrow transplant