EMBRYOLOGY
1. Prochordal plate & primitive streak is seen on: 14th day
2. Oogonia & germ cell are derived from: Yolk sac
3. 1st polar body is formed during: Oogenesis
4. 1st polar body is extruded: At the time of ovulation
5. Sperms are stored in: Epididymis
6. Y chromosome is: Acrocentric
7. Length of human sperm: 50-60 microns
8. In humans, implantation begins on the: 6th day after fertilization
9. Number of chromosomes are reduced down to half in: 1st meiotic division
10. Primitive streak develops in which week: 3rd week
11. Initiation and maintainance of primitive streak is because of: Nodal gene
12. Anomaly of pancreas in which the parts of the pancreas derived from the dorsal & ventral buds fail to fuse with each other: Divided pancreas
Structure developed from cloaca-
-The cloaca develops into the rectum and upper 2/3 of the anal canal,
-While its anterior subdivision, the urogenital sinus, develops into the bladder and
-In the female, the urethra and vestibule,
-While in the male the prostatic urethra.
EMBRYOLOGY OF GENITOURINARY SYSTEM
1. Collecting duct develops from: Ureteric bud
2. Epithelium of ureter develops from: Mesonephros
3. Uterus/ appendix testes develops from: Mullerian duct/ paramesonephric duct
4. Ovary develops from: Genital ridge
5. Scrotum develops from: Genital swelling
6. Clitoris develops from: Genital tubercle
DERIVATIVES OF GERMS LAYERS
Derivatives of neural crest:
- Neurons of
Dorsal root,
Sensory &
Autonomic/ sympathetic ganglia
- Schwann cells,
- Melanocytes,
- Mesenchyme of dental papillae etc.
- Mesodermal in origin:Kidney, Muscle (EXCEPT musculature of iris), Bone etc.
- Trigone of bladder:Mesoderm
- Somites: Paraxial mesoderm
- Epithelial lining of biliary tract:Endoderm
- Tympanic membrane:All the 3 germ layers
FETAL STRUCTURES & ADULT REMNANTS
1. Meckel's divertculum: Remnant of vitelline duct
2. Ligamentum arteriosum: Remnant of ductus arteriosus
3. Ligamentum venosum: Remnant of ductus venosus
4.
Medial umbilical ligaments: Remnant of 2
umbilical arteries
5. Median umbilical ligament: Remnant of urachus
