This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
From which of the following layers the regeneration of endometrium take place : 
Select and explain. 
A. Zona basalis, B. Zona pellucidum, C. Zona compacta, D. Zona spongiosum
A: Zona basalis
Answer: A: Zona basalis 
Explanation: Zona basalis Endometrium Superficial layer (2/3) Deep layer (1/3) It consists of stratum compactum stratum spongiosum These Layers are supplied by sprial which undergo vasocostriction during secretory phase | This causes necrosis or sloughing of these layers at the time of menstruation Stratum basale (Zona basalis) it is supplied by basllar aeries | During secretory phase these basilar aeries remain straight, so the blood supply stratum basale remains intact. Therefore this layer is not shed and during secretory phase it causes the regeneration.