In human female, the blastocyst

  • forms placenta even before implantation

  • gets implanted into uterus three days after ovulation

  • gets nutrition from uterine endometrail secreation only after implantation

  • gets nutrition from uterine endometrail secreation only after implantation


D.

gets nutrition from uterine endometrail secreation only after implantation

Implantation is the attachment of blastocyst to the uterine wall (endometrium). It occurs after 6-7 days of fertilisation. during Implantation, the trophectoderm (trophoblast) comes in contact with the endometrium of the uterus and sinks into a pit formed in the endometrium and get completely buried in the endometrium. Trophoblast cells form specialised structures called villi, which help in absorption of nutrient materials.

483 Views

Signal from fully developed foetus and placental ultimately lead to parturition which requires the release of 

  • oestrogen fro placenta

  • oxytocin from maternal pituitary

  • oxytocin from foetal pituitary

  • oxytocin from foetal pituitary


B.

oxytocin from maternal pituitary

The process of giving birth to a baby is called parturition. Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully-developed foetus and t he placenta which requires the release of oxytocin from the posterior lobe of the maternal pituitary.

453 Views

Advertisement

Which one of the following correctly describes the location of some body parts in the earthworm Pheretima?

  • Two pairs of  accessory glands in 16-18 segments

  • Four pairs of spermathecae in 4-7 segments

  • One pair of ovaries attached at intersegmental septum of 14th and 15th segments

  • One pair of ovaries attached at intersegmental septum of 14th and 15th segments


B.

Four pairs of spermathecae in 4-7 segments

In earth, two pairs of testes are found in 10th and 11th segments, accessory four glands in 17th and 19th segments, four pairs of spermatheca from 6th 9th segment and one pair of ovarises in 13th segment.

467 Views

Advertisement

Secretions from which one of the following are rich in fructose, calcium and some enzymes?

  • Male accessory glands

  • Liver

  • Pancreas

  • Pancreas


A.

Male accessory glands

Seminal Plasma is the fluid in which the sperms are bathed. It contains secretions from male accessory glands (ie, seminal vesicles, prostate gland, and bulbourethral glands).
Seminal fluid contains fructose, citrate, inositol, prostaglandins and several proteins. Prostate secretes a thin, milky fluid that contains calcium, citrate ions, phosphate ions, a clotting enzyme and a profibrinolysin.

489 Views

Which one of the following is the most likely reason of not occurring regular menstruation cycle in females? 

  • Fertilisation of the ovum

  • maintenance of the hypertrophical endometrial lining

  • Maintenance of high concentration of sex hormones in the blood stream

  • Maintenance of high concentration of sex hormones in the blood stream


A.

Fertilisation of the ovum

If fertilisation occurs and the foetus is implanted in the endometrium the trophoblast cells of the developing placenta secrete a hormone human chorionic Gonadotrophic (hCG). This hormone-like LH maintains the corpus luteum and the secretion of progesterone and estradiol by it. These two hormones check the breakdown of the endometrium of the uterus. The absence of menstrual bleeding is the earilest sign of pregnancy.

594 Views

Advertisement