Menstrual cycle, Biology

Assignment Help:

MENSTRUAL CYCLE -

It occurs only in Primates. Start at the age of 13 yrs. upto menopouse.

During this period, generally one egg is released every 28 dyas or so alternately from the two ovaries. Since the female is fertile for about 32 years and about 13 eggs mature each year, only about 466 eggs have a chance of reaching maturity.

Menstrual cycle consists of 3 phases.

1.       FOLLICULAR (PROLIFERATING) PHASE -

It lasts for about 14 days.

It comprises the following events -

1.       Level of FSH is increased in the blood early in the cycle.

2.       FSH stimulates the grwoth of the selected primary ovarian follicle.

3.       FSH stimulates follicle to secrete estradiol.

4.       Estradiol inhibit secretion of FSH & stimulate secretion of LH.

5.       LH induces graffian follicle to burst & eject its egg in to fallopian tube. It occurs after about 14 days.

6.       Estradiol stimultes the uterus to prepare for implantation & nourishment of foetus.

7.       Lining of fallopian tube becomes thick to move ova into uterus.

2.       LUTEAL OR SECRETORY PHASE -

This phase lasts for 10 days. It involves following events -

1.       LH stimulates graffian follicle to convert into corpus luteum.

2.       Corpus luteum secretes progesteron and little amount of estradiol.

3.       Progesteron inhibits the release of FSH so that it may not develop additional follicle & eggs.

3.       MENSTRUAL OR BLEEDING CYCLE -

It lasts about for 4 days.

It involves following events -

(i) If fertilization does not occur, secondary oocyte undergoes autolysis.

(ii) In some wall of uterus secretes a luteolysine. It reaches to ovary where it causes autolysis of corpus luteum.

(iii) Stratum functionalis of endomatrium is given out with bleeding.

(iv) Menstrual flow continues for 3-5 days.

(v) Endomatrium tissue, unfertilised egg & 500-600 ml of blood are lost during this period.

Menstural is often described as funeral of unfertilized egg or weeping of uterus for the last ovum.


Related Discussions:- Menstrual cycle

Emphysema, Emphysema Emphysema is destructive changes in alveolar wall...

Emphysema Emphysema is destructive changes in alveolar walls and enlargement of air spaces distal to the terminal non-respiratory bronchioles. It is characterized physiolog

How can we check bp without stethoscope, How can we check BP without stetho...

How can we check BP without stethoscope In this case the procedure is same except you place your hand on radial pulse. You can read systolic pressure only by this method. -

Illustrate ploidies of zygote, Q. What are the respective ploidies of zygot...

Q. What are the respective ploidies of zygote, gamete and somatic cells in a species with gametic meiosis? Adopting as pattern an "x" quantity of chromosomes for gametes, somat

Describe the implant in an infected socket, Placement of the Implant in an ...

Placement of the Implant in an Infected Socket or a Pathologic Lesion Dental implants may fail due to: 1) Placement of the implant fixture into an infected socket (during im

Ingestion of foreign bodies, Ingestion of Foreign Bodies: As we know  ...

Ingestion of Foreign Bodies: As we know  that small children are curious and  innocence children are notorious for inserting various object into their orifices like mouth, nos

Explain the conjunctival impression cytology (cic), Explain the Conjunctiva...

Explain the Conjunctival impression Cytology (CIC)? Conjunctival impression cytology (CIC) is a simple, rapid and inexpensive method which is suitable for a field survey. By to

List four possible after-effects of solvent abuse, List four possible after...

List four possible after-effects of solvent abuse (glue-sniffing). Possible after-effects of solvent abuse are headache, nausea, vomiting, convulsions, runny nose, a rash round

Define about the concept of sports nutrition, Define about the concept of s...

Define about the concept of sports nutrition? The concept of sports nutrition was evolved fundamentally with integration of different disciplines in order to collectively striv

Define function of the iron uptake by cells, Define Function of the Iron Up...

Define Function of the Iron Uptake by Cells? Iron has several vital functions in the body. It serves as a carrier of oxygen to the tissues from the lungs by red blood cell haem

Explain chilling temperatures - method of food preservation, Explain chilli...

Explain chilling temperatures - method of food Preservation? (a) Cellar storage temperatures (about 15° C): It is usually used for the storage of surplus foods like root crops,

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd