Reproductive cycle - human development, Biology

Reproductive Cycle

The whole reproductive cycle consists of an ovarian cycle and a uterine cycle. Figure illustrates one complete reproductive cycle. You can observe in the figure the - interrelationship among the hypothalamus, pituitary, ovaries and uterus. The average reproductive cycle is spread over 28 days. It commences at puberty and generally continues throughout the reproductive years. The cycle readies the reproductive system for pregnancy. Refer to figure frequently as you read the following discussion. It will assist you to understand the close relationship between the two components of the whole reproductive cycle.

1726_reproductive cycle.png

Figure: interrelationship of the hypothalamus, pituitary, ovaries and endometrium. One complete menstrual cycle shown. Note that the cyclic activity of the ovary is intimately linked with the changes in the endometrium.

The hypothalamus synthesizes the gonadotropins releasing hormone (GnRH) which stimulates the anterior pituitary to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH). The ovarian cycle starts with the phase of follicular growth in the ovary after the end of preceding, menstrual cycle and lasts for about 14 days. In the first half of this period FSH stimulates the growth of 5-12 primary follicles out of that usually only one matures at a time. The maturing follicle secretes estrogen that exerts a feedback control on anterior pituitary inhibiting further FSH production therefore preventing maturation or more follicles. The follicular phase comes to an end along with the maturation of one follicle and its release from the ovary leading to ovulation, on day 14. At the time of ovulation the ovum is in the secondary oocyte stage surrounded by the non-cellular zona pellucida and follicle cells which make the zona radiata (or corona radiata). Following ovulation, from day 15 to 28 production of LH from anterior pituitary stimulates the formation of corpus luteum from the follicle cells left at the back in the ovary. The corpus luteum secretes the hormone progesterone which makes the endometrium for implantation of embryo and later maintenance of pregnancy during early stages. If the ovum is not fertilized, the corpus luteum degenerates and menstruation starts again.



Posted Date: 2/1/2013 4:20:26 AM | Location : United States

Related Discussions:- Reproductive cycle - human development, Assignment Help, Ask Question on Reproductive cycle - human development, Get Answer, Expert's Help, Reproductive cycle - human development Discussions

Write discussion on Reproductive cycle - human development
Your posts are moderated
Related Questions
Consider cell with a diploid chromosome number of 4 (2n=4), one pair of the chromosomes is metacentric,the other is acrocentric. The metacentric is labeled a 1 a 1 while the acr

Tpes of Diarrhoea: Diarrhoea can be acute, chroniclpersistent diarrhoea and dysentery.  If an episode of diarrhoea lasts less than 14 days, it is acute diarrhoea. Acute wat

STIMULENT S - It makes a person more wakeful, alert and active. (i) Caffeine ( C 8 H 10 N 4 O 2 ) - It is 1,3,7-trimethylxanthine obtained from tea leaves ( Thea si

Radiant Warmer A radiant warmer is a device used to maintain the body temperature of the newborn and thus play an essential role in influencing oxygen consumption, apnea and

Diabetes Mellitus in the World As per the International Diabetes Federation Directory, in 1994 the global burden of the disease was estimated at 110 million. These cases will i

Describe the term - Intellectual Processes scales The 269 items are divided into 11 content scales, each of which may be administered individually. Since these scales contain v

Q. What are organogenesis and histogenesis? Histogenesis is the procedure of tissue formation in the embryonic development. Organogenesis is the procedure of organ formation. B

Lipolysis What do we mean by lipolysis? Hydrolysis of ester bonds in lipids is called lipolysis. This may occur by enzyme action or by heat and moisture, resulting in the liber

Q. What are instances of nematodes? Ascaris, filaria and hookworm, all parasites of humans, are instance of nematodes also known as roundworms. Q. Are nematodes exclusively

A n t h r a x It is also known as spleenic fever. The peracute form of the disease in animals is manifested by sudden death with oozing of dark-coloured blood from body o