• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The role of hormones in the female reproductive system.

Extracts from this document...


The role of hormones in the female reproductive system The oestrus cycle is the continuing process of fertility and non-fertility controlled by several hormones and the endocrine system. This consists of the hypothalamus, the anterior pituitary gland, the ovaries and the uterus, known as the hypothalamic-pituitary-ovarian-uterine axis. Oestrus normally lasts for 18 to 24 days but this figure can vary in specific circumstances such as early puberty when the cycle lasts for a lot less time (3 to 12 days) and also when the cycle commences after pregnancy and parturition (Fuquay 2002). The oestrus cycle halts during pregnancy due to the large amounts of progesterone in the blood supplied by the Corpus Luteium (CL). Progesterone is vital for maintaining pregnancy and also for stimulating the growth of mammary alveoli for the purpose of lactation. Gonadotrophin releasing hormone (GnRH) begins a cascade of hormones through the animal that are responsible for the oestrus cycle taking place. ...read more.


High concentrations of progesterone and oestradiol in the blood act to lower the amount of gonadotrophins released. The granulosa cells of follicles release inhibin, inhibins are a set of hormones that help control gonadotrophins as well by suppressing the synthesis and secretion of FSH. They are made up of two protein sub-units, ? and ?, that are linked by a disulphide bridge. It is these cells that form the CL due to the luteinization of them by LH and once they have been changed, they will respond to LH by producing progesterone. Prostaglandin F2? (PG) is the major luteolytic hormone in ruminants, it is secreted by the uterus. This also is secreted in a pulsing manner and is responsible for the lysis of the luteal cells (essentially the destruction of the CL) if pregnancy has not occured. If the ruminant is pregnant then the CL is maintained, as progesterone is needed in order to maintain the foetus. ...read more.


The contractions soon become a lot stronger and regular, more frequent intervals until the foetus is pushed into the cervix that triggers the release of oxytocin from the posterior pituitary. It is this hormone that regulates the strength and timing of the contractions until the foetus has been expelled. Some contractions still occur and a second surge of oxytocin is connected to the expulsion of the placenta. Nearly all hor monal activity ceases once the cow has calved, with some levels dropping at a very high rate. The cow returns to a normal cycle after 20 to 30 days but with the difference of showing no visible signs of it happening. This is known as a quiet or silent oestrus and will usually only happen once and will be followed by a completely normal oestrus approximately 50 days after parturition. Suckling can affect the length of time it takes to return to oestrus, with LH, FSH and GnRH pulses being inhibited by the suckling reflex. ANIM 221 Reproductive Physiology James Crawley Animal Science (Behaviour & Welfare) James Crawley Animal Science (Behaviour & Welfare) ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our University Degree Developmental & Reproductive Biology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related University Degree Developmental & Reproductive Biology essays

  1. The polymerase chain reaction (PCR) is an in vitro technique, which allows the amplification ...

    Since all DNA polymerases require primers to initiate strand synthesis, the target for PCR amplification can be specified by designing primers to anneal to particular unique DNA sequences. 2. PCR primers are chemically synthesized oligonucleotides and their design is crucial for the success of the PCR.

  2. Mitochondrial genetics. Are there really only maternally inherited mitochondria in our cells? What happens ...

    There is a mistake in ubiquitination - sperm is not marked when developed, or b. The cellular structures of the egg do not recognize foreign mitochondria (Ankiel-Simons, Cummins, 1996; Foley, 2003). Several experiments were conducted on sperm penetration and acrosome reaction to show the impossibility for a normal organism to inherit paternal mtDNA.

  1. The Endocrine systems involvement in the control of the female reproductive system.

    Oxytocin encourages the contraction of the smooth muscle cells in the uterus and around the milk glands in the breasts. Anti diuretic hormone (vasopressin) endorses the re-absorption of water from the urine in the kidney, consequently controlling the salt levels in the blood.

  2. The Female Orgasm: Adaptation, Artefact or culturally learned? ( Department of Psychology - University ...

    pair bond is adaptive and that female orgasm helped with pair bonding. Possibly the most developed theory is that of Desmond Morris's (1967) which will briefly be presented and critically evaluated. Morris (1967) attempts to determine that pair bonding would itself be a significant evolutionary adaptation for our pre-hominid and hominid ancestors.

  1. Life cycle

    Cell division has two major roles. It enables a fertilized egg to develop through various embryonic stages, and an embryo to develop into an adult organism. It ensures the continuity from generation to generation; it is the basis of both asexual reproduction and sperm and egg formation in sexual reproduction.

  2. Contrast the Biological Differences between Heterosexual Males and Homosexual Males

    The researchers explained that this was an unusually distressing time in German history and perhaps the effect of stress-hormones took hold of a generation of men. Of course it is difficult to prove this relationship because it is too far in the past, however further studies have investigated stress-levels as cause for sexual diversion.

  1. DNA and Manipulating Reproduction.

    > One way of combating this infertility in older women is to insert mitochondria from a donor egg into a recipitant egg, which means the cell has/can produce much more energy to divide and therefore develop into a foetus. However, there seems to be a very serious implication of using

  2. Discuss The Significance Of Normal And Abnormal Mitosis And Meiosis In The Lifecycle Of ...

    There is no Interphase between Meiosis I and Meiosis II and the latter begins with Prophase II. A new set of spindle fibers forms and the chromosomes begin to move toward the equator of the cell. All the chromosomes in the two cells align with the metaphase plate.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work