Custom «The Reproduction System» Essay Paper

1. How does the female reproductive system produce eggs and support pregnancy?

Formation process of egg is called ovogenesis.

Eggs are formed in ovaries. As well as at formation of spermatozoid, the introduction in meiosis female sexual cells is preceded by a stage of reproduction of primary sexual cells - oogonia - by mitosis. The number of mitotic is usually  less than divisions and reproduction of spermatogonia.

Having entered in prophase meiosis, oogonium becomes oocyte of the first order. At mammals and the person this process comes to an end till a birth of the individual. Generated by the time of the birth of oocytes the first order remains for many years without change. With approach of the sexual maturity separate oocytes periodically enter a growth stage. The growth stage of the oocyte differs from a corresponding stage of spermatogenesis by the duration. Sometimes this stage may take some months as it  reaches the huge sizes. In its cytoplasm a lot of mitochondria is formed, ribosomes develop  a smooth and rough endoplasmic network; there is a synthesis of nutrients which are reserved in a kind of vitelline and protein granules.

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The day before meiotic divisions which usually occur one behind another already after penetration of the spermatozoid in oocyte, the kernel of the oocyte moves more close to a cell surface so that the division spindle is formed almost about the most cellular membrane and it is perpendicular to it. At cytokinesis is the one large cell containing almost all cytoplasm (oocyte the second order), another one is small, consisting in essence of a kernel with a cytoplasm, the minimum quantity of which turns out. This cell names the 1st reducing little body.

After the second division meiosis  a large cell occurs in the same way and after that appears large egg, or ootid, and the 2nd  one is  reducing the little body. The first reducing of the  little body is also shared as a rule. Thus, there are four haploid cells. Unlike spermatogenesis which is formed in a course meiosis cells are equal to each other and form the female sexual cells. As a result meiosis one is ready for fertilization of the egg and the third one is reducing little bodies which degenerate soon.

2. How does the male reproductive system deliver sperm?

Sperm is a mix allocated during ejaculation products of secretion of man's genitals: testicular and their appendages, prostate, seed vials, urethra. Sperm consist  of two separate parts: seed plasma - basically formed of secretion prostate, testicular liquids, their appendages and channels of seed gland, and from uniform elements (spermatozoids or primary sexual cells of testicular).

• Liquid from the seminal vesicles (65 %);
• Liquid from the prostate (30 %);
• Spermatozoids (5 %).

Ejaculation is an extraction of sperm from male reproduction tract. This process consists of two phases:

1) Seed deducing in a part of urethra from an appendage of testicular;

2) Emission of a seed liquid from urethra.

The first phase of ejaculate reflex is under the control of sympathetic nervous system. The second phase (eruption of a seed from urethra) is about the spinal reflex at level of backs of spinal cord. Transfer of the nervous impulse provides the end of ejaculation and occurs on the pudenda nerve. After the end of ejaculation comes the refractory period during which repeated achievement of ejaculation is impossible or complicated.

3-4. How is the menstrual cycle regulated by hormones? What keeps the ovarian and uterine cycles always exactly in phase with each other even though the length of the menstrual cycle may vary slightly?

Menstrual cycle is a difficult periodic biological process preparing an organism of the woman for pregnancy. The first menstruation appears in 12 - 14 years and proceeds at genital age (to 45 - 50 years). Fertilization comes in the middle menstrual cycle after ovulation, non-impregnated egg quickly perishes, and the mucous membrane of a uterus prepared for implantation of egg, is torn away and results in menstrual bleeding.

Menstrual function is regulated in a neurohumoral way by:

1) Cerebral cortex;

2) the sub crustal vegetative centers located mainly in hypothalamus;

3) pituitary;

4) ovaries.

The cerebral cortex regulates the processes connected with the development of menstrual function. Through it the influence of an environment on the underlying departments of nervous system participating in regulation of a menstrual cycle is carried out.

In hypothalamus concentrates the influence of impulses of nervous system and hormones of peripheral glands of internal secretion. In its cells there are receptors for all peripheral hormones  including estrogen and progesterone. Neurohormons of hypothalamus, stimulating clearing trophic hormones in a forward share of a pituitary, are called releasing-factors.

In ovaries there is a biosynthesis of three groups of steroid hormones: estrogen, progestogen and androgen.

Estrogens are secreted by cells of an internal cover of a follicle. They are also formed in the  insignificant quantity  in a yellow body and cortical body of adrenal glands.

Menstrual function is a set ovarian and uterine cycles and if uterine cycle (again endometria and its tearing away) is eliminated it does not mean that ovarian cycle will be eliminated. Ovary will continue to produce also hormones which will have an effect on fabrics - targets, including a mammary gland fabric. There are no contra-indications (except oncopathology) to hormone therapy; there is a contra-indication to a concrete hormone, and doctor’s task is to find that hormone which will approach woman.

5. Identify and describe two sexually transmitted diseases. How is each disease caused, and how is each disease treated?

The gonorrhea is the infection transmitted by a sexual way; it is caused by gonococcus Neisseria gonorrhea. The transferred disease does not protect from repeated infection in the future that is why it is possible to have been ill with gonorrhea for a few times during life. Disease affects mainly mucous membranes of urogenital bodies.

Less often there is an inflammation of a rectum and drinks (infection as a result of anal and oral sex). Gonococci also can affect conjunctive (in this case disease is called blennophthalmia). In some case gonococcus infection can extend on other parts of a body, such as joints, skin, heart and blood. The woman sick of gonorrhea can infect the child at the time of delivery. In newborns gonococci can cause meningitis, sepsis, arthritis, blennophthalmia.

Gonorrhea is usually treated in the conditions of hospitalization, mainly by antibiotics of group of penicillin, rarely – with sulphanilamides.

Syphilis is a chronic infectious disease. In case of syphilis the skin, mucous membranes, an internal, immune, nervous system are stroke. The activator is Treponema pallidum.

The most frequent way of infecting with syphilis is sexual, at various forms of sexual contacts.

Infection with syphilis occurs through small genital or extra genital defects of a skin, or through epithelium at contact with chancre, erosive papules on a skin and mucous membranes of genitals, an oral cavity, wide condylomas, containing a significant amount of Treponema pallidum.

In a saliva Treponema pallidum can be only in case when acnes on an oral cavity mucous membrane are present.

The syphilis can be caught through sperm of the patient at absence and at visible changes on genitals.

Infection with syphilis can seldom occur at close household contact, in exceptional cases - through the common subjects. Infection with syphilis through milk of the feeding woman sick of syphilis is possible. Cases of infection by syphilis through urine and sweat are also noted. The syphilis from the moment of infection is the general infectious disease which lasts at untreated patients for many years.

During an illness aggravation on mucous membranes, skin, in internal active displays of syphilis is observed.

One of the principal causes of changes of clinic duration of the incubatory period depends on  the latent current of syphilis, frequent application of antibiotics, change of the immune status of an organism and other factors. The classical current of syphilis is characterized by alternation of active displays of disease with the latent period. Classification of a current of syphilis is divided into the incubatory period, the primary, secondary and tertiary periods.

Syphilis treatment is spent only after a diagnosis has been acknowledged.

Treatment principal view is antibacterial therapy. Treponema pallidum is sensitive to antibiotics of group of penicillin (penicillin, bitsillin - 1, 3, 5, etc.). 

It is dangerous to self-medicate syphilis because recovery is defined only by laboratory methods.