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Relationship between Body and Pregnancy

Know Your Body - Anatomy Of The Human Reproductive System

Couples trying to conceive may save themselves from a lot of heartache and stress if they know their bodies well! It is quite surprising that we know so less about how our body works. If we have this knowledge, we can support our bodies in its function…even help ourselves to conceive a baby successfully!

Organs that work in coordination with each other to help in reproduction constitute the reproductive system. Females and males have different organs for reproduction. The male reproductive organs produce sperms, and the female reproductive organs produce ovum or egg. The sperm and the egg fuse, which is known as fertilization, to form, what is called a zygote, which grows inside the womb into a baby.

Hormones- The triggers for reproduction

Hormones, are chemical that are produced in our bodies from various glands. Each hormone has a specific function to perform. Hormones from the pituitary gland in the brain and the hormones produced by some organs of the reproductive system help in the maturation of reproductive system and in the development of sexual characteristics in humans. These hormones are different in males and females. These hormones also affect the reproductive ability of the individuals.

The Reproductive system in Men

The primary function of the reproductive organs in men is to produce sperms. The organs involved in this process include:

1. A pair of testes
2. Epididymis
3. Vas deferens
4. Seminal vesicles
5. Prostate gland
6. Bulbourethral glands
7. Penis

Reproductive system in Men

Testes:

A pair of testes acts as the primary reproductive organs of the male reproductive system. They develop in the abdominal cavity before birth and descend into the pouch like structures called scrotum shortly after birth or during the last month when the baby is in the womb. Each testis is an oval shaped structure and contains highly coiled tubes called seminiferous tubules. These tubes produce sperms by the process known as spermatogenesis. Another types of structure called the Leydig cells, present inside the testis, produces the male hormone, testosterone. This hormone is responsible for the pubic hair and moustache in men. Testosterone also helps in production of sperms.

In males, sperm production starts at puberty and continues throughout the life. The sperm can survive for about 48 hours in the female reproductive tract.

Epididymis:

Sperms are produced in the testes and reach the highly coiled structure called epididymis. The sperms become mature in the epididymis. Epididymis stores the mature sperms until they reach the female reproductive system after sexual intercourse.

Vas deferens:

Vas deferens includes a pair of tubes that start at the end of the epididymis and extend up to the prostate gland. The vas deferens helps in the forward motion of sperm along with seminal fluid in to the ejaculatory ducts.

Ejaculatory ducts:

The sperm enters the ejaculatory ducts along with seminal fluid. The ejaculatory ducts open in to the urethra.

Urethra:

The urethra opens out through the urethral opening at the end of the penis. It is a common passageway for both urine and the sperm in males.

Seminal vesicles, Prostate and bulbourethral glands:

The secretions of organs called seminal vesicles and prostate gland collectively form the seminal fluid. Bulbourethral glands are present at the base of penis and they also open in to the urethra. They provide some lubrication for the penis during intercourse.

Penis:

Penis helps in the transfer of sperms in to the female reproductive tract. Sexual stimulation causes the blood vessels of penis to dilate and this causes penile erection.

The Reproductive System in Women

The primary function of the female reproductive system is to produce egg or ovum. Fertilization of the ovum by the sperm cell also takes place in the female reproductive system. The female reproductive system includes:

1. Ovaries
2. Fallopian tubes
3. Uterus
4. Vagina
5. Vulva

Ovaries:

Ovaries are a pair of oval shaped organs responsible to produce egg cells or ova. In females, all the ova develop before birth and they start maturing after puberty under the influence of female sex hormones. When the ovary releases an egg, the process is called ovulation.

Fallopian tubes:

There are two fallopian tubes, which are funnel shaped with finger-like projections at the end. These help to capture the egg after ovulation. Fertilization, or the fusion of egg and sperm, takes place inside the fallopian tubes.

Uterus:

Uterus is a highly muscular organ that receives the fertilized ovum. The development of fetus or embryo takes place inside the uterus. Uterus directly opens into the vagina, which acts as a birth canal during labor.

Vagina:

Vagina is a muscular tube and extends from the uterus to the outside of the female reproductive tract. The vagina provides a passageway for the menstrual flow during menstruation, for the baby during childbirth and receives the sperm during intercourse.

Vulva:

Vulva includes the external reproductive organs of the female reproductive system. The secretions of paraurethral and vestibular glands of vulva aid in the lubrication of penis during intercourse.

What is fertilization?

During sexual intercourse, vagina of the female reproductive system receives the sperm after ejaculation. Only one sperm cell can fertilize an egg cell or an ovum and the remaining sperm cells present in the seminal fluid degenerate. The sperm is mobile and reaches the fallopian tube where it fertilizes the ovum. The fertilized ovum or the zygote then enters the uterus, and gets implanted in the uterus. The development of the fetus or the embryo starts after the implantation of the fertilized ovum in the uterus. The fetus then develops in to a baby.

For a successful conception, it is necessary that the reproductive organs produce healthy sperm and ovum. The timing of sexual intercourse should be near the time of ovulation, so that the sperm survives to fertilize the ovum. The fallopian tubes should be healthy enough to transfer the fertilized ovum into the uterus. Finally, the uterus should be able to receive the fertilized ovum and provide an environment conducive to implantation and further growth and development.

How do sperm and ovum form?

Girls and boys are born with eggs and sperms, respectively. However, these are immature and not active until puberty is achieved. At puberty, reproductive hormones activate the dormant ova and sperms. For most adolescent girls, every month only one egg becomes fully mature. If not fertilized, the egg dies within 2 weeks. In comparison in an adolescent boy millions of sperms mature at the same time, which survive inside the man’s body for at least 42 days.

Egged on…

The egg or ovum is produced in the ovary. The female baby may have about one to two million eggs in the ovary even before the birth. However, these eggs do not mature until puberty. As the female reaches puberty, the hormones produced by the brain promote maturation of these eggs. Most of the eggs waste away leaving around 300000 eggs during puberty, which remain dormant until the hormones promote their maturation. Out of these, only 400 eggs may mature and release during a woman’s lifetime. The dormant eggs cannot repair any damage if occurs in them. Therefore, the eggs released during the later stages in the life or when the woman ages, have more chances of carrying a genetic or chromosomal abnormality. Therefore, conceiving a baby later in life may increase the risk of developmental abnormalities in the baby.

Egged

Sperms- Unbelievable numbers

Sperms are produced in the male’s testes. It is quite interesting to know that a man releases 40 million to 1.2 billion sperms in a single act of ejaculation! Surprisingly, these many sperms compete to fertilize a single ovum. Over a lifetime, a man produces around 500-600 billion sperms. Imagine if each sperm could fertilize an egg, a single man could populate the whole earth!!!

The basic cells from which the sperms develop, are present in the male baby during birth. During puberty, the brain releases male sex hormones, which promotes maturation of these bells into sperms. The sperm production continues in the old age as well, therefore, there is no age limit for fathering a child!

Hormones- The wonder chemicals

Hormones have a crucial role in production and maturation of sperms and eggs. In females, the follicle-stimulating hormone (FSH) helps in maturation of the egg. The luteinizing hormone (LH) helps the egg to be released from the ovary. Estrogen and progesterone are important female hormones that help in regulation of menstrual cycle, and also promotes pregnancy if conception takes place.

In men, testosterone hormone is crucial for production of sperms and maintaining fertility. Follicle-stimulation hormones (FSH) are also important for maturation of sperms.

The levels of these hormones in the body may affect fertility. The hormone levels may fluctuate in response to stress, change in level of physical activity, change in food habits, presence of underlying diseases, and other lifestyle habits such as alcohol and smoking. Therefore, if a couple is unable to conceive, they should be evaluated for any or all of the above-mentioned causes.