Category Human Body

Once a sperm cell and an egg cell join, the fertilized egg begins to grow inside the woman’s uterus. During pregnancy the female body becomes a complete support system for the unborn baby.

It takes almost nine months for the fertilized egg to become a fully formed baby. Throughout this time, the uterus provides protection and warmth. As the baby develops, the uterus stretches until it is larger than any other organ in the body. The growing foetus shows in the pregnant woman’s “bump” at the front of her abdomen.

Your baby will change a lot throughout a typical pregnancy. This time is divided into three stages, called trimesters. Each trimester is a set of about three months. Your healthcare provider will probably talk to you about your baby’s development in terms of weeks. So, if you are three months pregnancy, you are about 12 weeks.

 

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Each sperm cell has a head made up of genetic material and a tail that enables speedy swimming. Up to 300 million sperm can be released at one time, and they compete to be first to fertilize the female egg.

Inside a woman’s fallopian tube, her egg is surrounded by perm, but only one will gain entry to the egg. As the winning sperm pushes through the outer case of the egg, a chemical reaction shuts out all the other sperm. The successful sperm then fuses with the nucleus of the egg, and fertilization is complete. An embryo is formed, which will eventually develop into a baby.

The term “gestational age” basically means how far along into a pregnancy you are. Gestational age is counted by starting with the first day of your last menstrual period (called LMP).

Gestational age can be kind of confusing, since it measures pregnancy from your last period — about 3-4 weeks BEFORE you’re actually pregnant. Common knowledge about pregnancy says it lasts 9 months, and it’s true that you’re usually pregnant for about 9 months. But the way pregnancy is measured makes it a little longer. A typical full-term pregnancy ranges from 38-42 weeks LMP — around 10 months.

 

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To join with an egg, sperm cells must complete 20-30 cm (8-12 in) journey from the woman’s vagina, via the uterus, to the egg in her fallopian tube. This is the equivalent of a 10-km (6-mile) swim for a human, millions of sperm begin the journey, but just a few survive to reach the egg – and only one will fertilize it.

Stage 1

The race begins

The vagina is an acidic environment for the sperm. Millions don’t make it beyond this stage.

Stage 2

Through the gap

The surviving sperm swim through the entrance to the uterus, which is slightly open.

Stage 3

The race gets rough

Many sperm fail to get through the cervix’s protective mucus. The successful ones now face attack from immune system cells in the uterus.

Stage 4

The last effort

Uterus muscles contract to push the sperm towards the fallopian tubes. Half of them swim towards the correct tube, where the egg is.

Stage 5

Fertilization

A handful of sperm arrive at the egg. Only one succeeds in burrowing through the egg’s outer layer to fertilize it.

 

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Inside the reproductive system

The testes and penis, which are outside the body, are connected by a series of internal tubes and glands. The whole male reproductive system is adapted to produce, mature, and transport sperm to where they can fertilize a female egg.

Sperm factory

Inside the testes, sperm cells are constantly being made. They form inside coiled tubes called seminiferous tubules, before moving to the epididymis where they mature. From there, they can move into the vas deferens, ready to leave the body.

Vas deferens

The vas deferens is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. Sperm from each testis pass through this tube towards the penis.

Prostate gland

The prostate gland is a walnut-sized structure that is located below the urinary bladder in front of the rectum. The prostate gland contributes additional fluid to the ejaculate. The prostate gland adds substances that protect and nourish the sperm cells.

Erectile tissue

This fills with blood to make the penis stiff enough to enter the woman’s vagina to deliver sperm.

Seminal vesicle

The seminal vesicles are sac-like pouches that attach to the vas deferens near the base of the bladder. This releases fluid that combines with sperm cells to make semen.

Urethra

The urethra is the tube that carries urine from the bladder to outside of the body. In males, it has the additional function of expelling (ejaculating) semen when the man reaches orgasm. Sperm-carrying semen leaves the body through this tube.

Penis

The penis is the male organ for sexual intercourse. It has three parts: the root, which attaches to the wall of the abdomen; the body, or shaft; and the glans, which is the cone-shaped end of the penis. The penis transfers sperm into woman’s vagina.

Testis

The testes are oval organs about the size of very large olives that lie in the scrotum, secured at either end by a structure called the spermatic cord. Also called testicles, the two testes make and release sperm cells.

Scrotum

The scrotum is the loose pouch-like sac of skin that hangs behind the penis. It contains the testicles (also called testes), as well as many nerves and blood vessels. The testes are supported and protected by this pouch or skin and muscle.

Sperm cells

Sperm cells are among the tiniest human cells but the nucleus carries half the genetic instructions for creating a new life. Sperm are well adapted to produce enough energy for the long swim to the female egg.

 

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The male reproduction organs’ role in creating new life is to make sperm (sex cells). The sperm swim to a female egg, where one of them joins with it to create a fertilized egg that will grow into a baby.

A man’s main reproductive organs are the testes and penis. The two tests are where sperm are made and stored. Each testis is connected to a tube, which carries sperm to the penis. On the way, the sperm mix with other substances to make a liquid called semen. During the act of sexual intercourse, the penis becomes stiff and is inserted into a woman’s vagina, where it releases the sperm-containing semen.

The entire male reproductive system is dependent on hormones, which are chemicals that stimulate or regulate the activity of cells or organs. The primary hormones involved in the functioning of the male reproductive system are follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone.

FSH and LH are produced by the pituitary gland located at the base of the brain. FSH is necessary for sperm production (spermatogenesis), and LH stimulates the production of testosterone, which is necessary to continue the process of spermatogenesis. Testosterone also is important in the development of male characteristics, including muscle mass and strength, fat distribution, bone mass and sex drive.

 

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Inside the reproductive system

The uterus is in the middle of the lower abdomen, between the bladder and the rectum. The two ovaries are on either side of the uterus, connected to it by the fallopian tubes.

Inside the ovary

The ovaries contain many thousands of immature eggs, each enclosed in a bag-like follicle. Every month, hormones trigger a process where one of the eggs starts to outgrow the others. When it is mature, the egg is released from the ovary.

Right ovary

The ovary is a ductless reproductive gland in which the female reproductive cells are produced. Females have a pair of ovaries, held by a membrane beside the uterus on each side of the lower abdomen. The ovaries store, then release eggs.

Right fallopian tube

The uterine tubes, also known as oviducts or fallopian tubes, are the female structures that transport the ova from the ovary to the uterus each month. Each fallopian tube connects an ovary with the uterus.

Uterus

This hollow, stretchy organ is where the embryo develops. It functions to nourish and house a fertilized egg until the fetus, or offspring, is ready to be delivered.

Cervix

The cervix is the lower portion of the uterus, an organ of the female reproductive tract. The cervix is the point where the uterus opens into the vagina. Anatomically and histologically, the cervix is distinct from the uterus, and hence we consider it as a separate anatomical structure.

Bladder

This stretchy bag stores and releases urine. The bladder is a pyramidal shaped organ, which sits in our pelvis (the bony structure which helps form our hips).
The main function of the bladder is to store urine, and under the appropriate signals, release it into a tube which carries the urine out of the body.

Rectum

The lowest part of the large intestine is where faeces are stored. The rectum begins at the height of S2-S3 and ends at the perineum. It is about 12 to 16 cm long.

Vagina

The vagina is a fibromuscular (made up of fibrous and muscular tissue) canal leading from the outside of the body to the cervix of the uterus or womb. It is also referred to as the birth canal in the context of pregnancy. The uterus is linked to the outside of the body by this stretchy tube.

Pelvic floor

The uterus and bladder are supported by these strong muscles. These muscles extend across the pelvic region, below other muscles that give humans the ability to walk upright.

 

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