Category Zoology

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.

Picture Credit : Google

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.

Picture Credit : Google

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.

Picture Credit : Google

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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Every month or so, a woman’s body goes through the process of preparing for a possible pregnancy. This sequence is called the menstrual cycle.

Phase 1

Egg ripens: Prompted by hormones, an immature egg starts to grow inside a soft casing called a follicle. Your period may last 2 – 7 days, with most fluid being lost in the first two days.

Phase 2

Egg is released: The uterus lining thickens to prepare to receive an egg. Meanwhile, the follicle bursts and releases a ripe egg into the fallopian tube.  During this phase, due to the oestrogen, your skin could be smoother, your breasts a little bigger and any discharge will be clear.

Menstrual cycle: This shows a typical 28-day menstrual cycle. In fact, it can take from 21 to 35 days to complete, and the times between stages vary a good deal.  

Phase 3

Egg arrives in the uterus: At this point, if the egg is fertilized, it embeds itself in the uterus wall and starts to grow. You may feel slightly ‘bloated’ as this phase can trigger fluid retention throughout your body – but it’s not dangerous and doesn’t last.

Phase 4

Menstruation: If the egg is not fertilized, both the egg and the uterus lining fall apart and leave the body along with some blood. This is called menstruation, or having a period. This sudden change can cause mood swings (also called PMS Pre-Menstrual Stress) and you may also experience cramps as the uterus contracts in readiness to shed the built-up layer – which takes you back to Phase 1; having your period.

Picture Credit : Google

From her teenage years to about her mid-fifties, the role of a woman’s reproductive organs is, combination with a man’s sex cells (sperm), to create a new human life – a baby.

A woman’s main reproductive organs are her ovaries and uterus. The two ovaries are where eggs are stored, then released at regular intervals. If an egg is fertilized by male sperm, the job of the uterus is to nurture and protect the egg as it develops – first into an embryo, then a foetus, which grows into a baby, ready to be born.

The vast majority of the eggs within the ovaries steadily die, until they are depleted at menopause. At birth, there are approximately 1 million to 2 million eggs; by the time of puberty, only about 300,000 remain. Of these, only about 500 will be ovulated during a woman’s reproductive lifetime. Any remaining eggs gradually die out at menopause.

Picture Credit : Google