The miracle of the Quran in unlock the secrets of

the early embryonic developmental stages in the mum womb

Professor Dr Abdelrazak M Ali,

FERTILIZATION AND IMPLANTATION.

Fertilization

Our modern understanding of changes taking place within the embryo can be traced to the rise of the cell theory at 1838. Scientists finally discovered the process by which sperm cells from a male and egg cells from a female combine to form a zygote. Studies by the Austrian Monk Gregor Mendel (1822–1884) opened a way to explain how genetic characteristics were transmitted from one generation to another. Finally in 1953, the discovery of the molecular structure of DNA (deoxyribonucleic acid) by the American biologist James Watson (1928– ) and the English chemist Francis Crick (1916 ) provided a chemical explanation of changes that take place during fertilization and development. Millions of sperms are deposited into the vagina during sexual intercourse. The sperms make their way through the cervix into the uterus and then on to the fallopian tubes. As they swim along this way their numbers decline. Only a few hundred sperm will get close to the egg(ovum). During the trip, sperms prepare themselves to meet the egg by subtle alterations of their heads and their movement patterns.

Sperms are able to survive for 2-3 days within the female's reproductive tract. The length of the time that a woman's egg can be fertilized by a man's sperm ranges from 12-24 hours.

Once inside the fallopian tube, the sperm attracts the egg by releasing a chemical. The egg is surrounded by a protective covering called the zona pellucida, which allows only one sperm to penetrate it. Once inside the egg, the head of the fertilizing sperm releases its genetic contents, which fuses with the nucleus of the egg. Fertilization is now complete.

Fig (1) shows how only one sperm can penetrate the egg. Once inside the egg, the head of the fertilizing sperm releases its genetic contents, which fuses with the nucleus of the egg

Development of fertilized egg

The fertilized egg then undergoes several divisions to form a structure called the zygote. It moves into the uterus(womb) within a period of 5-7 days where it is then termed "embryo". In the uterus, the embryo implants or attaches itself and burrows into the endometrial tissue. After implantation it secretes a hormone called human chorionic gonadotrophin (hCG) which helps maintain the pregnancy. This is the hormone analyzed in the blood/urine to detect or confirm a pregnancy.

Implantation

The fertilized egg, now known as an embryo, develops in the fallopian tube for the first three days, then travels down into the uterus. By the fifth day it will become a blastocyst, a hollow ball of cells surrounding a cyst-like cavity. The blastocyst then breaks free from its shell, or hatches, and it is ready to adhere to the surface of the endometrium(linig of the uterus). It begins to secrete human chorionic gonadotrophin (hCG), a hormone that tells the corpus luteum to continue progesterone production. A home pregnancy test will detect hCG when checked after a missed period. Normally,the egg maintains its ability to be fertilised for about 12-24 hours after ovulation. Sperm can remain viable in the cervical mucus for 48-72 hours or more leading up to ovulation.

Following its adherence it penetrates inside the endometrium to get nourishment and oxygen from the newly formed placenta and now becomes covered with three layers of membranes ;

1-The Amnion;  It closely surrounds the Embryo to facilitate its free movement and to help it grows up.

2-The Chorion; It provides nourishment and oxygen to the Embryo and drains the waste products from the Embryo  through the maternal vasculature.

3-The Endometrium; The outermost layer and represents the room in which the newly formed baby is addressed to living.

The Holly Quran through many verses  had clarified and  unlocked the secrets of all the steps of Embryo developement from the moment of sperm ejaculation till delivery. In Suret Al Zomar( Chapter 39,Verse 6) God say'  Oh Our God, in mum womb He originated ourselves   creation after creation and in three darkened coverings, this is  your Lord Almighty, the owner of all property, no divinity except God, why you are distracted away.

Figure 2- The embryo lies within the chorionic and amniotic sacs. Note the yolk sac between them. The capsular chorionic villi associated with the evolving peripheral membranes are undergoing atrophy creating the discoid placenta at the base into which the cord inserts.

As it is clear, The embryo is completely covered by the three membranes, Amnion,Chorion and the lining of the womb.

Embryology

The study of changes that take place in the embryo is known as embryology. As one might imagine, the subject of embryology has fascinated humans since the dawn of time. Every culture has had its own theories and beliefs as to how the young of any species are created and born. The earliest formal writings on embryology and mummylogy can be traced in time of Ancient Pharoes, whose civilization is still the source of secrets and  inspiration, Until as recently as the 18th century, the belief that an embryo exists as a pre-formed entity contained inside semen was common.This concept, referred to as “preformation” held that a pre-formed, miniature human or “homonculus” was planted in the female during intercourse, which then grew into a larger being as it developed during pregnancy. The competing theory for the development of embryos, epigenesis, was proposed by Aristotle 2,000 years previously. Epigenesis refers to the unfolding development of an egg or seed through cell division and the formation of organs.

With advancements in microscopy during the 19th century, increasing numbers of biologists could examine the embryo and see it changing as it moved through the different stages of development. Eventually the theory of preformation was abandoned in favor of the epigenesis concept.

Words to Know.

Zygote: A fertilized egg.

Fetus: In the higher vertebrates, the complex stage of development that follows the completion of the embryonic stage until hatching or birth.

Differentiation: The process by which cells mature into specialized cell types, such as blood cells, muscle cells, brain cells, and sex cells.

Ectoderm: The outer layer or cells in the multilayered embryo.

Endoderm: The innermost wall of a multilayered embryo.

Mesoderm: The central layer of cells in an embryo covered by three walls.

Ultrasonography: A process used to obtain "pictures" of the developing embryo using ultrasound.

Embryonic development

The zygote is formed in one of the mother's fallopian tubes, the tubes that connect the ovaries with the uterus. It then travels to the uterus, where it becomes affixed to the uterine lining. Along the way, the zygote divides a number of times. By the time it reaches the uterus, it consists of about 100 cells and is called an embryoblast.

The exact day on which the embryoblast implants on the uterine wall varies, but it is usually about the sixth day after fertilization. By the end of the first week, a protective sac, the amniotic cavity, begins to form around the embryoblast. Changes now begin to take place at a rapid rate.

During week two of embryonic development, embryonic cells have begun the process of differentiation. The identical cells formed by the early divisions of the zygote are beginning to take on the different characteristic of muscle, blood, nerve, bone, and other kinds of cells. The embryo has burrowed deep into the uterine wall and is visible as a bump on the inner uterine surface. This position permits the embryo to receive oxygen and nutrients from the mother's blood and to excrete waste products into her bloodstream.

Miscarriages are not uncommon at this stage of pregnancy. The mother's immune system may react to cells from the embryo that it classifies as "foreign" and will begin to attack those cells. The embryo may die and be expelled.

During week three the embryo grows to a length of about 0.08 inches (2 millimeters) long and has become pear-shaped with a rounded head and a tapered tail end. Three distinct types of cells can be distinguished. Ectoderm cells will form the embryo's skin; mesoderm cells its bones, muscles, and organs; and endoderm cells its digestive tract.

Blood vessels have begun to form and, by day 20, the embryo has developed its own arteries and veins. Cells begin to collect along the embryo's back in a formation known as the neural tube, a structure that will eventually develop into the brain and spinal cord.

During the fourth week, the embryo becomes C-shaped with an enlarged forebrain and a visible tail. Eye stalks and ear pits appear. Upper and lower limb buds are observable. Lung, liver, pancreatic, and gall bladder buds emerge. The umbilical cord and early facial areas also form. By the end of this week, the embryo is comprised of millions of cells and is about 0.12 to 0.16 inches (3 to 4 millimeters) long. To the naked eye, the embryo looks like a small oval.

Extensive neural (nerve) and cardiac (heart) development takes place this week. Early bone formations, that will later be the vertebrae, appear along the neural tube. Nerves, muscle, and connective tissues emerge around the primitive bone formations.

By the end of fifth week, the embryo is almost 0.5 inch (about 7 to 9 millimeters) long and has all of its internal organs. The external ears emerge, and upper limb buds extend to form paddlelike hands. The mouth, stomach, and urinary bladder are present. Nose pits and eye lenses are visible. A few days after upper limb bud extension, the lower limb buds evolve further. Much more brain development occurs at this time, and the head enlarges, causing it to bend forward and appear large compared to the body. The umbilical cord becomes more clearly defined.

During the sixth week, the trunk straightens and the upper limb development continues. The neck, elbows, and wrists form. Mammary and pituitary gland buds appear. Bone, cartilage, and muscles become defined around the spinal cord and in the embryonic chest. Early in this week, tooth buds appear. These buds will become the baby's teeth that are lost in childhood. Rib cells line up horizontally along the trunk sides, and skin layers that will hold sweat glands develop. The regions of the brain that will become the cerebral hemispheres are very prominent at this time. The embryo appears more human by this point. It is about 0.44 to 0.56 inch (11 to 14 millimeters) long, and its heart is beating at the rate of 140 to 150 beats per minute.

During the seventh week, future fingers and thumbs are clearly visible on the hands. The torso lengthens, the tail begins to disappear, and the primitive organs continue to evolve. The heart has become divided into chambers. The cornea of the eye is also present. By the end of this week, the embryo is about 0.8 inch (20 millimeters) long and about the size of a quarter.

During the eighth week, remarkable development occurs. Nerve cells in the brain form at a rate of about 100,000 a minute. The top of the head becomes more rounded and erect. Between day 52 and day 56, the toes become seprarted after being webbed. The fingers are entirely distinct. The eyelids close over the eyes and become fused shut until about the twenty-sixth week. External genital (sex organ) differences begin to develop. All appearances of the tail are gone. By day 56, the embryo is roughly 1 to 1.25 inches (27 to 31 millimeters) long.

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