Auto news on Youtube Sep 9 2017

did you know you were once a stem-cell? believe it or not, on the day one the

embryo created you looked like a cell in this picture and you became an

eight-cell embryo on day three. What was your first stem-cell? How human

formed from just a single stem cell to a baby? molecular doctor will uncover the

mysteries of biological world, stay tuned!

A human body comprises more than 200 types of cells the largest cell in the

human body is the female egg also known as ovum, while the smallest cell is the

sperm. The ovaries produce the female egg cells, normally each woman has two

ovaries.

the ovaries a pair of tiny glands in the

female pelvic cavity are the female reproductive organs that house the

eggs, and are responsible for the production of sex hormones, progesterone

and estrogen. A human egg cell is immobile, the eggs love to stay at their

sweet home. The ovaries produce and release eggs.

typically only one ripe egg is released per menstrual cycle

Every 28 days or so one mature egg is released from the ovary, this is called

ovulation. Following ovulation the finger-like end of the Fallopian tube

are responsible for egg pick up and movement into the tube where the egg can

live for about 24 hours. Testis, an organ that produces sperm and

releases important sexual hormone of males, androgen particularly testosterone.

A pair of glands that produce the male reproductive cells, so the testes are

known as 'Sperm Factory'. the ultimate goal of sperm is to

fertilize the egg. To succeed in their mission sperm has to be good at two

things: swimming and drilling. Normal sperm motility plays a big role in men's

reproductive health.An egg lives about 24 hours after leaving the ovary, sperm

can fertilize the ready egg in the fallopian tube during a 6 to 12 hour

period that is the magic moment that sperm meeting with the egg. The average

of ejaculate contains 200 million sperm, it takes only one sperm to

fertilize an egg, therefore this is the toughest competition in the world.

200 million sperms start a dangerous journey. How fast do sperm swim? The

answer is about 5 millimeters per minute. How do they find the egg? Sperm

recognizes egg by two means, one is a thermal gradient; the second is that

egg oozes out various attractive molecules.

Fertilization occurs when the nucleus of both a sperm and an egg fused to form a diploid cell known as

a zygote, the first stem cell in human body.

All cells in human body are diploid except the germ cells, eggs and sperm. They have only

half the number of chromosomes(23 chromosomes). When egg and sperm fuse into

one, a new cell with 46 chromosomes containing both parents genetic material.

in the nucleus of each human cell the DNA molecule is packaged into

thread-like structures called chromosomes. The DNA molecule contains

part or all of the genetic material, genome of a person. A human cell contains

22 pairs of autosomes and one pair of sex chromosomes.

Females have two copies of the X chromosome, while males have One X and

one Y chromosome. Who determines the gender of the child? sperm or egg?

Scientists have found that some sperm carries the X chromosome and some sperm

carry the Y chromosome, and an egg will always have an X chromosome, therefore

the answer is the sperm determines the human baby's gender.

If the sperm carrying an X chromosome fertilizes the egg, the baby will be a

girl, if the sperm carrying a Y chromosome fertilizes the egg, the baby

is a boy. The one cell embryo undergoes a series of cleavage divisions progressing

through two cell four -cell, eight - cell, sixteen -cell (the marula )stages, usually

reach blastocyst stage by day five after fertilization. The fertilized egg then

undergoes several divisions to form a multicelled blastocyst, it moves into the

uterus within a period of five to seven days, and is then termed as an embryo.

When the embryo implants in the uterus it secretes a hormone called human

chorionic gonadotropin HCG which helps maintain the pregnancy, this is the

hormone analyzed in the blood or urine to detect or confirm the pregnancy.

A blastocyst is an embryo which has developed to the point of having two different cell components

and a fluid cavity, usually reach blastocyst stage by day five after

fertilization. Embryonic stem cells are the cells within the protective layer of

the blastocyst known as inner cell mass.

Embryonic stem cells have the ability to self-renewal to generate duplicate

multipotent copies of themselves. The embryo the stem cells are capable of

becoming all of the various cell types of the human body, such as muscle cells

nerve cells and many other cell types. It is hard to believe, just 10 days after

implantation is complete, the embryos heart begins to beat!

Once implantation is complete the embryo continues to grow inside the wall of the

uterus, the placenta which will nourish the baby also starts to form.

On an ultrasound scan of ten weeks the fetus can move and jump inside the womb. This is an amazing story of egg and sperm during human development.

A human egg is remarkably big can actually be seen with the naked eye and

16 times bigger than a sperm. The egg has a short life after released from the

ovary it lives about 24 hours if the egg is not fertilized by a sperm. The fusion

of sperm egg produces the first stem cell, zygote in human body.

Hi, I am a zygote, thanks for watching.

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