In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete — called an ovum ( or egg )— and a male produces the smaller tadpole-like type — called a sperm.

This is an example of anisogamy or heterogamy, the condition wherein females and males produce gametes of different sizes ( this is the case in humans ; the human ovum has approximately 100, 000 times the volume of a single human sperm cell ).

An ovum ( plural ova, from the Latin word ovum meaning egg or egg cell ) is a haploid female reproductive cell or gamete.

The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization.

In lower plants and algae, the ovum is also often called oosphere.

In the viviparous animals ( which include humans and all other placental mammals ), the ovum is fertilized inside the female body and the embryo then develops inside the uterus, receiving nutrition directly from the mother.

The ovum is one of the largest cells in the human body, typically visible to the naked eye without the aid of a microscope or other magnification device.

Ooplasm ( also: oöplasm ) is the yolk of the ovum, a cell substance at its center, which contains its nucleus, named the germinal vesicle, and the nucleolus, called the germinal spot.

The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube.

The embryo of a placental mammal is defined as the organism between the first division of the zygote ( a fertilized ovum ) until it becomes a fetus.

An ovum is fertilized in a fallopian tube through which it travels into the uterus.

When a woman's natural cycle is monitored to collect a naturally selected ovum ( egg ) for fertilisation, it is known as natural cycle IVF.

Some retroviruses are transmitted in the germ line, i. e. their genetic material is integrated into the DNA of either the ovum or sperm.

One chromosome of each pair is contributed by each parent: one by the female parent in her ovum, and one by the male parent in his sperm, which are joined at fertilization.

Sperm can be aspirated from the testicles or the epididymis, and while there is not enough for successful artificial insemination, there is enough to fertilize an ovum by ICSI.

However, it is only their mother that has any effect on the chances of having such twins ; there is no known mechanism for a father to cause the release of more than one ovum.

Although examples of half-identical twins have been found, the exact mechanism of their conception is not well-understood, but could theoretically occur in polar body twinning where sperm cells fertilize both the ovum and the second polar body.

A mother ( or mum / mom ) is a woman who has raised a child, given birth to a child, and / or supplied the ovum that united with a sperm which grew into a child.

A surrogate mother is, commonly, a woman who bears an embryo, that is from another woman's fertilized ovum, to term for a couple biologically unable to have children.

While it was commonly believed at the time that the female reproductive cycle was controlled by substance in the corpus luteum, Allen sought the answer in the follicles surrounding the ovum, leading to his discovery of estrogen, though it was identified six years later by Adolf Butenandt.

Eliza, who was delivered at Giuleşti Maternity Hospital in Bucharest, is Iliescu's biological ( but not genetic ) child, since she gestated in Iliescu's womb but was conceived by an ovum and sperm donated anonymously.

The Way teaches that at his birth, God created the sperm to fertilize Mary's ovum, and is the literal father of Jesus.

A male cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually.

Officially, his parents were Vyacheslav Tsyurupa and Stella Abalkina, who both participated in the " Yormala Project " ( submersion into the black hole EN-200056 ) in 2135, which means that Lev was a post mortem child, a child who, at the prior request of his parents, was grown " in vitro " from his mother's fertilized ovum.

However, if an ovum is released after the female was already impregnated when previously ovulating, there is a chance of a second pregnancy — albeit at a different stage of development.

The first of these markers to be discovered, human chorionic gonadotropin ( hCG ), was discovered in 1930 to be produced by the trophoblast cells of the fertilised ovum ( blastocyst ).

The first way is called preformistic and involves that the cells destined to become germ cells inherit the specific germ cell determinants present in the germ plasm ( specific area of the cytoplasm ) of the egg ( ovum ).

The first, " Biological Data ", describes the relationship of ovum to sperm in all kinds of creatures ( fish, insects, mammals ).

Alternatively males may evolve faster sperm to enable their sperm to reach and fertilize the ovum first.

Iliescu was first given hormone treatment to reverse menopause in 1995 and in vitro fertilisation ( three zygotes with sperm and ovum from two anonymous donors ) in 2004, becoming pregnant with triplets.

On the night of the first meeting, Huxley jokingly proposed that the club be named " Blastodermic Club ", in reference to blastoderm, a layer of cells in the ovum of birds that acts as the center of development for the entire bird.

The terminology stems from the Latin lac meaning " milk " ( as in ' lactation '), ovum meaning " egg ", and the English term vegetarian ( see Etymology of vegetarianism for the etymology of " vegetarian "), so as giving the definition of a vegetarian diet containing milk and eggs.

The process involves monitoring a woman's ovulatory process, removing ovum or ova ( egg or eggs ) from the woman's ovaries and letting sperm fertilize them in a fluid medium in a laboratory.

During its passage down the intestine, the ovum develops and thus the eggs passed in feces have a segmented ovum, usually with 4 to 8 blastomeres.

The Ziehl – Neelsen stain can also hinder diagnosis in the case of paragonimiasis because the eggs in a ovum and parasite sputum sample ( OnP ) can be dissolved by the stain, and is often used in this clinical setting because signs and symptoms of paragonimiasis closely resemble those of TB.

* Transvaginal ovum retrieval ( OCR ) is the process whereby a small needle is inserted through the back of the vagina and guided via ultrasound into the ovarian follicles to collect the fluid that contains the eggs.

* In gamete intrafallopian transfer ( GIFT ) a mixture of sperm and eggs is placed directly into a woman's fallopian tubes using laparoscopy following a transvaginal ovum retrieval.

The eggs will be harvested approximately 36 hours later, usually by transvaginal ovum retrieval.

The active enzyme functions in the lysis of the zona pellucida, thus facilitating penetration of the sperm through the innermost glycoprotein layers of the ovum.

Molecules of various proteins are present in the outer layer of the follicles, homologous to the zona pellucida of the ovum.

When a capacitated sperm reaches the ovum, it is able to penetrate this layer with the assistance of hyaluronidase enzymes present on the surface of the sperm.