Reproduction Test - 3

Oral contraceptives contain synthetic hormones. They contain both estrogen and progestin and mainly work by preventing ovulation and by making the lining of the uterus thinner. Hormonal contraceptives are best avoided in case of heart patients.

Spontaneous miscarriage is the spontaneous end of a pregnancy at a stage where the fetus is incapable of surviving independently. It can happen before the 20^th week of pregnancy.

This period of development starts during the ninth week and lasts until birth. The early body systems and structures formed in the embryonic stage continue to develop. In this stage the neural tube develops into the brain and spinal cord. In this stage all the organs of the fetus predicate their specialised functions.

Cephalocaudal development in an infant characterises development as starting with the head and brain areas and moving downwards. He gains control of his head movement, then neck, shoulders, back, hips, legs and feet.

An embryo is a multicellular diploid structure in its earliest stage of development, from the time of the first cell division until birth. The internal cluster of cells forming the blastocyst later forms an embryo.

It is the lining of the inside of the uterus. During the follicular phase of the menstrual cycle, the endometrium thickens in preparation to accept an embryo should conception occur. In a female, during the pregnancy, the blastocyst digests its way through the endometrium.

A spermatozoon is a motile sperm cell or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing a Y chromosome will lead to a male (XY) offspring, while one bearing an X chromosome will lead to a female (XX) offspring.

The tunica vaginalis is the serous covering of the testes.

On the superior end of the labia minora is a small mass of erectile tissue known as the clitoris that contains many nerve endings for sensing sexual pleasure.

The secretion of this gland is more serous in dogs and more mucous in bulls. It serves to promote the movement of spermatozoa in all the mammals and to form a vaginal plug.

Quickening is the early signs of the foetus movements during pregnancy.

It is the prenatal stage that begins at conception and lasts through the second week. In this stage zygote begins to have cell reproduction. Consequently, the zygote becomes a multi celled ball that attaches itself to the wall of the uterus of the mother.

The process of organogenesis takes place in the embryonic period. The formation of the nasal structure is a part of organogenesis and thus occurs in embryonic period.

An intrauterine device is a small contraceptive device, often 'T'-shaped and containing either copper or levonorgestrel, which is inserted into the uterus.

In 1909, Richard Richter developed the first intrauterine device made from silkworm gut.