placenta definition

Placenta - Placenta is the mechanical and physiological connection between foetal and maternal tissues for the nutrition, respiration and excretion of the foetus. The surface of the blastocyst gives rise to finger - like outgrowths called chorionic villi which penetrate into dep..

Placenta is the mechanical and physiological connection between foetal and maternal tissues for the nutrition, respiration and excretion of the foetu..

In this type, the ovary is monocarpellary, monolocular and the placenta is on the ventral suture. The ovules are attached to the placenta which is on the margin. e.g. Beans, Pea, et..

The arrangement of ovules on the placenta inside the ovary is called placentation. There are several types of palcentatio..

It stores the nitrogenous wastes of the embryo, so it acts as an extra embryonic kidney. In eutherian mammals it takes part in placenta formati..

As the cells of the morula continue to divide, a cavity appears inside the morula. It forms the blastocoel. It separates a surface layer of blastomeres from an inner cell mass. The blastomeres on the surface of the embryo become flattened and form the trophoectoderm or trophoblast. This layer on fu..

Progesterone is secreted by the corpus luteum which is a yellowish body formed in the empty graafian follicle after the release of the ovum. Ovulation, formation of corpus luteum and secretion of progesterone are stimulated by the luteinising hormone from the anterior pitutary. The main functions ..

The process of childbirth is known as parturition. The steps involved in parturition are: i) Onset of childbirth is followed by the opening of the cervix. ii) Powerful contractions ruptures the amnion and the amniotic fluid flows out through the vagina. iii) This is followed by the baby coming out ..

Fertilisation can be defined as the fusion of the sperm nucleus with the egg nucleus to form a diploid cell known as zygote. The fertilisation is internal in the human reproductive system. It is achieved by the insertion of the male organ, penis into the vagina of the female. The sperms ..

Each ovule is attached to the placenta by a stalk called funicle. The body of the ovule fuses with the funicle to form the hilum in the seed. The ovule consists of one or two integuments, accordingly the ovules are called unitegmic or bitegmic respectively. The integuments leave a small ..