Search results
Results From The WOW.Com Content Network
In anatomically simple animals, such as cnidarians and flatworms, the fetal development can be quite short, and even microlecithal eggs can undergo direct development. These small eggs can be produced in large numbers. In animals with high egg mortality, microlecithal eggs are the norm, as in bivalves and marine arthropods.
This is an accepted version of this page This is the latest accepted revision, reviewed on 26 August 2024. Union of gametes of opposite sexes during the process of sexual reproduction to form a zygote This article is about fertilisation in animals and plants. For fertilisation in humans specifically, see Human fertilization. For soil improvement, see Fertilizer. "Conceive" redirects here. For ...
Yolk. The yolk of a chicken egg. Diagram of a fish egg; the yolk is the area marked 'C'. Among animals which produce eggs, the yolk (/ ˈjoʊk /; also known as the vitellus) is the nutrient -bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example ...
The syncytiotrophoblast is in direct contact with the maternal blood that reaches the placental surface. It then facilitates the exchange of nutrients, wastes and gases between the maternal and fetal systems. In addition, cytotrophoblasts in the tips of villi can differentiate into another type of trophoblast called the extravillous trophoblast ...
The egg yolk is suspended in the egg white by one or two spiral bands of tissue called the chalazae (from the Greek word χάλαζα, meaning 'hailstone' or 'hard lump'). The shape of a chicken egg resembles a prolate spheroid with one end larger than the other and has cylindrical symmetry along the long axis.
Egg white. A raw egg with the round orange yolk (containing the visible white chalaza) in the center surrounded by the transparent yellow egg white. Egg white is the clear liquid (also called the albumen or the glair / glaire) contained within an egg. In chickens, it is formed from the layers of secretions of the anterior section of the hen's ...
The egg is not retained in the body for most of the period of development of the embryo within the egg, which is the main distinction between oviparity and ovoviviparity. [1] Oviparity occurs in all birds, most reptiles, some fishes, and most arthropods. Among mammals, monotremes (four species of echidna, and the platypus) are uniquely oviparous.
Animal-source foods are a diverse group of foods that are rich in bioavailable nutrients including calcium, iron, zinc, vitamins B12, vitamin D, choline, DHA, and EPA. [11] Animal-source and plant-based foods have complimentary nutrient profiles and balanced diets containing both reduce the risk of nutritional deficiencies. [ 11 ]