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An endosperm is formed after the two sperm nuclei inside a pollen grain reach the interior of a female gametophyte or megagametophyte, also called the embryonic sac.One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus).
There are many different surgical specialties, some of which require specific kinds of surgical instruments to perform.. General surgery is a specialty focused on the abdomen; the thyroid gland; diseases involving skin, breasts, and various soft tissues; trauma; peripheral vascular disease; hernias; and endoscopic procedures.
On the other hand, the strict meaning of "tissue culture" refers to the culturing of tissue pieces, i.e. explant culture. Tissue culture is an important tool for the study of the biology of cells from multicellular organisms. It provides an in vitro model of the tissue in a well defined environment which can be easily manipulated and analysed ...
In biology, matrix (pl.: matrices) is the material (or tissue) in between a eukaryotic organism's cells. The structure of connective tissues is an extracellular matrix. Fingernails and toenails grow from matrices. It is found in various connective tissues. It serves as a jelly-like structure instead of cytoplasm in connective tissue.
In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. [1] [2] Tissues occupy a biological organizational level between cells and a complete organ. Accordingly, organs are formed by the functional grouping together of multiple tissues. [3]
Pharmacology – Pharmacology is the branch of medicine and biology concerned with the study of drug action, [50] where a drug can be broadly defined as any human-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the ...
Dense connective tissue also known as fibrous tissue [8] is subdivided into dense regular and dense irregular connective tissue. [9] Dense regular connective tissue, found in structures such as tendons and ligaments , is characterized by collagen fibers arranged in an orderly parallel fashion, giving it tensile strength in one direction.
Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste and carbon dioxide away from the tissues. [ 2 ] Some tissues such as cartilage , epithelium , and the lens and cornea of the eye are not supplied with blood vessels and are termed avascular .