Nurse cell
Encyclopedia
Human physiology
Nurse cells are specialized macrophageMacrophage
Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...
s residing in the bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
that assist in the development of red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
s. They absorb the nuclei of immature red blood cells and may provide growth factor
Growth factor
A growth factor is a naturally occurring substance capable of stimulating cellular growth, proliferation and cellular differentiation. Usually it is a protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes....
s to help the red blood cells mature. In the bone marrow, immature red blood cells (erythroblasts) can be seen grouped in a cluster around a nurse cell.
Nurse Cell appears also to describe a type of specialized epithelial cell found in the cortex of the Thymus. These cells produce Thymic hormones which cause T Lymphocytes to mature and differentiate.
Microbiology
Nurse cell is a term used to describe an infected cell in the disease trichinosisTrichinosis
Trichinosis, also called trichinellosis, or trichiniasis, is a parasitic disease caused by eating raw or undercooked pork or wild game infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm. There are eight Trichinella species; five are...
discovered by Dickson Despommier
Dickson Despommier
Dickson D. Despommier is a microbiologist, ecologist and Professor of Public Health in Environmental Health Sciences at Columbia University. He conducts research on intracellular parasitism and teaches courses on Parasitic Diseases, Medical Ecology and Ecology. In recent years, Despommier has...
. A trichinella larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
enters a cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
and develops there, probably as a way of concealing itself from the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
. The parasite has evolved a way of stimulating blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
development around the cell, in order to receive the nutrients it needs. In trichinosis, nurse cells are invariably skeletal muscle
Skeletal muscle
Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...
cells; these are the only type of cell that can support the parasite.
Mycology
In mycology, nurse cell is used to refer to hyphae that supply food material to sporesBasidiospore
A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...
that have detached from the basidia; used especially in reference to taxa from the family Sclerodermataceae
Sclerodermataceae
The Sclerodermataceae are a family of fungi in the order Boletales, containing several genera of unusual fungi that little resemble boletes. Taxa, which include species commonly known as the ‘hard-skinned puffballs’, ‘earthballs’, or 'earthstars', are widespread in both temperate and tropical regions...
.
Cell biology
In respect to invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s, nurse cells are polytenic germline cells that contribute to the development of the oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...
, producing multiple nuclei
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
. For example, in fruit flies (Drosophila
Drosophila
Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...
), about 250-500 nuclei, all 15 of them in all oocytes creating 5,000 nuclei in total. They dump their cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
containing the nuclei into the oocyte via ring channels.