organ

Unsolved problems in biology

...he proteome proteins expressed by a cell or organ at a particular time and under specific conditions? What is the complete function of the regulator genes ? The building block of life may be a precursor to a generation of electronic devices and computers , but what are the electronic properties ...

T cell

...se . The abbreviation "T" stands for thymus , the organ in which their final stage of development occurs. There are many types of T cells: Cytotoxic T cells (CD8 + ) destroy infected cells. These cells function as 'killer' or cytotoxic cells because they are able to destroy target cells which expre...

Stroma

...ve framework of a biological cell , tissue , or organ . 2) The fluid filled area of a chloroplast outside of the thylakoid membranes wherein the light-independent reactions ( Calvin Cycle and Carbon fixation ) of photosynthesis take place....

Skin

In zootomy and dermatology , skin is an organ of the integumentary system ; which is composed ...the skin. The skin is often known as "the largest organ in the human body": this applies to exterior surface, as it covers the body, appearing to have the...

Signal transduction

...lay a key role in the regulation of metabolism , organ function, developmental processes and cell differentiation . The key value for the signal strength is the hormone concentration, which is regulated by : Biosynthesis and secretion of hormones in the endocrine tissue . As an example, the...

Rudolf Steiner

...n being, and that the human mind is ultimately the organ of the world's own process of self-revelation. In this view, the essential reality of nature is not separate, self-contained, and complete in itself, so that the human mind can examine it 'objectively' and register it from without. Rather, nature's...

Olfaction

...many vertebrates have an auxiliary olfactory sense organ called vomeronasal organ , located in the vomer, between the nose and the mouth. Snakes use it to smell prey, sticking their ...

Lung

...dition of Gray's Anatomy ) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates . Its function is to exchange oxygen from air with carbon dioxide from blood . The process in which this happens is called " externa...

Liver

The liver is an organ in vertebrates including humans. It plays a maj...dish-brown "wedge-shaped" organ. It is the largest organ in the abdomen and sits immediately under the diaphragm on the right side of the upper abdomen. ...

Leaf

... In botany , a leaf is an above-ground plant organ specialized for photosynthesis . For this purpose, a leaf is typically flat and thin, to expose the chloroplast containing cells ( chlorenchyma tissue) to light over a broad area, and to allow light to penetrate fully into the tissues. Leaves ...

Jean-Baptiste Lamarck

...lopment, a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that ...as been so used; while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, unt...

Insulin

...lantation of an entire pancreas (as an individual organ ) is technically difficult, and is not common. Generally, it is performed in conjunction with liver or kidney transplant surgery. However, transplantation of only pancreatic beta cells is a possibility. It has been highly experimental (for which ...

Immune system

...multicellular organisms , the immune system is an organ system that acts as a defense against foreign pathogens (such as viruses , bacteria , parasites ), some poisons , as well as cancer . Components of the immune system also function in the return of extracellular fluid to the blood. Bacteria an...

Hormone

...nimals, but hormones are produced by nearly every organ system and tissue type in a human or animal body....e action) in the same tissue or cells of a distant organ of the body. The function of hormones is to serve as a signal to the target cells; the action of ho...

Eye

...he same anatomy as a human eye. An eye is an organ that detects light . Different kinds of light-sensitive organs are found in a variety of creatures. The simplest eyes do nothing but detect whether the surroundings are light or dark. More complex eyes are used to provide the sense of vision ...

Evolution

...mple of such homologous structures . A vestigial organ or structure may exist with little or no purpose in one organism, though they have a clear purpose in others. The human wisdom teeth and appendix are common examples. Genetic sequence evidence Comparison of the genetic sequence of organisms ...

Edward's syndrome

...rd's syndrome also have heart defects , and other organ malformations such that most systems of the body are affected. Edward's Syndrome also results in significant developmental delays. For this reason a full-term Edward's syndrome baby may well exhibit the breathing and feeding difficulties of a pre...

Cold-blooded

...animals do not easily support complex, high-energy organ systems such as brains or wings. Some of the most... adaptations known involve poikilotherms with such organ systems. One example is the swimming muscles of Tuna , which are warmed by a heat exchanger .In g...

Ebola

...arrhea , oropharyngeal lesions , conjunctivitis , organ damage (notably the kidney and liver ) by co-localized necrosis , proteinuria (the presence of proteins in urine), and bleeding both internal and external, commonly through the gastrointestinal tract . Death or recovery to convalescence occu...

Drosophila

...nal tubes, the tracheae . This ectoderm -derived organ forms a highly branched tubular network which provides the organs with oxygen. Lifecycle and ecology Habitat Drosophila is found primarily in tropical regions. "The fruit fly, is a cosmopolitan holometabolous insect, that is found in all war...

Diabetes mellitus

...e disorder are chronic problems affecting multiple organ systems which will eventually arise in patients with poor glycemic control. Many of these arise from damage to the blood vessels. These illnesses can be divided into those arising from large blood vessel diseases, macroangiopathy , and those arising ...

Computed axial tomography

...on . CT is also the first line for detecting solid organ injury after trauma. Oral and/or rectal contrast is usually administered (more often iodinated contrast than barium due to the tendency of barium to cause imaging artifacts that limit evaluation of abdominal structures). CT has limited applicati...

Anabolism

...ng metabolic processes, whether at the cellular , organ or organism level is as anabolic or catabolic . Anabolic processes tend toward "building up" organs and tissues. These processes produce growth and differentiation of cells and increase in body size, a process that involves synthesis of complex m...

Cancer

... excised. The nature of the biopsy depends on the organ that is sampled. Many biopsies (such as those of the skin, breast or liver) can happen on an outpatient basis. Biopsies of other organs are performed under anesthesia and require surgery . Screening Cancer screening is the widespread uses of t...

Brain

...organs in the human body. Loss of function in this organ fufills some definitions of death . Injuries to the brain tend to affect large areas of the brain, sometimes causing major deficits in intelligence , memory and control of the body. Head trauma, caused by automobile accidents or other blows to the ...

Biomechanics

...acroscopic level, all the way up to the tissue and organ level. Some simple applications of Newtonian Mechanics can supply correct approximations on each level, but precise details demand the use of Continuum Mechanics . Some simple examples of biomechanics research include the investigation of the fo...

Biology

...ly from cell biology in describing the function of organ systems. Structure of life Schematic...an important part of physiology and considers how organ systems in animals such as the nervous , immune , endocrine , respiratory and circulatory sy...

B cell

..."B" stands for the bursa of Fabricius which is an organ unique to birds, where B cells mature. It does not (as commonly assumed among immunologists researching mammals) stand for bone marrow , where B cells are produced in all other vertebrates. The human body makes hundreds of different types of B ...

Apoptosis

...the adult organism, the number of cells within an organ or tissue has to be constant within a certain range. Blood and skin cells, for instance, are constantly renewed by their respective progenitor cells; but proliferation has to be compensated by cell death. This balancing process is part of the home...

Anatomy

...ntains first a description of the structures of an organ or system (such as nerves , arteries , heart , and so forth), as it is found in humans; this is followed by an account of the development (embryology) and comparative anatomy (morphology), as far as vertebrate animals are concerned; but only tho...

Anabolism

...ng metabolic processes, whether at the cellular , organ or organism level is as anabolic or catabolic . Anabolic processes tend toward "building up" organs and tissues. These processes produce growth and differentiation of cells and increase in body size, a process that involves synthesis of complex m...