The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organs and then organ systems. They ensure homeostasis and the viability of the human body.
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system.
The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.
An artificial organ is a human made organ device or tissue that is implanted or integrated into a human — interfacing with living tissue — to replace a natural organ, to duplicate or augment a specific function or functions so the patient may return to a normal life as soon as possible. The replaced function does not have to be related to life support, but it often is. For example, replacement bones and joints, such as those found in hip replacements, could also be considered artificial organs.
The stromal cell-derived factor 1 (SDF-1), also known as C-X-C motif chemokine 12 (CXCL12), is a chemokine protein that in humans is encoded by the CXCL12 gene on chromosome 10. It is ubiquitously expressed in many tissues and cell types. Stromal cell-derived factors 1-alpha and 1-beta are small cytokines that belong to the chemokine family, members of which activate leukocytes and are often induced by proinflammatory stimuli such as lipopolysaccharide, TNF, or IL1. The chemokines are characterized by the presence of 4 conserved cysteines that form 2 disulfide bonds. They can be classified into 2 subfamilies. In the CC subfamily, the cysteine residues are adjacent to each other. In the CXC subfamily, they are separated by an intervening amino acid. The SDF1 proteins belong to the latter group. CXCL12 signaling has been observed in several cancers. The CXCL12 gene also contains one of 27 SNPs associated with increased risk of coronary artery disease.
Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation form the internal organs of the organism.
Netrins are a class of proteins involved in axon guidance. They are named after the Sanskrit word "netr", which means "one who guides". Netrins are genetically conserved across nematode worms, fruit flies, frogs, mice, and humans. Structurally, netrin resembles the extracellular matrix protein laminin.
The interstitium is a contiguous fluid-filled space existing between a structural barrier, such as a cell membrane or the skin, and internal structures, such as organs, including muscles and the circulatory system. The fluid in this space is called interstitial fluid, comprises water and solutes, and drains into the lymph system. The interstitial compartment is composed of connective and supporting tissues within the body – called the extracellular matrix – that are situated outside the blood and lymphatic vessels and the parenchyma of organs. The role of the interstitium in solute concentration, protein transport and hydrostatic pressure impacts human pathology and physiological responses such as edema, inflammation and shock.
Corpora arenacea are calcified structures in the pineal gland and other areas of the brain such as the choroid plexus. Older organisms have numerous corpora arenacea, whose function, if any, is unknown. Concentrations of "brain sand" increase with age, so the pineal gland becomes increasingly visible on X-rays over time, usually by the third or fourth decade. They are sometimes used as anatomical landmarks in radiological examinations.
Transcytosis is a type of transcellular transport in which various macromolecules are transported across the interior of a cell. Macromolecules are captured in vesicles on one side of the cell, drawn across the cell, and ejected on the other side. Examples of macromolecules transported include IgA, transferrin, and insulin. While transcytosis is most commonly observed in epithelial cells, the process is also present elsewhere. Blood capillaries are a well-known site for transcytosis, though it occurs in other cells, including neurons, osteoclasts and M cells of the intestine.
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone, neurotransmitter and neuromodulator. The name "noradrenaline" is more commonly used in the United Kingdom, whereas "norepinephrine" is usually preferred in the United States. "Norepinephrine" is also the international nonproprietary name given to the drug. Regardless of which name is used for the substance itself, parts of the body that produce or are affected by it are referred to as noradrenergic.
In medicine, proteinopathy, or proteopathy, protein conformational disorder, or protein misfolding disease, is a class of diseases in which certain proteins become structurally abnormal, and thereby disrupt the function of cells, tissues and organs of the body. Often the proteins fail to fold into their normal configuration; in this misfolded state, the proteins can become toxic in some way or they can lose their normal function. The proteinopathies include such diseases as Creutzfeldt–Jakob disease and other prion diseases, Alzheimer's disease, Parkinson's disease, amyloidosis, multiple system atrophy, and a wide range of other disorders. The term proteopathy was first proposed in 2000 by Lary Walker and Harry LeVine.
Histamine N-methyltransferase (HNMT) is a protein encoded by the HNMT gene in humans. It belongs to the methyltransferases superfamily of enzymes and plays a role in the inactivation of histamine, a biomolecule that is involved in various physiological processes. Methyltransferases are present in every life form including archaeans, with 230 families of methyltransferases found across species.
An aging-associated disease is a disease that is most often seen with increasing frequency with increasing senescence. They are essentially complications of senescence, distinguished from the aging process itself because all adult animals age but not all adult animals experience all age-associated diseases. The term does not refer to age-specific diseases, such as the childhood diseases chicken pox and measles, only diseases of the elderly. They are also not accelerated aging diseases, all of which are genetic disorders.
Estrogen receptor beta (ERβ) also known as NR3A2 is one of two main types of estrogen receptor—a nuclear receptor which is activated by the sex hormone estrogen. In humans ERβ is encoded by the ESR2 gene.
Multidrug resistance-associated protein 1 (MRP1) is a protein that in humans is encoded by the ABCC1 gene.
G-protein coupled receptor 3 is a protein that in humans is encoded by the GPR3 gene. The protein encoded by this gene is a member of the G protein-coupled receptor family of transmembrane receptors and is involved in signal transduction.
An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved.
An organ-on-a-chip (OOC) is a multi-channel 3-D microfluidic cell culture, integrated circuit (chip) that simulates the activities, mechanics and physiological response of an entire organ or an organ system. It constitutes the subject matter of significant biomedical engineering research, more precisely in bio-MEMS. The convergence of labs-on-chips (LOCs) and cell biology has permitted the study of human physiology in an organ-specific context. By acting as a more sophisticated in vitro approximation of complex tissues than standard cell culture, they provide the potential as an alternative to animal models for drug development and toxin testing.
3DISCO is a histological method that make biological samples more transparent by using series of organic solvents for matching the refractive index (RI) of the tissues with that of the surrounding medium. Structures in transparent tissues can be examined by fluorescence microscopy, without the need for time-consuming physical sectioning and subsequent reconstruction in silico.
Natural luminescence of corpora amylacea in the lumen of the prostate in ultraviolet light
Histology of a multilayered corpus amylaceous of the prostate.
