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Jagged (ligand)
Jagged1 (JAG1) is one of five cell surface proteins (ligands) that interact with four receptors in the mammalian Notch signaling pathway. The Notch signaling pathway is a highly conserved pathway that functions to establish and regulate cell fate decisions in many organ systems. Once the JAG1-NOTCH (receptor-ligand) interactions take place, a cascade of proteolytic cleavages is triggered resulting in activation of the transcription for downstream target genes. Located on human chromosome 20, the ''JAG1'' gene is expressed in multiple organ systems in the body and causes the autosomal dominant disorder Alagille syndrome (ALGS) resulting from loss of function mutations within the gene. ''JAG1'' has also been designated as CD339 (cluster of differentiation 339). Structure and function JAG1 was first identified as a ligand that was able to activate notch receptors when the rat gene ''Jagged'' encoding a protein homolog was cloned in 1995. The structure of the JAG1 protein includes a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand (biochemistry)
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from Latin ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein. The binding typically results in a change of conformational isomerism (conformation) of the target protein. In DNA-ligand binding studies, the ligand can be a small molecule, ion, or protein which binds to the DNA double helix. The relationship between ligand and binding partner is a function of charge, hydrophobicity, and molecular structure. Binding occurs by intermolecular forces, such as ionic bonds, hydrogen bonds and Van der Waals forces. The association or docking is actually reversible through dissociation. Measurably irreversible covalent bonding between a ligand and target molecule is atypical in biological systems. In contrast to the definition o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Nucleus
The cell nucleus (; : nuclei) is a membrane-bound organelle found in eukaryote, eukaryotic cell (biology), cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have #Anucleated_cells, no nuclei, and a few others including osteoclasts have Multinucleate, many. The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and isolates its contents from the cellular cytoplasm; and the nuclear matrix, a network within the nucleus that adds mechanical support. The cell nucleus contains nearly all of the cell's genome. Nuclear DNA is often organized into multiple chromosomes – long strands of DNA dotted with various proteins, such as histones, that protect and organize the DNA. The genes within these chromosomes are Nuclear organization, structured in such a way to promote cell function. The nucleus maintains the integrity of genes and controls the activities of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metanephros
Kidney development, or nephrogenesis, describes the embryologic origins of the kidney, a major organ in the urinary system. This article covers a 3 part developmental process that is observed in most reptiles, birds and mammals, including humans. Nephrogenesis is often considered in the broader context of the development of the urinary and reproductive organs. Phases The development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the archinephros, pronephros, mesonephros, and metanephros. The pronephros is the most immature form of kidney, while the metanephros is most developed. The metanephros persists as the definitive adult kidney. Archinephros The archinephros is considered as hypothetical or primitive kidney. Pronephros The pronephros develops in the cervical region of the embryo. During approximately day 22 of human gestation, the paired pronephri appears towards the cranial end of the intermediat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Artery
A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and the smallest ones are the arterioles, which lead to the capillaries that surround the pulmonary alveoli. Structure The pulmonary arteries are blood vessels that carry systemic venous blood from the right ventricle of the heart to the microcirculation of the lungs. Unlike in other organs where arteries supply oxygenated blood, the blood carried by the pulmonary arteries is deoxygenated, as it is venous blood returning to the heart. The main pulmonary arteries emerge from the right side of the heart and then split into smaller arteries that progressively divide and become arterioles, eventually narrowing into the capillary microcirculation of the lungs where gas exchange occurs. Pulmonary trunk In order of blood flow, the pulmonary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucocytes
White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are generally larger than red blood cells. They include three main subtypes: granulocytes, lymphocytes and monocytes. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system. All white blood cells have nuclei, which distinguishes them from the other blood cells, the anucleated red blood cells (RBCs) and platelets. The different white blood cells are usually classified by cell lineage ( myeloid cells or lymphoid cells). White blood cells are part of the body's immune system. They help the body fight infection and other diseases. Types of white blood cells are granulocytes (neutrophils, eosinophils, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testis
A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, primarily testosterone. The release of testosterone is regulated by luteinizing hormone (LH) from the anterior pituitary gland. Sperm production is controlled by follicle-stimulating hormone (FSH) from the anterior pituitary gland and by testosterone produced within the gonads. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and compari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymus
The thymus (: thymuses or thymi) is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. The thymus is located in the upper front part of the chest, in the anterior superior mediastinum, behind the sternum, and in front of the heart. It is made up of two lobes, each consisting of a central medulla and an outer cortex, surrounded by a capsule. The thymus is made up of immature T cells called thymocytes, as well as lining cells called epithelial cells which help the thymocytes develop. T cells that successfully develop react appropriately with Major histocompatibility complex, MHC immune receptors of the body (called ''positive selection'') and not against proteins of the body (called ''negative selection''). The thymus is the largest and most active during the neonatal and pre-adolescent periods. By the early teens, the Thymic involuti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kidney
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal artery, renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the urinary bladder, bladder. The kidney participates in the control of the volume of various body fluids, fluid osmolality, Acid-base homeostasis, acid-base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus (kidney), glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the primary muscle that drives breathing is the Thoracic diaphragm, diaphragm. The lungs also provide airflow that makes Animal communication#Auditory, vocalisation including speech possible. Humans have two lungs, a ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate
The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemically, and physiologically. Anatomically, the prostate is found below the bladder, with the urethra passing through it. It is described in gross anatomy as consisting of lobes and in microanatomy by zone. It is surrounded by an elastic, fibromuscular capsule and contains glandular tissue, as well as connective tissue. The prostate produces and contains fluid that forms part of semen, the substance emitted during ejaculation as part of the male human sexual response cycle, sexual response. This prostatic fluid is slightly Alkalinity, alkaline, milky or white in appearance. The alkalinity of semen helps neutralize the acidity of the vagina, vaginal tract, prolonging the lifespan of sperm. The prostatic fluid is expelled in the first part of ej ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placenta
The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal physiology during pregnancy. The placenta connects to the fetus via the umbilical cord, and on the opposite aspect to the maternal uterus in a species-dependent manner. In humans, a thin layer of maternal decidual ( endometrial) tissue comes away with the placenta when it is expelled from the uterus following birth (sometimes incorrectly referred to as the 'maternal part' of the placenta). Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development. Mammalian placentas probably first evolved abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart
The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the thorax, chest, called the mediastinum. In humans, the heart is divided into four chambers: upper left and right Atrium (heart), atria and lower left and right Ventricle (heart), ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent cardiac regurgitation, backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
