Context: Amino acids are biologically important organic compounds containing amine (-NH) and carboxyl (-COOH) functional groups, along with a side-chain (R group) specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, though other elements are found in the side-chains of certain amino acids. About 500 amino acids are known (though only 20 appear in the genetic code) and can be classified in many ways. They can be classified according to the core structural functional groups' locations as alpha- (-), beta- (-), gamma- (-) or delta- (-) amino acids; other categories relate to polarity, pH level, and side-chain group type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acids comprise the second-largest component (water is the largest) of human muscles, cells and other tissues. Outside proteins, amino acids perform critical roles in processes such as neurotransmitter transport and biosynthesis., Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is inherently tied to embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated over immediate (embryology) and long (evolution) timescales. Human anatomy is one of the basic essential sciences of medicine., Modern humans ("Homo sapiens", primarily ssp. "Homo sapiens sapiens") are the only extant members of Hominina tribe (or human tribe), a branch of the tribe Hominini belonging to the family of great apes. They are characterized by erect posture and bipedal locomotion; manual dexterity and increased tool use, compared to other animals; and a general trend toward larger, more complex brains and societies., In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The hypophysis rests upon the hypophysial fossa of the sphenoid bone in the center of the middle cranial fossa and is surrounded by a small bony cavity (sella turcica) covered by a dural fold (diaphragma sellae). The anterior pituitary (or adenohypophysis) is a lobe of the gland that regulates several physiological processes (including stress, growth, reproduction, and lactation). The intermediate lobe synthesizes and secretes melanocyte-stimulating hormone. The posterior pituitary (or neurohypophysis) is a lobe of the gland that is functionally connected to the hypothalamus by the median eminence via a small tube called the pituitary stalk (also called the infundibular stalk or the infundibulum)., Peptide hormones and protein hormones are hormones whose molecules are peptides or proteins, respectively. The latter have longer amino acid chain lengths than the former. These hormones have an effect on the endocrine system of animals, including humans. Most hormones can be classified as either amino acidbased hormones (amine, peptide, or protein) or steroid hormones. The former are water-soluble and act on the surface of target cells via second messengers; the latter, being lipid-soluble, move through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei. , The sella turcica (Latin for Turkish seat) is a saddle-shaped depression in the body of the sphenoid bone of the human skull and of the skulls of other hominids including chimpanzees, orangutans, and gorillas. It serves as a cephalometric landmark. The seat of the saddle, the deepest part of the sella turcica known as the hypophyseal fossa, holds the pituitary gland (hypophysis)., A mitogen is a chemical substance that encourages a cell to commence cell division, triggering mitosis. A mitogen is usually some form of a protein. Mitogenesis is the induction (triggering) of mitosis, typically via a mitogen. Mitogens trigger signal transduction pathways in which mitogen-activated protein kinase (MAPK) is involved, leading to mitosis., Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 64,000 species described. Vertebrates include the jawless fish and the jawed vertebrates, which include the cartilaginous fish (sharks and rays) and the bony fish. , Growth hormone ( GH ) , also known as somatotropin ( or as human growth hormone ( hGH or HGH ) in its human form ) , is a peptide hormone that stimulates growth , cell reproduction , and cell regeneration in humans and other animals . It is thus important in human development . It is a type of mitogen which is specific only to certain kinds of cells . Growth hormone is a 191 - amino acid , single - chain polypeptide that is synthesized , stored , and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland . GH is a stress hormone that raises the concentration of glucose and free fatty acids . It also stimulates production of IGF - 1 . A recombinant form of hGH called somatropin ( INN ) is used as a prescription drug to treat children 's growth disorders and adult growth hormone deficiency . In the United States , it is only available legally from pharmacies , by prescription from a doctor . In recent years in the United States , some doctors have started to prescribe growth hormone in GH - deficient older patients ( but not on healthy people ) to increase vitality . While legal , the efficacy and safety of this use for HGH has not been tested in a clinical trial . At this time , HGH is still considered a very complex hormone , and many of its functions are still unknown . In its role as an anabolic agent , HGH has been used by competitors in sports since at least 1982 , and has been banned by the IOC and NCAA . Traditional urine analysis does not detect doping with HGH , so the ban was unenforceable until the early 2000s , when blood tests that could distinguish between natural and artificial HGH were starting to be developed . Blood tests conducted by WADA at the 2004 Olympic Games in Athens , Greece targeted primarily HGH . Use of the drug for performance enhancement is not currently approved by the FDA . GH has been studied for use in raising livestock more efficiently in industrial agriculture and several efforts have been made to obtain governmental approval to use GH in livestock production . These uses have been controversial . In the United States , the only FDA - approved use of GH for livestock is the use of a cow - specific form of GH called bovine somatotropin for increasing milk production in dairy cows . Retailers are permitted to label containers of milk as produced with or without bovine somatotropin ., The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head, usually close to the sensory organs for senses such as vision. The brain is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 1533 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells., The median eminence is part of the inferior boundary of the hypothalamus in the human brain. A small swelling on the tuber cinereum posterior to the infundibulum  atop the pituitary stalk  the median eminence lies in the area roughly bounded on its posterolateral region by the cerebral peduncles, and on its anterolateral region by the optic chiasm., Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis), and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes (meiosis). Meiosis results in twelve haploid daughter cells by undergoing one round of DNA replication followed by two divisions: homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in sexually reproducing organisms at some point in their life cycle, and both are believed to be present in the last eukaryotic common ancestor. Prokaryotes also undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication., Subject: growth hormone, Relation: found_in_taxon, Options: (A) homo sapiens (B) human (C) prokaryotes (D) vertebrata
Output: homo sapiens