Cells, Organs & Tissues, ABD-BOY
Even if you feel you have nothing in common with a stinkbug or a ficus, you're guaranteed to share one crucial aspect of life with these beings: you are all made up of cells, the fundamental molecules of life, of which all living things are composed. As an individual unit, the cell is capable of metabolizing its own nutrients, synthesizing many types of molecules, providing its own energy, and replicating itself. In a multicellular organism, cooperative assemblies of similar cells form tissues, and a cooperation between tissues in turn forms organs, which carry out the functions necessary to sustain the life of an organism.
Cells, Organs & Tissues Encyclopedia Articles By Title
abdominal muscle, any of the muscles of the anterolateral walls of the abdominal cavity, composed of three flat......
abductor muscle, any of the muscles that cause movement of a limb away from the midplane of the body or away from......
John Jacob Abel was an American pharmacologist and physiological chemist who made important contributions to a......
ABO blood group system, the classification of human blood based on the inherited properties of red blood cells......
action potential, the brief (about one-thousandth of a second) reversal of electric polarization of the membrane......
adductor muscle, any of the muscles that draw a part of the body toward its median line or toward the axis of an......
adipose cell, connective-tissue cell specialized to synthesize and contain large globules of fat. There are two......
adipose tissue, connective tissue consisting mainly of fat cells (adipose cells, or adipocytes), specialized to......
adrenal gland, either of two small triangular endocrine glands one of which is located above each kidney. In humans......
adrenergic nerve fibre, nerve fibre that releases the neurotransmitter norepinephrine (also known as noradrenaline)......
adventitious root, root that arises from any point other than the radicle (embryonic root) or the root axis of......
aerobe, an organism able to live and reproduce only in the presence of free oxygen (e.g., certain bacteria and......
agar, gelatin-like product made primarily from the red algae Gelidium and Gracilaria (division Rhodophyta). Best......
agglutinin, substance that causes particles to congeal in a group or mass, particularly a typical antibody that......
air sac, any of the air-filled extensions of the breathing apparatus of many animals. Air sacs are found as tiny......
Bernard Siegfried Albinus was a German anatomist who was the first to show the connection of the vascular systems......
Alcmaeon was a Greek philosopher and physiologist of the academy at Croton (now Crotone, southern Italy). He was......
all-or-none law, a physiological principle that relates response to stimulus in excitable tissues. It was first......
alveolar ridge, in anatomy, the raised thickened border extending from the maxilla (the upper jaw) and the mandible......
ambidexterity, the ability to use both the right and the left hand with equal ease. Handedness is the most visible......
amygdala, region of the brain primarily associated with emotional processes. The name amygdala is derived from......
anal canal, the terminal portion of the digestive tract, distinguished from the rectum because of the transition......
anaphase, in mitosis and meiosis, the stage of cell division in which separated chromatids (or homologous [like]......
anatomy, a field in the biological sciences concerned with the identification and description of the body structures......
androgen, any of a group of hormones that primarily influence the growth and development of the male reproductive......
ankle, in humans, hinge-type, freely moving synovial joint between the foot and leg. The ankle contains seven tarsal......
antibody, a protective protein produced by the immune system in response to the presence of a foreign substance,......
antithrombin (AT), an anticlotting substance occurring in the plasma of blood that functions primarily to block......
antitoxin, antibody, formed in the body by the introduction of a bacterial poison, or toxin, and capable of neutralizing......
anus, terminal opening of the anal canal, the portion of the digestive tract through which fecal material is excreted.......
apical meristem, region of cells capable of division and growth in the root and shoot tips in plants. Apical meristems......
aponeurosis, a flat sheet or ribbon of tendonlike material that anchors a muscle or connects it with the part that......
appendix, in anatomy, a vestigial hollow tube that is closed at one end and is attached at the other end to the......
aqueous humour, optically clear, slightly alkaline liquid that occupies the anterior and posterior chambers of......
archinephros, ancestral vertebrate kidney, retained by larvae of hagfish and of some caecilians and occurring in......
argentaffin cell, one of the round or partly flattened cells occurring in the lining tissue of the digestive tract......
artificial organ, any machine, device, or other material that is used to replace the functions of a faulty or missing......
artificial respiration, breathing induced by some manipulative technique when natural respiration has ceased or......
astrocyte, star-shaped cell that is a type of neuroglia found in the nervous system in both invertebrates and vertebrates.......
atrium, in vertebrates and the higher invertebrates, heart chamber that receives blood into the heart and drives......
auricle, in human anatomy, the visible portion of the external ear, and the point of difference between the human......
autoantibody, harmful antibody that attacks components of the body called self antigens. Normally autoantibodies......
autoimmunity, the state in which the immune system reacts against the body’s own normal components, producing disease......
autonomic nervous system, in vertebrates, the part of the nervous system that controls and regulates the internal......
autophagy, the degradation of worn, abnormal, or malfunctioning cellular components that takes place within organelles......
autosome, any of the numbered or nonsex chromosomes of an organism. Humans have 22 sets of autosomes; they are......
axial skeleton, the part of the bony structure of the body that consists of the bones of the skull, the vertebral......
axon, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically......
B cell, one of the two types of lymphocytes (the other is the T cells). All lymphocytes begin their development......
back pain, discomfort or sometimes debilitating suffering associated with an injury or some other affliction of......
bacteremia, the presence of bacteria in the bloodstream, whether associated with active disease or not. The transient......
baculum, the penis bone of certain mammals. The baculum is one of several heterotropic skeletal elements—i.e.,......
Bainbridge reflex, acceleration of the heart rate resulting from increased blood pressure in, or increased distension......
ball-and-socket joint, in vertebrate anatomy, a joint in which the rounded surface of a bone moves within a depression......
bark, in woody plants, tissues external to the vascular cambium (the growth layer of the vascular cylinder); the......
Caspar Berthelsen Bartholin was a Danish physician and theologian who wrote one of the most widely read Renaissance......
Thomas Bartholin was a Danish anatomist and mathematician who was first to describe fully the entire human lymphatic......
basal ganglia, group of nuclei (clusters of neurons) in the brain that are located deep beneath the cerebral cortex......
base excision repair, pathway by which cells repair damaged DNA during DNA replication. Base excision repair helps......
basisphenoid bone, in reptiles, birds, and many mammals, a bone located at the base of the skull. It is immediately......
basophil, type of white blood cell (leukocyte) that is characterized histologically by its ability to be stained......
bast fibre, soft woody fibre obtained from stems of dicotyledonous plants (flowering plants with net-veined leaves)......
Gaspard Bauhin was a Swiss physician, anatomist, and botanist who introduced a scientific binomial system of classification......
Sir William Maddock Bayliss was a British physiologist, co-discoverer (with the British physiologist Ernest Starling)......
beak, stiff, projecting oral structure of certain animals. Beaks are present in a few invertebrates (e.g., cephalopods......
Lorenzo Bellini was a physician and anatomist who described the collecting, or excretory, tubules of the kidney,......
Pierre Belon was a French naturalist whose discussion of dolphin embryos and systematic comparisons of the skeletons......
Edouard van Beneden was a Belgian embryologist and cytologist best known for his discoveries concerning fertilization......
Giacomo Berengario da Carpi was an Italian physician and anatomist who was the first to describe the heart valves.......
Ernst von Bergmann was a German surgeon and author of a classic work on cranial surgery, Die Chirurgische Behandlung......
Claude Bernard was a French physiologist known chiefly for his discoveries concerning the role of the pancreas......
Paul Bert was a French physiologist, politician, and diplomat, founder of modern aerospace medicine, whose research......
Charles H. Best was a physiologist who, with Sir Frederick Banting, was one of the first to obtain (1921) a pancreatic......
biceps muscle, any muscle with two heads, or points of origin (from Latin bis, “two,” and caput, “head”). In human......
Marie-François-Xavier Bichat was a French anatomist and physiologist whose systematic study of human tissues helped......
bile, greenish yellow secretion that is produced in the liver and passed to the gallbladder for concentration,......
bilirubin, a brownish yellow pigment of bile, secreted by the liver in vertebrates, which gives to solid waste......
Theodor Billroth was a Viennese surgeon, generally considered to be the founder of modern abdominal surgery. Billroth’s......
binary fission, asexual reproduction by a separation of the body into two new bodies. In the process of binary......
bioelectric organ, system of tissues specialized for the production and use of electrical power in a living organism.......
birth, process of bringing forth a child from the uterus, or womb. The prior development of the child in the uterus......
blind spot, small portion of the visual field of each eye that corresponds to the position of the optic disk (also......
Günter Blobel was a German-born American cellular and molecular biologist who was awarded the Nobel Prize for Physiology......
blood, fluid that transports oxygen and nutrients to the cells and carries away carbon dioxide and other waste......
blood cell formation, continuous process by which the cellular constituents of blood are replenished as needed.......
blood group, classification of blood based on inherited differences (polymorphisms) in antigens on the surfaces......
blood typing, classification of blood in terms of distinctive inherited characteristics that are associated with......
blood vessel, a vessel in the human or animal body in which blood circulates. The vessels that carry blood away......
bolus, food that has been chewed and mixed in the mouth with saliva. Chewing helps to reduce food particles to......
bone, rigid body tissue consisting of cells embedded in an abundant hard intercellular material. The two principal......
bone conduction, the conduction of sound through the bones of the skull. Two types of bone conduction are recognized.......
bone formation, process by which new bone is produced. Ossification begins about the third month of fetal life......
bone marrow, soft, gelatinous tissue that fills the cavities of the bones. Bone marrow is either red or yellow,......
bone mineral density, estimate of bone mass. Bone is a rich mineral reservoir, composed mainly of calcium and phosphorous,......
bone remodeling, continuing process of synthesis and destruction that gives bone its mature structure and maintains......
book lung, form of respiratory organ found in certain air-breathing arachnid arthropods (scorpions and some spiders).......
Sir Jagadish Chandra Bose was an Indian plant physiologist and physicist whose invention of highly sensitive instruments......
Geoffrey Bourne was an Australian-born American anatomist whose studies of the mammalian adrenal gland made him......
Bowman’s capsule, double-walled cuplike structure that makes up part of the nephron, the filtration structure in......
Zabdiel Boylston was a physician who introduced smallpox inoculation into the American colonies. Inoculation consisted......