Cells, Organs & Tissues, SMA-VAG
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
small intestine, a long, narrow, folded or coiled tube extending from the stomach to the large intestine; it is......
smell, the detection and identification by sensory organs of airborne chemicals. The concept of smell, as it applies......
smooth endoplasmic reticulum (SER), meshwork of fine disklike tubular membrane vesicles, part of a continuous membrane......
smooth muscle, muscle that shows no cross stripes under microscopic magnification. It consists of narrow spindle-shaped......
sodium-potassium pump, in cellular physiology, a protein that has been identified in many cells that maintains......
soft palate, in mammals, structure consisting of muscle and connective tissue that forms the roof of the posterior......
soleus muscle, a flat, broad muscle of the calf of the leg lying just beneath the gastrocnemius muscle. It arises......
soma, in biology, all the living matter of an animal or a plant except the reproductive, or germ, cells. The distinction......
sound reception, response of an organism’s aural mechanism, the ear, to a specific form of energy change, or sound......
- Introduction
- Invertebrate Organs
- Tympanal Organs, Hearing, Ears
- Electrophysiology, Hearing, Perception
- Fishes, Amphibians, Mechanisms
- Hearing, Ears, Sensory Cells
- Amphibians, Hearing, Sensitivity
- Lizard Hearing, Acoustic Signals, Vibrations
- Turtle Hearing, Low Frequency, Adaptations
- Auditory Perception, Bird Hearing, Acoustic Signals
- Mammal Hearing, Frequency, Acoustics
- Echolocation, Bats, Sonar
- Echolocation, Mammals, Bats
Lazzaro Spallanzani was an Italian physiologist who made important contributions to the experimental study of bodily......
sperm, male reproductive cell, produced by most animals. With the exception of nematode worms, decapods (e.g.,......
spermatic cord, either of a pair of tubular structures in the male reproductive system that support the testes......
spermatogenesis, the origin and development of the sperm cells within the male reproductive organs, the testes.......
Roger Wolcott Sperry was an American neurobiologist. He was a corecipient with David Hunter Hubel and Torsten Nils......
sphincter muscle, any of the ringlike muscles surrounding and able to contract or close a bodily passage or opening.......
spinal cord, major nerve tract of vertebrates, extending from the base of the brain through the canal of the spinal......
spinal nerve, in vertebrates, any one of many paired peripheral nerves that arise from the spinal cord. In humans......
spinalis muscle, any of the deep muscles of the back near the vertebral column that, as part of the erector spinae......
spiracle, in arthropods, the small external opening of a trachea (respiratory tube) or a book lung (breathing organ......
Ernest Henry Starling was a British physiologist whose prolific contributions to a modern understanding of body......
Ralph M. Steinman was a Canadian immunologist and cell biologist who shared the 2011 Nobel Prize for Physiology......
stem, in botany, the plant axis that bears buds and shoots with leaves and, at its basal end, roots. The stem conducts......
stem cell, an undifferentiated cell that can divide to produce some offspring cells that continue as stem cells......
Nicolaus Steno was a geologist and anatomist whose early observations greatly advanced the development of geology.......
Elizabeth Stern was a Canadian-born American pathologist, noted for her work on the stages of a cell’s progression......
sternum, in the anatomy of tetrapods (four-limbed vertebrates), elongated bone in the centre of the chest that......
stolon, in biology, a special slender horizontal branch serving to propagate the organism. In botany a stolon—also......
stomach, saclike expansion of the digestive system, between the esophagus and the small intestine; it is located......
stomate, any of the microscopic openings or pores in the epidermis of leaves and young stems. Stomata are generally......
sucking, drawing of fluids into the mouth by creating a vacuum pressure in the oral cavity. Mammalian infants rely......
John Sulston was a British biologist who, with Sydney Brenner and H. Robert Horvitz, won the Nobel Prize for Physiology......
summation, in physiology, the additive effect of several electrical impulses on a neuromuscular junction, the junction......
sunburn, acute cutaneous inflammation caused by overexposure to ultraviolet (UV) radiation of the so-called UVB......
Earl W. Sutherland, Jr. was an American pharmacologist and physiologist who was awarded the 1971 Nobel Prize for......
swallowing, the act of passing food from the mouth, by way of the pharynx (or throat) and esophagus, to the stomach.......
sweat, the moisture excreted in visible quantities through the openings of the sweat glands. See...
sweat gland, either of two types of secretory skin glands occurring only in mammals. The eccrine sweat gland, which......
Emanuel Swedenborg was a Swedish scientist, Christian mystic, philosopher, and theologian who wrote voluminously......
swim bladder, buoyancy organ possessed by most bony fish. The swim bladder is located in the body cavity and is......
Franciscus Sylvius was a physician, physiologist, anatomist, and chemist who is considered the founder of the 17th-century......
sympathetic nervous system, division of the nervous system that functions to produce localized adjustments (such......
synapse, the site of transmission of electric nerve impulses between two nerve cells (neurons) or between a neuron......
synovial tissue, thin, loose vascular connective tissue that makes up the membranes surrounding joints and the......
syrinx, vocal organ of birds, located at the base of the windpipe (trachea), where the trachea divides into the......
systemic circulation, in physiology, the circuit of vessels supplying oxygenated blood to and returning deoxygenated......
systole, period of contraction of the ventricles of the heart that occurs between the first and second heart sounds......
T cell, type of white blood cell (leukocyte) that is an essential part of the immune system. T cells are one of......
taproot, main root of a primary root system, growing vertically downward. Most dicotyledonous plants (see cotyledon),......
target theory, in biology, the concept that the biological effects of radiations such as X rays result from ionization......
tarsal, any of several short, angular bones that in humans make up the ankle and that—in animals that walk on their......
taste, the detection and identification by the sensory system of dissolved chemicals placed in contact with some......
taste bud, small organ located on the tongue in terrestrial vertebrates that functions in the perception of taste.......
tear duct and glands, structures that produce and distribute the watery component of the tear film. Tears consist......
telomere, segment of DNA occurring at the ends of chromosomes in eukaryotic cells (cells containing a clearly defined......
telophase, in mitosis and meiosis, the final stage of cell division in which the spindle disappears and the nucleus......
tendon, tissue that attaches a muscle to other body parts, usually bones. Tendons are the connective tissues that......
tendril, in botany, plant organ specialized to anchor and support vining stems. Tendrils may be modified leaves,......
test, in zoology, a protective, loose-fitting shell secreted by some protozoans (especially foraminiferans and......
testis, in animals, the organ that produces sperm, the male reproductive cell, and androgens, the male hormones.......
testosterone, hormone produced by the male testis that is responsible for development of the male sex organs and......
thalamus, either of a pair of large ovoid organs that form most of the lateral walls of the third ventricle of......
thermoreception, sensory process by which different levels of heat energy (temperatures) in the environment and......
thermoregulation, the maintenance of an optimum temperature range by an organism. Cold-blooded animals (poikilotherms)......
Kenneth V. Thimann was an English-born American plant physiologist who isolated auxin, an important plant growth......
thoracic duct, in mammalian anatomy, a principal channel for lymph. From about the level of the small of the back......
thrombocyte, a small, nucleated, spindle-shaped cell of nonmammalian vertebrates that plays a role in the clotting......
thymus, pyramid-shaped lymphoid organ that, in humans, is immediately beneath the sternum (breastbone) at the level......
thyroid gland, endocrine gland that is located in the anterior part of the lower neck, below the larynx (voice......
tibia, inner and larger of the two bones of the lower leg in vertebrates—the other is the fibula. In humans the......
tissue, in physiology, a level of organization in multicellular organisms; it consists of a group of structurally......
tongue, in most vertebrates, an organ, capable of various muscular movements, located on the floor of the mouth.......
tooth, any of the hard, resistant structures occurring on the jaws and in or around the mouth and pharynx areas......
tooth germ, embryonic tooth, derived from the mesodermal (middle) and ectodermal (outer) layers of embryonic tissues.......
touch reception, perception by an animal when in contact with a solid object. Two types of receptors are common:......
trachea, in vertebrates and invertebrates, a tube or system of tubes that carries air. In insects, a few land arachnids,......
tracheid, in botany, primitive element of xylem (fluid-conducting tissues), consisting of a single elongated cell......
transfection, technique used to insert foreign nucleic acid (DNA or RNA) into a cell, typically with the intention......
transferrin, protein (beta1 globulin) in blood plasma that transports iron from the tissues and bloodstream to......
transformation, in biology, one of several processes by which genetic material in the form of “naked” deoxyribonucleic......
transient receptor potential channel, superfamily of ion channels occurring in cell membranes that are involved......
transpiration, in botany, a plant’s loss of water, mainly through the stomata of leaves. Stomatal openings are......
trapezius muscle, large, superficial muscle at the back of the neck and the upper part of the thorax, or chest.......
triceps muscle, any muscle with three heads, or points of origin, particularly the large extensor along the back......
trichocyst, a structure in the cortex of certain ciliate and flagellate protozoans consisting of a cavity and long,......
tuber, specialized storage stem of certain seed plants. Tubers are usually short and thickened and typically grow......
turgor, Pressure exerted by fluid in a cell that presses the cell membrane against the cell wall. Turgor is what......
tympanic membrane, thin layer of tissue in the human ear that receives sound vibrations from the outer air and......
ulna, inner of two bones of the forearm when viewed with the palm facing forward. (The other, shorter bone of the......
ultimobranchial gland, in biology, any of the small bodies in the pharynx that develop behind the fifth pair of......
umami, savory or meaty taste, one of the five fundamental taste sensations. The taste of umami is derived from......
ureter, duct that transmits urine from the kidney to the bladder. There normally is one ureter for each kidney.......
urethra, duct that transmits urine from the bladder to the exterior of the body during urination. The urethra is......
urethral gland, in male placental mammals, any of the glands that branch off the internal wall of the urethra,......
urinary bladder, in most vertebrates, except birds, organ for the temporary storage of urine from the kidneys,......
urination, the process of excreting urine from the urinary bladder. Nerve centres for the control of urination......
urine, liquid or semisolid solution of metabolic wastes and certain other, often toxic, substances that the excretory......
urogenital system, in vertebrates, the organs concerned with reproduction and urinary excretion. Although their......
uterus, an inverted pear-shaped muscular organ of the female reproductive system, located between the bladder and......
vacuole, in biology, a space within a cell that is empty of cytoplasm, lined with a membrane, and filled with fluid.......
vagina, canal in female mammals that receives the male reproductive cells, or sperm, and is part of the birth canal......