Anatomy & Physiology, TIS-WHY
Human beings have long been curious about the way that things work, and that curiosity includes wondering about how we ourselves work. The fields of anatomy and physiology involve studying the structures of bodies and the way that those structures and bodies function.
Anatomy & Physiology Encyclopedia Articles By Title
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.......
tonsil, small mass of lymphatic tissue located in the wall of the pharynx at the rear of the throat of humans and......
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,......
trachoma, chronic inflammatory disease of the eye caused by Chlamydia trachomatis, a bacterium-like microorganism......
transcription factor, molecule that controls the activity of a gene by determining whether the gene’s DNA (deoxyribonucleic......
transfer RNA (tRNA), small molecule in cells that carries amino acids to organelles called ribosomes, where they......
transferrin, protein (beta1 globulin) in blood plasma that transports iron from the tissues and bloodstream to......
transient receptor potential channel, superfamily of ion channels occurring in cell membranes that are involved......
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......
triglyceride, any one of an important group of naturally occurring lipids (fat-soluble components of living cells).......
tumour necrosis factor (TNF), a naturally occurring protein that is produced in the human body by the phagocytic......
twin, either of two young who are simultaneously born from one mother. Twinning, common in many animals, is of......
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......
umbilical cord, narrow cord of tissue that connects a developing embryo, or fetus, with the placenta (the extra-embryonic......
uracil, a colourless, crystalline organic compound of the pyrimidine family that occurs as a component of ribonucleic......
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,......
urethritis, infection and inflammation of the urethra, the channel for passage of urine from the urinary bladder......
uric acid, a compound belonging to the purine group, and the chief form in which nitrogen, resulting from the breakdown......
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 malformation, any defect in the organs and tissues responsible for the formation and excretion of urine......
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......
uveitis, inflammation of the uvea (or uveal tract), the middle layer of tissue surrounding the eye that consists......
vagina, canal in female mammals that receives the male reproductive cells, or sperm, and is part of the birth canal......
vaginismus, involuntary muscle spasm that closes the opening to the vagina in the female reproductive tract. The......
vaginitis, inflammation of the vagina, usually due to infection. The chief symptom is the abnormal flow of a whitish......
vagus nerve, longest and most complex of the cranial nerves. The vagus nerve runs from the brain through the face......
valve, in anatomy, any of various membranous structures, especially in the heart, veins, and lymph ducts, that......
vascular system, in vascular plants, assemblage of conducting tissues and associated supportive fibres that transport......
vein, in human physiology, any of the vessels that, with four exceptions, carry oxygen-depleted blood to the right......
vena cava, in air-breathing vertebrates, including humans, either of two major trunks, the anterior and posterior......
venous sinus, in human anatomy, any of the channels of a branching complex sinus network that lies between layers......
ventricle, muscular chamber that pumps blood out of the heart and into the circulatory system. Ventricles occur......
ventricular assist device (VAD), machine designed to facilitate the pumping of blood from the ventricles (lower......
vertebral artery, in anatomy, one of two arteries that begin deep in the neck as the first branches of the subclavian......
vertebral column, in vertebrate animals, the flexible column extending from neck to tail, made of a series of bones,......
vesiculitis, inflammation and infection of the seminal vesicles in the male reproductive tract. The seminal vesicles......
vestibular system, apparatus of the inner ear involved in balance. The vestibular system consists of two structures......
vestibulocochlear nerve, nerve in the human ear, serving the organs of equilibrium and of hearing. It consists......
vibrissae, stiff hairs on the face or nostrils of an animal, such as the whiskers of a cat. Vibrissae often act......
villus, in anatomy any of the small, slender, vascular projections that increase the surface area of a membrane.......
vision, physiological process of distinguishing, usually by means of an organ such as the eye, the shapes and colours......
visual field defect, a blind spot (scotoma) or blind area within the normal field of one or both eyes. In most......
visual pigment, any of a number of related substances that function in light reception by animals by transforming......
viviparity, retention and growth of the fertilized egg within the maternal body until the young animal, as a larva......
vocal cord, either of two folds of mucous membrane that extend across the interior cavity of the larynx and are......
vocal sac, the sound-resonating throat pouch of male frogs and toads (amphibians of the order Anura). Vocal sacs......
vocalization, any sound produced through the action of an animal’s respiratory system and used in communication.......
von Willebrand factor (vWF, or VWF), glycoprotein that plays an important role in stopping the escape of blood......
vulva, the external female genitalia that surround the opening to the vagina; collectively these consist of the......
vulvitis, inflammation and infection of the vulva—the external genitalia of the female. The external organs of......
warm-bloodedness, in animals, the ability to maintain a relatively constant internal temperature (about 37° C [99°......
Wernicke area, region of the brain that contains motor neurons involved in the comprehension of speech. This area......
whalebone, series of stiff keratinous plates in the mouths of baleen whales, used to strain copepods and other......
Elephants use their trunks as multifunctional appendages for a variety of tasks essential to their survival and......
Turtle shells are made of bone and cartilage, but it is the form and function of the shells that make them unique......
Allergic reactions are caused by substances known as allergens. These substances can be found in a variety of sources......
A variety of theories have been proposed for the specific function of the narwhal’s long, straight tusk, but first......
An individual’s height is determined by the interplay between inherited genes and environment. A person’s genetics......
What happens to our bodies after we die isn’t a mystery, even if we may want it to be. If you want to confront......
Your parents may have warned you not to swallow your chewing gum because it would remain in your stomach for seven......
Proteins and peptides are fundamental components of cells that carry out important biological functions. Proteins......
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are complex molecular structures that control all hereditary......
The largest animal on Earth is the blue whale (Balaenoptera musculus). It is also the largest animal to have ever......
How large an eagle’s wingspan is depends on the species of the eagle. It may be less than 1 meter (3.28 feet) in......
Veins and arteries are major players in the circulatory system of all vertebrates. They work together to transport......
white blood cell, a cellular component of the blood that lacks hemoglobin, has a nucleus, is capable of motility,......
Bees are crucial to our world for several reasons, primarily due to their role as pollinators. The approximately......
An elephant’s large ears serve several purposes. Thermoregulation—an organism’s maintenance of its own body temperature......
Flamingos are long-legged wading birds that are usually covered in bright pink feathers. With a name that derives......
Mosquitoes that feed on human blood are attracted to certain people more than others due to a combination of factors......
Most reptiles are cold-blooded (ectothermic) because they rely on external sources to regulate their body temperature.......
Robin eggs are blue due to a fascinating evolutionary adaptation that may help protect them from sun exposure.......
The color of an eggshell is determined primarily by the breed of the hen that laid it. This trait is genetic: hens......
Different blood groups are the result of genetic variations that determine the presence or absence of specific......
At some point in your life you’ve probably been tickled—repeatedly touched in a way that induced smiling, laughter,......
There are numerous reasons why many animals have a tail. One answer is that a tail of some kind has helped different......
Bats sleep upside down because their anatomy and physiology are adapted for this position. Their legs are slender......
Cats blink slowly as a form of nonverbal communication, often interpreted as a sign of trust and affection toward......
Cats have slit pupils primarily to enhance their ability to see in varying light conditions. They are crepuscular......
Cats have whiskers primarily for tactile sensing, which is crucial for their survival and daily activities. Whiskers,......
Deer shed their antlers as part of hormonal changes linked to their survival and mating season. In all but one......
Dogs have wet noses mainly to enhance their sense of smell. The moisture on the nose traps scent particles in the......
Dogs wag their tails primarily as a form of communication, allowing them to express a range of emotions. Tail wagging......
The long neck of a giraffe (genus Giraffa) is a classic example of adaptation, which is the process by which a......
Gray hairs are indeed unusual, and not only because of their color. Gray hair is stiffer and more wiry than hair......
Some consider this a trick question. That’s because horses actually doze while on their feet and lie down for REM......
Eyebrows are an often overlooked feature of the face. Without much fanfare they automatically do their job of protecting......