Anatomy & Physiology, HYA-LYM
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
Hyaluronic acid
Hyaluronic acid, naturally occurring polysaccharide found in the extracellular matrix of vertebrate tissues, particularly......
hydrocele
hydrocele, excessive accumulation of fluids in the scrotal sac that surrounds the testes in the male reproductive......
hymen
hymen, in the female reproductive system, the membrane that encircles or covers part of the opening of the vagina.......
hyoid bone
hyoid bone, U-shaped bone situated at the root of the tongue in the front of the neck and between the lower jaw......
hyperaldosteronism
hyperaldosteronism, increased secretion of the hormone aldosterone by the cells of the zona glomerulosa (the outer......
hyperopia
hyperopia, refractive error or abnormality in which the cornea and lens of the eye focus the image of the visual......
hyperparathyroidism
hyperparathyroidism, abnormal increase in the secretion of parathormone by one or more parathyroid glands. Hyperparathyroidism......
hypertension
hypertension, condition that arises when the blood pressure is abnormally high. Hypertension occurs when the body’s......
hyperthyroidism
hyperthyroidism, excess production of thyroid hormone by the thyroid gland. Most patients with hyperthyroidism......
hypoaldosteronism
hypoaldosteronism, abnormally low serum levels of aldosterone, a steroid hormone secreted by the adrenal gland.......
hypogonadism
hypogonadism, in men, decreased testicular function that results in testosterone deficiency and infertility. Hypogonadism......
hypoparathyroidism
hypoparathyroidism, inadequate secretion of parathormone. Hypoparathyroidism can be due to decreased secretion......
hypopituitarism
hypopituitarism, deficiency of pituitary hormones caused by damage to the pituitary gland. Patients may have a......
hypotension
hypotension, condition in which the blood pressure is abnormally low, either because of reduced blood volume or......
hypothalamus
hypothalamus, region of the brain lying below the thalamus and making up the floor of the third cerebral ventricle.......
hypothyroidism
hypothyroidism, a deficiency in hormone production by the thyroid gland. Hypothyroidism usually results from a......
Ii blood group system
Ii blood group system, classification of human blood based on the presence of antigens I and i on the surface of......
ileum
ileum, the final and longest segment of the small intestine. It is specifically responsible for the absorption......
iliocostalis muscle
iliocostalis muscle, any of the deep muscles of the back that, as part of the erector spinae (sacrospinalis) muscle......
immune system
immune system, the complex group of defense responses found in humans and other advanced vertebrates that helps......
- Introduction
- Interferons, Antibodies, Cells
- Macrophages, Antigens, Defense
- Lymphocytes, Antigens, Immunity
- Antigens, Cells, Receptors
- Lymphocytes, Diversity, Adaptive
- IgA, IgG, IgM
- T Cells, Antigens, Receptors
- T Cells, B Cells, Activation
- Antibodies, Mediated, Mechanisms
- Killer Cells, Antigens, Defense
- Cancer Immunity, T-cells, Antigens
- Evolution, Defense, Adaptation
immunity
immunity, in biology, the ability of the body to prevent or defeat infection from invading microorganisms or parasites.......
immunization
immunization, process by which resistance to disease is acquired or induced in plants and animals. This discussion......
immunology
immunology, the scientific study of the body’s resistance to invasion by other organisms (i.e., immunity). In a......
implantation
implantation, in reproduction physiology, the adherence of a fertilized egg to a surface in the reproductive tract,......
incontinence
incontinence, inability to control the excretion of urine or feces. Starting and stopping urination relies on normal......
Incubation
Incubation, the maintenance of uniform conditions of temperature and humidity to ensure the development of eggs......
induction
induction, in embryology, process by which the presence of one tissue influences the development of others. Certain......
infancy
infancy, among humans, the period of life between birth and the acquisition of language approximately one to two......
infant and toddler development
infant and toddler development, the physical, emotional, behavioral, and mental growth of children from ages 0......
infectious bovine keratoconjunctivitis
infectious bovine keratoconjunctivitis, an inflammation of the conjunctiva or the cornea of the eye in cattle as......
inner ear
inner ear, part of the ear that contains organs of the senses of hearing and equilibrium. The bony labyrinth, a......
Inosinic acid
Inosinic acid, a compound important in metabolism. It is the ribonucleotide of hypoxanthine and is the first compound......
Integument
Integument, in biology, network of features that forms the covering of an organism. The integument delimits the......
- Introduction
- Invertebrate Groups, Structure, Function
- Parasites, Adaptations, Protection
- Exoskeleton, Cuticle, Segmentation
- Hair, Glands, Nails
- Epidermal, Scales, Reptiles
- Skin, Hair, Glands
- Fish Scales, Skin, Protection
- Reptiles, Scales, Skin
- Skin, Hair, Sweat Glands
- Embryology, Evolution, Protection
intercostalis muscle
intercostalis muscle, in human physiology, any of a series of short muscles that extend between the ribs and serve......
Interferon
Interferon, any of several related proteins that are produced by various types of cells in the body as a defensive......
Interleukin
Interleukin (IL), any of a group of naturally occurring proteins that mediate communication between cells. Interleukins......
intestinal gas
intestinal gas, material contained within the digestive tract that consists principally of swallowed air and partly......
intestinal juice
intestinal juice, clear to pale yellow, watery secretion composed of hormones, digestive enzymes, mucus, and neutralizing......
intestine
intestine, tubular part of the alimentary canal that extends from the stomach to the anus. The intestine is the......
intracellular fluid
intracellular fluid, substance within living cells that is made up primarily of water and molecules such as dissolved......
Intrinsic factor
Intrinsic factor, a glycoprotein (i.e., a complex compound containing both polysaccharide and protein components)......
Inulin
Inulin, polysaccharide that is a commercial source of the sugar fructose. It occurs in many plants of the family......
ion channel
ion channel, protein expressed by virtually all living cells that creates a pathway for charged ions from dissolved......
iris
iris, in anatomy, the colored muscular part of the eye surrounding the pupil, the small black opening in the center.......
Is It Really Dangerous to Swim After Eating?
Common wisdom holds that it is unsafe to swim after eating unless one waits for some prescribed period of time—usually......
Is Magnesium Good for Sleep?
Despite its reputation as a natural sleep remedy, magnesium is not a cure for insomnia or other sleep disorders.......
Is Spontaneous Human Combustion Real?
Late at night on Christmas Eve 1885, in the small farming town of Seneca, Illinois, a woman named Matilda Rooney......
Isoprenoid
Isoprenoid, any of a class of organic compounds composed of two or more units of hydrocarbons, with each unit consisting......
Ivory
Ivory, variety of dentin of which the tusk of the elephant is composed and which is prized for its beauty, durability,......
Jacobson’s organ
Jacobson’s organ, an organ of chemoreception that is part of the olfactory system of amphibians, reptiles, and......
jaw
jaw, either of a pair of bones that form the framework of the mouth of vertebrate animals, usually containing teeth......
joint
joint, in anatomy, a structure that separates two or more adjacent elements of the skeletal system. Depending on......
jugular vein
jugular vein, any of several veins of the neck that drain blood from the brain, face, and neck, returning it to......
Kell blood group system
Kell blood group system, classification of human blood based on the presence on the surfaces of red blood cells......
Keratin
Keratin, fibrous structural protein of hair, nails, horn, hoofs, wool, feathers, and of the epithelial cells in......
keratitis
keratitis, inflammation of the cornea, the transparent domelike portion of the eyeball in front of the iris and......
Kidd blood group system
Kidd blood group system, classification of human blood based on the presence of glycoproteins known as Kidd (Jk)......
kidney
kidney, in vertebrates and some invertebrates, organ that maintains water balance and expels metabolic wastes.......
kinocilium
kinocilium, filamentous structure occurring on auditory hair cells in the inner ear that functions in the development......
knee
knee, hinge joint that is formed by the meeting of the thigh bone (femur) and the larger bone (tibia) of the lower......
knuckle
knuckle, the joint of a finger. The knuckle joint of an animal killed for eating is the tarsal or carpal joint......
Kupffer cell
Kupffer cell, any of the stellate (star-shaped) cells in the linings of the liver sinusoids. The sinusoids are......
labia majora
labia majora, in the female reproductive system, the outer folds of skin that form part of the external genitalia,......
labia minora
labia minora, in the female reproductive system, two thin folds of skin situated within the vulva, lying between......
labyrinthodont
labyrinthodont, a type of tooth made up of infolded enamel that provides a grooved and strongly reinforced structure.......
lactation
lactation, secretion and yielding of milk by females after giving birth. The milk is produced by the mammary glands,......
lacteal
lacteal, one of the lymphatic vessels that serve the small intestine and, after a meal, become white from the minute......
Lactose
Lactose, carbohydrate containing one molecule of glucose and one of galactose linked together. Composing about......
Lamaze
Lamaze, method of childbirth that involves psychological and physical preparation by the mother for the purpose......
Langerhans, islets of
islets of Langerhans, irregularly shaped patches of endocrine tissue located within the pancreas of most vertebrates.......
large intestine
large intestine, posterior section of the intestine, consisting typically of four regions: the cecum, colon, rectum,......
larynx
larynx, a hollow, tubular structure connected to the top of the windpipe (trachea); air passes through the larynx......
lateral line system
lateral line system, a system of tactile sense organs, unique to aquatic vertebrates from cyclostome fishes (lampreys......
laterality
laterality, in biological psychology, the development of specialized functioning in each hemisphere of the brain......
latissimus dorsi
latissimus dorsi, widest and most powerful muscle of the back. It is a large, flat, triangular muscle covering......
lecanemab
lecanemab, human monoclonal antibody used for the treatment of Alzheimer disease. Lecanemab clears away and blocks......
Lecithin
Lecithin, any of a group of phospholipids (phosphoglycerides) that are important in cell structure and metabolism.......
leg
leg, limb or appendage of an animal, used to support the body, provide locomotion, and, in modified form, assist......
lens
lens, in anatomy, a nearly transparent biconvex structure suspended behind the iris of the eye, the sole function......
lens dislocation
lens dislocation, abnormal position of the crystalline lens of the eye. The dislocation, which may be congenital,......
levator muscle
levator muscle, any of the muscles that raise a body part. In humans these include the levator anguli oris, which......
levonorgestrel
levonorgestrel, synthetic progestogen (any progestational steroid, such as progesterone) that is used as a form......
Lewis blood group system
Lewis blood group system, classification of human blood based on the expression of glycoproteins called Lewis (Le)......
ligament
ligament, tough fibrous band of connective tissue that serves to support the internal organs and hold bones together......
limbic system
limbic system, group of structures in the brain that governs emotions, motivation, olfaction (sense of smell),......
Lipid
Lipid, any of a diverse group of organic compounds including fats, oils, hormones, and certain components of membranes......
- Introduction
- Saturated Fatty Acids
- Fatty Acids, Esters, Alcohols
- Digestion, Fatty Acids, Diet
- Waxes, Fatty Acids, Esters
- Cholesterol, Sterols, Lipoproteins
- Steroid Hormones, Synthesis, Receptors
- Fats, Oils, Phospholipids
- Apolipoproteins, Functions, Recycling
- Mobilization, Fatty Acids, Metabolism
- Structure, Function, Types
- Membrane, Structure, Function
- Phospholipids, Steroids, Signaling
Lipoprotein
Lipoprotein, any member of a group of substances containing both lipid (fat) and protein. They occur in both soluble......
lips
lips, soft pliable anatomical structures that form the mouth margin of most vertebrates, composed of a surface......
List of the tallest NBA players
Most NBA players are tall. Just how tall? The average height of a player is approximately 6 feet 7 inches (2 meters).......
liver
liver, the largest gland in the body, a spongy mass of wedge-shaped lobes that has many metabolic and secretory......
loin
loin, that part of an animal lying between the upper part of the hipbone and the last of the false ribs on either......
loop of Henle
loop of Henle, long U-shaped portion of the tubule that conducts urine within each nephron of the kidney of reptiles,......
Lorica
Lorica, a tubular, conical, or vaselike structure secreted by some protozoans (e.g., Stentor) and many rotifers.......
lucid dreaming
lucid dreaming, phenomenon of sleep in which one is aware that one is dreaming. During lucid dreaming, individuals......
lung
lung, in air-breathing vertebrates, either of the two large organs of respiration located in the chest cavity and......
Lutheran blood group system
Lutheran blood group system, classification of human blood based on the presence of substances called Lutheran......
lymph
lymph, pale fluid that bathes the tissues of an organism, maintaining fluid balance, and removes bacteria from......
lymph node
lymph node, any of the small, bean-shaped masses of lymphoid tissue enclosed by a capsule of connective tissue......
lymph nodule
lymph nodule, small, localized collection of lymphoid tissue, usually located in the loose connective tissue beneath......
lymphatic system
lymphatic system, a subsystem of the circulatory system in the vertebrate body that consists of a complex network......