Biology, HYD-LAC
How do plants feed themselves? How did dogs evolve from wolves? What good is the appendix in humans, anyway? Such questions fall within the domain of biology, which seeks to understand living organisms and their vital processes (although the jury’s still out on what our appendixes are for). Biology’s diverse fields include botany, ecology, evolution, genetics, medicine, physiology, and zoology.
Biology Encyclopedia Articles By Title
hydramnios, excess of amniotic fluid, the liquid that surrounds the fetus in the uterus. Chronic hydramnios, in......
hydrocephalus, accumulation of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain, causing......
hydrogenosome, membrane-bound organelle found in the cytoplasm of eukaryotic cells (cells with clearly defined......
hymenium, a spore-bearing layer of tissue in fungi (kingdom Fungi) found in the phyla Ascomycota and Basidiomycota.......
hymenomycetes, name often given to an informal grouping of fungi that are members of the phylum Basidiomycota (kingdom......
hypercalcitoninemia, abnormally high blood concentrations of calcitonin, a protein hormone secreted by parafollicular......
hyperglycemia, elevation of blood glucose concentrations above the normal range; it is the laboratory finding that......
hyperkeratosis, in cattle, a disease characterized by inflammation and thickening of the horny covering of the......
hypermastigote, any member of the zooflagellate protozoan order Hypermastigida. Hypermastigotes are complex, uninucleate,......
hyperopia, refractive error or abnormality in which the cornea and lens of the eye focus the image of the visual......
hypertension, condition that arises when the blood pressure is abnormally high. Hypertension occurs when the body’s......
hyperthyroidism, excess production of thyroid hormone by the thyroid gland. Most patients with hyperthyroidism......
hypoglycemia, reduction of the concentration of glucose in the blood below normal levels, commonly occurring as......
hypogonadism, in men, decreased testicular function that results in testosterone deficiency and infertility. Hypogonadism......
hypophosphatemia, reduction in the concentration of phosphate in the blood serum, thus disrupting the body’s energy......
hypoprothrombinemia, disease characterized by a deficiency of the blood-clotting substance prothrombin, resulting......
hypothalamus, region of the brain lying below the thalamus and making up the floor of the third cerebral ventricle.......
hypothyroidism, a deficiency in hormone production by the thyroid gland. Hypothyroidism usually results from a......
hypoxia, in biology and medicine, condition of the body in which the tissues are starved of oxygen. In its extreme......
ich, parasitic disease that affects a variety of freshwater fish species and that is caused by the ciliated protozoan......
ichthyology, scientific study of fishes, including, as is usual with a science that is concerned with a large group......
ichthyosis, a hereditary condition involving dryness and scaliness of the skin brought about by excessive growth......
Ii blood group system, classification of human blood based on the presence of antigens I and i on the surface of......
ileum, the final and longest segment of the small intestine. It is specifically responsible for the absorption......
iliocostalis muscle, any of the deep muscles of the back that, as part of the erector spinae (sacrospinalis) muscle......
iliotibial band syndrome (ITBS), inflammation of the band of fibrous tissue known as the iliotibial band (or tract),......
iminoglycinuria, inborn impairment of the transport system of the kidney tubules, which normally reabsorb the amino......
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
immune system disorder, any of various failures in the body’s defense mechanisms against infectious organisms.......
immunization, process by which resistance to disease is acquired or induced in plants and animals. This discussion......
immunodeficiency, defect in immunity that impairs the body’s ability to resist infection. The immune system may......
immunology, the scientific study of the body’s resistance to invasion by other organisms (i.e., immunity). In a......
impetigo, inflammatory skin infection that begins as a superficial blister or pustule that then ruptures and gives......
implantation, in reproduction physiology, the adherence of a fertilized egg to a surface in the reproductive tract,......
imposter syndrome, a persistent unjustified feeling that one’s success is fraudulent. Imposter syndrome is characterized......
in vitro fertilization (IVF), medical procedure in which mature egg cells are removed from a woman, fertilized......
inborn error of metabolism, any of multiple rare disorders that are caused by an inherited genetic defect and that......
inbreeding, the mating of individuals or organisms that are closely related through common ancestry, as opposed......
incidence, in epidemiology, occurrence of new cases of disease, injury, or other medical conditions over a specified......
inclusive fitness, theory in evolutionary biology in which an organism’s genetic success is believed to be derived......
induced pluripotent stem cell (iPS cell), immature cell that is generated from an adult (mature) cell and that......
induction, in embryology, process by which the presence of one tissue influences the development of others. Certain......
industrial melanism, the darkness—of the skin, feathers, or fur—acquired by a population of animals living in an......
infancy, among humans, the period of life between birth and the acquisition of language approximately one to two......
infant and toddler development, the physical, emotional, behavioral, and mental growth of children from ages 0......
infantile hemangioma, a congenital benign tumour made up of endothelial cells (the cells lining the inner surface......
infarction, death of tissue resulting from a failure of blood supply, commonly due to obstruction of a blood vessel......
infectious bovine keratoconjunctivitis, an inflammation of the conjunctiva or the cornea of the eye in cattle as......
infectious disease, in medicine, a process caused by an agent, often a type of microorganism, that impairs a person’s......
- Introduction
- Rickettsias, Bacteria, Symptoms
- Fungal, Pathogens, Prevention
- Commensalism, Pathogens, Immunity
- Transmission, Prevention, Control
- Occupation, Commerce, Prevention
- Immune Response, Pathogens, Prevention
- Natural Immunity, Acquired Immunity
- Immunization, Prevention, Vaccines
- Polio Vaccine, Prevention, Eradication
- Hepatitis B, Vaccine, Prevention
infertility, the inability of a couple to conceive and reproduce. Infertility is defined as the failure to conceive......
inflammation, a response triggered by damage to living tissues. The inflammatory response is a defense mechanism......
influenza, an acute viral infection of the upper or lower respiratory tract that is marked by fever, chills, and......
influenza A H1N1, virus that is best known for causing widespread outbreaks, including epidemics and pandemics,......
inky cap, (genus Coprinus), genus of about 350 cosmopolitan mushroom species. Inky caps are so named for the disintegration......
inner ear, part of the ear that contains organs of the senses of hearing and equilibrium. The bony labyrinth, a......
inoculation, process of producing immunity that consists of introduction of the infectious agent into the body.......
instinct, an inborn impulse or motivation to action typically performed in response to specific external stimuli.......
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, in human physiology, any of a series of short muscles that extend between the ribs and serve......
International HapMap Project, an international collaboration aimed at the identification of genetic variations......
intestinal gas, material contained within the digestive tract that consists principally of swallowed air and partly......
intestinal juice, clear to pale yellow, watery secretion composed of hormones, digestive enzymes, mucus, and neutralizing......
intestine, tubular part of the alimentary canal that extends from the stomach to the anus. The intestine is the......
intracellular fluid, substance within living cells that is made up primarily of water and molecules such as dissolved......
ion channel, protein expressed by virtually all living cells that creates a pathway for charged ions from dissolved......
iridovirus, any virus belonging to the family Iridoviridae. Iridoviruses possess large enveloped or nonenveloped......
Irish moss, (Chondrus crispus), species of red algae (family Gigartinaceae) that grows abundantly along the rocky......
itching, a stimulation of free nerve endings, usually at the junction of the dermis and epidermis of the skin,......
jaw, either of a pair of bones that form the framework of the mouth of vertebrate animals, usually containing teeth......
Johne’s disease, serious infectious disease caused by Mycobacterium avium paratuberculosis. Although principally......
joint, in anatomy, a structure that separates two or more adjacent elements of the skeletal system. Depending on......
joint disease, any of the diseases or injuries that affect human joints. Arthritis is no doubt the best-known joint......
K-selected species, species whose populations fluctuate at or near the carrying capacity (K) of the environment......
kappa organism, gram-negative symbiotic bacterium found in the cytoplasm of certain strains of the protozoan Paramecium......
karyotype, visual representation of the complete set of chromosomes in a cell. In a karyotype, the chromosomes,......
Kawasaki syndrome, rare, acute inflammatory disease of unknown origin that is one of the leading causes of acquired......
Kell blood group system, classification of human blood based on the presence on the surfaces of red blood cells......
kelp, (order Laminariales), any of about 30 genera of brown algae that grow as large coastal seaweeds in colder......
keratitis, inflammation of the cornea, the transparent domelike portion of the eyeball in front of the iris and......
keratosis, any protuberance on the skin resulting from the overdevelopment of the horny outermost covering of the......
kernicterus, severe brain damage caused by an abnormal concentration of the bile pigment bilirubin in brain tissues......
ketogenic diet, dietary regime that eliminates or severely limits carbohydrates in favour of proteins and fats......
ketosis, metabolic disorder marked by high levels of ketones in the tissues and body fluids, including blood and......
Kidd blood group system, classification of human blood based on the presence of glycoproteins known as Kidd (Jk)......
kidney, in vertebrates and some invertebrates, organ that maintains water balance and expels metabolic wastes.......
king oyster mushroom, (Pleurotus eryngii), widely cultivated edible mushroom. King oyster mushrooms are native......
kinocilium, filamentous structure occurring on auditory hair cells in the inner ear that functions in the development......
klebsiella, (genus Klebsiella), any of a group of rod-shaped bacteria of the family Enterobacteriaceae. Klebsiella......
knee, hinge joint that is formed by the meeting of the thigh bone (femur) and the larger bone (tibia) of the lower......
knee-jerk reflex, sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which......
Kupffer cell, any of the stellate (star-shaped) cells in the linings of the liver sinusoids. The sinusoids are......
kuru, infectious fatal degenerative disorder of the central nervous system found primarily among the Fore people......
kwashiorkor, condition caused by severe protein deficiency. Kwashiorkor is most often encountered in developing......
K–T extinction, a global mass extinction event responsible for eliminating approximately 80 percent of all species......
Laboulbeniales, an order of fungi in the class Laboulbeniomycetes (phylum Ascomycota, kingdom Fungi) that includes......
labour, in human physiology, the physical activity experienced by the mother during parturition (q.v.), or...
lactation, secretion and yielding of milk by females after giving birth. The milk is produced by the mammary glands,......
lactic-acid bacterium, any member of several genera of gram-positive, rod- or sphere-shaped bacteria that produce......
Lactobacillus, (genus Lactobacillus), any of a group of rod-shaped, gram-positive, non-spore-forming bacteria of......
lactose intolerance, inability to digest lactose, the predominant sugar in dairy products. It affects people by......
