Life Cycle, Processes & Properties, POT-RES
None of us are born looking exactly the way that we do today; this is because humans, like other species, undergo a series of changes as they mature and age, in accordance with their biological life cycle. This process can look very different across different species. In many simple organisms and in higher animals, the life cycle is completed within a single generation, while in most plants, the life cycle is multigenerational.
Life Cycle, Processes & Properties Encyclopedia Articles By Title
potassium deficiency
potassium deficiency, condition in which potassium is insufficient or is not utilized properly. Potassium is a......
Pott disease
Pott disease, disease caused by infection of the spinal column, or vertebral column, by the tuberculosis bacillus,......
Powdery mildew
Powdery mildew, plant disease of worldwide occurrence that causes a powdery growth on the surface of leaves, buds,......
pox disease
pox disease, any of a complex of viral diseases in humans and other animals, marked chiefly by eruptions of the......
Prader-Willi syndrome
Prader-Willi syndrome (PWS), a rare human genetic disorder characterized by weak muscle tone at birth, small stature,......
precocious puberty
precocious puberty, abnormally early onset of human sexual development. In girls, precocious puberty is defined......
Predation
Predation, in animal behaviour, the pursuit, capture, and killing of animals for food. Predatory animals may be......
preeclampsia and eclampsia
preeclampsia and eclampsia, hypertensive conditions that are induced by pregnancy. Preeclampsia, also called gestational......
pregnancy
pregnancy, process and series of changes that take place in a woman’s organs and tissues as a result of a developing......
- Introduction
- Duration, Development, Trimesters
- Uterus, Placenta, Development
- Fertilization, Embryo, Implantation
- Anatomy, Physiology, Organs
- Gastrointestinal, Nutrition, Development
- Urinary Tract, Nutrition, Development
- Blood Changes, Nutrition, Care
- Metabolism, Hormones, Nutrition
- Prenatal Care, Testing, Nutrition
- Abnormal Changes, Complications, Risks
- Abortion, Fetal Development, Complications
- Systemic Diseases, Complications, Risks
- Adrenal Glands, Hormones, Development
- Gastrointestinal, Diseases, Symptoms
- Gestational Diabetes, Nutrition, Exercise
- Placental Inflammation
- Trophoblastic Disease, Placenta, Embryo
premature birth
premature birth, in humans, any birth that occurs less than 37 weeks after conception. A full-term pregnancy lasts......
premenstrual syndrome
premenstrual syndrome (PMS), a medical condition in which a group of characteristic physical and emotional symptoms......
prenatal development
prenatal development, in humans, the process encompassing the period from the formation of an embryo, through the......
- Introduction
- Implantation, Placentation
- Amniotic Sac, Embryo, Fetus
- Growth, Differentiation, Fetal
- Embryonic Form, Growth, Development
- Fetal Growth, Nutrition, Environment
- Fetal Growth, Organs, & Systems
- Brain Development, Neural Migration, Neurons
- Sense Organs
- Muscles, Growth, Development
- Urinary System, Fetal Growth, Hormones
- Embryo, Placenta, Amniotic Sac
- Abnormalities, Complications, Risks
presbycusis
presbycusis, gradual impairment of hearing in old age. Ordinarily it is not experienced until after the age of......
presbyopia
presbyopia, loss of ability to focus the eye sharply on near objects as a result of the decreasing elasticity of......
presentation
presentation, in childbirth, the position of the fetus at the time of delivery. The presenting part is the part......
prevalence
prevalence, in epidemiology, the proportion of a population with a disease or a particular condition at a specific......
priapism
priapism, a persistent, painful erection of the penis unaccompanied by sexual excitation or desire. When normal......
primary sex character
primary sex character, features present at birth that comprise the external and internal genitalia, including the......
processionary caterpillar
processionary caterpillar, (genus Thaumetopoea), small genus of moths, the larval stage of which is known for marching......
proctitis
proctitis, acute inflammatory infection of the anus and rectum. The most common cause of proctitis is the direct......
progeria
progeria, any of several rare human disorders associated with premature aging. The two major types of progeria......
prolapse
prolapse, a downward protrusion of an internal organ out of its normal cavity. The term is usually applied to protrusion......
prophase
prophase, the initial stage of mitosis and of the mitotic division of meiosis, characterized by the formation of......
proprioception
proprioception, the perception by an animal of stimuli relating to its own position, posture, equilibrium, or internal......
prosopagnosia
prosopagnosia, neurological disorder in which affected persons are unable to recognize faces, despite having healthy......
prostate cancer
prostate cancer, disease characterized by uncontrolled growth of cells within the prostate gland, a walnut-sized......
prostatic disorder
prostatic disorder, any of the abnormalities and diseases that afflict the prostate gland in the male reproductive......
Protein
Protein, highly complex substance that is present in all living organisms. Proteins are of great nutritional value......
- Introduction
- Amino Acids, Structure, Function
- Amino Acids, Physicochem.
- Alpha Helix, Beta Sheet, Coil
- Isolation, Determination, Structure
- Structure, Folding, Conformation
- Hydration, Structure, Function
- Electrophoresis, Separation, Structure
- Spectroscopy, Structure, Function
- Denaturation, Structure, Function
- Interfaces, Conformation, Structure
- Structure, Function, Amino Acids
- Keratin, Structure, Function
- Muscle, Structure, Function
- Blood Serum, Structure, Function
- Plant Sources, Structure, Function
- Nucleic Acids, Structure, Function
- Hormones, Structure, Function
- Immunoglobulins, Antibodies, Immunity
- Enzymes, Structure, Function
- Enzymes, Metabolism, Catalysis
- Structure, Function, Metabolism
- Cofactors, Enzymes, Amino Acids
- Active Site, Structure, Function
- Enzymes, Specificity, Structure
- Enzymes, Action, Mechanism
- Enzymes, Inhibition, Regulation
Protein Calculator
Proteins are the major building blocks of the body, serving most notably as the fundamental architects of muscle......
proteinuria
proteinuria, presence of protein in the urine, usually as albumin. Protein is not normally found in the urine of......
prothallium
prothallium, the small, green, heart-shaped structure (gametophyte) of a fern that produces both male and female......
protozoal disease
protozoal disease, disease caused by protozoans. These organisms may remain in the human host for their entire......
Pseudocopulation
Pseudocopulation, the action of a male insect, such as a bee, wasp, or fly, that tries to mate with a flower whose......
pseudohermaphroditism
pseudohermaphroditism, a condition in which the individual has a single chromosomal and gonadal sex but combines......
Pseudopodial locomotion
Pseudopodial locomotion, movement that results when a cell extends a temporary projection of membrane and then......
pseudorabies
pseudorabies, viral disease mainly of cattle and swine but also affecting sheep, goats, dogs, cats, raccoons, opossums,......
pseudotuberculosis
pseudotuberculosis, any of several diseases that are marked by the formation of tubercle-like nodules, similar......
pseudoxanthoma elasticum
pseudoxanthoma elasticum, inherited disease in which the premature breakdown of exposed skin occurs. It is characterized......
psittacine beak and feather disease
psittacine beak and feather disease, debilitating disease of birds cause by a circovirus that infects wild and......
psittacosis
psittacosis, infectious disease of worldwide distribution caused by the bacterial parasite Chlamydia psittaci and......
psoriasis
psoriasis, a chronic, recurrent inflammatory skin disorder. The most common type, called plaque psoriasis (psoriasis......
Psorosis
Psorosis, disease of Citrus plant species caused by several related viruses (family Ophioviridae). Given that the......
psychological development
psychological development, the development of human beings’ cognitive, emotional, intellectual, and social capabilities......
psychopathology
psychopathology, the study of mental disorders and unusual or maladaptive behaviours. An understanding of the genesis......
psychopathy
psychopathy, personality disorder characterized by a set of dysfunctional interpersonal, emotional, lifestyle,......
psychosis
psychosis, any of several major mental illnesses that can cause delusions, hallucinations, serious defects in judgment......
psychosomatic disorder
psychosomatic disorder, condition in which symptoms of physical (somatic) illness or disease are worsened by mental......
pterygium
pterygium, abnormal wing-shaped fold of the conjunctiva (the mucous membrane lining the eyelids and covering most......
ptosis
ptosis, drooping of the upper eyelid. The condition may be congenital or acquired and can cause significant obscuration......
puberty
puberty, in human physiology, the stage or period of life when a child transforms into an adult normally capable......
puerperal fever
puerperal fever, infection of some part of the female reproductive organs following childbirth or abortion. Cases......
puerperium
puerperium, the period of adjustment after childbirth during which the mother’s reproductive system returns to......
pulmonary alveolar proteinosis
pulmonary alveolar proteinosis, respiratory disorder caused by the filling of large groups of alveoli with excessive......
pulmonary circulation
pulmonary circulation, portion of the circulatory system that carries blood between the heart and the lungs. Its......
pulmonary edema
pulmonary edema, buildup of excess fluid in the alveoli (air sacs) of the lungs. Alveoli are the sites of oxygen......
pulmonary embolism
pulmonary embolism, obstruction of a pulmonary artery or one of its branches. The pulmonary arteries carry blood......
pulmonary fibrosis
pulmonary fibrosis, end result of a variety of inflammatory diseases of the lungs in which dense fibrous connective......
pulmonary stenosis
pulmonary stenosis, narrowing of either the pulmonary valve—the valve through which blood flows from the right......
pupa
pupa, life stage in the development of insects exhibiting complete metamorphosis that occurs between the larval......
pupil
pupil, in the anatomy of the eye, the black centre opening within the iris through which light passes before reaching......
Purkinje, Jan Evangelista
Jan Evangelista Purkinje was a pioneer Czech experimental physiologist whose investigations in the fields of histology,......
purpura
purpura, presence of small hemorrhages in the skin, often associated with bleeding from body cavities and in tissues.......
pus
pus, thick, opaque, usually yellowish white fluid matter formed in association with inflammation caused by the......
pustule
pustule, a small circumscribed elevation of the skin that is filled with pus, a fluid mixture containing necrotic......
pyelonephritis
pyelonephritis, infection and inflammation of the kidney tissue and the renal pelvis (the cavity formed by the......
pyothorax
pyothorax, presence of pus in the pleural cavity, between the membrane lining the thoracic cage and the membrane......
pyromania
pyromania, impulse-control disorder characterized by the recurrent compulsion to set fires. The term refers only......
Q fever
Q fever, acute self-limited systemic disease caused by the rickettsia Coxiella burnetii. Q fever spreads rapidly......
Questions About COVID-19 Answered
Through illness, community and national lockdowns, and economic downturn, the COVID-19 pandemic has upended the......
quinsy
quinsy, pus-filled swelling in the throat that develops infrequently as a complication of acute tonsillitis. It......
rabies
rabies, acute, ordinarily fatal, viral disease of the central nervous system that is usually spread among domestic......
radiation injury
radiation injury, tissue damage or changes caused by exposure to ionizing radiation—namely, gamma rays, X-rays,......
Radium Girls: The Women Who Fought for Their Lives in a Killer Workplace
At the onset of World War I, several factories were established across the United States to produce watches and......
radula
radula, horny, ribbonlike structure found in the mouths of all mollusks except the bivalves. The radula, part of......
rat-bite fever
rat-bite fever, relapsing type of infection in which the causative bacteria are transmitted to humans by the bite......
Rathke, Martin H
Martin H. Rathke was a German anatomist who first described the gill slits and gill arches in the embryos of mammals......
Raynaud syndrome
Raynaud syndrome, condition occurring primarily in young women that is characterized by spasms in the arteries......
reactive arthritis
reactive arthritis, disorder characterized primarily by joint pain that also sometimes affects the eyes, urogenital......
reactive attachment disorder
reactive attachment disorder, rare condition in which infants and young children fail to form emotional bonds with......
reagin
reagin, type of antibody found in the serum and skin of allergically hypersensitive persons and in smaller amounts......
receptor
receptor, molecule, generally a protein, that receives signals for a cell. Small molecules, such as hormones outside......
rectocele
rectocele, disorder in which the rectum bulges into the back wall of the vagina. It is caused when the muscles......
Redi, Francesco
Francesco Redi was an Italian physician and poet who demonstrated that the presence of maggots in putrefying meat......
Regeneration
Regeneration, in biology, the process by which some organisms replace or restore lost or amputated body parts.......
rejection sensitive dysphoria
rejection sensitive dysphoria (RSD), a feeling of severe emotional pain in response to rejection, criticism, or......
relapsing fever
relapsing fever, infectious disease characterized by recurring episodes of fever separated by periods of relative......
REM sleep
REM sleep, one of two phases in the sleep cycle, in which a person experiences dreams, atonia (reduced muscle tone),......
Remak, Robert
Robert Remak was a German embryologist and neurologist who discovered and named (1842) the three germ layers of......
renal carcinoma
renal carcinoma, malignant tumour affecting the epithelial (covering and lining) cells of the kidney. Most renal......
renal cell carcinoma
renal cell carcinoma, a disease arising from malignant epithelial cells in the kidneys. Renal cell carcinoma is......
renal cyst
renal cyst, cyst in the kidney. A cyst is an enclosed sac or pouch that usually contains liquid or semisolid material.......
renal osteodystrophy
renal osteodystrophy, complex bone disorder that occurs as a complication of chronic kidney disease (CKD), particularly......
renal system disease
renal system disease, any of the diseases or disorders that affect the human urinary system. They include benign......
repetitive strain injury
repetitive strain injury (RSI), any of a broad range of conditions affecting muscles, tendons, tendon sheaths,......
Reproduction
Reproduction, process by which organisms replicate themselves. In a general sense reproduction is one of the most......
Reproductive behaviour
Reproductive behaviour, any activity directed toward perpetuation of a species. The enormous range of animal reproductive......
- Introduction
- Hormones, Courtship, Mating
- Courtship, Mating, Parenting
- Protective Adaptations
- Group Care, Parental Investment, Social Structure
- Invertebrates, Mating, Courtship
- Mollusks, Courtship, Spawning
- Insects, Courtship, Mating
- Courtship, Mating, Parenting
- Courtship, Nesting, Mating
- Evolution, Animals, Mating
reproductive system disease
reproductive system disease, any of the diseases and disorders that affect the human reproductive system. They......
- Introduction
- Infertility, Endometriosis, PCOS
- Intersexuality, Hormones, Disorders
- Precocious Puberty, Hormone Imbalance, Endocrine Disorders
- Menorrhagia, Endometriosis, Uterine Fibroids
- Impotence, Infertility, Endocrine Disorders
- Syphilis, STD, Bacteria
- Genital Herpes, Symptoms, Treatment
- Genital Warts, HPV, Symptoms
- Trichomoniasis, Symptoms, Treatment
- Infections, Symptoms, Treatments
- Tumours, Diagnosis, Treatment
- Testicular Cancer
- Uterine Fibroids, Symptoms, Treatment
respiratory disease
respiratory disease, any of the diseases and disorders of the airways and the lungs that affect human respiration.......
- Introduction
- Immunity, Pathogens, Defense
- Morphology, Pathology, Diagnosis
- Asthma, COPD, Pneumonia
- Legionnaires, Bacteria, Symptoms
- Asthma, Symptoms, Treatment
- Bronchi, Acute, Symptoms
- Chronic Bronchitis, Symptoms, Treatment
- Lung Cancer, Symptoms, Treatment
- Occupational Lung, Prevention, Treatment
- Industrial Chemicals, Toxicity, Symptoms
- Circulation, Symptoms, Treatment
respiratory distress syndrome of newborns
respiratory distress syndrome of newborns, a common complication in infants, especially in premature newborns,......
respiratory system, human
human respiratory system, the system in humans that takes up oxygen and expels carbon dioxide. The human gas-exchanging......
- Introduction
- Pharynx, Airways, Lungs
- Trachea, Stem Bronchi
- Lungs, Airways, Oxygen
- Blood Vessels, Lymphatic Vessels, Nerves
- Control, Lungs, Airway
- Chemoreceptors, Lungs, Airways
- Lung Receptors, Muscle Receptors, Ventilation
- Mechanics, Lungs, Airways
- Lungs, Airways, Oxygen
- Oxygen Transport, Lungs, Airways
- Gas Exchange, Lungs, Airways
- Abnormal Gas Exchange
- Circulation, Metabolism, Oxygen
- Adaptations, Lungs, Airways
- Swimming, Diving, Lungs