Anatomy & Physiology, PON-SCR
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
pons
pons, portion of the brainstem lying above the medulla oblongata and below the cerebellum and the cavity of the......
portal vein
portal vein, large vein through which oxygen-depleted blood from the stomach, the intestines, the spleen, the gallbladder,......
postsynaptic potential
postsynaptic potential (PSP), a temporary change in the electric polarization of the membrane of a nerve cell (neuron).......
Preen gland
Preen gland, in birds, an organ located on the back near the base of the tail. Paired or in two united halves,......
pregnancy
pregnancy, process and series of changes that take place in a womanās 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
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
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......
priapism
priapism, a persistent, painful erection of the penis unaccompanied by sexual excitation or desire. When normal......
prion
prion, an abnormal form of a normally harmless protein found in the brain that is responsible for a variety of......
Progesterone
Progesterone, hormone secreted by the female reproductive system that functions mainly to regulate the condition......
Prolamin
Prolamin, any of certain seed proteins known as globulins that are insoluble in water but soluble in water-ethanol......
pronephros
pronephros, most primitive of the three vertebrate kidneys, active in the adults of some primitive fish (lampreys......
proprioception
proprioception, the perception by an animal of stimuli relating to its own position, posture, equilibrium, or internal......
Prostaglandin
Prostaglandin, any of a group of naturally occurring lipid compounds that act as chemical messengers, having diverse......
prostate cancer
prostate cancer, disease characterized by uncontrolled growth of cells within the prostate gland, a walnut-sized......
prostate gland
prostate gland, chestnut-shaped reproductive organ, located directly beneath the urinary bladder in the male, which......
prostatic disorder
prostatic disorder, any of the abnormalities and diseases that afflict the prostate gland in the male reproductive......
Protamine
Protamine, simple alkaline protein usually occurring in combination with a nucleic acid as a nucleoprotein. In......
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......
Proteolysis
Proteolysis, Process in which a protein is broken down partially, into peptides, or completely, into amino acids,......
prothrombin
prothrombin, glycoprotein (carbohydrate-protein compound) occurring in blood plasma and an essential component......
Pseudocopulation
Pseudocopulation, the action of a male insect, such as a bee, wasp, or fly, that tries to mate with a flower whose......
psychological development
psychological development, the development of human beingsā cognitive, emotional, intellectual, and social capabilities......
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......
puerperium
puerperium, the period of adjustment after childbirth during which the motherās reproductive system returns to......
pulmonary alveolus
pulmonary alveolus, any of the small air spaces in the lungs where carbon dioxide leaves the blood and oxygen enters......
pulmonary circulation
pulmonary circulation, portion of the circulatory system that carries blood between the heart and the lungs. Its......
pupil
pupil, in the anatomy of the eye, the black centre opening within the iris through which light passes before reaching......
purine
purine, any of a class of organic compounds of the heterocyclic series characterized by a two-ringed structure......
Purkinje cell
Purkinje cell, large neuron with many branching extensions that is found in the cortex of the cerebellum of the......
pylorus
pylorus, cone-shaped constriction in the gastrointestinal tract that demarcates the end of the stomach and the......
pyrimidine
pyrimidine, any of a class of organic compounds of the heterocyclic series characterized by a ring structure composed......
quadriceps femoris muscle
quadriceps femoris muscle, large fleshy muscle group covering the front and sides of the thigh. It has four parts:......
Queen Mabās Stable: 7 of the Smallest Animals
Size isnāt everything. These Lilliputian creatures, the smallest in their respective taxonomic groups, show that......
quill
quill, hollow, horny barrel of a birdās feather, used as the principal writing instrument from the 6th century......
radius
radius, in anatomy, the outer of the two bones of the forearm when viewed with the palm facing forward. All land......
radula
radula, horny, ribbonlike structure found in the mouths of all mollusks except the bivalves. The radula, part of......
reagin
reagin, type of antibody found in the serum and skin of allergically hypersensitive persons and in smaller amounts......
receptive field
receptive field, region in the sensory periphery within which stimuli can influence the electrical activity of......
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......
rectum
rectum, terminal segment of the digestive system in which feces accumulate just prior to discharge. The rectum......
red blood cell
red blood cell, component of blood, millions of which in the circulation of vertebrates give the blood its characteristic......
Relaxin
Relaxin, in common usage, the two-chain peptide hormone H2 relaxin, which belongs to the relaxin peptide family......
REM sleep
REM sleep, one of two phases in the sleep cycle, in which a person experiences dreams, atonia (reduced muscle tone),......
renal artery
renal artery, one of the pair of large blood vessels that branch off from the abdominal aorta (the abdominal portion......
renal capsule
renal capsule, thin membranous sheath that covers the outer surface of each kidney. The capsule is composed of......
renal collecting tubule
renal collecting tubule, any of the long narrow tubes in the kidney that concentrate and transport urine from the......
renal corpuscle
renal corpuscle, filtration unit of vertebrate nephrons, functional units of the kidney. It consists of a knot......
renal lobe
renal lobe, region of the kidney consisting of the renal pyramid and the renal cortex. See renal...
renal pelvis
renal pelvis, enlarged upper end of the ureter, the tube through which urine flows from the kidney to the urinary......
renal pyramid
renal pyramid, any of the triangular sections of tissue that constitute the medulla, or inner substance, of the......
renal system
renal system, in humans, organ system that includes the kidneys, where urine is produced, and the ureters, bladder,......
- Introduction
- Vessels, Nerves, Function
- Ureters, Urinary Bladder, Kidneys
- Urine, Excretion, Bladder
- Urine, Kidneys, Excretion
- Blood Flow, Glomerulus, Nephron
- Tubule Function, Urine Formation, Excretion
- Urine Concentration, Kidneys, Excretion
- Acid-Base Balance, pH Regulation, Homeostasis
- Urine Collection, Emission
- Tests, Function, Kidney
- Hormones, Regulation, Function
renin-angiotensin system
renin-angiotensin system, physiological system that regulates blood pressure. Renin is an enzyme secreted into......
reproductive system, Animal
Animal reproductive system, any of the organ systems by which animals reproduce. The role of reproduction is to......
- Introduction
- Sponges, Coelenterates, Flatworms
- Annelids, Mollusks, Reproduction
- Arthropods, Fertilization, Reproduction
- Fertilization, Gametes, Union
- Parthenogenesis, Reproduction, Fertilization
- Embryo Development, Fertilization, Nutrition
- Vertebrates, Fertilization, Reproduction
- Male Systems, Hormones, Reproductive Organs
- Accessory Glands, Fertilization, Reproduction
- Female Anatomy, Fertilization, Reproduction
- Tracts, Hormones, Fertilization
- Internal Fertilization, Adaptations, Reproduction
- Gonads, Hormone Cycles, Reproduction
reproductive system, human
human reproductive system, organ system by which humans reproduce and bear live offspring. Provided all organs......
Respiratory system
Respiratory system, the system in living organisms that takes up oxygen and discharges carbon dioxide in order......
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
resting potential
resting potential, the imbalance of electrical charge that exists between the interior of electrically excitable......
reticular fibre
reticular fibre, in anatomy, fine fibrous connective tissue occurring in networks to make up the supporting tissue......
reticulocyte
reticulocyte, non-nucleated stage in the development of the red blood cell, just before full maturity is reached.......
retina
retina, layer of nervous tissue that covers the inside of the back two-thirds of the eyeball, in which stimulation......
retinitis pigmentosa
retinitis pigmentosa, group of hereditary eye diseases in which progressive degeneration of the retina leads to......
retinopathy
retinopathy, damage affecting the small blood vessels in the retina, the light-sensitive layer at the back of the......
retinopathy of prematurity
retinopathy of prematurity, disease in which retinal blood vessels develop abnormally in the eyes of premature......
Rett syndrome
Rett syndrome, rare progressive neurological disorder characterized by severe intellectual disability, autism-like......
Rh blood group system
Rh blood group system, system for classifying blood groups according to the presence or absence of the Rh antigen,......
rhabdom
rhabdom, transparent, crystalline receptive structure found in the compound eyes of arthropods. The rhabdom lies......
Rhodopsin
Rhodopsin, pigment-containing sensory protein that converts light into an electrical signal. Rhodopsin is found......
rib
rib, any of several pairs of narrow, curved strips of bone (sometimes cartilage) attached dorsally to the vertebrae......
rib cage
rib cage, in vertebrate anatomy, basketlike skeletal structure that forms the chest, or thorax, and is made up......
Ribose
Ribose, five-carbon sugar found in RNA (ribonucleic acid), where it alternates with phosphate groups to form the......
ribosomal RNA
ribosomal RNA (rRNA), molecule in cells that forms part of the protein-synthesizing organelle known as a ribosome......
ricin
ricin, toxic protein (toxalbumin) occurring in the beanlike seeds of the castor-oil plant (Ricinus communis). Ricin,......
Riedel thyroiditis
Riedel thyroiditis, extremely rare form of chronic inflammation of the thyroid gland, in which the glandular tissues......
Rigor mortis
Rigor mortis, physiological process that occurs within hours after death, wherein muscle tissue stiffens. Rigor......
RNA
RNA, complex compound of high molecular weight that functions in cellular protein synthesis and replaces DNA (deoxyribonucleic......
rod
rod, one of two types of photoreceptive cells in the retina of the eye in vertebrate animals. Rod cells function......
saccade
saccade, fast, intermittent eye movement that redirects gaze. Saccades may involve the eyes alone or, more commonly,......
Sacroiliac
Sacroiliac, weight-bearing synovial joint that articulates, or connects, the hip bone with the sacrum at the base......
sacrum
sacrum, wedge-shaped triangular bone at the base of the vertebral column, above the caudal (tail) vertebrae, or......
sago
sago, food starch prepared from carbohydrate material stored in the trunks of several palms, the main source being......
saliva
saliva, a thick, colourless, opalescent fluid that is constantly present in the mouth of humans and other vertebrates.......
salivary gland
salivary gland, any of the organs that secrete saliva, a substance that moistens and softens food, into the oral......
sap
sap, watery fluid of plants. Cell sap is a fluid found in the vacuoles (small cavities) of the living cell; it......
Sarcoplasmic reticulum
Sarcoplasmic reticulum, intracellular system of closed saclike membranes involved in the storage of intracellular......
sartorius muscle
sartorius muscle, (from the Latin sartor, āmenderā), long, narrow, ribbonlike thigh muscle beginning at the front......
scale
scale, in zoology, small plate or shield forming part of the outer skin layers of certain animals. Scales provide......
scapula
scapula, either of two large bones of the shoulder girdle in vertebrates. In humans they are triangular and lie......
Schmidt sting pain index
Schmidt sting pain index, measure of the relative amount of pain that various insects of the order Hymenoptera......
Schwann cell
Schwann cell, any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal......
sciatic nerve
sciatic nerve, largest and thickest nerve of the human body that is the principal continuation of all the roots......
scleritis
scleritis, inflammation of the sclera, the white part of the eye. The inflammation is immune-mediated and is commonly......
Scleroprotein
Scleroprotein, any of several fibrous proteins of cells and tissues once thought to be insoluble but now known......
Sclerotin
Sclerotin, a dark-brown biological pigment formed by an enzyme-catalyzed tanning of protein. Sclerotin is found......
scrotum
scrotum, in the male reproductive system, a thin external sac of skin that is divided into two compartments; each......