Anatomy and Physiology of Animals/Glossary/Q,R,S

A-B | C-D | E-F | G-H | I-J | K-L | M-N | O-P | Q,R,S | T,U,V,W,X,Y,Z | Print version WordMeaningRRadiusThe shorter bone of the forelimb between the humerus and the “wrist”ReceptorA specialized cell that responds to specific sensory stimuli such as touch,pressure, light etc.Red marrowBone marrow found in the spaces of spongy bone.Makes red blood cellsReflexA fast automatic response to a stimulusReflex arcConsists of receptor, sensory, relay and motor neurons and effectorRefractionBending of light as it passes from one medium to anotherRelaxinThe hormone secreted by the placenta and ovaries that eases the joint between the right and left pelvis and dilates the cervix for birthRenalTo do with the kidneyRenal pelvisThe cavity in the centre of the kidneyRenal pyramidA cone shaped structure in kidney medullaRenal systemThe body system involving the kidneysReticulumThe part of the modified stomach of ruminants with honeycomb of raised folds on its inner surfaceRetinaThe inner coat of the eyeball. Nerve calls here (rods and cones) respond to light rayRibosomeThe organelle in the cell that makes proteinsRicketsA bone disorder caused by inadequate vitamin DRodThe photoreceptor in the retina, specialized for vision in dim lightRostralTowards the muzzleRumenThe first and largest compartment of the modified stomach of ruminants.It houses the microorganismsRuminantAn animal with a rumen e.g. sheep, cow, camelRuminationChewing the “cud”SSacrumThe triangular bone formed from fused sacral vertebrae.Located between the two hipbonesSagittal planePlane that divides the body into left and right portionsSagittal sectionLengthwise slice of an animal or organSalivaThe secretion from the salivary glandsSalivary amylaseThe starch digesting enzyme in salivaSaturated fatA fat containing saturated fatty acidsScapulaThe shoulder bladeSciatic nerveThe large nerve that passes down the hind legScleraThe fibrous outer coat of eyeballSeasonal breedingBreeding confined to certain seasons of the yearSebaceous glandAn exocrine gland in the dermis of the skin associated with a hair follicleSebumThe waxy secretion from a sebaceous glandSecondary sex characteristicA characteristic that develops at sexual maturity. e.g. large body size of males, manes in lionsSecretionThe production or release of a fluid from a glandSemenThe fluid discharged at ejaculation of male. Consists of sperm and fluidSemicircular canalsThe membranous fluid filled canals containing receptors for equilibriumSemilunar valveThe valve guarding the entrance to the aorta or the pulmonary arterySeminal vesicleA gland that secretes a component of semenSeminiferous tubuleThe tightly coiled duct in the testis where sperm are producedSemi-permeable membraneA membrane that allows some substances to cross more easily than othersSensory neuronA neuron that carries a nerve impulse towards the central nervous systemSerumPlasma minus its clotting proteinsSesamoid bonesSmall bones usually found in tendonsShockReduced cardiac output resulting in failure to deliver adequate oxygen and nutrients to the bodyShoulderThe synovial joint where the humerus joins the scapulaSinusAn air cavity in a bone especially in the bones of the face or skullSkeletal muscleTissue specialized for contraction with striated fibres. Attached to the bones of the skeletonSkullThe skeleton of the headSmall intestineThe long tube of the gut that begins at the stomach and ends at the large intestineSmooth muscleTissue specialized for contraction with spindle shaped non striated fibresSoft palateThe posterior portion of the roof of the mouthSolutionOne or more substances dissolved in a liquidSpecific gravityA measure of the density of a liquid or solid, as compared with that of water.Sperm ductThe tube that carries sperm from the epididymis to the urethra. Also called the vas deferensSpermatic cordThe structure in the male reproductive system attached to the testis that carries the vas deferens, arteries, veins, etc.SpermatozoonA mature sperm cellSphincterA ring-like muscle that controls movement along a body passage or orificeSpinal cordThe mass of nerve tissue in the vertebral columnSpinal nerveOne of the nerves that originate in the spinal cordSpleenThe large lymphatic organ near the stomach that stores blood and produces lymphocytesSpongy boneThe inner layer of bone; found at the ends of long bones less dense than compact boneSquamousScale likeStarchThe storage polysaccharide in plants consisting of many glucose moleculesSterileFree from any living micro organismsSternumThe breastboneStifleThe joint between the femur and the tibia on the hind legStimulusAny change in the environment capable of initiating a nerve impulseStomachThe large baglike part of the gut between the oesophagus and the small intestineStriated muscleStriped or skeletal muscleSubcutaneousBeneath the skinSubmandibular glandThe salivary gland beneath the tongueSubstrateA substance on which an enzyme actsSulcusA groove or depression between the convolutions of the brainSuperficialNearer to the surface ofSutureAn immoveable joint in the skullSympathetic divisionOne of the two subdivisions of the autonomic nervous system concerned with reacting to emergency situationsSynapseThe junction between two neuronsSynovial jointA fully moveable jointSystemAn association of organs that have a common function, e.g. digestive system, respiratory systemSystemic circulationThe blood circulation from the left ventricl through the aorta to all the organs of the body and back to the heart SystoleThe phase of the heartbeat involving contraction of the ventriclesSystolic blood pressureThe blood pressure during passage of the pulseSynapseThe junction between two neuronsSynovial jointA fully moveable joint