Anatomy Science Olympiad

Skeletal System - Functions
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Terms in this set (137)
Skeletal System - Functions
Support & shape to body
Protection of internal organs
Movement in union with muscles
Storage of minerals (calcium, phosphorus) & lipids
Blood cell production
How many total bones are there?
206 bones
Axial skeleton
(80 bones) in skull, vertebrae, ribs, sternum, hyoid bone
Appendicular Skeleton
(126 bones)- upper & lower extremities plus two girdles. Half of bones in hands & feet
Long bones
longer than they are wide; shaft & 2 ends (e.g.: bones of arms & legs,except wrist, ankle & patella)
Short bones
roughly cube-shaped (e.g.: ankle & wrist bones)
Sesamoid bones
short bones within tendons (e.g.: patella)
Flat bones
thin, flat & often curved (e.g.,: sternum, scapulae, ribs & most skull bones)
Irregular bones
odd shapes; don't fit into other classes (e.g.: hip bones & vertebrae)
What are the types of vertebrae?
cervical, thoracic, and lumbar
How many cervical vertebrae?7How many thoracic vertebrae?12How many lumbar vertebrae?5What the the first two vertebrae?Atlas (1st) supports head Axis (2nd) pivots to turn headThoracic VertebraeLong spinous processes rib facetsLumbar VertebraeLarge bodies; thick, short spinous processesWhat are the different types of joints?Ball and socket Pivot Saddle Hinge Elipsoid Plane or Gliding vertebraeBones- cellular and physiologycross section structures, cellular composition, bone marrow, cartilage, fracturesOsteoblastsone forming cells synthesize and secrete unmineralized ground substance and are found in areas of high metabolism within the boneOsteocytesmature bone cells made from osteoblasts that have made bone tissue around themselves. They maintain healthy bone tissue by secreting enzymes and controlling the bone mineral content; they also control the calcium release from the bone tissue to the blood.Osteogenic cellsrespond to traumas, such as fractures, by giving rise to bone-forming cells and bone-destroying cellsOsteoclastsbone absorbing cell - large cells that break down bone tissue - important to growth, healing, remodelingBone lining cellsmade from osteoblasts along the surface of most bones in an adult. Bone-lining cells are thought to regulate the movement of calcium and phosphate into and out of the boneLong Bone StructureCompact Bone- (Outer Layer; Haversian System) Spongy Bone- (Ends of long bones) CartilagehematopoiesisThe formation of blood cells takes place mainly in the red marrow of the bones.Where is red marrow found in infants?red marrow is found in the bone cavities. With age, it is largely replaced by yellow marrow for fat storage.Where is red marrow found in adults?red marrow is limited to the spongy bone in the skull, ribs, sternum, clavicles, vertebrae and pelvis. Red marrow functions in the formation of red blood cells, white blood cells and blood platelets.Cartilage - CharacteristicsMostly water; no blood vessels or nerves Tough, resilient New cartilage forms from chondrocytes Heal poorly3 types of Skeletal CartilageHyaline, Elastic, FibrocartilageHyaline Cartilagesfine collagen fiber matrix- most abundant type- found in articular (movable joint) cartilages, costal cartilages (connect ribs tosternum), respiratory cartilages (in larynx & upper respiratory passageways) & nasal cartilagesElastic Cartilagessimilar to hyaline cartilage, more elastic fibers (very flexible) - found in external ear & epiglottis (larynx covering)Fibrocartilagerows of chondrocytes with thick collagen fibers; highly compressible with great tensile strength- found in menisci of knee, intervertebral discs & pubic symphysisTypical Bone FracturesGreenstick spiral comminuted transverse compound vertebral compressionsBone Repair SequenceInjury - broken blood vessels, hematoma Invasion of blood vessels & generalized cells (2-3 days) Fibroblasts develop (1 week) Chondroblasts develop Callus forms (4 weeks) Remodeling with osteoclasts (8 weeks)Disease/Injury LevelsOsteoarthritis Osteoporosis Fractures (via pictures and x-rays) Disc herniation Scoliosis ACL and MCL injuriesMuscle FunctionStabilizing joints Maintaining posture Producing movement Moving substances within the body Stabilizing body position and regulating organ volume Producing heat- muscle contraction generates 85% of the body's heatExcitabilityreceive and respond to stimuliContractilityability to shorten and thickenExtensibilityability to stretchElasticityability to return to its original shape after contraction or extensionSkeletal MuscleAttached to bone move the whole body multiple, peripheral nucleus voluntary striated cylindrical cell shapeSmooth MuscleHollow organs, glands and blood vessels Compression of tubes & ducts Single, central nucleus involuntary not striated spindle-shaped cellsCardiacheart heart contraction to propel blood central & single involuntary striated branchedSkeletal muscleswork in pairs: one muscle moves the bone in one direction and the other moves it back again.Most musclesextend from one bone across a joint to another bone with one bone being more stationary than another in a given movement.Muscle movementbends the skeleton at moveable joints.Tendonsmade of dense fibrous connective tissue shaped like heavy cords anchor muscles firmly to bone.Tendon injurythough very strong and secure to muscle, may be injured.originAttachment to the more stationary bone by tendon closest to the body or muscle head or proximalinsertionattachment to the more moveable bone by tendon at the distal end During movement, the origin remains stationary and the insertion moves.a pull of contractionThe force producing the bending; Reversing the direction is produced by the contraction of a different set of muscles. As one group of muscles contracts, the other group stretches and then they reverse actionsMuscle Bodythousands of muscle fibers in a bundle running from origin to insertion bound together by connective tissue through which run blood vessels and nerves.Each muscle fibercontains many nuclei, an extensive endoplasmic reticulum or sarcoplasmic reticulum, many thick and thin myofibrils running lengthwise the entire length of the fiber, and many mitochondria for energysacromereThe basic functional unit of the muscle fiber consists of the array of thick and thin filaments between two Z disks.thick filamentswith myosin (protein) moleculesthin filamentswith actin (protein) molecules plus smaller amounts of troponin and tropomysin.striationsof dark A bands and light I bands.A bandsare bisected by the H zone with the M line or band running through the center of this H zone.I bandsare bisected by the Z disk or line.Sliding Filament ModelThick filaments, - myosin molecules contain a globular subunit, the myosin head, which has binding sites for the actin molecules of the thin filaments and ATP. Activating the muscle fiber causes the myosin heads to bind to actin molecules pulling the short filament a short distance past the thick filaments. Linkages break and reform (using ATP energy) further along the thick filaments. Ratchet-like action pulls the thin filaments past the thick filaments in a. Individual filaments - No shortening, thickening or folding occurs.muscle contractsthe width of the I bands and H zones decrease causing the Z disks to come closer together, but there is no change in the width of the A band because the thick filaments do not move.muscle relaxes or stretchesthe width of the I bands separate as the thin filaments move apart but the thick filaments still do not move.StrainsInjuries from overexertion or trauma which involve stretching or tearing of muscle fibers. They often are accompanied by pain and inflammation of the muscle and tendon.Sprainthe injury near a joint and involves a ligamentCrampspainful muscle spasms or involuntary twitches.Stress-induced muscle tensionmay cause back pain and headaches.Poliomyelitisviral infection of the nerves that control skeletal muscle movement.Muscular Dystrophiesmost common caused by mutation of gene for the protein dystrophin which helps in attaching and organizing the filaments in the sacromere. Duchenne Muscular Dystrophy and Becker muscular dystrophy are the two most common types. The gene for dystrophin is on the X chromosome so the disorder is sex-linked.Myasthenia Gravisautoimmune disease affecting the neuromuscular junction. affecting the ability of the impulse to cause the muscle contraction. Administering an inhibitor of acetylcholinesterase can temporarily restore contractibility.Effects of Exercise on Muscular SystemExercise helps muscles become more effective and efficient. Tendons will become thicker and stronger High intensity exercise for short duration produces strength, size and power gains in muscles Low intensity exercise for long durations will give endurance benefits Trained muscles have better tone or state of readiness to respond Exercise promotes good posture enabling muscles to work effectively and helps prevent injuryThe integumentary system consists ofthe skin, hair, nails, the subcutaneous tissue below the skin, and assorted glandsSkin FunctionsProtection from injury Protection against infection Regulates body temperature Regulates water loss Chemical synthesis Sensory perceptionTypes of MembranesSerous, Mucous, Synovial, CutaneousSerous MembranesLine body cavities that have no opening to the outside Secrete a watery fluid called serous fluid that lubricates surfacesMucous MembranesLine cavities and tubes that open to the outsideSynovial MembranesForm the inner lining of joint cavities Secrete a thick fluid called synovial fluidCutaneous Membranealso known as skinThin skin1-2 mm on most of the body and 0.5 mm in eyelids - Hairy; Covers all parts of the body except palms, solesThick Skinup to 6 mm thick on palms of hands and soles of feet; Hairless; Covers palms, and solesEpidermal Cell TypesKeratinocytes, Melanocytes, Langerhans cells, Merkel cellsKeratinocytes90 % of epidermal cells are keratinized contains keratin (fibrous protein) protects and waterproofs the skinMelanocytes8% of the epidermal cells produces melanin contributes to skin color and absorbs UV lightLangerhans cellsArise from red bone marrow and migrate to the epidermis -Constitute small portion of epidermal cells -Participate in immune responses Easily damaged by UV lightMerkel cellsLeast numerous of the epidermal cells Found in the deepest layer of the epidermis-Along with tactile discs, they function in sensation of touchEpidermal LayersStratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basaleStratum corneumnuclei and organelles are destroyed by lysosomes and the cells fill with keratinStratum lucidumonly found in the palms and soles of feet 3-5 layers of clear, flat, dead keratinocytes -Dense packed intermediate filaments Thick plasma membranesStratum granulosumcells start to become keritanized --Secretes lipid-rich secretion that acts as a water sealantStratum spinosum8-10 layers of keratinocytes skin both strength and flexibilityStratum basaleAlso referred to as stratum germinatum -where new cells are formedGrowth of EpidermisNewly formed cells in the stratum basale undergo keratinazation as they are pushed to the surface and accumulate more keratin during the process Then they undergo apoptosis or death Eventually they slough off and are replaced The process takes about 4 weeks Rate of cell division in the stratum basale increases during injuryDermisSecond deepest part of skin composed of connective tissue (collagen and reticular fibers)Papillary Layersurface area is increased due to projections called dermal papillae which contains capillaries or tactile receptors -Epidermal ridges conforms to the dermal papillaeReticular LayerContains hair follicles, nerves, sebaceous and sudoriferous glandsHypodermis(Subcutaneous) Attaches the skin to underlying organs and tissues Not part of the skin - lies below the dermis Contains connective tissue and adipose tissues (subcutaneous fat) for insulation Infants and elderly have less of this than adults and are therefore more sensitive to coldFactors that affect Skin ColorGenetics, Environment, Volume of bloodGenetic FactorsSkin pigmentation All humans have the same number of melanocytes How much melanin they produce is controlled by several genes Lack of pigment is called albinismEnvironmental FactorsExposure to sunlightVolume of BloodHemoglobin in bloodMelaninocated mostly in epidermis Two types of melanin: eumelanin which is brownish black and pheomelanin which is reddish yellow Fair-skinned people have more pheomelanin and dark skinned people have more eumelaninEnvironmental Factors Affect Melanin ProductionUV light increases enzyme activity in melansomes - increased melanin production A tan = amount of melanin increases + darkness of melanin Eumelanin = protection from UV radiation but pheomelin breaks down with too much UV Too much UV radiation may cause skin cancerCaroteneyellow -orange pigment precurser of Vitamin A - important for vision Found in Stratum corneum and fatty areas of dermis and hypodermal layerHemoblobinoxygen carrying pigment in red blood cellsfriction ridgesmarkings on fingertips characteristic of primates -allow us to manipulate objects more easily fingerprints are friction ridge skin impressionsflexion lineson flexor surfaces of digits, palms, wrists, elbows etc.- skin is tightly bound to deep fascia at these pointsfrecklesflat melanized patches vary with heredity or exposure to sunmoleselevated patch of melanized skin, of the with hair mostly harmless, beauty marksAging SkinIn our 20s, the effects of aging begin to be visible in the skin. Stem cell activity declines: skin thin, repair difficult Epidermal dendritic cells decrease: reduced immune response Vitamin D3 production declines: calcium absorption declines and brittle bones Glandular activity declines: skin dries, body can overheat Blood supply to dermis declines: tend to feel cold Hair follicles die or produce thinner hair Dermis thins and becomes less elastic - wrinklesSkin DerivativesDuring embryonic development thousands of small groups of epidermal cells from stratum basale push down into dermis to form hair follicles and glandsFunctions of HairHair on the head protects scalp from injury and sunlight Eyelashes and eyebrows protect eyes Nostril and ear hairs protect from foreign particles Help in sensing light touch due to the touch receptors associated with the hair root plexuses.Functions of the NailsGrasping objects Manipulating objects Protects ends of digits from trauma ScratchingShaftportion of hair that projects from skin surfaceRootportion of hair deep to the shaft penetrating the dermis. 3 layers (medulla, cortex, cuticle)Base of the hair follicleBulb: houses the papilla which contains the blood vessels that nourishes the growing hair follicle. Matrix: responsible for hair growth and produces new hairArrector pili: smooth muscleExtends from the dermis to the side of hair follicle.Hair root plexusdendrites of neurons which are sensitive to touchHair Features & TextureAlmost every part of body is covered with hair except palms of hands, soles of feet, sides of fingers and toes, lips and parts of genitals Hair shafts differ in size, shape, and color. In the eyebrows they are short and stiff while on the scalp they are longer and more flexible. Over the rest of the body they are fine and nearly invisible Oval shaped hair shafts produce wavy hair, Flat or ribbon-like hair shafts produce curly or kinky hair Round hair shafts produce straight hair. Roughly 5 million hairs cover the body of an average individualHair GrowthHair follicles grow in repeated cycles. One cycle can be broken down into three phases. Anagen - Growth Phase Catagen - Transitional Phase Telogen - Resting Phase Each hair passes through the phases independent of the neighboring hairsSudoriferous - sweat glandsEccrine sweat glands -Secretes cooling sweat Appocrine sweat glands - during emotional stress/excitementSebaceous - oil glandsAcne - inflammation of sebaceous gland ductsCeruminousmodified sweat glands of the external ear that produce ear waxNailsMade of tightly packed, hard, keratinized epidermal cellsNail bodyportion of the nail that is visible- Free edge: part that extends past the distal end of the digitNail rootportion buried in a fold of skinLunulameans little moon - Crescent shaped area of the nailHyponychiumsecures the nail to the fingertip -Thickened stratum corneumEponychium or cuticlenarrow band of epidermis-Growth of nails is in the nail matrix.Skin ReceptorsHeat Cold Light pressure Heavy Pressure PainSkin InfectionsViral as cold sores, herpes simplex, warts (HPV) Bacterial as bioles, carbuncles, inflammmation of hair follicles and subaceous glands. Impetigo Fungal as athletes food, TineaContact DermatitisIrritant Dermatitis as soaps, detergents, shampoo Allergic Dermatitis as poison ivy, poison oak, rubber gloves, nickel and other medals, fragrancesPsoriasischronic, noninfectious skin disease skin becomes dry and scaly, often with pustules and many varieties stratum corneum gets thick as dead cells accumulate often triggered by trauma, infection , hormonal changes or stressVitiligoa autoimmune pigmentation disorder where melanocytes in the epidermis are destroyed eg Michael JacksonBasal Cell CarcinomaSpread uncommon, very curable if found earlySquamous Cell CarcinomaOccurs parts exposed to the sunMalignant MelanomaMost common in southern hemisphere where the ozone layer is thin. Deadly if not caught early!!Skin CancerAsymmetry Borders Color DiameterSkin Cancer PreventionUse SPF 15 minimum. Wear hats and shirts with sleeves. Wear sunglasses to protect eyes from UV. Avoid tanning beds