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Lecture Exam #2
Skeletal system & muscular system
| Term | Definition |
|---|---|
| Function of skeletal system | Support framework, movement, organ protection, mineral storage, blood-cell formation, fat storage, hormone synthesis |
| Axial skeleton | Central bones like skull, ribs, spine, hips |
| Appendicular skeleton | Limb bones in arms and legs |
| Long bone description | Longer than wide |
| Long bone examples | Femur, humerous, metacarpals, phalanges, tibia, etc |
| Short bone description | Cubish, small bone |
| Seismoid bone | Special short bone forming in a tendon (Ex. patella) |
| Short bone examples | Carpals, tarsals |
| Flat bone description | Thin, flat, slightly curved |
| Flat bone examples | Sternum, ribs, scapula, skull |
| Irregular bone description | A bone that doesn't fit any of the other description |
| Irregular bone examples | Vertebra, hip bones, sphenoid, ethanoid |
| Epiphysis | The ends of a long bone |
| Diaphysis | Shaft of a long bone |
| Spongy bone | Network of trabeculae often filled with red bone marrow |
| Compact bone | Dense bone tissue comprised of circular osteons |
| Medullary cavity | Hollow cavity in long bones with yellow bone marrow |
| Nutrient artery/vein | Main blood vessels for long bone diaphysis |
| Epiphyseal artery/vein | Main blood vessel for long bone epiphyses |
| Articular cartilage | Hyaline cartilage covering epiphyses and joint areas on bones |
| Diploe | Layer of spongy bone in between compact bone in flat bones |
| Periosteum | Outer covering of bone with two layers |
| Superficial periosteum layer | Dense irregular connective tissue to resist tensile forces |
| Deep layer/osteogenic periosteum layer | Layer of bone remodeling with osteoblasts, osteoclasts, stem cells |
| Endosteum | Inner bone lining for medullary cavity, trabeculae, central canal of areolar connective tissue with osteogenic cells |
| Perforating (Sharpey's) fibers | Collagen fibers attaching periosteum to bone, concentrated at attachment points for muscles, ligaments, tendons |
| Percentage of bone made of organic components | 35% |
| Osteoid | Organic matrix part of collagen, proteoglycans, glycoproteins, water, GAGs |
| Percentage of bone made of inorganic components | 65% |
| Hydroxyapatites | Inorganic bone components (mainly Ca and P) |
| Osteon (Haversian system) | Structural unit of compact bone |
| Circumferential lamellae | External and internal rings around bone |
| Interstitial lamellae | Incomplete rings in between osteons |
| Central canal (Haversian canal) | Central tube of an osteon lined with endosteum, holds blood vessels and nerves |
| Lamellae | Concentric rings forming osteons, has parallel collagen fibers for resistance to tensile forces |
| Perforating canal | Canals in between osteons allowing blood and nerves through |
| Osteocyte | Cell living in osteon lacunae that help with repair |
| Lacunae | Gaps in lamellae for osteocytes to reside |
| Canaliculi | Small cracks for osteocyte extensions to connect between cells |
| Ossification/osteogenesis | Bone tissue formation |
| Before 8 weeks, embryo skeleton is mostly _____ | Hyaline cartilage |
| Intramembranous ossification | Bone forms directly from mesenchymal cells (stem cells) |
| Bones formed by intramembranous ossification | Flat skull bones and clavicle |
| Endochondral ossification | Bone develops from hyaline cartilage |
| Bones formed by endochondral ossification | Every other bone besides clavicle and flat skull bones |
| Bone growth occurs at the ___ | Epiphyseal plates |
| Bone growth occurs due to ____ | Growth and hardening of hyaline cartilage |
| Interstitial growth | Bones lengthen by epiphyseal plate growth |
| Appositional growth | Bone widens due to addition of bone tissue on surface |
| Epiphyseal plate closure | When epiphysis and diaphysis fuse, halting interstitial growth |
| Resting zone | Zone of amitotic hyaline cartilage |
| Proliferation zone | Zone of actively mitotic hyaline cartilage where cartilage growth occurs |
| Hypertrophic zone | Zone where chondrocytes enlarge and begin to disintegrate |
| Calcification zone | Zone where enlarged chondrocytes absorb Ca and P |
| Ossification zone | Zone where bone tissue replaces cartilage |
| Bone remodeling | Constant removal and replacement of bone tissue occurring at endosteal surface of bone |
| Bone resorption | Removal of bone tissue by osteoclasts |
| Bone deposition | Bone tissue added by osteoblasts |
| Growth hormone | Secreted from pituitary to stimulate epiphyseal plate growth |
| Thyroid hormone | Controls growth hormone to ensure proper skeleton proportions |
| Sex hormones | Promote bone growth in adolescence, later induces closure of epiphyseal plate |
| Calcitonin | Thyroid hormone that decreases blood Ca levels through osteoblast/osteoclast regulation |
| Parathyroid hormone | Hormone that increases blood Ca levels by osteoblast/osteoclast and urine regulation |
| Fracture | Break or crack in bone |
| Greenstick | Incomplete fracture in kids |
| Open (compound) fracture | Bone penetrated skin |
| Closed (simple) fracture | Bone hasn't penetrated skin |
| Comminuted fracture | Bone breaks into 3+ pieces |
| Closed reduction | Doctor manually realigns bone into normal position |
| Open reduction | Bone is realigned by surgical plates, screws, or pins |
| Immobilization | Bone held in place by cast or traction |
| Complete fracture | Break cuts through both sides of the bone |
| Incomplete fracture | Break doesn't cut through both sides |
| Displaced fracture | Broken bone ends are misaligned |
| Non-displaced fracture | Broken bone ends are still aligned properly |
| Osteoporosis | When bone resorption outpaces deposition |
| Prevention/treatment for osteoporosis | Weight-bearing exercise, dietary Ca and Vitamin D, estrogen replacement, osteoclast-suppressing drugs, selective estrogen receptor modulators |
| Osteomalacia | Inadequate bone mineralization in adults |
| Rickets | Osteomalacia in kids causing bone malformations |
| Osteosarcoma | Type of bone cancer mainly in long bones around knee, cause of death usually secondary tumor in lungs |
| Synarthrosis | Immovable joint |
| Amphiarthrosis | Slightly moveable joint |
| Diarthrosis | Freely moveable joints |
| Synarthrosis Example | Sutures, tibia-fibula joint |
| Amphiarthrosis Example | Pubic symphysis, intervertebral discs |
| Diarthrosis Example | Synovial joints |
| Fibrous joints | Mostly immovable joints without joint cavities made of collagen ligaments |
| Suture joint | Fibrous joint with minimal short fibers, immovable |
| Syndesmosis joint | Fibrous joint with collagen fibers, fiber length determines movement, slightly moveable |
| Gomphosis joint | Fibrous joint to fibrous periodontal ligaments attaching tooth to socket, immovable |
| Cartilaginous joints | Joints connected by cartilage, no joint cavity |
| Synchondroses (primary) | Cartilaginous joint made of hyaline cartilage, synarthrotic |
| Symphysis (secondary) | Cartilaginous joint made of fibrocartilage, amphiarthrotic |
| Synchondrosis example | Epiphyseal plate, 1st sternocostal joint |
| Symphysis example | Pubic symphysis, intervertebral discs |
| Synovial joints | Diarthrotic joints with a fluid filled joint cavity |
| Synovial joint stability depends on ___ | Articular surface shape, ligaments, and muscle tone |
| Muscle tone | Constant low level contraction keeping tendons tense for stabilization |
| Joint cavity/synovial cavity | Contains synovial fluid for friction reduction and nutrients |
| Articular cartilage | Hyaline cartilage covering bone surfaces in joint |
| Fibrous capsule | Forms joint capsule, outer layer of dense irregular CT, inner synovial membrane of loose areolar CT that makes synovial fluid |
| Synovial fluid | Blood filtrate that lubricates and nourishes joint |
| Reinforcing ligaments | Attach bone to bone, stabilizing joint |
| Ligament | Attach bone to bone |
| Tendon | Attach bone to muscle |
| Proprioceptors | Sensory nerves monitoring stretch of joints |
| Nociceptors | Sensory nerves, pain receptors |
| Articular discs | Fibrocartilage disc in joint cavity, improve fit of bones or allow 2 different motions |
| Bursa | Flattened, fluid-filled, fibrous sac lined by synovial membrane, reduce friction between joint parts |
| Tendon sheath | Elongated, fluid filled sac wrapping around tendons subject to friction |
| Nonaxial (translational) | No angular motion, gliding only |
| Uniaxial | 1 axis of movement |
| Biaxial | 2 axes of movement |
| Multiaxial | All 3 axes of movement |
| Hinge joint | Uniaxial synovial joint, elbow, ankle, interphalangeal joints |
| Pivot joint | Ring of encircling ligament, uniaxial, proximal radioulnar joint, alantoaxial joint |
| Saddle joint | Biaxial synovial joint, thumb (carpometacarpal joint) |
| Plane/Planar joint | Nonaxial synovial joint, vertebral joints, intercarpal and intertarsal joints |
| Condyloid joint | egg-shaped, biaxial synovial joint, wrist (metacarpophalangeal joints) |
| Ball-and-socket joint | Multiaxial synovial joint, hip and shoulder |
| Muscle function | Produce movement, maintain posture, stabilize joints, generate head, open/close passageways |
| Excitability (responsiveness) | Ability to be stimulated by electric nerve impulses |
| Conductivity | Waves of excitation can travel along muscle fiber |
| Contractility | Cell shortens (contracts) when stimulated |
| Extensibility | Can be stretched between contractions |
| Tendon | Connects muscle to bone, made of dense regular CT |
| Epimysium | External muscle covering of dense irregular CT |
| Perimysium | Dense regular CT covering each fascicle |
| Fascicle | Bundle of muscle fibers |
| Endomysium | Areolar CT covering muscle fibers in a fascicle |
| Muscle fiber | Cellular unit of muscles |
| Myofibril | Contractile organelle made of sarcomeres, multiple in a muscle fiber |
| Origin | Less movable muscle attachment |
| Insertion | More movable muscle attachment |
| Direct attachment | Epimysium directly attached to periosteum |
| Indirect attachment | Tendons/aponeurosis/raphe attach epimysium to periosteum |
| Aponeurosis | Sheet-like thin tendon |
| Raphe | Seam-like tendon without bony attachement, soft tissue only |
| Myofilaments | Contractile proteins making up a myofibril |
| Sarcolemma | Plasma membrane of myofibril |
| Transverse (T) tubules | Sarcolemma extensions for nerve impulse to travel through |
| Triad | A T tubule and adjoining terminal cisternae of SR |
| Sarcoplamic reticulum | Smooth ER of muscle fiber containing Ca2+ |
| Myoglobin | Similar protein to hemoglobin found in muscles |
| Sarcomere | Basic unit of contraction comprising myofibrils |
| Titin | Huge springy protein stabilizing thick filament |
| Dystrophin | Protein linking outermost actin to sarcolemma to transfer contraction to CT |
| Muscular dystrophy | Progressive disease caused by genetic defect in dystrophin |
| Thick filament | Many strands of myosin proteins |
| Fibrous (F) actin | 2 intertwined strands of G actin |
| Globular (G) actin | Actin subunits with myosin binding sites |
| Tropomyosin | Protein strand blocking active sites on G actin |
| Troponin | Protein binds to Ca and shifts tropomyosin to uncover binding sites |
| I band | Light striation band, only thin filaments covering adjacent sarcomeres, shortens when contracted |
| A band | Dark striation band, full length of thick filament |
| Z disc | Boundary edge of sarcomere, move closer together when contracted |
| H zone | Zone of thick filament without thin filament, disappears when contracted |
| M line | Rods in middle of H zone holding thick filament |
| Somatic motor neuron | Cell body in spinal cord, axons branch out to muscle fibers |
| Synapse | Where nerve fiber (axon) meets target cell |
| Neuromuscular junction | Synapse for muscle fiber |
| Motor end plate | Wide axial end of motor neuron stimulating muscle fiber at many neuromuscular junctions |
| Synaptic knob | Wide end of motor nerve fiber |
| Synaptic cleft | Gap between knob and plasma membrane |
| Junctional folds | Folds in sarcolemma increasing surface area for more transmission |
| Schwann cell | Myelin sheath on neuron preventing signal loss |
| Basal lamina | Layer in neuromuscular junction with AChE |
| Synaptic vescicle | Holds neurotransmitters like ACh |
| Acetylocholine (ACh) | Neurotransmitter |
| Acetylocholisterase (AChE) | Enzyme breaking down ACh |
| ACh receptor channels | Ligand-gated channels in sarcolemma binding to 2 ACh |
| End Plate Potential (EPP) | Muscle fiber specific change in membrane potential causing a brief, short range signal |
| Electric potential | Difference in electrical charge across membrane |
| Local potential | EPP but for general synapse |
| Action potential | Large change in membrane potential creating brief, long range signal, only occurs if threshold is reached |
| Resting membrane potential | -90 mV for skeletal muscles |
| Muscle excitation | Nerve action potentials that can lead to contraction |
| Depolarization | Interior of muscle fiber becomes more positive |
| Repolarization | Interior of muscle fiber returns to negative baseline |
| Excitation-Contraction Coupling | Action potentials in sarcolemma trigger events that cause muscle contraction |
| Sliding filament mechanism | Interaction of thick and thin filaments contract sarcomeres |
| Rigor mortis | Muscle/body stiffness 3-4 hours after death |
| Motor unit | Group of muscle fibers innervated by same nerve |
| Small motor units | Good for fine degree of control |
| Large motor units | Good for powerful contractions |
| Muscle twitch | Quick cycle of contraction from a single action potential |
| Latent period | Delay between stimulus and contraction for excitation-contraction coupling |
| Contraction phase | Cross-bridge formation occurs |
| Relaxation phase | Ca reenters SR to decrease tension, usually lasts longer than contraction |
| Subthreshold stimuli | Stimulus isn't enough to cause contraction |
| Higher voltage leads to ____ | More activated nerve fibers and more motor units recruited |
| Recruitment | Increasing stimuli activates more motor units |
| Stimulus frequency | How often stimulus is sent |
| Temporal (wave) summation | Each new twitch builds on previous, increasing tension |
| Incomplete tetanus | Partial relaxation causes fluttering contraction |
| Complete (fused) tetanus | Steady max contraction caused by unnaturally high stimuli frequency |
Created by:
XiaoYiSheng