MUSCLESKELETAL SYSTEM Flashcards
(47 cards)
1
Q
FUNCTIONS OF BONE
A
- framework of the body
- attachment for muscles and tendons
- movement
- protection for major organs
- Haemopoiesis (production of blood cells in red bone marrow)
- mineral storage - calcium phosphate (matian maintaining blood calcuim levels)
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Q
CLASSIFICATION OF BONES
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- bones = the thin outer layer of compact bone
- spongy bone = inside contains red bone marrow
> long bone: 2 extremities
short bones: chunky and boxy
flat bones, curved and thin
irregular bones: multiple processes and projections
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Q
BONE DEVELOPMENT
A
- The process of bone formation is called osteogenesis or ossification.
- Three stages of development of cell differentiation:
> proliferation,
> maturation of matrix,
> mineralisation. - Embryological origin, there are two types of ossification, called intramembranous ossification, which occurs in mesenchymal cells that differentiate into osteoblasts in the ossification centre directly without prior cartilage formation and endochondral ossification, in which bone tissue mineralisation is formed through cartilage formation
Intramembranous ossification, bone development occurs directly. In this process, mesenchymal cells proliferate into areas with high vascularisation in embryonic connective tissue to form cell condensation or primary ossification centres. - The cell will synthesise bone matrix in the periphery, and the mesenchymal cells continue to differentiate into osteoblasts. After that, the bone will be reshaped and replaced by mature lamellar bone.
- Endochondral ossification will form the center of primary ossification, and the cartilage extends by proliferation of chondrocytes and deposition of cartilage matrix
- Begins before birth and finishes at about 21 - 30 years.
Long, short and irregular bones develop in the foetus from rods of cartilage, called cartilage models. - Flat bones develop from membrane models and sesamoid bones from tendon models
- During ossification, osteoblasts secrete osteoid (unmineralized bone tissue), which gradually replaces cartilage. They then lay down calcium and phosphate salts through the osteoid, calcifying it – hardening the structure into bone.
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Q
BONE STRUCTURE & DEVELOPMENT - EMBRYOLOGY
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- Bone is connective tissue
- calcium phosphate = makes the bones hard
BONE CELLS: osteoblasts, osteoclasts, osteocytes
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BONE CELL TYPES
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6
Q
OSTEOBLASTS - B = BUILD
A
- bone-forming cells, deposit inorganic salt & osteoid into bone tissue
- involved in bone growth, repair, and remodelling
- Osteoblasts deposit new bone tissue around themselves and become trapped in lacunae (pockets) & differentiate (change into osteocytes
- Osteocytes are mature bones that don’t divide
- monitor and maintain bone tissue &nourished by tissue fluid in canaliculi
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Q
OSTEOCLASTS - C =CLEAR
A
- Break down the release of calcium and phosphate
- 50 nuclei
- found in the bone where active growth, repair or remodelling
> under periosteum (maintain the shape) - perisoteum membrane of blood vessels and nerves that rap around most of your bones
- round wall of the medullary canal during growth
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Q
COMPACT (CORTICAL) BONE
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- osteon - harversian system = function of units of bone (vascular tunnels)
- Osteons aligned according to the forces that are applied to the bone
- LAMELLAE (layers) of bone arranged around each central canal
- lacunae communciate with canalicli = ciruclation of interstitial fluid
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Q
CANCELLOUS (SPONGY, TRABECULAR) BONE
A
- honeycomb arrangement
- space contains red bone marrow = produces blood cells
- bone tissue isnt dense it does contain osteons
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Q
SPONGY BONE
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- space to store red bone marrow
- tradbeculae - thin columns of bone
- lamellae - layers of bone
11
Q
LONG BONE STRUCTURE
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Hyaline cartilage provides mechanical support. slippery and smooth to reduce friction
- diaphysis - shaft, compact bones, with central medullary canal, yellow bone marrow. Nutrient arteries supply the diaphysis
- Sensory nerve supply = diaphysis
-EPIPHYSES: extremities, compact bone, spongy bone inside. Epiphyses have their own blood supply
- metaphases between epiphysis and diaphysis
- long bones are mostly covered with vascular membrane (periosteum)
2 layers: periosteum (outer tough, fibrous layer) & endosteum (inner layer of bone cells)
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Q
ANTERIOR SKELETON
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12
Q
THE SKULL
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13
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THE SKULL
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13
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THORAX AND RIBS
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14
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VERTEBRAL COLUMN
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15
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VERTEBRAL COLUMN
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SACRUM & COCCYX
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SCAPULA
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SCAPULA
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HUMERUS
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RADIUS & ULNA
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HAND
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PELVIS
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FEMUR
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TIBIA & FIBULA
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FOOT
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TYPES OF JOINTS
FIBROUS JOINTS:
- bone joined by fibrous tissue
- No movement between the bones
- sutures between skull bone, teeth and between the tibia and fibula
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TYPE OF JOINTS
- CARTILAGINOUS JOINTS
- FIBROCARTILAGE between bones = shock absorber
- EPIPHYSEAL PLATE between diaphysis & epiphysis (growing children)
- vertebral bodies - separated by intervertebral dics
- symphysis pubis - fibrocartilage softened by hormones during pregnancy
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CARTILAGINOUS JOINTS SYNOVIAL JOINTS
- space or capsule between bones
- the bone end held together by sleeve or fibrous tissue (joint capsule)
- bone ends covered with hyaline cartilage
- joint lubricated with synovial fluid.
- fluid nourishes the joint cavity contains phagocytes
- moveable joints
ENTHESIS - tendons/ligaments insert into bone
LIGAMENT: bone to bone
TENDON: muscle to bone
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SHOULDER JOINT
GLENOID CAVITY: pear-shaped dip in scapula (puzzle piece)
GLENOID LABRUM: cartilage ring helps stabilise joints & deepen the space for the humerus
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HIP JOINT
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KNEE JOINTS
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SYNOVIAL JOINT MOVEMENTS
FLEXION: bending (forward, but can be backwards)
EXTENSION: straightening/bending backwards
ABDUCTION: movement away from midline
ADDUCTION: movement towards the midline of the body
CIRUCLATION: movement of limbs or digits describes the shape of a cone
ROTATION: movement around the long axis of a bone
PROTATION: turning the palm of the hand down
SUPINATION: turning the palm of the hand up
INVERSION: turning the sole of the foot inwards
EVERSION: turning the sole of the foot outwards
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TYPES OF SYNOVIAL JOINTS - MOVEMENT
BALL &N SOCKET: shoulder and hip
HINGE: elbow, ankle, interphalangeal
GLIDING: intercarpal, intertarsal, between spinous processes
PIVOT: head rotates on the pivot joint between the axis and atlas
CONDYLOID: joint between the condylar process of the mandible and the temporal bone; joints between metacarpals/metatarsals and phalanges
SADDLE: joint between trapezium and first metacarpal
KNEE JOINT: hinge movement is greater
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SKELETAL MUSCLE
TENDONS: hold muscle to bone
LIGAMENTS: hold bone to bone
- contractile cenlls = fibres
- skeletal muscles = volentary control = attached to bone via tendon
- muscle contains thousands of muscle fibres & blood vessels & connective tissue
- epimysium: outer connective tissue sheath
- Bundles = fascicles contain muscle cells (fibres). Fascicle surrounded by perimysium (connective tissue)
- muscle fibre surrounded by endomysium (fine connective tissue)
- 3 layers run down the length of muscle and with fibres, they blend together to form tendons
- fleshy part of muscle in belly
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MUSCLE FIBRES
- coordinated contraction of fibres in the contracted in whole skeletal muscle
- muscle fibre = cylindrical and parallel to each other = banded with dark and light strips
- Fibres have multiple nuclei, = proteins and enzymes can be produced
- The cell membrane in cells is called the sarcolemma. Fluids inside cells (cytoplasm) in the sarcoplasm contain many contractile filaments - MYOFIBRILS
- contain many mitochondria (generate chemical energy in cell) produce andenosine triphosphrate (ATP) from glucose & oxygen = muscle contrations
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MYOFIBRILS
- 2 types of contractile proteins = actin. (thin filaments) & myosin (thick filaments)
- repeating un of sarcomeres (functional unit of muscle cells) what gives the muscle there stripes
- MYOSIN: thick filaments seen as darker vs thinner and lighter filamen s of actin
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DISCS, LINES, BANDS AND ZONES
- sacromeres = dense stripes at each end, where anti fibres are attached
- M LINES: run up middle of sarocomere mysoin fibres
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POSTERIOR MUSCULATURE
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FACE & NECK MUSCLES
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ABDOMINAL WALL MUSCLES
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SHOULDER AND ARM MUSCLES
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LEG MUSCLES
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NEUROMUSCULAR JUNCTION
- contraciton happens in respsons to stiumualtion from notor nerve fibre
- nerve fibre synapase with muscle fibre filimanets
- neurotranmitter acetylcholine = released ACh stimulates muscle cell contraction
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SKELETAL MUSCLE CONTRACTION
1. Release of ACh generates an action potential (Rapid sequence of changes in voltage across a cell membrane) that spreads rapidly along the muscle fibre membrane.
2. Calcium is released from the intracellular stores.
3. This triggers binding of actin and myosin, forming cross-bridges (The myosin heads grab onto the actin fibres)
4. ATP provides energy for actin and myosin filaments to slide over each other, pulling the Z lines closer together and shortening the sarcomere = contraction.
(Myosin filaments pull the Actin filaments closer)
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SKELETAL MUSCLE RELAXATION
1. When the motor nerve stimulation stops, calcium is pumped back to the intracellular stores
2. This breaks the cross-bridges between actin and myosin filaments
(The Myosin lets go of the Actin)
3. They slide back to their resting positions
4. The sarcomere lengthens and returns the muscle to its original length
