Bioscience And Nursing Musculoskeletal System Flashcards
Bone functions
Support
Protection
Store minerals and triglycerides
Maintain homeostatic blood calcium levels
Blood cell production (haemotopiesis)
Movement
Origin
Fixed point of muscle attachment (bone don’t move when muscle contracts)
Insertion
Moveable point of muscle attachment (bone moves when muscle contracts)
Axial skeleton
Made up of bones of the skull, vertebral column and rib cage
Appendicular skeleton
Made up of bones of upper limbs (arms, forearms & hands), lower limbs (thighs, legs & feet)
Shoulder (pectoral) girdles & pelvic girdle
Long bones
Long slender bones, have a shaft (diaphysis) & bone ends (epiphysis) e.g humerous
Short bones
Small cube shaped bones e.g tarsals, carpals, patella
Flat bones
Thin, flat & often curved e.g sternum, ribs & scapula
Irregular bones
Complex shaped bones e.g vertebrae & hip bones
Bone structure
Contains: connective tissue, adipose tissue, osseous tissue & hyaline cartilage
Osseous tissue
Connective tissue which contains specialised cells & a matrix
Matrix
Consists of ground substance, collagen fibres & calcium phosphate crystals
makes bones flexible hard and strong
Collagen fibres
Gives bones flexibility and tensile strenght
Calcium phosphate crystals
Makes bones hard and provide compressive strenght
Bone without crystals
Has tensile strength but lacks compressive strength-soft and flexible
Bone without collagen fibres
Hard with compressive strength, lack flexibility & tensile strength-brittle
Osteoprogenitor cells
Stem cells which differentiate into osteoblasts
Osteoblasts
Bone building cells-produce and secrete collagen fibres and ground substance
Osteoclasts
bone reabsorbing cells-breakdown matrix and release stored minerals
Osteocytes
mature bone cells which maintain the matrix
layers of bones
outer layer of compact bone & internal layer of spongy bone
outer connective tissue membrane=periosteum
covers compact bone, contains blood vessels & nerves
internal connective tissue membrane=endosteum
covers spongy bone
yellow bone marrow
stores adipose tissue
red bone marrow
making of RBC’s (hematopoiesis)
spongy bone
contains trabeculae (thin needle-like structures)
lighter than compact bone-reduces weight off skeleton
trabeculae function
resist forces from all directions without breaking
interstitial growth
new cartilage is formed on the epiphyseal plate & old cartilage is turned to bone-diaphysis gradually lengthens
Bone remains strong because growth is at the top and bottom at the same time
interstitial growth makes bones longer, occurs at epiphyseal gate
appositional growth
makes bones grow wider-occurs on outer surface of all bones.
step 1. osteoblasts secrete layers of new matrix onto bone surface-becomes contact bone & bone widens
step 2. (In long bones) osteoclasts remove old matric from inner surface, enlarges medullary cavity, so bones don’t become too heavy.
occurs at bone surface
Bone deposition
Osteoblasts produce new matrix
Bone remodelling
Maintain bone mass & strength. Replaces old matrix with new matrix. Involves bone resorbtion & bone deposition
Bone resorption
Osteoclasts break down old matrix
What decreases bone mass
Age & decline in sex hormones-rate of bone resorption exceeds the rate of bone deposition
Loss of calcium phosphate crystals and collagen fibres = thin, weak brittle bones
Factors affecting bone remodelling
Good amounts of vitamins C, A, D, K & B12 as well as calcium and phosphate
Comminuted fracture
Bone fragmented into 3 or more pieces
Compression fracture
Bone is crushed
Greenstick fracture
Bone is bent and cracked but it’s an incomplete break
Spiral fracture
Ragged break that occurs when excessive twisting forces are applied to a bone
Epiphyseal
Bone breaks along the epiphyseal plate
Transverse fracture
Bone completely breaks along the diaphysis
Depressed fracture
Broken bone is pressed inwards
Avulsion fracture
Tendon or ligament pulls off a fragment of bone
Pathological fracture
Caused by a disease that weakens bone structure e.g osteoporosis
Colles fracture
Break at distal end of radius
Scaphoid fracture
Common carpal bone fracture
Potts fracture
Break in medial malleolus of the tibia and/or lateral malleolus
Treatment of fracture
Reduction-bone realignment
Immobilisation of realigned bones
Rehabilitation-restore function
Fracture Repair step 1
Haematoma Forms
Torn blood vessels, clot forms, site swollen and sore
Fracture Repair step 2
Fibrocartilaginous Callus Forms
Fibroblasts produce collagen fibres
Chondroblasts produce cartilage
Fibrocartilaginous Callus splints broken bone ends
Fracture Repair step 3
Bony Callus of Spongy Bone Forms
Fibrocartilaginous callus is replaced by spongy bone
Bone ends united
Fracture Repair step 4
Bone Remodelling
Compact bone replaces spongy bone at diaphysis
Osteoclasts remove excess bone
Bone returns to normal shape
Osteomalacia (adults) & Rickets (children)
Poorly mineralised bones-lack calcium phosphate crystals
Bones=soft, flexible
Causes=vitamin D deficiency or not enough calcium intake
Osteogenesis Imperfecta (Brittle bones disease)
Affects quantity and quality of collagen fibres
Brittle bones-fracture easily
No cure
Osteoporosis
Reduction in bone mass affects bone function
Reduced amount of matrix components=porous, light, fragile easily fractured bones
Joint
Point of contact between 2 or more bones. Holds skeleton together and give skeleton mobility and flexibility
Synarthrosis joint
Immovable joint
Amphiarthrosis joint
Slightly movable joint
Diarthrosis
Freely movable joint
Fibrous joint
No joint cavity
Fibrous tissue unites articulating bones
Are synthetic or amphiarthrotic
Cartilaginous joint
Cartilage (hyaline or fibrocartilage) unites articulating bones
No joint cavity
Synarthotic or amphiarthrotic
Synovial joint
Articulating bone ends are covered in articular cartilage
Joint cavity present
Diarthrotic joint
Allow wide range of movement
Pivot joint
Allows rotation e.g proximal radio ulnar joint
Plane joint
Allows gliding movement e.g intertarsal joint
Condular joint
Allows flexion, extension, addiction, abduction & circumduction e.g metacarpophalangeal (knuckle & wrist joints)
Saddle joint
Allows flexion, extension, adduction, abduction & circumduction e.g carpometacarpal joint of the thumb
Hinge joint
Allows flexion & extension e.g elbow, knee & ankle joints
Ball & socket joint
Allow flexion, extension, abduction, adduction, circumduction & rotation e.g hip & shoulder joints
Skeletal muscles components
Muscle fibres, cells, connective tissue, blood vessels & neurons
Muscle fibres
Surrounded by 3 connective tissue sheaths
Endomysium
Surrounds each individual muscle fibre
Perimysium
Surround a bundle (fascicle) of muscle fibres
Epimysium
Surrounds the entire skeletal muscle
Tendon
Formed when 3 membranes blend together attach muscle to bone
Myofibriles
Composed of contractile units (sacromere) extend entire length of muscle fibres
Sacromeres
Composed of thick and thin myofilaments
Thick myofilments
Composed of myosin
Thin myofilaments
Composed of actin
Steps in muscle contraction
- Primary motor cortex sends message to lower motor neurons about muscle contraction
- Lower motor neuron conducts somatic motor output from CNS to a skeletal muscle
- Axon terminals of a lower motor neuron forms a synapse (neuromuscular junction) with a muscle fibre
Events stimulating a muscle contraction
- Somatic motor output in form of an action potential travels along the axon of a lower motor neuron to axon terminals
- Voltage gated Ca2 (calcium) channels open and Ca2+ enters axon terminal
- Ca2+ entry causes synaptic vesicles to release ACH into the synaptic cleft
- ACH diffuses across the synaptic and binds to chemically gated ion channels on sarcolemma
- Channels open-influx of Na+
-sarcolemma depolarises
-graded potential produced - Graded potential opens voltage gated Na+ channels in sarcolemma-action potential produced
- Action potential travels along the length of sarcolemma
- The action potential travels the length of the t tubules deep into muscle fibre
- Action potential stimulates sarcoplasmic reticulum Ca2+ release channels to open
- Ca2+ flows into cytoplasm of the muscle fibre
- Binding of Ca2+ to troponin pulls tropomyosin away from actin active sites
- Myosin heads bind to the active sites forming cross bridges & contraction begins
Process of contraction
- Myosin heads bind to the actin sites on thin myofilaments
- Myosin heads pull the thin myofilament towards centre of sacromere (m line) then detach ATP breaks detachment of myosin & actin
Cycle repeats
Muscle relaxation steps
- ACH within synaptic cleft is degraded by the enzyme acytlecholmesterase (ACHE)
- Sarcolemma (SR) return to its rmp
- Calcium release channels in sr close
- Calcium ions ultimately pumped back into SR
- Troponin returns to its original shape
- Tropomyosin blocks actin active sites
Ligament
Bone to bone
Tendon
Muscle to bone
Osteoporosis
Low bone mass & microarchitectural deterioration of bone tissue
Bone loss occurs slowly
Risk factors: family history, increase in age, vitamin d deficiency & early menopause
Inflammatory conditions
Rheumatoid arthritis
Ankylosing spondylitis
Degenerative disease
Osteoarthritis
Osteoporosis
Treatment of fractures, tissue injuries & dislocation
Rest
Ice
Compression
Elevated
(R)efferal
Why do an Neurovascular Assessment
Injuries & haemorrhage can cause interruptions to nerve & vascular supply—early detection is important
Distance of limbs from heart and lack of potential secondary sources of supply place them at risk
How to complete an NVO
Assessing pulse
Neurological functioning of limbs
Will determine vascular or neurological function
NVO
Pain
Pulse
Pallor
Paresthesia
Paralysis
Compartment syndrome
Build up pressure within a compartment compromises tissue perfusion
Build up reduces capillary blood flow to said space
Plaster cast
Tissue fascia
Bandage
Nurse interventions for diagnostic tests
Prepare patient for respective scan
Patient must lie still
Assess for conditions which may require special consideration e.g for disability etc
Check for allergies to contrast agent
Past arthrogram applies compression bandage to joint if prescribed & rest for 12 hours
Administer analgesia as required
Ankylosing spondylitis
A systemic inflammatory condition of the skeleton. A disease of the cartilaginous joints of the spine & surrounding tissues (occasionally large synovial joints (hips, knees & shoulders) may be involved). Back pain is a common characteristic. Complicates osteoporosis because of the inflammatory process & bone turnover. Systemic effects of uveitis in 20-25% of cases
Atrophy
Age and disease can cause the loss of muscular function as fibrotic tissue replaces contractile muscle tissue. The decrease in muscle size is called atrophy
Crepitus
A grating sound at the point of abnormal movement
Frozen shoulder (adhesive capsulitis)
Fibrous tissue form in the joint capsule causing stiffness, limitation of motion & pair
Gouty arthritis
Joint effusion or synovial thickening seen as a bulge or pullness in grooves on either side of the olecranon process. Redness & heat beyond the synovial membrane. Over secretion of uric acid or renal defect resulting in decreased uric acid which results in hyperarianaemia which can cause urate or crystal deposition
Joint effusion
Excessive fluid within the joint capsule. May present as swelling & bony landmarks are obscured
Articular capsule
Outer tough layer stabilises articulating bones
Inner membrane produces synovial fluids
Joint cavity
Holds synovial fluid separates articulating bones
Synovial fluid
Shock absorbing median supplies chondroblasts with O2 and nutrients-remove wastes
Ligaments
Allow movement-stabilises the joint
