MODULE 1 Flashcards
Role of Ligaments
Connect articulating bones at a joint, stabilise connecting bones
Role and composition of Cartilage
Has tensile strength - composed of chondrocytes and an extracellular matrix
Hyaline Cartilage
Articular cartilage, costal cartilage (ribs to sternum), forms epiphyseal plate
Elastic Cartilage
Forms the oracle of the ear
Fibrocartilage
Forms menisci, connects intervertebral discs, connects pubic symphysis
Function of Bones
Support, protection, storage of minerals and triglycerides, blood cell production and movement
Origin
The fixed point of muscle attachment
Insertion
Moveable point of muscle attachment
What is included within the axial skeleton?
Skull, vertebral column, rib cage
What is included within the appendicular skeleton?
Upper limbs, lower limbs, shoulder girdles, pelvic girdle
Connective tissue contains
Osseous tissue, adipose tissue (yellow bone marrow) and hyaline cartilage (growth plates)
Nervous tissue contains
Sensory neurons
Muscle tissue and Epithelial tissue contains
Blood vessels
Osseous tissue contains
specialised cells and an extracellular matrix
The Matrix consists of
ground substance, collagen fibres and calcium phosphate crystals
Collagen Fibres provide
flexibility and tensile strength
Calcium Phosphate Crystals
make our bones hard and provide compressive strength
Osteoprogenitor Cells are
Stem cells that differentiate into osteoblasts
Osteoblasts are
bone “building” cells that secrete collagen fibres and ground substance
Osteoclasts are
bone “reabsorbing” cells that break down the matrix and release stored minerals
Osteocytes are
mature bone cells that maintain the matrix
Periosteum
outer connective tissue membrane, covers contact bone, contains blood vessels and nerves
Endosteum
internal connective tissue membrane, covers spongy bone
Compact Bone
Osseous tissue arranged into osteons, each osteon: runs parallel to the long axis of bone. Consists of: a central canal (blood vessels and nerves), concentric circles of matrix, osteocytes (between matrix). Acts as a tiny weight bearing pillar.
Spongy Bone
Osseous tissue is arranged into an irregular lattice of thin needle like structures called trabeculae. Which resist forces from all directions and transfer weight. Lighter than compact bone, mainly found in the proximal and distal epiphysis.
What is and where does interstitial growth occur?
Bones lengthen by interstitial growth, occurs at the epiphyseal plates of long bones
What is and where does appositional growth occur?
Bones widen by appositional growth, occurs at the outer surface of all bones
What is growth controlled by during childhood?
Growth hormone and thyroid hormone
What is growth controlled by during adolescence?
Growth hormone, thyroid hormone, testosterone and oestrogen
Bone remodelling
Maintains bone mass and strength, replaces old matrix with new matrix
Bone resorption
osteoclasts break down old matrix
Bone deposition
osetoblasts produce new matrix
The rate of bone deposition and resorption…
equals each other, bone mass remains constant in healthy young adults
At around 30 years of age…
loss of bone mass occurs where the rate of resorption exceeds the rate of deposition
Factors that affect bone growth:
Calcium and phosphate, vitamin C (collagen synthesis), vitamin A (stimulates osteoblast activity), vitamin D (Ca2+ absorption), vitamins K and B12 (synthesis of proteins that form ground substance), weight bearing exercises
Fractures: closed (simple)
broken bone does not break the skin
Fractures: open (compound)
broken bone protrudes through skin
Fractures: comminute
bone fragments into 3 or more pieces
Fractures: greenstick
incomplete break
Fractures: compression
bone is crushed
Fractures: spiral
ragged break that occurs with excessive twisting
Fractures: epiphyseal
bone breaks along epiphyseal plate
Fractures: transverse
bone breaks across its long axis
Fractures: depressed
broken bone is pressed inward
Fractures: avulsion
bone fragment tears away from main mass of bone - usually occurs at the site of muscle tendon or ligament attachment
Fractures: Pathological
caused by a disease that weakens bone structure e.g. osteoporosis
Fractures: Colles
break at the distal end of the radius
Fractures: scaphoid
common carpal bone fracture
Fractures: Pott’s
fracture of both the tibia and the fibula
Fracture Treatment: reduction
the realignment of bone ends
Fracture Treatment: immobilisation
of realigned bones, i.e. cast, sling, brace etc.
Fracture Treatment: rehabilitation
restore function
Fracture repair step 1:
Haematoma forms - torn blood vessels haemorrhage, clot forms, site swollen and sore
Fracture repair step 2:
Fibrocartilaginous callus forms - fibroblasts produce collagen fibres, chondrocytes produce cartilage, fibrocartilaginous callus splints broken bone ends.
Fracture repair step 3:
Bony callus forms - fibrocartilaginous callus is converted to spongy bone, bone ends firmly reunited
Fracture repair step 4:
Bone remodelling - compact bone replaces spongy bone at the bone surface (diaphysis of long bone), osteoclasts remove excess bone, bone returns to normal shape
What is Osteomalacia (adults) and Rickets (children)?
bones are poorly mineralised, lack calcium phosphate crystals, bones are soft, flexible an deform easily. Caused by insufficient calcium intake or vitamin D deficiency.
Osteogenesis imperfecta is
Brittle bone disease, congenital bone disorder that affects the quantity or the quality of collagen fibres, no cure, treatment involves strengthening bones to reduce incidence of fractures
Osteoporosis is where
bone resorption outpaces bone deposition, reduction in bone mass
Synarthrosis
immoveable joint
Amphiathrosis
slightly moveable joint
Diarthrosis
freely moveable joint
Fibrous joints
Articulating bones united by fibrous connective tissue. Joint cavity absent, are synarthrosis or amphiathrosis joints
Sutures
immoveable fibrous joints that unite the bone of the skull
Tibiofibular joint
slightly moveable fibrous joints that unites tibia and fibula
Cartilaginous joints
Articulating bones are united by cartilage, hyaline or fibrocartilage, joint cavity absent, synarthrosis or amphiathrosis
Synovial joints
Articulating bone ends are covered in articular cartilage, joint cavity present, diarthrosis joints.
The 5 features that define a synovial joint are:
articular capsule, joint cavity, synovial fluid, articular cartilage and reinforcing ligament
Articular capsule, 2 layers include…
surrounds entire joint and encloses joint cavity. Tough outer fibrous layer and an inner synovial membrane
Joint cavity
separates articulating bones and contains synovial fluid
Synovial fluid helps with
shock absorption, reduces friction, circulates to supply oxygen and nutrients to chondrocytes and remove wastes
Articular cartilage
covers the end of each articulating bone, shock absorption, reduces friction
Reinforcing ligaments
stabilises synovial joints
Menisci
stabilise synovial joints, reduce friction, shock absorption
Muscle tendons
stabilise synovial joints
Bursae
bags of synovial fluid, reduce friction between adjacent joint structures
Tendon sheaths
tubular synovial fluid which wraps around a tendon
Bursa
small synovial fluid pocket that lies between two structures e.g. a tendon and bone or a ligament and bone
Fat pads
mass of adipose tissue, protect joint structures
Synovial joints allow: 1
Angular movements - flexion, extension, adduction abduction, circumduction, dorsiflexion and plantar flexion
Synovial joints allow: 2
Rotational movements - rotation, supination, pronation
Synovial joints allow: 3
Special movements - protraction, retraction, opposition, depression, elevation, inversion, eversion
Type of synovial joint: pivot joint
allows rotation
Type of synovial joint: plane joint
allows gliding movements e.g. intercarpal and intertarsal joints
Type of synovial joint: condylar joint
allows flexion, extension, adduction, abduction and circumduction
Type of synovial joint: saddle joint
allows flexion, extension, adduction, abduction, and circumduction
Type of synovial joint: hinge joint
allows flexion and extension
Type of synovial joint: ball and socket joint
allows flexion, extension, adduction, abduction, circumduction and rotation
Sprains
ligaments are stretched or torn, poorly vascularised
Oseteoarthritis is
a form of chronic arthritis, degenerative joint disease
Rheumatoid arthritis is
autoimmune disease that targets the synovial membrane lining synovial joints
Functions of muscle tissues: skeletal, cardiac and smooth
Produces body movements, maintains posture and body position, stabilises joints, generates heat
Excitability
(responsiveness) the ability to receive and respond to a stimulus
Contractibility
the ability to shorten forcibly when stimulated
Extensibility
the ability to be stretched, for example when relaxed
Elasticity
the ability to recoil to resting length after it has been stretched
Skeletal muscle composition and function
composed of skeletal muscle fibres, maintains posture, stabilises joints and generates heat, voluntary and controlled by the somatic nervous system
Cardiac muscle composition and function
Located in the heart and forms the bulk of myocardium, autonomic nervous system (involuntary)
Smooth muscle composition and function
found mainly in the walls of hollow visceral organs, involuntary (ANS), contractions force fluid and other substances through internal body channels, regulate passage of substances through internal body openings, alter blood vessel and pupil diameter
Skeletal Muscles: Endomysium
is the innermost membrane and it encloses each individual muscle fibre
Skeletal Muscles: Perimysium
surrounds a bundle of muscle fibres, called a fascicle
Skeletal Muscles: Epimysium
the outer membrane that covers the entire skeletal muscle, provide strength and support, can attach a muscle directly to surface of bone
The 3 events that lead to muscle contraction:
Neural stimulation, excitation-contraction coupling and contraction “sliding filament theory”
- Neural Stimulation
somatic nervous system stimulates skeletal muscle contraction, action potentials are generated and sent to skeletal muscles via lower motor neurons, chemical synapse forms (neuromuscular junction)
- Excitation-Contraction Coupling
is a sequence of events that link the action potential to contraction. An electrical signal (excitation) and a mechanical response (contraction) is coupled
- Contraction “sliding filament theory”
contraction begins when the myosin heads bind to the active sites on actin. Myosin generates force pulling them towards the centre of the sarcomere. Thin filaments slide past the thick filaments and the sarcomere shortens. The entire muscle ends up shortening (lengths of filaments DO NOT CHANGE, just slide past each other)
What is a motor unit?
one lower motor neuron and all the muscle fibres it innervates
What is a small motor unit?
4-6 muscle fibres innervate muscles that control fine, delicate movements
What is a large motor unit?
1000-2000 muscle fibres innervate muscles that control coarse, powerful movements
