Module One - Musculoskeletal system Flashcards
What is a joint?
Sites where two or more bones meet. Facilitates bone movement.
What is a ligament?
Connect the articulating bones at a joint.
What is cartilage?
supports body structure, connects bones, maintains shape of body structures, resists compression, has tensile strength and is composed of chondrocytes and on extra cellular matrix.
What are the three different types of cartilage?
Hyaline cartilage, elastic cartilage and fibrocartilage
Hyaline Cartilage
covers the ends of the articulating bones, connects ribs to sternum and forms the epiphyseal plate of bones
elastic Cartilage
forms the auricle of the ear
Firbocartilage
forms menisci, connects individual vertebrae, connects hip bones
What are the 5 functions of bones?
Support, protection, storage of minerals and triglycerides, blood cell protection, and movement.
The axial skeleton
Includes bones of the skull, vertebral column and rib cage
The appendicular skeleton
Upper limbs, lower limbs, shoulder girdles and pelvic girdle
What are the different shapes of bones?
Long bones, shorts bones, flat bones and irregular bones
What are surface features (landmarks) of bones?
Projections, depressions, and openings on the surface of bones function as:
- Site of muscle, tendon or ligament attachment
What are the different types of tissues bones contain?
- Connective tissue (osseous tissue, adipsoe tissue and hyaline caritilage)
- Nevrous tissue (sensory neurons)
- Muscle and epithelial tissue (blood vessels)
Osseous tissue
A connective tissue that contains specialised cells and in extracellular matrix
What is the matrix made of?
Consists of ground substance, collagen fibres and calcium phosphate crystals. Makes bones hard, slightly flexible and strong.
Collagen fibres (matrix component)
Provides felxibilty and tensile strength
Calcium Phosphate crystals
Makes bones hard and provides compressive strength
What are the different types of specialised cells?
- Osteoprogenitor cells (stem cells that differentiate into osteoblasts)
- Osteoblasts (bone building cells that secrete collegen fibres and ground substance
- Osteoclasts (bone resorbing cells that break down the matric and release stored minerals)
- osteocytes (mature bone cells that maintain the matrix)
Structure of bone
Every bone has an:
-outer layer of dense, smooth compact bone and an internal layer of spongy bone.
outer connective tissue membrane = periosteum (covers compact bone and contains blood vessles and nerves)
internal connective tissue membrane = endosteum (covers spongy bone)
Compact bone
Osseous tissue is arranged into osteons.
Each osteon:
- runs parallel to the long axis of bone
consists of:
- a central canal (blood vessels and nerves)
- concentric circles (hollow circles) of matrix
- Osteocytes - lies between the cylinders of matrix
Acts as tiny weight bearing pillar (resists force applied)
Spongy bone
Osseous tissue arranged into an irregular lattice of thin needle like structure called trabeculae (precisely orientated to resist forces from all directions and transfer wieght without breaking.
What are the types of bone growth?
Appositional growth and interstitial growth
Interstitial growth
Occurs at the epiphyseal plates of long bones (lengthens bones)
Appositional growth
Occurs at outer surface of all bones (widens)
What hormones regulate bone growth in children?
Growth hormone and thyroid hormone
What hormones regulate growth in adolesence
GH, TH, testosterone and estrogen
How do hormones regulate bone growth?
Promote the growth spurt in adolesense.
End growth by inducing epiphyseal plate closure
Bone remodelling
Occures throughout life
Maintains bone mass and strength
Replaces old matrix
Involves bone resorbtion and bone deposition
Bone resorption
Osteoclasts break down old matrix
Bone deposition
osteoblasts produce new matric
Factors that affect bone growth and remodelling
Adequate amounts of:
- calcium
- vitamin c
- vitamin A
- vitamin D
- Vitmain K and B
- weight bearing exercise
What is a bone fracture
Any crack or break in a bone, and can be classified as:
- classified (simple) fracture: bone doesnt break skin
- open (compound) fracture: bone protrudes through the skin
- greenstick: incomplete
- compression fracture: bone is crushed
- spiral fracrure: ragged break caused by exessive twisting
- epiphyseal fracture
What are some more types of bone fractures?
- transverse fracture: breaks along the long axis
- depressed fracture: broken bone is pressed inwards
- avulsion fracture: tears away from bone
- pathological fracture: caused by a disease that weakens bones
- colles fracture: radius
- scaphoid fracture: carpals
- Potts fracture: tib/fib
What does fracture treatment involve?
- reduction: realignment of bone ends
- immobilisation: cast, sling etc
- rehabilitation: restore function
What are the four steps to fracture repair?
- Haematoma forms
- Fibrocartilaginous callus forms
- Bony callus forms
- Bone remodelling
What are different types of bone diseases?
- osteomalacia or rickets (bones are poorly mineralised)
- osteogenesis imperfecta (brittle bones)
- osteoporosis (reduction in bone mass)
What is a joint?
Formed where the surfaces of two or more bones connect. Holds the skeleton together.
How are joints functionally classified?
- synarthrosis (immovable joint)
- ampiarthrosis (slighlty moveable)
- diarthrosis (freely moveable)
How are joints structurally classified?
- Fibrous
- Cartilaginous
- synovial
Fibrous joints
articulating bones are united by fibrous connective tissue. Joint cavity is absent.
- are immovable or slightly moveable
Cartilaginous joints
articulating bones are united by cartilage (hyaline or fibrocartilage). joint cavity is absent.
- Immovable or slightly moveable
Synovial joints
articulating bone ends are covered in articulating cartilage. Joint cavity present.
- freely movable (wide range)
What is the general structure of a synovial joint?
- articulating capsule (surround entire joint and encloses joint cavity. 2 layers : tough outer fibrous layer, inner synovial membrane)
- Joing (synovial) cavity (seperates articulating bones, contains synovial fluid)
- synovial fluid (shock absoption, reduces friction)
- articular cartilage (covers ends or articulating bones, shock absoprtion and redecues friction)
- reinforcing ligament (stabilises synovial joint)
What are some additional structures that may be present at a synovial joint?
- Menisci: discs of fibrocartilage
- Muscle tendons: stabilise
- Bursae and tendon sheaths: bags of synovial fluid
- Fat pads: mass of adipose tissue (protects joint structure)
Type of movement allowed by synovial joints
- angular movements: flextion, extension, adduction, abduction etc.
- rotational movements: rotation (medial and lateral), supination and pronation
- special movements: protraction, retraction, opposition, depression, elevation etc.
What are the 6 types of synovial joints?1
- pivot joint
- plane joint (gliding)
- condylar joiny (flexion etc.) e.g. metacarpophalangeal joint and wrist
- saddle joint e.g. thumb
- hinge joint e.g. elbow
- ball and socket joint e.g. shoulder and hip
What is a sprain?
ligaments are stretched or torn.
- painful and immobilising
Osteoarthrisis
most prevelant form of chronic arthrisis. degenerative joint disease in which joint cartilage gradually deteriorates
Rheumatoid arthrisis
autoimmune disease that targets the synovial membranes lining synovial joints
