Session 1 Introduction Flashcards
Developmental origin of bones, connective tissue and skeletal muscle
Mesoderm of trilaminar disc
Functions of bone 6
- Support
- Storage
- Metabolic
- Movement
- Protection
- Haemoatopoiesis
SS MM P H
Characteristics of skeletal muscle
Striated and voluntarily controlled
Functions of skeletal muscle 6
- Locomotion
- Posture
- Metabolic
- Venous return
- Heat production
- Continence
Love possibly makes very hot couples
Metabolic roles of bone
Homeostasis of calcium and phosphate, storage and release
Storage roles of bone
Calcium and phosphate, protein, bone marrow rich in fat, growth factors and cytokines
What do tendons and ligaments do
Tendons Connect muscle to bone
Ligaments connect bone to bone
What is fascia
Sheets of connective tissue which envelop groups of muscles and divide body parts, protective function
What is hyaline cartilage
Found at ends of bones contributing to joints, for frictionless motion
What is fibrocartilage
For shock absorption, increases bony congruity, higher collagen content
E.g. menisci of knee
What is synovial membrane
Tissue found within joints, bursae and tendon sheaths. Produces synovial fluid which lubricates joints
Bone components are divided into
Cellular and non-cellular
Cellular components of bones
Osteocytes, osteoblasts, osteoclasts
Also fibroblasts, macrophages, mast cells and adipocytes
What mineralises the extracellular matrix
Calcium phosphate
Major fibre type in bone and other contents
Collagen, not much elastin,
Bone also contains water, glycosaminoglycans, proteoglycans
2 major components giving bone its mechanical properties are
Collagen and calcium phosphate
Collagen- tensile strength
Calcium phosphate- Compressive strength
Osteoblast role
OsteoBlast = Builder
Synthesise new bone, migrate over matrix, synthesise and deposit osteoid (matrix protein) and deposit calcium phosphate into it
Osteoclast role
Multi nucleated cells which secrete acidic chemicals to dissolve bone.
Minerals in ionic form are absorbed into osteoclast and released into extracellular fluid
Resorption
osteoblasts form osteocytes when they are
Trapped within the bone matrix in lacunae. Become involved in signalling processes. Communicate via filipodia (projections)
Two types of bone
Compact (dense outer layer) and spongy bone/cancellous bone (meshwork of trabeculae)
2 divisions of skeleton
Axial and appendicular skeleton
Long bones features
- Diaphysis is the shaft
- Flares out at each end to metaphysis, adjacent to growth plate, on other side is epiphysis
- Articulating surfaces covered in hyaline cartilage
- other bony surfaces covered with periosteum
- Medullary cavity lined with endosteum
What is in medullary cavity
red marrow in child, high fat content in adults, nutrient artery supplies marrow
What are sesamoid bones
Bones embedded in tendons
Short, flat, sesamoid and irregular bones features
2 layers of compact bone with a layer of spongy bone between them
bone marrow contained between trabeculae of spongy bone
No growth plate or epiphysis
What is bone remodelling
Occurs in response to environmental factors- change in balance of activity between osteoblasts and osteoclasts
What is a joint
An articulation between 2 or more bones
Fibrous joints key features
very limited mobility and high stability
e.g. sutures of skull, inferior tibiofibular joint, posterior sacroiliac joint
What are cartilaginous joints
- Joints that use cartilage to unite bones
- Typically in midline and epiphyseal plates of long bones
- Primary: hyaline cartilage and are completely immobile e.g. epiphyseal growth plates of long bones
- Secondary: hyaline cartilage and pad of fibrocartilage between them. Also known as symphyses. E.g. symphysis pubis in pelvis
Major features of synovial joint
Joint cavity containing synovial fluid, lubrication to articular surfaces, high degree of mobility
Articulating surfaces within a synovial joint are usually covered with
Hyaline cartilage (exceptions include acromioclavicular joint which is covered in fibrocartilage)
Fibrous capsule is composed of
Collagen in bundles, stabilises joint, continuous with periosteum covering surface of adjacent bones
What is synovial membrane
Thin highly-vascularised membrane that produces synovial fluid
What is a bursa
Small sac lined by synovial membrane and containing a thin layer of synovial fluid- reduces friction and allows free movement
What are tendon sheaths
Elongated bursae that wrap around a tendon and reduce friction
What is in synovial fluid
Hyaluronic acid, lubricin, proteinases and collagenases
Main functions of synovial fluid
- Reduce friction
- Shock absorber
- transport nutrients and remove waste (articular cartilage)
Articular cartilage blood supply
Avascular
Fibrous capsule and ligaments have a
Poor blood supply
Factors affecting range of motion of joints
- Structure or shape of articulating bones
- Strength and tension of joint ligaments
- Arrangement and tone of muscles around the joint
- Apposition of neighbouring soft tissues
- Hormones
- Disuse
