Week 2 Flashcards
Functions of skeleton
Gives the body its shape
It supports the weight of the body
Provides sites for muscle attachment, allowing movement
It protects delicate tissues and organs
It makes blood (haemopoiesis)
It stores calcium and phosphorus
Composition of the skeleton
Specialised connective tissues: bone and cartilage
Skeleton mainly develops as cartilage first ossifying later
Cartilage persists at some sites, Articular cartilage at joints, costal cartilage
Functions of cartilage
Supports soft tissues
Provides smooth surface at joints - most synovial joints are lined with hyaline cartilage
Enables long bone growth
Characteristics of cartilage
Stiff load-bearing
Cells (chondrocytes and chondroblasts) embedded in a matrix of proteoglycans and collagen
Virtually avascular, no nerves- no pain if cartilage damaged, doesn’t bleed when torn but doesn’t heal
Resists compression, tension and shearing
Types of cartilage
Hyaline- e.g articular cartilage (lines surface of joints, provides low friction sliding surface)
Elastic- e.g external ear, flexible
Fibrocartilage- e.g intervertebral disc, mix fibrous tissue and cartilage, lines few joint surfaces- clavicular joints and temporomandibular joint
Growth and repair of cartilage
Develops from embryonic mesenchyme (loose connective tissue)
Interstitial and appositional growth
Poor repair- replaced by fibrous tissue
Many cartilages ossify with age
Characteristics of bone
Hard, resilient
Cells (osteoblasts, osteocytes, osteoclasts) embedded in a mineralised matrix
Highly vascular, periosteum well innervated
Extremely strong
Types of bone
Compact (cortical)- outer layer of long bones
Trabecular (cancellous/spongy)- inside long bones
Growth and repair of bone
Most bones preformed as cartilage- develop by endochondral ossification
Some bones develop from embryonic mesenchyme by intramembranous ossification- bones in skull, face, clavicle
Only appositional growth
Spontaneous repair after fracture
Development and growth of a long bone
Primary ossification centres in shaft of bone
Ossification spreads along shaft
Growth plates- cartilage present while bone is still growing
Secondary ossification centres in epiphysis
Fracture healing
Inflammation- swelling, blood cells arriving
Soft callus- not mineralised
Hard callus and remodelling
What do girdles do
Attach limbs to axial skeleton
Classification of bones
Long bones
Short bones
Flat bones
Irregular bones
Sesamoid bones
