Skeleton Flashcards
What is the function of the skeleton?
Support Protection Shape Movement / Locomotion Source of materials Supports weight against gravity Reinforced by action of muscles Divided into units for movement Variations dependent on whether bipedal, quadrupedal, swimming, flying.
What are the three parts of the skeleton?
- Axial =
skull, vertebral column
(cervical; lumbar; sacral; coccygeal), ribs & sternum - Appendicular =
bones of the limbs,
includes: pelvic girdle, and pectoral girdles - Visceral = skeleton in soft tissues e.g. bones of the inner ear
os cordis (in ox heart) os penis (in dog, mouse)
What is the skull and what is it made up of?
Skull - protects the brain & major sense organs – Human: 29 head bones • 8 Cranial • 14 Facial • 1 Hyoid bone • 6 Auditory ossicles
What is the vertebrae and what is it made up of?
Vertebral column -protects the spinal chord – Human: 33 • 7 cervical • 12 Thoracic • 5 Lumbar • 5 (fused) Sacrum • 4 (fused) coccyx
What is the thorax and what is it made up of?
Thorax - protects heart & lungs and aids respiratory movements – Human: 24 (12 pairs) • 24 ribs – 14 true – 6 false – 4 floating • Sternum
What are the extremity bones?
Upper extremity bones: – Clavicle – Scapula – Humerus, radius, ulna • 16 Carpal bones • 38 Metacarpus and phalange bones Lower extremity bones: – Hip – Femur, patella, tibia, fibula • 14 Tarsal bones • 38 Metatarsus and phalange bones
What is skeletal tissue?
Includes bone, cartilage, ligaments and tendons
– Functional differences are primarily due to differences in the proportion of ground substance and fibres in the extracellular matrix.
What is bone?
Is a hard connective tissue
Matrix produced by bone cells – osteocytes Becomes impregnated with Ca salts (65-75 % of
the matrix is inorganic) and collagen fibres.
Adapted to withstand forces.
(Ca ≠ compression, collagen ≠ tension)
Low metabolic rate
Highly adaptable, meeting changes as required
What are the two types of bone?
1.Compact (Cortical) – Hard – Cortical – Long bones 2.Cancellous (Trabecular) – Haematopoietic or fatty marrow
What are the five types of bone?
- Long
Connected with large movement Long and cylindrical Appendicular skeleton
Femur, humerus - Short
Smaller, more complex movements Almost cube shaped
Carpals and tarsals - Flat
protect the internal organs
skull (cranium), ribs, scapula, sternum, pelvic girdle. - Irregular
irregular in shape
vertebrae and some facial bones. - Sesamoid
small bones held within tendons
include the patella and pisiform bone of palm
What is the periosteum and what are its layers?
Periosteum Covers most of a long bone (Except regions covered by articular cartilage or ligamentous, tendonous or capsular attachments) – Outer, fibrous layer • Permeated by blood vessels and nerve fibres • Supportive – Inner, osteogenic layer • Appositional growth • Repair
What is the microstructure of bone?
Microstructure
– Cells
– Organic extracellular matrix – Inorganic extracellular matrix
What are osteoprogenitor cells?
Osteoprogenitor cells
– Derived from mesenchyme cells
– Found in the periosteum and endosteum
– Mitosis and differentiation into bone cells (osteogenic potential)
What are osteoblasts?
Osteoblasts – First cells to develop from the osteoprogenitor cells – Cover majority of bone surface – Formation of organic matrix – Osteoid – Abundant ER, ribosomes, Golgi apparatus, mitochondria – High rate of metabolic activity – Produce • Collagen • Proteoglycans • Noncollagenous proteins
What are osteocytes?
Osteocytes
– 10% of osteoblastic population • Enclosed in matrix
• Mature to osteocytes
– Fewer metabolic cellular components
– Cytoplasmic processes into surrounding matrix
– Fill canaliculi
– Intricate transport and communication system
– Flow of mineral ions: extracellular space around osteoblasts => osteocytes => surrounding extracellular space
