Bioscience And Nursing Musculoskeletal System Flashcards
Bone functions
Support
Protection
Store minerals and triglycerides
Maintain homeostatic blood calcium levels
Blood cell production (haemotopiesis)
Movement
Origin
Fixed point of muscle attachment (bone don’t move when muscle contracts)
Insertion
Moveable point of muscle attachment (bone moves when muscle contracts)
Axial skeleton
Made up of bones of the skull, vertebral column and rib cage
Appendicular skeleton
Made up of bones of upper limbs (arms, forearms & hands), lower limbs (thighs, legs & feet)
Shoulder (pectoral) girdles & pelvic girdle
Long bones
Long slender bones, have a shaft (diaphysis) & bone ends (epiphysis) e.g humerous
Short bones
Small cube shaped bones e.g tarsals, carpals, patella
Flat bones
Thin, flat & often curved e.g sternum, ribs & scapula
Irregular bones
Complex shaped bones e.g vertebrae & hip bones
Bone structure
Contains: connective tissue, adipose tissue, osseous tissue & hyaline cartilage
Osseous tissue
Connective tissue which contains specialised cells & a matrix
Matrix
Consists of ground substance, collagen fibres & calcium phosphate crystals
makes bones flexible hard and strong
Collagen fibres
Gives bones flexibility and tensile strenght
Calcium phosphate crystals
Makes bones hard and provide compressive strenght
Bone without crystals
Has tensile strength but lacks compressive strength-soft and flexible
Bone without collagen fibres
Hard with compressive strength, lack flexibility & tensile strength-brittle
Osteoprogenitor cells
Stem cells which differentiate into osteoblasts
Osteoblasts
Bone building cells-produce and secrete collagen fibres and ground substance
Osteoclasts
bone reabsorbing cells-breakdown matrix and release stored minerals
Osteocytes
mature bone cells which maintain the matrix
layers of bones
outer layer of compact bone & internal layer of spongy bone
outer connective tissue membrane=periosteum
covers compact bone, contains blood vessels & nerves
internal connective tissue membrane=endosteum
covers spongy bone
yellow bone marrow
stores adipose tissue
red bone marrow
making of RBC’s (hematopoiesis)
spongy bone
contains trabeculae (thin needle-like structures)
lighter than compact bone-reduces weight off skeleton
trabeculae function
resist forces from all directions without breaking
interstitial growth
new cartilage is formed on the epiphyseal plate & old cartilage is turned to bone-diaphysis gradually lengthens
Bone remains strong because growth is at the top and bottom at the same time
interstitial growth makes bones longer, occurs at epiphyseal gate
appositional growth
makes bones grow wider-occurs on outer surface of all bones.
step 1. osteoblasts secrete layers of new matrix onto bone surface-becomes contact bone & bone widens
step 2. (In long bones) osteoclasts remove old matric from inner surface, enlarges medullary cavity, so bones don’t become too heavy.
occurs at bone surface
Bone deposition
Osteoblasts produce new matrix
Bone remodelling
Maintain bone mass & strength. Replaces old matrix with new matrix. Involves bone resorbtion & bone deposition
Bone resorption
Osteoclasts break down old matrix
What decreases bone mass
Age & decline in sex hormones-rate of bone resorption exceeds the rate of bone deposition
Loss of calcium phosphate crystals and collagen fibres = thin, weak brittle bones
Factors affecting bone remodelling
Good amounts of vitamins C, A, D, K & B12 as well as calcium and phosphate
Comminuted fracture
Bone fragmented into 3 or more pieces
Compression fracture
Bone is crushed
Greenstick fracture
Bone is bent and cracked but it’s an incomplete break
Spiral fracture
Ragged break that occurs when excessive twisting forces are applied to a bone
Epiphyseal
Bone breaks along the epiphyseal plate
Transverse fracture
Bone completely breaks along the diaphysis