Study Guide - Lecture Test 2 Flashcards
Location & function of Chondrocytes
Mature cartilage cells found within small space called lacunae
Maintain matrix
Location & function of Chondroblast
Produce matrix cartilage
Become chondrocytes when completely surrounded by matrix
Location & function of Osteoprogenitor cells
Found in the endosteum, inner layer of periosteum, central canals
Differentiate into osteoblasts
Location & function of Osteoblast
Bone forming cells
Line endosteum and inner layer of periosteum
Add to bone matrix
Location & function of Osteocyte
Mature bone cells
Located in lacunae
Maintain bone matrix
Location & function of Osteoclast
Bone dissolving microphages
Remove bone matrix
Functions of bones
Support
Protection
Movement
Hemopoiesis
Storage of minerals and energy reserves
Structure of long bones
Diaphysis
-elongated, cylindrical shaft
-walls composed of compact bone
-provides leverage and weight support
Epiphysis
-expanded end
-spongy bone tissue surrounded by thin layer of compact bone
-attachment for ligaments and tendons
Metaphysis
-region between epiphysis and diaphysis
-contains epiphyseal plate/line
Medullary cavity
-central cavity of diaphysis
-filled with yellow bone marrow
Endosteum
-covers internal surfaces of bone
Epiphyseal plate
-growth plate
-becomes epiphyseal line when ossified
Articular cartilage
-hyaline cartilage
-provides smooth surface for joint
Periosteum
-fibrous connective tissue covering outer bone surface
Nutrient foramen
-allows blood vessels, nerves and lymphatic vessels to enter/leave bone
What is the main inorganic material in bone matrix?
Hydroxyapatite
What is the main protein in bone matrix?
Collagen
What is the structural unit of spongy bone? Compact bone?
Spongy bone - trabeculae
Compact bone - osteon
Structure of the Osteon
Central Canal
-carries nerves/blood vessels
Lamellae
-concentric rings of bone matrix surrounding central canal
Osteocytes
-within lacunae between adjacent lamellae
Canaliculi
-small canals between lacunae
-nutrients diffuse from central canal through canaliculi to surrounding osteocytes
Perforating Canals
-transverse passages
-contain blood vessels and nerves
Circumferential lamellae
-rings of bone just internal to periosteum or endosteum
Interstitial lamellae
-leftover parts of osteons that have been partially reabsorbed
Describe how blood vessels enter bone and reach medullary cavity
Enters the bone through nutrient foramen
Via perforating and central canals to medullary cavity
Where is yellow marrow found in adult bones? Where is red marrow located?
Yellow bone marrow
- medullary cavity
Red bone marrow in children
-spongy bone and medullary cavity
Red bone marrow in adults
-flat bones of the skull, vertebrae, ribs, sternum, hip bones
Name and describe the 2 types of bone formation (ossification).
Intramembranous Ossification
-produces flat bones of skull and clavicle
-begins as a fibrous sheet
Endochondral Ossification
-bone develops from hyaline cartilage
-six weeks fetal development to early 20s
-most bones develop this way
What is the difference between appositional growth, interstitial growth and bone
remodeling?
Appositional growth
-bone widening and thickening
Interstitial growth
-bone elongation
-occurs at epiphyseal plate
Remodeling
-reshaping of bones due to mechanical stress
-absorption of old bone and deposition of new bone
What are the actions of calcitonin and parathyroid hormones?
Calcitonin
-secreted by Thyroid gland
-stimulates osteoblast activity
-decreases blood Calcium
Parathyroid hormone
-stimulates bone reabsorption by osteoclasts
-increases blood Calcium
What is the difference between pathological and stress fractures?
Pathological
-due to weakening of the bone causes by disease or osteoporosis
Stress
-caused by abnormal trauma to the bone
Be able to identify a bone as part of the axial or appendicular skeleton. Be careful
about the scapula, clavicle, hyoid and coxal bones.
Axial
-skull
-vertebral column
-thoracic cage
-hyoid
Appnedicular
-pectoral girdle
-pelvic girdle
-scapula
-clavicle
-coxal bones
-upper and lower extremities
How many bones in typical adult?
206
Know how many bones in each region particularly # facial bones, # cranial bones, #
vertebrae in adult (total and by region), # vertebrae in child (total and by location).
Axial
-80 bones
Appendicular
-126 bones
Skull
-8 cranial
-14 facial
Vertebral Column - child
-33 total
-7 cervicle
-12 thoracic
-5 lumbar
-5 sacral
-4 coccygeal
Verterbral column - adult
-26 total
-1 sacrum
-1 coccyx
Know location of cranial bones and bones of orbit. Examples: Which bones form the
skull cap or the floor of the cranium? Which bones form the medial wall of the orbit?
Cranial bones - roof
-squamous part of frontal bone
-parietal bones
-squamous part of occipital bone
Cranial bones - floor
-ethmoid, sphenoid, occipital and temporal
Orbit bones - medial wall
-maxilla, lacrimal bone, ethmoid
Orbit bones - lateral wall
-zygomatic bone, sphenoid bone, frontal bone
Location/functions of paranasal sinuses
Located within frontal, sphenoid, ethmoid and maxillary bones
Reduce weight of skull
Resonate voice
What are fontanels? Functions?
Connective tissue membranes that cover the gaps between developing cranial bones
Permits molding during birth and accomodates rapid growth of brain
Ossification complete by 18-24 months