Chapter 6 - Skeletal System Flashcards
Osteogenic cell function..
- Actively dividing stem cells for bone
- the location is in the periosteum, endosteum, and canals that contain bone tissue
- differentiate into osteoblasts
Cells of bone tissue?
Osteogenic cells
Osteoblasts
Osteocytes
Osteoclasts
Osteoblast function..
Bone building cells secrete matrix trap them selves into matrix begin calcification differentiate into osteocytes Located in periosteum, endosteum
Osteocyte function..
Mature bone cell, metabolically active cells, maintain bone tissue,
location Lacunae
Osteoclast function..
Bone breaking cells
location in the endosteum
Intramembraneous ossification stages..
Formation of ossification center
Calcification
Formation of trabeculae
Formation of periosteum
Formation of ossification center.
Mesenchymal cells, cluster together
Differentiate to osteogenic cells
Osteoblasts secrete matrix and trap themselves.
Calcification
Trapped osteoblasts -> osteocytes
Osteocytes extend cytoplasmic projections forming canaliculi
~ few days matrix hardens (calcify)
Formation of trabeculae..
Osteoblasts continue to lay down matrix, forming trabeculae = spongy bone
BV’s grow in spaces btwn trabeculae
CT in walls give rise to red bone marrow
Formation of periosteum..
Edges of bone remodeled into compact bone
Periosteum forms outside of bone
Sharpey’s fibers
Attach periosteum to bone
Circumferential lamellae
Around diaphysis of bone
Concentric lamellae
Around osteon
Interstitial lamellae
Bits and pieces
Perforating canal
Between central canal
Canaliculi
Help transport nutrients between cells
Functions of bone
Support Protection Assistance in movement Mineral homeostasis Blood cell production Triglyceride storage
Structure of bone
Diaphysis Epiphysis Metaphysis Articular cartilage Periosteum Medullary cavity Endosteum
Components of the sternum
Manubrium
Sternal angle
Gladiolus
Xiphoid process
Components of sacrum
Lateral mass
Auricular surface
Sacral foramina
Components of clavical
Sternal end
Acromial end
Conoid tubercle
Superior surface
Occipital bone features
External occipital protuberance
Occipital condyles
Foramen magnum
Hypoglossal canal (inside)
Sphenoid bone features
Sella turcica Optic foramen Sphenoid sinus Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum
Ethmoid bone features
Perpendicular plate Crista galli Ethmoid sinus Cribriform plate Olfactory foramen Nasal concha (superior, middle)
Mandible bone features
Mandibular condyle
Mandibular angle
Coronoid process
Temporal bone features
Mastoid process Styloid process Stylomastoid foramen Zygomatic process Mandibular fossa External auditory meatus Carotid canal Mastoid sinus
Fissure
Narrow slit
Fossa
Shallow depression
Sulcus
Furrow along bone
Condyle
Large round protuberance
Crest
Prominent ridge or elongated projection
Epicondyle
Typically roughened projection above condyle
Trochanter
Very large projection
Tubercle
Variably sized rounded projection
Tuberosity
Variably sized projection that has a rough bumpy surface
Auditory ossicles features
Malleus
Incus
Stapes
Rib bone features
Head Neck Tubercle Costal groove Inferior margin Shaft
Lordosis
Exaggerated lumbar curvature
Scoliosis
Lateral curvature
Kyphosis
Exaggerated thoracic curvature
Rib bone facts
7 cervical
12 thoracic
5 lumbar
8-10 false ribs
11 & 12 floating ribs
(Bone growth)
Interstitial growth
Growth in length
Epiphyseal plate becomes epiphyseal line in adults
New cartilage on epiphyseal side, new bone on diaphyseal side
(Bone growth)
Appositional growth
Growth in thickness
Fxn of periosteum - wraps around BV’s to outside of diaphysis, new bone matrix is produced, circumferential lamellae become concentric
+ new osteons
Osteoclasts work on medullary cavity at a slower rate than the osteoblasts on the outside of the bone
Factors affecting bone growth
Calcium + phosphorus -fluoride, magnesium, manganese Vit A - stimulates osteoblast activity Vit C - for collagen synthesis Vit D - increase calcium absorption GI Vit K & B12 - needed for bone proteins
Insulin life growth factors (IGF)
Human Growth Hormone
Estrogen/testosterone - growth spurt
T3/T4 - thyroid hormones
Fractures
Simple - closed Compound - open sticks out of skin Communited - pieces Green stick - one side breaks Impacted - bone driven in another Potts - distal fibula Colles - distal radius
Fracture repair
Hematoma formation
Fibrocartilage callus formation
Bony callus formation
Bone remodeling
Hematoma formation
Massive blood clot
Inflammation, vasodilation
Osteoclasts and phagocytes (clean)
Fibrocartilage callus formation
Cells from periosteum differentiate into chondroblasts
Chondroblasts produce fibrocartilage matrix
Cells from periosteum -> fibroblasts ->
Form collagen fibers
Fibrocartilage callus bridges ends of bone
Bony callus formation
Osteogenic cells of periosteum differentiate to osteoblasts
Osteoblasts replace fibrocartilage callus w/ bone callus
Bone remodeling
Both osteoclasts + osteoblasts at work
(Bone to original shape)
Will be thicker and stronger
Blood homeostatic range
9-11 mg / 100mL
If Ca2+ is too high - cardiac arrest
If too low - respiratory arrest
Regulation through negative feedback loops.
Blood Ca2+ too low..
Detected by parathyroid gland Release hormone (parathyroid)
(Bone) increase osteoclasts activity
= more Ca2+ in blood
(Kidneys) retain Ca from urinary tract
Increase calcitriol production = Ca absorption increase in GI tract.
Blood Ca2+ too high
Thyroid gland (receptor, ctrl ctr) Secrete calcitonin Bone tissue (effector) Increase osteoblast activity - increase bone deposition
Endochondral ossification
- Development of cartilage model
- Perichondrium forms around cartilage model
- growth of cartilage model
- development of primary ossification center
- development of medullary cavity
- development of secondary ossification center
- development of Articular cartilage and epiphyseal plate
Metaphysis
Region between diaphysis and epiphysis
Hyaline cartilage growth plate
Articular cartilage
Thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms and articulation with another bone
Periosteum
Tough connective tissue sheath and it’s associated blood supply that surrounds the bone surface wherever it is not covered by Articular cartilage
Medullary cavity
Marrow cavity
Hollow space in diaphysis
Reduces weight
Has yellow bone marrow and blood vessels
Endosteum
Thin membrane that lines the medullary cavity
Contains a single layer of bone forming cells and a small amount if connective tissue
Bone support
Supports soft tissue
Attachment points for tendons
Bone blood cell production
Red bone marrow produces red blood cells, white blood cells, and platelets
Bone triglyceride storage
Yellow bone marrow consists mainly of adipose cells which store triglycerides
These are potential chemical energy, reserves
Development of cartilage model
Cells in mesenchyme cluster -> chondroblasts -> chondrocytes ->
Lay down cartilage matrix and trap themselves
Perichondrium forms around cartilage model
Growth of cartilage model
Chondrocytes in center shaft get big
Cartilage matrix calcifies
Chondrocytes die (no nutrients)
Spaces left -> lacunae
Development of primary ossification center
Endochondral ossification
Nutrient artery penetrate shaft Cells in perichondrium -> osteogenic cells Osteoblasts form - make bone matrix, trap themselves -> osteocytes Trabeculae form -> spongy bone forms
Development of medullary cavity
Endochondral ossification
Osteoclasts break down ctr shaft
Edge of diaphysis spongy bone is replaced by compact bone
Development of secondary ossification center
Endochondral ossification
2 more nutrient arteries penetrate epiphysis of cartilage model
Cells of periosteum -> osteogenic cells -> osteoblasts -> bone matrix -> trabeculae -> spongy bone
Skull features
Hard palate
Nasal septum
Zygomatic arch
Orbit
Hard palate
Roof of mouth
Maxillary + palatine
Nasal septum
Perpendicular plate of ethmoid bone + vomer
Zygomatic arch
Temporal bone + zygomatic bone
Orbit
Palatine + lacrimal + ethmoid + zygomatic + frontal + maxillary + sphenoid
