Skeletal System Flashcards
Components (4)
Bones
Cartilage
Tendons
Ligaments
Functions (5)
Body Support Organ Protection Body movement Mineral Storage Blood cell production
Ligaments
The connective tissue that holds bones together
Tendon
Strong bands of connective tissue that attach to bones
What minerals are stored in the bones? (2)
Calcium and phosphorus
What other tissue is stored in bone cavities?
Adipose - used as a source of energy if needed
Types of cartilage (3)
Hylanine cartalige
fibrocartilage
elastic cartilage
Hyaline Cartliage as related to. bone (2)
- Most bones in body start out as hyaline cartilage model
2. Bone growth and repair begin with hyaline cartilage
Chondroblasts
Immature hyaline cartilage cells
produce a matrix surrounding themselves
Chondrocyte
Mature chondroblasts with a matrix around it
Lacuna
The space occupied by a chondrocyte
What makes up the chondrocyte matrix? (2)
Collagen - for strength
Proteoglycans - trap water to make cartilage resilient
Perichondrium
- a protective connective tissue that covers cartilage
- Blood vessels and nerves penetrate the outer layer of the perichondrium but do not enter the cartilage matrix
Cartilage gets nutrients by
Diffusion in cartilage matrix
Layers of perichondrium
Outer - dense irregular connective tissue with fibroblasts
inner layer - delicate, fewer fibers, contains condroblasts
Articular cartilage
Hyaline cartilage covers the ends of bones where they come together to form joints
Does not have perichondrium, blood, or nerves.
Types of cartilage growth
appositional
interstitial
Appositional growth
chondroblasts in perichondrium add new cartilage to the outside edge of existing cartilage
Interstitial growth
chondrocytes in the center of tissue divide and add more matrix in-between existing cells
Bone Matrix composition
35% organic - collagen and proteoglycans
65% inorganic material - calcium phosphate crystal hydroxyapatite
Functional characteristics of bone (2)
as compared to reinforced concrete
Flexible strength - collagen (steel bars)
Weight-bearing strength - mineral components (concrete)
Bone cells (3)
Osteoblasts
Osteocytes
Osteoclasts
Osteoblasts
What they do, what differentiates them, and what 2 things do they produce?
Bone-forming
Extensive endoplasmic reticulum; numerous ribosomes
Produce collagen and proteoglycans
Derived from osteochondral progenitor cells
Matrix vesicles
Released by Osteoblasts
high concentrations of Ca2+ and Po43-
Ossification
What is it & how does it grow?
formation of new bone by osteoblasts
Appositional growth
Osteocytes
An osteoblast that has secreted enough bone matrix to become surrounded by it
Relatively inactive
Retain connection to other osteocytes through cell extensions
Derived from osteoblasts
Lacunae
Spaces without matrix but occupied by osteocyte
Canaliculi
Spaces occupied by osteocyte cell extension
Osteoclasts
Bone-destroying cells
Reabsorb (breakdown) bone to get Ca2+ and phosphate ions (send the Ca2+ back to the blood)
Multi-nucleated
Derived form stem cells in red bone marrows
Ruffled border
Highly folded, differentiated cell membrane of the osteoclast
Osteogenesis imperfecta
Brittle Bone disorder
Mutations the make defective type I collagen
Type 1 OI
Type 1 OI > mild, most common. Caused by too little formation of normal type 1 collagen
- predisposed to fracture, spinal curvature, loose joins, brittle teeth, hearing loss, blue tint to the white of eyes
Type 2 OI
Most severe
Lethal within the first week of life
BReathing failure due to rib fractures
Type 3 OI
Bones that fracture easily, before and during birth
Osteochondral progenitor cells
Stem cells that can become osteoblasts or chondroblasts
Located in the inner layer of the perichondrium
When does ossification occur?
In a fetus
When growing
When repairing a fracture
Woven bone
The first type of bone formed
Weak
Collagen fibers randomly oriented in many directions
Lamellar bone
Mature bone
Collagen fibers lie parallel to one another
Lamellae
Layers of lamellar bone
Spongy bone
Appears porous, has less bone matrix, and more space
Compact bone
more bone matrix and less space
Trabeculae
Interconnecting rodes/ plate of the bone in spongy bone
Between the rods are bone marrow and blood vessels
No blood vessels penetrate trabeculae, so osteocytes must get nutrients through canaliculi
Osteon
The functional unit of a long bone, compact bone
Made of concentric rings of matrix
Central canal
Center of the “target” of the osteon
Where blood vessels enter the bone
Concentric lamellae
circular layers of bone matrix that surround central canal
Circumferential lamellae
Thin plates that extend around the bone
Interstitial lamellae
Between osteons
Remnants of concentric or circumferential lamellae that were removed during bone remodeling
