Skeletal System (Exam II) Flashcards
What is the primary function of bone?
Support & locomotion/movement
What is the secondary function of bone?
Protection, mineral storage, hemopoeisis
Bone is ____, while cartilage is _____.
Rigid; semi-ridid
Both bone and cartilage are derived from:
Primitive mesenchymal cells
What is the relative strength of bone and cartilage due to?
Properties of ground substance and extracellular fibers
_____ is a bone precurser
Cartilage
Cartilage formation begins with ____ cells which differentiated into ______.
Stellate mesenchymal cells; rounded chondroblasts
The rounded chondroblasts of cartilage grow and synthesize:
Ground substance and fibrous extracellular matrix
When the chondroblasts grow and synthesize ground substance & fibrous extracellular matrix, what happens?
The chondroblasts get trapped inside lacunae
In cartilage, further mitotic divisions produces clusters of mature _____ referred to as _____.
Chondrocytes; isogenous groups
The isogenous groups of chondrocytes are separated by:
Extracellular matrix
The ECM surrounding the isogenous groups
Territorial matrix
The pink ECM between the isogenous groups of chondrocytes:
Interteritorial matrix
Cartilage is surrounded by:
Perichondrium
The peripheral zone of dense connective tissues, containing fibroblasts, collagen & immature chondroblasts
Perichondrium
In what type of growth, does cartilage form within the mass?
Interstitial growth
What type of growth allows chondrocytes to retain the ability to divide
Interstitial growth
Type cartilage growth where new cartilage forms at surface of pre-existing cartilage
Appositional growht
What type of cartilage growth is more common?
Appositional
In appositional growth, new chondrocytes are derived from mesenchymal cells of the:
Inner perichondrium
In appositional growth, the new chondrocytes derived form mesenchymal cells of inner perichondrium differentiate first into:
Chondroblasts
In appositional growth, more mature chondrocytes present at _______, while the younger cells present at ________.
Center of cartilage mass; periphery
Bone growth can be directly ______ cells to ______ OR ____ cells to _______ to ________
Mesenchymal cells —-> bone
Mesenchymal cells ——> cartilage ——> bone
What is found in the perichondrium? (Peripheral zone of dense connective tissue)
- Fibroblasts
- Collagen
- Immature chondroblasts
What type of connective tissue is cartilage?
Avascular
Cartilage lacks:
Blood vessels
Since cartilage is a vascular, exchange of metabolites occurs via:
Diffusion through ground substance
Since cartilage relies on diffusion of metabolites through the ground substance, this limits the:
Thickness of cartilage
If cartilage is thick, it will have blood vessels in:
Secondary cartilage canals
Cartilage contains an ECM of ______ containing ___.
Amorphous ground substance containing collagen
The ECM of cartilage is hydrates and contains ~60-80% H20 bound to:
Proteoglycans
The hydration status of the matrix accounts for its: (2)
Flexibility & incompressibility
The GAGs found in cartilage (3):
- Hyaluronic acid (non-sulfated)
- Chondroitin sulfate
- Heparin sulfate
The most common glycoprotein in cartilage is:
Chondronectin
Potentially, chondronectin can have:
Anti-cancer properties
What determines the different types of cartilage:
Amounts of fibers embedded within matrix
Type of cartilage found within articular surfaces, growth plates, nasal septum, coastal cartilage (ribs), tracheal and bronchial rings:
Hyaline cartilage
Precursor of bone in most skeleton:
Hyaline cartilage
Collagen type that is characterized by aggregates of chondrocytes in amorphous matrix of ground substance & reinforced with type II collagen fibers:
Hyaline cartilage
What type of collagen fibers are present in hyaline cartilage:
Hyaline cartilage
What is the most common type of cartilage:
Hyaline cartilage
The Greek term hylos means:
Glass look
Specific locations for what type of cartilage:
- End of long bones
- Growth plates
- Nasal septum
- Articular surfaces
- Octal cartilage
- Tracheal & bronchial rings
Hyaline cartilage
What is a common precursor for bone in the skeleton?
Hyaline cartilage
Consists of alternating layers of hyaline cartilage and dense connective tissue:
Fibrocartilage
What type of collagen fibers are present in fibrocartilage:
Type I & Type II collagen
Fibrocartilage is less ____ than the other types of cartilage
Cellular
Fibrocartilage lacks:
Perichondrium
What type of cartilage is present in intervertebral discs?
Fibrocartilage
What type of cartilage is found in these articular areas:
Knee
Mandible (TMJ)
Shoulder
Sternum
Ligaments
Tendons
Joint capsules
Pubic symphysis
Fibrocartilage
Cartilage that is histologically similar to hyaline cartilage with addition of large numbers of elastic fibers in ECM:
Elastic cartilage
What type of collagen fibers are present in elastic cartilage?
Type II
Type of cartilage found in the external ear, auditory eustachian canals, epiglottis, and larynx?
Elastic cartilage
Type of cartilage that has a very limited distribution throughout the body?
Elastic cartilage
____ in cartilage is limited because it requires blood flow
Repair
Because repair in cartilage is limited, because it requires blood flow, this results in production of:
Dense connective tissue (fibrosis)
Production of dense connective tissue:
Fibrosis
Invasion of cartilagenous site by blood vessels frequently results in: (2)
- Death of chondrocytes
- Formation of bone
There is a tendency for all hyaline cartilage to:
Calcify with age
The calcification of hyaline cartilage is due to the deposition of _______ within the matrix
Calcium phosphate crystals
The deposition of calcium phosphate crystals within the matrix of hyaline cartilage eventually results in:
Bone
The most common repair of cartilage is done via:
Fibrosis
In the healing process of cartilage, the chondrocytes get replaced with:
Osteocytes
Old people are stiff because they do not have the same amount of ____ in there cartilage as younger people do:
Turgor pressure
Specialized support tissue in which the extracellular components are mineralized
Bone
What are two characteristics of bone
Strength & rigidity
What are the two main forms of bone?
Woven & lamellar
Immature form of bone characterized by random orientation of collagen fibers
Woven bone
describe the orientation of collagen fibers of woven bone
Random, disorganized
Immature woven bone is later remodeled into:
Lamellar bone
Lamellar bone contains concentric layers called:
Circumferential lamellae
In lamellar bone, the collagen fibers fibers of the circumferential lamellae are oriented:
Parallel
The extracellular components of bone are:
Mineralized
Lamellar bone can be either:
Dense & compact or cancellous & spongy
Where might we find dense and compact lamellar bone?
Cortex of long bones
Where might we find cancellous & spongy lamellar bone?
Ends of bones
Cancellous bone contains a network of thing, bony: (2)
Trabeculae and open spaces
Trabeculae of cancellous bone can also be called:
Spicules
The open spaces of cancellous bone:
Marrow cavity
What types of bones are found in the limbs?
Long bones
Shaft of long bones:
Diaphysis
The diaphysis of long bones contains compact bone in the _____, & spongy cancellous bone in the ____
Cortex
Medullary cavity (marrow)
What type of marrow is contained within long bones?
Red marrow or yellow marrow
Red bone marrow is:
Hematopoietic
Yellow bone marrow is:
Fatty bone marrow
Ends of long bones:
Epiphysis
The epiphysis of long bones is composed of ____ bone covered with _____.
Spongy/cancellous bone covered with hyaline articular cartilage
Flared regions between epiphysis & diaphysis:
Metaphysis
The metaphysis contains the ____ of long bones:
Epiphyseal plate
The swollen ends of long bones:
Epihysis
The external surface of bone is covered by:
Periosteum
A layer of fibrous connective tissue that covers the external surface of bone
Periosteum
What type of cells are found within periosteum?
Fibroblasts & osteoprogenitor cells
The internal marrow cavity is lined by:
Endosteum
Parallel bundles of collagen fibers, that extend from the periosteum or muscle tendon and insert into the superficial layer of bone:
Sharpeys fibers
Sharpeys fibers provide:
Anchorage & support
Resting mesenchymal cells that reside in the periosteum and endosteum
Osteoprogenitor cells
Where do osteoprogenitor cells reside?
Periosteum & endosteum
Osteoprogenitor cells can differentiate into:
Osteoblasts & osteocytes
Roughly polygonal, mesenchymal cells derived from osteoprogenitor cells
Osteoblasts
Osteoblasts are very ____ due to the synthesis of large amount of protein and proteoglycans
Basophilic
Osteoblasts synthesize large amounts of:
Proteins & proteglycans
Osteoblasts are responsible for synthesis of ECM & collagen, collectively referred to as:
Osteoid
Osteoid is similar to _____ and later mineralizes to form ___.
Cartilage; bone
Osteoblasts are responsible for calcification of matrix via:
Secretion of matrix vesicles
The matrix vesicles secreted by osteoblasts contain:
Alkaline phophatase
The matrix vesicles bud off the osteoblasts into the matrix causing precipitation of:
Mineral salts
Mineral salts that precipitate due to matrix vesicles budding off the osteoblasts:
Calcium and PO4
After the osteoid matrix mineralizes, osteoblasts mature into osteocytes in the:
Lacunae
Mature bone cells:
Osteocytes
Large multinucleate bone cells:
Osteoclasts
osteoclasts are likely derived from _____ & have _____ properties
Monocyte-macrophage lineage; phagocytic
Osteoclasts are actively involved in:
Resorption & remodeling of bone
Where are osteoclasts usually found:
Howships lacunae or resorption bays
What are howships lacunae or resorption bays?
Endosteal/periosteal surface depressions
Type of cell that function in calcium homeostasis:
Osteoclasts
