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Body Tissues
Bone and Cartilage
61
Histology
Professional
09/14/2013

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Cards

Term
3 Types of Cartilage
Definition
Hyaline Cartilage

Elastic Cartilage

Fibrocartilage
Term
Hyaline
Definition
• Has collagen in it, not really concentrated
• Appears to not have any fibers
• Glossy homogenous appearance
• can twist and bend it
• Conduit – blood / nutrients can go through (percolate)
Term
Elastic Cartilage
Definition
• Contains a lot elastic fibers
• Desmosome and isodesmosine
Term
Fibrocartilage
Definition
• Easy to stain
• Easy to make out fibrous matrix
• Many collagen bundles
Term
Percolate
Definition
to filter gradually through a porous surface or substance.
Term
Why isn't hyaline cartilage hard?
Definition
so that bloom vessels on the outside can release nutrients that can go through the matrix
Term
Under a microscope, what does hyaline cartilage look like?
Definition
smooth, glassy appearance. collagen fibers are barely identifiable

very light colored inter territorial matrix

isogenic groups of lacunae, which stain darkly around each one
Term
What part of the ground substance will stain when examining hyaline cartilage?
Definition
Proteoglycans and other carbohydrates (use eosin)
Term
What time of staining would best be used to stain hyaline cartilage?
Definition
Eosin will stain the proteoglycans
Term
What does the matrix of elastic cartilage contain?
Definition
contains ELASTIC and COLLAGEN fiber
Term
What is fibrocartilage less pliable than other forms?
Definition
less pliable because of the presence of thick collagen bundles, which give it tensile strength
Term
Where are chondrocytes housed?
Definition
In spaces in the matrix called lacunae
Term
Describe the continuous turnover in cartilage?
Definition
Active in recycling materials/ components to the matrix….so exocytosis and endocytosis (inside and outside the cell)…materials broken down and recycled
Term
Perichondrium
Definition
cartilage covering

surrounds HYALINE and ELASTIC cartilage only
Term
What types of cartilage contain a perichondrium?
Definition
Hyaline and elastic
Term
Describe the matrix of fibrocartilage
Definition
ground substance is less concentrated (like hyaline)
Term
How many layers are there in the perichondrium?
Definition
2 layers
The outer layer is fibrous, which contains fibroblasts, collagen, and blood vessels

Inner layer lays directly over the cartilage layer, gives rise to chondroblasts (chondrogenic), which results in new cartilage cells
Term
What are the 2 types of growth in cartilage?
Definition
Interstitial growth and Appositional Growth
Term
Interstitial Growth
Definition
occurs within the matrix of the cartilage

this growth occurs inside the cartilage and expands it

an individual progenitor cell divides, forming cell nests

cells of the lacunae divide, forming new daughter cells
Term
Isogenous groups (cell nests)
Definition
a cluster of chondrocytes, all formed through division of a single progenitor cell, found in hyaline cartilage growing by interstitial growth.
Term
Appositional Growth
Definition
occurs on the inner layer of the perichondrium

applies more cartilage to the outer surface
Term
Periosteum
Definition
Covering the surface of the inside and outside of bone
Term
2 Types of Bone
Definition
spongy bone- spaces and gaps (called cancellous bone)

Compact bone - thick, densely packed
Term
Hydroxyapatite
Definition
formed by calcium and phosphate

main ingredient that makes bone hard
Term
Is bone vascularized?
Definition
Yes, bone contains blood vessels in its matrix, via the Haversian Canal
Term
How does bone grow?
Definition
Only via appositional growth
Term
2 layers of bone tissue?
Definition
Periosteum (contains outer layer and inner osteogenic layer)

Endosteum (One cell layer thick lining the inner surfaces)
Term
Endosteum
Definition
(One cell layer thick lining the inner surfaces of ALL BONE)

Has osteogenic potential

between the inner surfaces in spongy bone

no fibrous connective tissue like the periosteum

layer of cells that osteoclasts remove bone from
Term
Outer and inner circumferential lamellae
Definition
Outer lines the circumference of the outer layer

Inner circumferential lines circumference of each osteon
Term
Intersitial Lamellae
Definition
bone tissue that doesn't follow circular pattern, linear….forms connections between osteons
Term
Haversian Canal (central canal)
Definition
located at the center of each osteon

houses blood vessels and nerves
Term
During bone growth, how does the bone prevent itself from becoming too thick?
Definition
As bone is being added to the by osteoblasts on the inner layer of the periosteum, osteoclasts perform bone resorption of the endosteum.
Term
Cannaliculi
Definition
channels that radiate from central canal (one per osteon)

o Connect lacunae to the central canal
o Blood vessels in the central canal
o osteons receive important materials
Term
Do bone contain lacunae like cartilage?
Definition
Yes, the lacunae house the osteoclasts
Term
Volkmann's Canals
Definition
perpendicular to central canals

carry blood vessels from the periosteum into the bone
Term
Spiracles
Definition
Refer to the thin pieces of connections between spongy bone
Term
Trabeculae
Definition
Refers to the thick pieces of connections between spongy bone
Term
What parts of bone have osteogenic potential?
Definition
The inner layer of the periosteum and the endosteum
Term
Where do hydroxyapatite crystal grow?
Definition
crystal nucleate and grow along collagen fibers

they also provide tensile strength
Term
Osteoclasts
Definition
resorptive cells found in Howship’s lacunae multinuclear, giant cells
Term
Where are osteoclasts found?
Definition
Howership's lacunae
Term
Describe the appearance of osteoclasts
Definition
multinuclear, giant cells
Term
What type of stain would you use to identify osteoclasts?
Definition
Feulgen's Stain since it contains a quantitative density of DNA

could also use heatoxylin
Term
How osteoclasts work?
Definition
• Secrete phosphatase that breaks down the hydroxyappetite crystals and softens the surface
• Border agitates and degrades the soft surface
Term
Epiphysis
Definition
the ends of each bone
Term
Spongy Bone
Definition
found in the epiphysis of long bone
Term
Diaphysis
Definition
long part of the bone
Term
Compact Bone
Definition
follows the length of the long bone...found in the diaphysis
Term
Epiphyseal Plate
Definition
Known as growth plate…critical in lengthening of long bone
Term
Sharpey’s (Peforating) Fibers
Definition
o Large bundles of collagen to help anchor periosteum to bone
• Found in periodontal ligament to help maintain connection of alveolar bone to cementum of tooth
Term
What is the purpose of collagen fibers in bone?
Definition
Collagen fibers have great tensile strength

Their alternating pattern helps bone resist various pulling and twisting forces applied to it
Term
2 Method of Ossification (formation of bone)
Definition
Intramembranous

Endochondral
Term
Intramembranous Ossification
Definition
(flat bones of the skull, jaw, clavicles, etc…)

•Start with a membrane of mesynchymal cells…differentiate into osteoblasts, forming an ossification center

•When secretions (osteoid) are released, not calcified immediately (soft at first)
• In time, osteoid begins to calcify
• Lacunae now form and canulicula forming
• On surface the new cells are forming and osteocytes become less active
• Eventually get a spongy bone, covered in endosteum
• Compact bone forms on the outer surfaces
• Periosteum on outer surface
• Diploe allows vascular tissue growth
Term
Osteoid
Definition
secretions of osteoblasts in the beginning stages of intramembranous ossification
Term
Endochondral Ossification (within cartilage)
Definition
• Start with mesenchyme…initially differentiate into chondroblasts
• These form a model of cartilage
• Cartilage starts to calcify over time and become replaced with new osteoblasts that make bone

• Bone collar – allows blood supply to enter
• First sign bone will be formed (Cartilage is avascular)
• Marrow cavity gets cleared out, leaving endostial lining
• Epiphyseal plate (hyaline) not replaced by spongy bone
• Allow intersitital growth
• Cartilage continues to grow and lay new bone down
• Cartilage will age and be replaced by bone on the inner side of the epiphyseal plate
• Spongy bone is calcified cartilage
Term
After ossification, where are the only two places that cartilage remain?
Definition
• Epiphyseal Plate
• Articular Cartilage (located at each end
Term
When looking at slide of bone near epiphyseal plate what are the 5 zones?
Definition
(From top to bottom)
1. Resting Zone
2. Growth (Proliferation Zone) - cartilage cells undergo mitosis
3. Hypertrophic Zone - older cartilage cells enlarge
4. Calcification Zone - matrix becomes calcified, cartilage cells die, matrix begins deteriorating
5. Ossification (osteogenic zone) - new bone formation occurs
Term
2 hormones that regulate bone growth
Definition
Calcitonin - a hormone that lowers blood calcium

Parathyroid Hormone (PTH) - a hormone that lowers calcium levels in blood
Term
Calcitonin
Definition
Made in the Thyroid

a hormone that lowers blood calcium
➢ Causes cells to create additional osteoblasts/osteocytes
➢ Calcium is taken from blood and incorporated into hydroxyappetite
Term
Parathyroid Hormone (PTH)
Definition
Made in the Parathyroid


➢ Osteoclasts increase in number to break down calcified crystals
• Freed calcium get released into the blood, ultimately raising blood calcium level
Term
4 steps of healing resulting from a bone fracture
Definition
• Hematoma Formation - (a solid swelling of clotted blood within the tissues)
• Fibrocartilaginous callus formation
• Bony callus formation
• Bone remodeling
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