Cartilage and Bone Flashcards

1
Q

What are the fundamental cells of connective tissue fibers?

A

Fibroblasts

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2
Q

What are the 3 types of connective tissue fibers?

A
  1. Collagen fibers
  2. Reticular Fibers
  3. Elastic fibers
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3
Q

What are reticular fibers made of?

A

Type III collagen

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4
Q

What are elastic fibers made of?

A

Elastin and Fibrillin

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5
Q

What kind of connective tissue is Fascia?

A

Loose irregular connective tissue

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6
Q

What type of connective tissue makes up a Aponeurosis?

A

Dense irregular connective tissue

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7
Q

What type of connective tissue is tendons and ligaments?

A

Dense regular connective tissue

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8
Q

Cartilage characteristics

A

Avascular
Alymphatic
Aneural

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9
Q

Cartilage cells

A

Chondroblasts
Chondrocytes

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10
Q

Chondroblasts

A
  • located at periphery of growing cartilage
  • oval basophilic cell located in lacuna
  • dividing cell that forms matrix
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11
Q

Chondrocytes

A

-elongated to spherical cell
- glycogen and lipid droplets in older chondrocytes
- fill lacunae in living state, but have artifactual space in fixed tissue

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12
Q

Components of cartilage matrix

A
  • mainly type II collagen fibers (type I in fibrocartilage)
  • ground substance: glycosaminoglycans
  • aggrecan (formed from binding proteoglycans and hyaluronic acid
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13
Q

Role of aggrecans in cartilage matrix

A

transport water and electrolytes

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14
Q

Role of proteoglycans in cartilage matrix

A

Create sieves

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15
Q

Perichondrium

A

Surrounds cartilage!

Has inner cellular layer and outer fibrous layer of cartilage

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16
Q

Types of cartilage

A
  1. Hyaline
  2. Elastic
  3. Fibrocartilage
17
Q

Hyaline Cartilage

A
  • firm gel with type II collagen fibers
  • located on articular surface or embedded in tissues
  • Has small chondrocytes in elliptical lacunae running parallel to surface
  • Has large and polyhedral chondrocytes in deeper part
  • Can have multiple chondrocytes per lacuna
18
Q

Elastic cartilage

A
  • located where elasticity and rigidity is needed
  • few elastic fibers near perichondrium, but dense network of elastic fibers deeper
  • greater variation in lacunae compared to hyaline cartilage
  • Ex. epiglottis, ear
19
Q

Fibrocartilage

A
  • least common
  • Type I collagen fibers in matrix
  • rows of small lacunae with chondrocytes parallel to collagen bundles
  • amorphous matrix near lacunae
  • lacks cellular chrondrogenic layer of perichondrium
  • Located in areas such as intervertebral discs and stifle joint
20
Q

Development of cartilage

A

Embryonic origin from mesenchymal cells
Steps:
1. Chondroblasts cluster at site of chondrification
2. Chondroblasts secrete amorphous substance and type II collagen which increases the matrix
3. Increased matrix results in isolation of chondrocytes

21
Q

Two methods in which cartilage can develop

A
  1. Interstitial growth
  2. Appositional growth
22
Q

Nutrition of cartilage

A
  • Mainly gets nutrients from diffusion because cartilage is avascular
  • use capillaries outside perichondrium or from synovial fluid
  • vascular channels penetrate if cartilage is thicker than 3mm
23
Q

Characteristics of Bone

A
  • firm and less pliable than cartilage
  • vascular
  • contain bone marrow in medullary cavity
  • dynamic tissues (always renewing and remodelling)
24
Q

Bone cells

A
  • Osteoblasts
  • Osteocytes
  • Osteoclasts
25
Q

Osteoblasts

A
  • involved in active formation and mineralization of the matrix
  • Deposits osteoid
  • located near the surface (flat by columnar cells)
  • intense basophilic cytoplasm (prominent rER and Golgi)
26
Q

Components of osteoid

A

collagen type I and proteoglycans

27
Q

Osteocytes

A
  • principle cell in mature bone; needed for bone structure
  • formed when osteoblasts surround themselves with osteoid
  • less rER and golgi than osteoblasts, more lysosomes
  • resides in lacuna and extend processes through canaliculi
  • removes and replaces perilacunar bone
28
Q

Osteoclasts

A
  • large multinucleated cells on the surface of bone
  • reabsorb bone; secrete acid and lysosomal enzymes
  • ruffled borders in activated cells
29
Q

Bone matrix

A
  • Type I collagen fibers an ground substance (sulfated glycosaminoglycans &glycoproteins)
  • secreted by osteoblasts
  • store calcium and phosphorus allowing for osteoid mineralization
30
Q

Macroscopic structure of bone

A
  1. Epiphyses- located at both extremities. Spongy bone covered by articular cartilage
  2. Diaphysis (shaft of the bone)- compact bone containing medullary cavity. Covered by periosteum and lined by endosteum
31
Q

Medullary cavity

A

Filled with red bone marrow (young animals) or yellow (adults)

32
Q

Physis and metaphysis

A

Between the epiphysis and diaphysis

  • composed of hyaline cartilage
  • growth plate
33
Q

Microscopic components of bone

A
  1. Periosteum- surrounds bone (has inner osteogenic layer and outer fibrous layer)
  2. Circumferential lamellae surround bone inside the periosteum.
  3. Osteons- multiple make up bone.
  4. Central haversian canal- runs down middle of osteon
  5. Perforating Volkmann’s canals connect haversian canals of osteons
  6. Lacunae with osteocytes- in between lamellae layers of osteons. Connected by canaliculi.
  7. Interstitial lamellae- lie outside the osteons in the bone
34
Q

Endosteum

A

Inner surface of bone wall that separates bone from bone marrow

Also lines the haversian canal and internal cavities of bone.

35
Q

Bone nutrition

A
  • unique lacunar-canalicular system
  • no osteocyte more than 100 micrometers from a capillary
  • growth by apposition