EXAM2_HE10_11_Cartilage_Bone Flashcards Preview

Histology/Embryology > EXAM2_HE10_11_Cartilage_Bone > Flashcards

Flashcards in EXAM2_HE10_11_Cartilage_Bone Deck (63):
1

Hyaline Cartilage 7 Locations and Function

Resists compression
-Articular cartilage
-Trachea, bronchi
-Embryonic skeleton
-Growth plate
-Larynx
-Nose
-Costal Cartilage

2

Elastic Cartilage 4 Locations and Function

Elastic support
1. Pinna
2. External auditory meatus
3. Larynx
4. Auditory tube

3

Fibrocartilage 3 locations and function

Resist tension & compression
1. Articular & Intervertebral disks
2. Labra, menisci
3. Tendon insertions

4

Perichondrium two layers? What cells within? what is it a mixture of?

Outer- DiRCT
Inner- Chondrogenic cells (stem cells) that can turn into cartilage cells.
-Contains Fibroblast cells
-Type I Collagen CT associated with Cartilage

5

If cartilage is avascular- what cells support/nourish cartilage?

Cartilage is Avascular and depends on Diffusion from Perichondrium for its blood supply/nourishment

6

Perichondritis or Perichondrium hematoma what is it? Where? repair? associated abnormalities?

Blood between perichondrium and cartilage tissues.
Ct repaired by fibroblasts laying down type 3 and replacing with type 1
Fibrosis of type 1-->cauliflower ear

7

Chondrocyte Function. Replication?

Regulate ECM Synthesis by using MGP's to mechanically sense any changes in ECM. and it then adjusts the gene expression for SECRETION
-multiply mitotically- form isogenous groups (clusters of recently divided chondrocytes)

8

What are isogenous groups? What happens when it develops?

-clusters of recently divided chondrocytes.
-Clusters will separate and push each other away when they start secreting their own ECM
-mitotic-stim by mechano sensation of mgp's

9

Where are chondrocytes derived?

Mesoderm- mesenchymal stem cells- chondrogenic cell- chondrocyte

10

What is the 3 components of ECM of hyaline cartilage?
2 Functions? How do they stain?

-Type 2 Collagen
-Proteoglycan Agregates
-MGP's
1. Resists compression
2. Diffusion of nutrients/waste (sponge)
collagen pink (acidophilic)
PG's blue/purple (basophilic)

11

What are the two types of cartilage growth?

1. Appositional growth- on surface (surface is under perichondrium)-- chondrogenic cells make chondrocytes that secrete ECM onto cartilage surface

2. Interstitial growth- from within- Chondrocytes divide & secrete ECM within cartilage

12

What is the limitation of cartilage growth? What happens if it gets too thick?

Cartilage is Avascular so it's growth is limited by the ability of diffusion of nutrients/waste
ie: it can get too big in the perichondrium that the blood can't diffuse down into the cartilage and the tissue will start to die

13

An Orcein stain displays_____(color) for _____ fibers and H&E/Orcein stain shows___color for _____fibers.
What is differs Hyaline from Elastic cartilage?

Black for elastic fibers
Blue for elastic fibers/cartilage
Elastic cartilage has elastic fibers in ECM

14

How does hyaline cartilage differ from Fibrocartilage?

Fibrocartilage has Type 1 and 2 collagen fibers in ECM
-NO PERICHONDRIUM
(but has fibroblasts, isogenous groups,

15

What is an example of hyaline cartilage that does NOT have a perichondrium?

Articular cartilage because CT can't resist the compression of an articulating joint (it would get crushed).

16

where does articular cartilage get its nutrient if it is avascular and it doesn't have a perichondrium? What is a side effect of this?

Fluid in the joints- degenerates without scarring (no perichondrium, Ct, fibroblasts, thus no fibrosis)

Damage is Irreversible and can damage bone if bad enough

17

What are two crystal induced arthropathies? (crystal types)

Gout (monosodium urate crystals)- too much uric acid
Pseudo-gout (calcium pyrophosphate dihydrate CPPD)
Lysosomal enzymes released during inflammatory response destroy tissue

18

What is mechanically/physical trauma induce degeneration of cartilage?

Osteoarthritis (OA)

19

What is RA (rheumatoid arthritis) what caused by? what is an indication of RA?

Inflammation - autoimmune disease- no known cause-
RF- rheumatoid factor (antibody) may or may not be increased

20

3 terms for the lattice looking type of bone. Where found? Function?

-Trabecular*, spongy, cancellous.
-Epiphysis & medullary cavity.
-Stores Bone Marrow
Forms internal structure- Stores calcium
ION EXCHANGE between bone & blood

21

Compact (cortical) bone- where? composition? Function?

1. Diaphyses & on external surfaces of bone
2. Lamellae (sheets) concentric rings of bone (looks like lines)
3. Has bv canals
4. Supports, forms external bone surfaces

22

Osteon- 3 Structure details, function?

Cylinders of bone, bv central/haversian canal, concentric lamellar rings
- abundant in adults- increase w/ age
-formed during bone remodeling/repairs

23

what canals link the central canals?

Perforating canals- Volkmann's canals- important nutrient exchange

24

Perforating fibers (sharpy's fibers)- structure- function-

Type 1 Collagen fibers in the bone periosteum that are embedded in the bone ECM.
-Attach muscle tendons & ligaments to bone

25

Endosteum- structure- function- 3 cell types found there?

THIN- Monolayer of cells lining all the inner surfaces of the bone (all the trabeculae/spongy bone "medullary surfaces")
-protect/monitor surface of bone
1. osteoprogenitor cells
2. osteoblasts
3. bone-lining cells

26

Osteoclasts- structure-function-derivation

Big multi-nucleated cells;
- Resorb Bone
- derived from granulocyte/macrophage progenitor cells in bone marrow
-All osteoclast cells fuse together to form one big multi-nucleated cell

27

RANKL and OPG

RANKL- stimulates formation of osteoclasts (Bone resorption)

OPG- inhibits RANKL (inhibits osteoclast activity/resorption)

28

Clear zone-structure/ function

- Adherence site of osteoclast to bone
-seals cavity so lysosomal contents don't leak out into the cell.

29

Ruffled border- structure and function

osteoclast folded plasma membrane increases surface area to increase amount of proton pumps so it can breakdown minerals and elevate serum calcium levels
-increase level of secretion for lysosomal enzymes (like secretory vesicles)
- ca transcellular transport through osteoclast, exocytosed into ECM into blood

30

What elevates serum CTX?

Lysosomes inside osteoclasts secrete lysosomal enzymes that are exocytosed into the resorptive bay where they break down collagen which then gets reabsorbed into the osteoclast and exocytosed back into the blood.

this collagen breakdown elevates CTX
indicates how much resorption occurred/collagen has been broken down and returned into the blood

31

Osteoblasts Structure- Function- Derivation- shape location

-cuboidal shape on bone surface
-derived from mesenchymal cells in bone marrow-> osteoprogenitor cells-> osteoblasts
can become osteocytes or bone-lining cells

FORM BONE

32

What are the two fates of osteoblasts

-2 fates
- become bone lining cells when quiescent (appear flat) or
-become osteocytes (when embedded in ECM)

33

What are 3 secretions of osteoblasts?

1. procollagen for extracellular formation of type 1 collagen
2. alkaline phosphatase vesicles promote mineralization
3. Ca-binding proteins (OSTEOCALCIN) to bind ECM components together

34

What are two blood serum markers for bone formation?

Alkaline phosphatase
Osteocalcin

35

Bone ECM- Structure- function
mineralized/vs non- 2 names

Type 1 Collagen
Non-mineralized bone (Osteoid)
Mineralized bone (hydroxyapatite crystals)

36

Osteocytes structure. where found? how do they communicate? how do they sense and function?
What cells are the most similar to?

Osteoblasts that become embedded in ECM during bone formation
Found in Lacunae & have canaliculi
communicate via gap junctions
mechanosensitive
DIRECTS BONE REMODELING
JUST LIKE CHONDROCYTES

37

What is the Reversal (cement) line?

boundary between pre-existing bone and newly formed bone

38

How is bone remodeling regulated? 2 ways w examples. Why is bone remodeling important?

regulated by mechanical regulation via osteocytes
and by PTH, CALCITONIN, & ESTROGEN (hormonal).
repairs microfractures, aids in calcium metabolism

39

Calcitonin - from? (structure) binding site? function- inhibition-

DECREASE BLOOD Ca levels
-secreted by C-cells in thyroid
-bind receptors on osteoclasts
-inhibit osteoclast resorption

40

PTH- from? binding? secrete? function?

-chief cells of parathyroid
-bind OSTEOBLASTS and secrete RANKL
-RANKL stimulates osteoclasts
INCREASE BLOOD Ca2+ levels
protection mechanism- bind to -blasts to make sure they are around before resorbing bone.

41

Estrogen- from? bind? secrete? Function?

-secreted by gonads
-bind receptors on osteoblasts & osteoclasts
-osteoblasts secrete OPG (rANKL inhibitor)
BONE MAINTENANCE

42

OPG

RANKL inhibitor
inhibits osteoclasts
when estrogen levels drop osteoporosis is a concern

43

Osteopetrosis

Skeletal sclerosis (hardening) caused by osteoclast dysfunction

44

Osteopenia

Mild form of osteoporosis

45

Osteomyelitis

inflammation of bone, mostly due to infection

46

Ricket & osteomalacia

Vit D deficiency, disruption of vit D metabolism

47

Osteitis deformans (Pagets disease)

Rapid resorption followed by disorganized growth
-caused by slow virus

48

Osteogenesis imperfecta (brittle bone disease)

Mutation in gene for type I collagen

49

Where do pelvis, shoulder, limbs, and sternum arise from?

Lateral plate Parietal mesoderm

50

Where does mandible, and anterior cranium arise from?

Neural crest cells

51

Where does posterior cranium, vertebrae, and ribs arise from?

Paraxial mesoderm

52

Calcification vs ossification

Ossification reserved for BONE FORMATION
Calcification can occur in many types of tissues
-ECM calcifies (usually in cartilage)

53

What affects how mesenchymal cells differentiate?
Two states, what each turns into/forms

Oxygen availability
Hypoxic (like in cartilage); mesenchymal cells-> chondrogenic cells
High oxygen- mesenchymal cells -> osteoprogenitor cells & form ossification centers

54

What are the two types of ossification?
What is required for each?

1. Intramembranous ossification- req vascularized mesenchyme
2. Endochondral ossification- req hyaline cartilage template

55

3 steps of intramembranous ossification
What 3 types of bone does it form?

-Req-vascular mesenchyme->osteoprogenitor cells (OPC's) make ossification centers
1. mesenchymal cells differentiate into OPC's at ossification centers (near bv)
2. OPC's differentiate into OSTEOBLASTS that form bone trabeculae
3. Trabeculae enlarge and fuse together
Mandible, flat bones of cranium, clavical

56

Endochondral ossification 5 steps

1. mesenchymal cells differentiate into chondrogenic cells (hypoxic environment)
2. Chondrogenic cells differentiate into chondrocytes that build Hyaline Cartilage Template
3. Blood vessels invade: oxygen rich environment induces chondrocytes to calcify their matrix
4. Calcified cartilage starts to be replaced with bone (making ossification centers & growth plates)
5. bone Growth ends when plates replaced with bone

57

What ossification zone supplies/directs proliferation?

1. Zone of reserve- Hyaline

58

What zone for mitosis, ECM secretion?

2. Zone of proliferation

59

What zone for cells enlarge, secrete VEGF for BV growth?

3. Zone of hypertrophy

60

What zone for cartilage ECM calcification and apoptosis?

4. Zone of calcification

61

What zone for calcified cartilage replaced with bone?

5. Zone of ossification

62

What are the 5 zones for endochondral ossification?

1. Zone of reserve
2. Zone of proliferation
3. Zone of hypertrophy
4. Zone of calcification
5. Zone of ossification

63

Woven bone- where does it happen- what is it?

Calcified cartilage replaced with bone in zone of ossification :
immature bone that is weaker and more disorganized
1. first type of bone laid down during ossification and also in fracture repair
2. Quickly replaced by lamellar (mature) bone