Cartilage and Bone Flashcards
What are the three types of cartilage?
Elastic, Hyaline, and Fibrocartilage
Elastic cartilage is found where?
Pinna of ear, epiglottis, certain laryngeal cartilages, pharyngo-tympanic tubes
Where is hyaline cartilage found?
Nose, upper respiratory tract, coastal cartilage, and articular cartilages
Where is fibrocartilage found?
Intervertebral discs, pubic symphisis, meniscus of knee, insertion of Achilles tendon
What are the three cell types in cartilage?
Chondrogenic cells, chondroblasts, and chondrocytes
What is the cartilage ground substance made up of?
GAGs and PGs and fibers (depend on type of cartilage)
Hyaline cartilage has what type of ground substance fiber?
Type II collagen
Elastic cartilage has what type of fibers in the ground substance?
Type II collagen and elastic fibers
Fibrocartilage has what type of fibers in the ground substance?
Type I collagen
Describe the organization of cartilage from the top down
Perichondrium to chondrogenic layer (only if perichondrium is present, chondroblasts are here), Intercellular substance with some chondrocytes in lacuna, and cell nest
T or F: Cartilage is older the deeper you do
T
What is appositonal growth?
Growth to the outer layer
What is the mature cell type of cartilage?
Chondrocytes
Where are chondroblasts located?
Chondrogenic layer
What are cell nests in cartilage?
Oldest cells that are immobile due to territorial membranes being formed due to build up of GAG
T or F: Cartilage is avascular
T. Nutrients come from diffusion from capillaries in the CT
What is the most common proteoglycan in hyaline cartilage?
Chondroitin sulfate
Describe the path of cartilage cell development
Chondrogenic cells to Chondroblasts to Chondrocytes (all while getting deeper in the cartilage)
Chondrocytes are located in what are commonly called?
Lacunae
What is the difference between chondroblasts and chondrocytes?
Chondrocytes are chondroblasts that have been enveloped in lacunae
What is the cause of caulliflower ears?
loss of elastin blood supply in elastic cartilage
T or F: Fibrocartilage is tough and thick
T
What are isogenous groups in cartilage??
Divided cells that are unable to disassociate due to dense ground substance (older cells)
What is the bone matrix composed of?
Osteoid (soft,type I collagen, GAGs and PGs) and hydroxyapatite (mineralization, hard)
What cells are located in bone?
Osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts
What is the difference between osteoblasts and osteocytes?
Osteocytes are older osteoblasts that have become enclosed in osteoid and mineral
What is the function of osteoclasts?
Break down bone
What are the three types of bone?
Long bone, Short bone, Flat Bone
From the center of the bone to the middle of the bone to the end of the bone longitudinally, name the regions?
Diaphysis, Metaphysis, Epiphysis
What is the periosteum?
Hard outer layer of bone
Articular cartilage usually covers?
The caps of long bone
Where is spongy/cancellous bone found?
Typically in the end/heads of long bone or in short bone
What is the epiphyseal plate?
The face of the long bone in the epiphysis region
Medullary cavity of bone is found where?
The middle of bone
What is the diploe?
The core of flat bone
What two layers compose flat bone?
Outer table and inner table
T or F: Osteoid stains darker than cartilage
T (dark red versus dark pink)
T or F: There are Haversian systems in spongy bone
F
Describe the organization of compact bone
Osteons (haversian systems) composed of a Haversian canal ringed by osetocytes and canaliculi in concentric lamellae
What are the three types of lamellae?
Intersitial lamellae (not part of haversian or circumferential), circumferential (outer and inner), and osteon/concentric
What is the function of canaliculi?
Microscopic canals that connect the lacunae of osteocytes (communicate via gap junctions)
Haversian canals run?
Longitudinally in compact bone
Volkmann’s canal run?
Horizontally in compact bone
What are Sharpey’s fibers?
Connective tissue that connects periosteum to bone
What is periosteum?
Dense irregular connective tissue that covers most bone
What is the function of osteoblast?
Synthesize osteoid, deposit inorganic component, located at the surface of bone tissue
What is the function of osteocyte?
Derived from osteoblasts, sit in lacuna surrounded by bone matrix, connect to other osteocytes via gap junctions between cytoplasmic processes in canliculi. Maintain the bone matrix
What is the function of osteoclasts?
Large, motile, multinucleate cells, make contact with the bone via a ruffled border, secrete enzymes that breakdown bone matrix resulting in the Howship’s lacuna
What is the Howship’s lacuna?
The depression in bone made by degradation due to osteoclasts
What does lamella mean?
Plate like structure usually very close to one another
How do osteoclasts function?
Lots of lysosomes that produce carbonic anhydrase to take CO2 and water to carbonic acid to proton and bicarbonate. Bicarbonate is sent to blood in capillary for buffer and proton is used to create the ruffled border (acidic decay). Microenvironment of low pH and lysosomal enzyme
Describe how osteons are made?
Osteoclasts bore holes through bone and osteoblasts make concentric layers down to fill making lamellae
What is osteoporosis?
Estrogen dependent decline in osteoblast activity
What is osteomalacia (Rickets)?
Disturbance in bone mineralization mostly due to lack of vitamin D and calcium
What is osteosarcoma?
Malignant tumor derived from osteoblasts
What are the two modes of bone formation?
Intramembranous bone formation and Endochondral bone formation
Describe intramembranous bone formation
Lead to flat bone production, appear in mesenchyme via condensation of cells
Describe endochondral bone formation
Long and short bones are made this way via the hyaline cartilage model
Describe the stages of Endochondral bone formation
Chondroblasts and early perichondrium develop enveloping primative mesenchyme. Cartilage is developed and bone collar forms. Thee primary ossification center forms and blood veseels and trabeculae form. Secondary ossification occurs in the epiphysis
What are the two modes of bone growth?
Increase in diameter (subperiosteal appositional growth). Increase in length (at the epiphyseal plates)
Describe the hierarchy of the epiphyseal plate
Epiphysis down to epiphyseal plate down to diaphysis
Describe the top down growth of the epiphyseal plate?
Cartilage divides and enlarges. It is calcified as it moves down. It is eventually eroded and replaced with bone by osteoblasts. Osteoclasts remodel
Interstitial growth achieves growth in? Appositional growth achieves growth in?
Length, width
