Cartilage is similar to epithelium in being that it is _________________________.
What is the function of chondroblasts?
They lay down the matrix (fibers and ground substance)
They are the cartlige forming cells
They are located at the inner chondrenic layer of the perichondrium.
What is the function of chondrocytes?
They are adult chondroblasts trapped in their own matrix
Located in Lacunae (compartments)
They help maintain the cartilage matrix
What types of fibers are in cartlidge and what is the function of each?
Collagen - adds tensile strength
Elastic fibers - impart (give) elasticity to cartilage
Ground substance conains proteoglycans that are responsible for ___________________.
The weight bearing property of cartilage.
The glycosaminoglycans are responsible for __________________________________ due to their negative charges.
attracting water and forming a hydrated gel
What are the functions of the perichondrium?
nutrition - since cartilage is avascular
growth of cartilage
regeneration of cartilage
What are the types of cartilage without perichondrium?
Articular cartilage of synovial joints due to the causing of friction.
What are the mechanisms of growth of cartilage?
Appositional growth by adding new cartilage under the perichondrium through the activity of the chondrogenic layer of the perichondrium
Interstitial growth - Growth from inside out
chondrocytes in lacunae undergo mitosis forming cell nests/isogenous groups MITOTIC GROWTH
Mention six locations for hyaline cartilage
epiphyseal growth plate - area between the shaft and head of the long bone
respiratory system (larynx, trachea, bronchi)
Costal cartilage attaches to the sternum
articular cartliages (synovial joints with no perichondrium)
What is the type of collagen is in hyaline cartilage and fibrocartilage?
Hyaline cartilage has Type II collagen
Fibrocartilage has Parallel bundles of type I collagen fibers for tensile strength
Mention four locations for elastic cartilage
auricle of the ear
external auditory meatus of the ear
eustachian tube of the ear
epiglottis in throat - the moving piece that keeps food from going down your trachea.
What are the two factors that limits the ability for cartilage to regenerate?
because it is avascular
and it's limited ability for chondrocytes to divide
Where does cartilage originate from?
Where does cartilage obtain it's nutrients from?
the blood vessels around it
Glycoprotiens have more __________.
Proteoglycans have more ___________.
What do GAGS bind to?
The core proteins of proteoglycans
Name three glycosaminoglycans
If cartilage does not cover articular surfaces of bones then how do the bones get their nourishment?
from synovial fluids
What is the strongest type of cartilage?
How does cartilage heal?
through ossification except for elastic cartilage because it NEVER ossifies.
Enumerate the four bone cells
Osteoprogenitor cells - stem cells that develop from undifferentiated mesenchymal cells UMC
Osteoblasts - form from osteoprogenitor cells
Osteocytes - maintain bone matrix
Osteoclasts - phagocytic cells of bone
Which bone cell is not found on the bone surface?
What is the function of osteoblasts?
they form the bone matrix
Mention the enzyme secreted by osteoblasts and its significance
Osteoblasts secrete alkaline phosphatase that leads to the deposition of calcium salts
What is the function of osteocytes?
they function to maintain the bone matrix
Which bone cells have gap junctions?
What are the enzymes secreted by osteoclast and the action of each?
carbonic anhydrase - produces carbonic acid which leads to the decalcification of the bone matrix
Collagenase enzyme - breaks down collage fibers
Which hormone stimulates osteoclastic activity?
What do you know about Howship's lacunae?
It is the space left after the osteoclast cells eat away the bone.
Name the cell with the ruffled border?
What is the major organic component of bone matrix?
95% collagen fibers
What are the main minerals of bone matrix
What are the forms of calcium phosphate
Crystalline calcium in the form of Hydroxyappetite crystals
Calcium carbonate salts
What do you know about Sharpey's fibers?
Collagen fibers that connect periosteum to outer circumferential lamellae of compact bone
What is the function of the periosteum?
lines the outside of the bone
What is the function of the endosteum?
lines the inside of the bone
Which bone is stronger woven or lamellar?
lamellar due to collagen fibers
What are the two types of lamellar bones and the location of each?
compact bones - outer shells resist deformation because of the structural unit which is osteon/haversian system.
Spongy bone - trabecular meshwork provides strength by acting as a complex system of internal struts and their structural unit is trabeculum.
What is the unit structure of compact bone?
concentric rings of bone around haversian canals interconnected by transverse canals AKA Volkman's canals
Which canal is parallel to the long axis of bone Haversian or Volkman's canal?
Haversian canals are parallel to the long axis of the diaphysis
What is the function of Volkman's canals?
To provide communication with blood vessels in the endosteum and periosteum through transverse canals
What is the function of bony canniculi around osteocyte processes?
they transmit interstitial fluid and nutrients
What covers the surface of trabeculae of spongy bone?
A thin endosteum with odontoblasts
Define intramembraneous ossification
bone growth within a vascularized embryonic connective tissue (mesenchyme)
Give an example of bones that ossify through intramembraneous ossification
Spongy bone first forms diploe
Compact bone forms on its outer and inner aspects
Which zone contains degenerating cartilage cells?
Which cells lay down bone in the ossification zone?
What effect does estrogen have on bones?
decreased osteoblast activity
What effect does parathyroid hormone have on bone?
raises the blood Ca levels and increases osteoclastic activity
What effect does Thyrocalcitonin have on bone?
inhibits bone resorption and lowers blood Ca levels
What effect does growth hormone have on bones ?
Gigantism if gets too much
Dwarfism if does not get enough
What effect does Vitamin D deficiency have on bones?
Deficiency - rickets in children
osteomalacia in adults
leaves bones soft but strong
What does Vitamin C deficiency have on bones?
Scurvy - bleeding gums
leaves bones rigid but weak
After menopause, what is the percentage of bone mass lost per year?
3 to 5%
Can bone grow by interstitial method like cartilage?
bone grows appositionally only
How do bones grow in length?
Through the activity of hyaline cartilage of epiphyseal plate
What is the main mineral in bone matrix?
calcium hydroxy appatite
What is the embryonic layer of bone?
What is the diaphysis of a bone?
What is the epiphysis of bones?
What is the metaphysis?
The area between the the epiphysis and diaphysis
What are the main functions of bone?
Protection of internal organs
muscle attachment, mobility
hematopoiesis - formation of blood cells
mineral storage - calcium and phosphate
What do flat bones consist of?
two layers of compact bone with a spongy layer between. spongy bone is called diploe
Give three examples of flat bones.
flat bones of the skull cap, ribs and sternum
From where do osteoprogenitor cells develop?
Undifferentiated Mesenchymal Cells UMC's
What is osteoid tissue made of?
collagen fibers Type I and ground substance
What flows the interstitial fluids for nourishment?
What are the spaces next the the trabeculae filled with?
What does trabeculae mean?
Where does intramembraneous ossification start?
in the mesenchyme
What makes osteoclasts?
The fusion of monocytes
What is apoptosis?
programmed cell death
What are some ways to prevent osteoporosis?
weight bearing exercise
avoid smoking or drinking
bone density tests
estrogen replacement therapy following menopause
Taking a prescription medication that inhibits osteoclastic activity e.g. - Fosamax