LEC-8 Bone and Cartilage Flashcards
The smallest functional unit of bone is a(n) __________.
Osteon
Anything referring to bone begins with the prefix ________.
Osteo
Anything referring to cartilage begins with the prefix ________.
Chondro
What are the three types of bone cell?
- Osteoblasts
- Osteocytes
- Osteoclasts
What are the four types of bone?
- Woven
- Lamellar (created by remodeling of woven bone)
- Compact
- Cancellous (Soft)
Bone is primarily made from what type of collagen?
Type I
What are the two types of cartilage cell?
- Chondroblasts
- Chonrdocytes
Cartilage is primarily made from what type of collagen?
- Type II
- Type I also (minor)
The vascular tissue enveloping the bone at all places except joints is referred to as the ______________.
Periosteum
The connective tissue that envelopes cartilage at all regions except joints is known as ___________.
Perichondrium
What is the mechanism for bone growth?
Appositional
What is the mechanism for cartilage growth?
Appositional AND Interstitial
What are the three types of cartilage?
- Hyaline
- Elastic
- Fibrocartilage
The base of skull, appendicular skeleton, and axial skeleton is formed through what type of ossification?
Endochondrial
The bones of the skull and a few bones within the face are developed through what type of ossification?
Intramembranous
- Mandible and Maxilla are intramembranous ossifications
Describe the steps of intramembranous ossification.
- An ossification center forms within the mesenchyme.
- Blood vessels develop and carry factors into the ossification center.
- Mesenchymal cells differentiate into osteoblasts and begin to secrete osteoid.
- Osteoid mineralizes to form woven bone.
- Woven bone is then remodeled into lamellar bone.
(Woven/Lamellar) bone is formed first by the secretion of osteoid from osteoblasts. It consists of haphazardly organized collagen fibers and is relatively weak. Of the two, this type is the quickest to form, especially following breaks or Paget’s disease.
Woven
(Woven/Lamellar) bone consists of regularly spaced, parallel, concentric alignments of collagen into sheets. This type of bone is mechanically stronger than its counterpart but takes longer to develop.
Lamellar
(T/F) There are a great deal of blood vessels within cartilage during chondrification.
False. There are no blood vessels present in cartilage during chondrification.
Describe the process of chondrification.
- Mesenchymal cells differentiate into round chondroblasts.
- Chondroblasts secrete cartilage matrix.
- Chondroblasts then become chondrocytes that divide and proliferate.
The __________________ induces mesenchymal cells to form into chondroblasts during chondrification.
Extracellular matrix
The outline for endochondral ossification begins as __________ cartilage.
Hyaline
What is the bony collar?
A cuff of periosteal bone that forms around the diaphysis of the hyaline cartilage outline in developing long bones.
A bony collar is utilized during (intramembranous/endochondral/both) ossification.
Both
(T/F) Although used in endochondral ossification, the bony collar is formed through intramembranous ossification.
True.
Chondrocytes within a cartilage matrix receive nutrients through _____________.
Diffusion
Describe the general formation of a primary ossification center.
- The bony collar forms on the outside of the hyaline cartilage outline.
- Blood vessels invade this space and begin to release osteoprogenitor cells
- The osteoprogenitor cells differentiate into osteoblasts.
- Osteoblasts secrete osteoid for further bone formation.
After the bony collar is formed, receiving nutrients through diffusion is no longer possible and the chondrocytes die, leaving behind a hollowed __________ within the bone.
Merocavity
Where is the primary ossification center in long bones?
Diaphysis (shaft)
Where is the secondary ossification center in long bones?
Epiphysis (rounded bone end)
Bone elongates through interstitial growth (proliferation) of the ______________.
Epiphyseal plate (or physis)
Bone widens through the __________ growth of the (epiphysis/metaphysis/diaphysis).
Appositional growth of the diaphysis
What is happening at each of the following regions within the epiphyseal plate?
- Cells are at rest (reserve)
- Cellular proliferation (interstitial growth)
- Hypertrophy (apoptosis)
- Calcification and ossification of cells
Bone grows (toward/away from) an epiphyseal plate.
Toward
Label the following parts of a long bone:
Image
90% of organic bone matrix protein consists of ___________.
Type I collagen
Besides type I collagen, what else makes up the organic portion of the bone matrix?
- Glycoproteins
- Proteoglycans
- Alkaline Phosphatase
What serves as an important biomarker for osteoblast presence?
Alkaline phosphatase
The primary inorganic component of bone that bestows its solid properties is ______________.
Hydroxyapatite
The small tubes or holes in bone that contain blood vessels and nerves are known as _____________.
Haversian canals
What are the four primary bone matrix glycoproteins?
- Osteocalcin
- Osteopontin
- Osteonectin
- Sialoprotein
Which bone matrix glycoprotein promotes the conversion of minerals to collagen components?
Osteonectin
Which bone matrix glycoprotein binds to the calcium ions within hydroxyapatite, attracts osteoclasts to promote bone remodeling, and is indicative of disease when found within the urine?
Osteocalcin
Which bone matrix glycoprotein promotes the organization of bone cells into a crystalline matrix, most likely by serving as the nucleus for the formation of the first apatite crystals?
Sialoprotein
Which bone matrix glycoprotein binds to integrins and hydroxyapatite, attracting osteoblasts and osteoclasts to promote bone formation and resorption?
Osteopontin
(Cancellous/Compact) bone consists of trabeculae/bony spicules with marrow between each. It possesses irregular lamellae (sheets) and is bound to the epiphyseal plate. It has no osteons.
Cancellous (spongy)
There (are/aren’t) blood vessels within the bony spicules (trabeculae) of cancellous bone.
Aren’t blood vessels
There (are/aren’t) blood vessels within the dividing marrow of cancellous bone.
Are blood vessels
Nutrients reach osteocytes within cancellous bone through ______________, or hollow tubes.
Canaliculi
The bony spicules of cancellous bone are lined by the endosteum, which contains ___________, ___________, and ____________.
- Osteoprogenitors
- Osteoblasts
- Osteoclasts
(Cancellous/Compact) bone consists of periosteum that lines the exterior of the bone, endosteum that lines the marrow cavity and haversian canals, osteons, and lamellae (sheets).
Compact
What are the two layers of periosteum associated with compact bone?
- Fibrous
- Osteogenic (contains osteoprogenitors)
The endosteum of compact bone also contains _____________, ____________, and _____________.
- Osteoprogenitors
- Osteoblasts
- Osteoclasts
What is one of the most primary differences between compact bone and cancellous bone?
Compact bone contains osteons (haversian systems).
A(n) __________________ connects two Haversian canals.
Volkmann’s canal (perforating canal)
- Osteonic canal is another name for a Haversian canal
The following is an example of (mature/immature) periosteum and bone formation.
- Immature
- Type I collagen containing blood vessels outlined in red.
- Thick osteoprogenitor layer outlined in blue.
- Osteocytes of bone found within lacunae outlined in green.
The following is an example of (mature/immature) periosteum and bone formation.
- Mature
- Type I collagen layer outlined in red.
- Thin or almost nonexistent osteoprogenitor layer outlined in blue.
- Osteocytes of bone found within lacunae outlined in green.
The arrows in the following picture indicate _______________.
Sharpey’s Fibers
(Interstitial/Concentric) lamellae are the lamellae found within osteons themselves. They are oldest at the concrete line, proceeding in the opposite age order of the rings found within a tree trunk.
Concentric
(Interstitial/Concentric) lamellae are lamellae of partially resorbed, older osteons occurring between newer, complete osteons.
Interstitial
The youngest concentric lamellae are found on the (outermost/innermost) region of the osteon.
Innermost, nearest the center
Label the following image:
Image
What structure is indicated by the black arrows in the following image?
Volkmann’s Canals
(Osteoclasts/Osteoblasts/Osteocytes) display basophilic staining properties, possess a stellate shape, are used to produce bone, express PTH receptors on their surfaces, and secrete osteoid.
Osteoblasts
(T/F) Osteoblasts may function in the absence of vitamin C.
False. Osteoblasts need vitamin C to function.
(Osteoclasts/Osteoblasts/Osteocytes) are found within lacunae of bone, extend processes into canaliculi that serve as gap junctions, possess very small golgi and RER, are nondividing, perform lysis on other cells to increase serum Ca2+ concentration, and recruit further bone formation progenitors following excessive pushing and pulling motions (e.g. exercising).
Osteocytes
(Osteoclasts/Osteoblasts/Osteocytes) form from hematopoietic stem cells, are large, motile, multinucleated, and acidophilic,live in Howship’s lacunae (resorption pits), possess a ruffled border, express integrins on their surfaces, have numerous mitochondria, golgi, lysosomes, and RER, and are nondividing. Their primary function is to resorb bone.
Osteoclasts
Too much bone resorption results in (osteoporosis/osteopetrosis).
Osteoporosis
- May help to imagine that too much resorption leaves pores within bone.
Too little bone resorption results in (osteoporosis/osteopetrosis).
Osteopetrosis
- May help to image that too little resorption results in excess calcium, leaving bones and tissue petrified.
Digestion and resorption of bone occurs in the resorption pit at the ______________.
Ruffled border
Osteoclasts accomplish bone resorption through a combination of _____________ and ____________.
- Lysosomal enzymes
- Acidic environment
In what three ways do osteoclasts create an acidic environment within the resorption pit?
- Carbonic acid
- CO2 + H2O → H2CO3 → H+ + HCO3-
- Proton pump
- Actively pumps H+ ion back into resorption pit
- Na+/H+ antiporter
- Uses electrochemical energy created by Na+ moving down its concentration gradient and into the cell to transport H+ up its concentration gradient and into the resorption pit
In what way do osteoclasts degrade collagen within bone?
Lysosomal enzymes
- TRAP (Tartrate Resistant Acid Phosphatase)
- Cystein-Proteinases (Cathepsins)
What lysosomal enzymes do osteoclasts utilize to degrade collagen?
- TRAP (Tartrate Resistant Acid Phosphatase)
- Cysteine-Proteinases (Cathespins)
Hyaline cartilage consists of type (I/II/III/IV) collagen.
Type II
Elastic cartilage consists of type (I/II/III/IV) collagen.
Type II
Fibrocartilage consists of type (I/II/III/IV) collagen.
Type I
(Fibro/Hyaline/Elastic) cartilage is different from the other two types in that it contains the glycosaminoglycans (GAGs) chondroitin and dermatan sulfate.
Fibrocartilage
(Fibro/Hyaline/Elastic) cartilage is different from the other two types in that it contains no perichondrium.
Fibrocartilage
(Fibro/Hyaline/Elastic) cartilage possesses isogenous nests.
Hyaline
(Fibro/Hyaline/Elastic) cartilage possesses isogenous rows.
Fibrocartilage
(Fibro/Hyaline/Elastic) cartilage may be described as “glassy”.
Hyaline
(Fibro/Hyaline/Elastic) cartilage is found in the embryonic skeleton, the epiphyseal plates, articular cartilage on the ends of bone, nasal cartilages, and tracheal ring cartilages.
Hyaline
(Fibro/Hyaline/Elastic) cartilage is found within the pinna of the ear and the epiglottis of the throat.
Elastic
(Fibro/Hyaline/Elastic) cartilage is found within the intervertebral discs of the spine and the menisci of joints.
Fibrocartilage
