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