Bone & Cartilage Histology Flashcards
This is a semi-rigid tissue comprised of cell and ECM. The ECM contains collagen and elastic fibers and is typically surrounded by perichondrium.
Cartilage
These cells secrete cartilage matrix and have mitotic capabilities.
Chondroblasts
These are mature cartilage cells in lacunae. They are surrounded by matrix and form isogenous groups.
Chondrocytes
Cartilage lacks neurovasculature, so it receives nutrients from…
Diffusion via surrounding capillaries
T/F. Cartilage is very rigid and can easily be broken. It has a rough surface and cannot bear much stress.
False. Cartilage is flexible and resilient. It is smooth, lubricated and can bear mechanical stress without permanent distortion.
This type of tissue is ideal for mechanical and protective support.
Cartilage
ECM for cartilage is secreted by cells during development and for maintenance. The fiber types are…
Type II – predominant
Type I – may be present
Elastin – in elastic cartilage
What are the ground substances present in the ECM?
Hyaluronic acid
Chondroitin sulfate
***These are ground substances with proteoglycans
During chondrogenesis, differentiation takes place from the center and moves outward. Central cells are _______ and peripheral cells are ________.
Chondrocytes
Chondroblasts
What embryonic component does cartilage arise from?
Embryonic mesenchyme
What embryonic component does perichondrium arise from?
Superficial mesenchyme
Put the following steps of chondrogenesis in order:
A. ECM production traps cells in lacunae
B. Cells ‘round up’, divide, and are densely packed
C. Isogenous groups housed in lacunae
D. Cartilage arises from embryonic mesenchyme
- D
- B
- A
- C
***At the start they chondroblasts, by the end they are chondrocytes
This is a layer of dense irregular CT covering hyaline and elastic cartilage. It is not present in fibrocartilage and articular cartilage (subtype of hyaline cartilage). It is essential for growth and maintenance of cartilage.
Perichondrium
What is the outer/fibrous layer of Perichondrium made of?
Type I collagen
Fibroblasts
What is the inner/chondrogenic layer of Perichondrium made of?
Adjoins cartilage matrix
Contains mesenchymal stem cells
What layer of the Perichondrium is the source for new chondroblasts (divide/differentiate into chondrocytes)?
Inner/chondrogenic layer
This type of cartilage is homogeneous and semitransparent (in its fresh state). It is located in:
- Articular surfaces of synovial joints
- Large respiratory passages
- Costal cartilages
- Epiphyseal plates of long bones
- Portions of embryonic skeleton
Hyaline cartilage
In hyaline cartilage, the chondrocytes are located in lacunae and combine as _______ _______.
Isogenous groups
In hyaline cartilage, the chondrocytes secrete a matrix of _______ _______, which results in diffuse ________ staining.
Type II collagen
Basophilic
What are the types of cartilage?
Hyaline cartilage
Elastic cartilage
Fibrocartilage
In hyaline cartilage, this matrix immediately surround each chondrocyte and has the following characteristics:
- ECM consists of Type II collagen
- High GAGs
- Staining is more basophilic
Territorial matrix
In hyaline cartilage, this matrix surrounds the territorial matrix (surrounds isogenous groups) and has the following characteristics:
- ECM has more Type II collagen
- Fewer GAGs
- Staining is less basophilic
Interterritorial matrix
T/F. Elastic cartilage is the exact same as hyaline cartilage but with elastic fibers embedded in the ECM with Type II collagen.
True
What are elastic fibers useful for?
Recoil or rebound – allow for shape retention after deformation
Elastic cartilage is more flexible than hyaline cartilage, and is located where?
Auricle of ear
Walls of external auditory canals
Auditory (Eustachian) tubes
Epiglottis
This type of cartilage is formed from a mix of hyaline cartilage and dense CT, and lacks a perichondrium.
Fibrocartilage
Fibrocartilage is very tough, yet provides cushioning support tissue for bone. It is located in…
Intervertebral discs
Pubic symphysis
Meniscus
In this type of cartilage, chondrocytes are typically singly arranged in rows of isogenous groups. The matrix consists of sparse Type II collagen with fibroblasts and dense bundles of Type I collagen.
Fibrocartilage
Fibrocartilage matrix fibers are oriented in the direction of functional _______ and provides extra tensile strength.
Stress
This type of cartilage growth is done via mitotic division of preexisting chondrocytes in the lacunae. Secretion of new matrix separates daughter cells and increases mass of cartilage.
Interstitial growth
This type of cartilage growth is done when chondroblasts differentiate from progenitor cells in the perichondrium. They secrete Type II collagen and ground substance.
Appositional growth
Except in young children, damaged cartilage undergoes slow and incomplete repair. Why is this?
Due to its avascularity and low metabolic rate
In cartilage injury, cells of the _________ invade the injured area and produce new cartilage and/or dense CT. It may also be replaced with bone.
Perichondrium
Bone is a specialized CT that provides support and protection. It is comprised of ________ that are housed in lacunae.
Osteocytes
What is the matrix of bone made of?
Calcium phosphate as hydroxyapatite crystals
Type I Collagen
Proteoglycans
These are mesenchymal cells that produce osteoblasts, and are found in the periosteum and endosteum.
Osteoprogenitors
These cells produce and control osteoid, which is the non-mineralized organic matrix.
Osteoblasts
Some osteoblasts differentiate into ________, which are mature bone cells house in lacunae and maintain the bone matrix. Have long, spider-like processes.
Osteocytes
Osteocytes and osteoblasts communicate with each other to increase deposition of what?
Bone matrix
The are multi-nucleated cells that are formed via the fusion of monocytes. They exhibit a “ruffled border” which resorbs bone through H+ and lysosomal proteins.
Osteoclasts
________ and osteoblasts are typically located together, in developing bone.
Mesenchyme
This type of bone is solid and relatively dense. It makes up the external surfaces of long and flat bones. It is lamellar bone (mature bone).
Compact (cortical) bone
***Encompasses cancellous (spongy) bone