Cartilage - Histology

What are the three types of carilage?

Hyaline cartilage, fibrocartilage, and elastic cartilage

What type of cartilage is found in the external ear?

Elastic cartilage

What are some general characteristics of cartilage?

Avascular, no nerves, may have perichondrium, cells are in lacuna, isogenous groups, territorial and interterritorial matrix

What's an isogenous group?

A cluster of chondrocytes in cartilage which can still divide

What's the difference between territorial and interterritorial matrix in cartilage?

Territorial is around an isogenous group, interterritorial is between isogenous groups

What is a lacuna?

Means "lake" so it is around chondrocytes, where the cell has shrunk away from the matrix it's embedded in

What cell types are found in cartilage?

Chondroblasts, chondrocytes, chondroclasts?

What type of cell is considered an adult cell in cartilage?

Chondrocyte

What type of cell is considered a precursor cell in cartilage?

Chondroblast

How does appositional growth occur in cartilage?

It occurs from chondroblasts in the perichondrium. Mesenchymal cells/fibroblasts become chondroblasts that produce cartilage-specific matrix, then become surrounded by matrix to become chondrocytes.

How does interstitial growth occur in cartilage?

It occurs from within. Chondrocytes divide and form isogenous groups where the same cell has divided over and over.

How are bone osteocytes different from cartilage chondrocytes?

Osteocytes are single cells found in lacunae while chondrocytes are found in isogenous groups.

What is the perichondrium?

It consists of a fibrous layer with fibroblasts and mesenchymal cells and a chondrogenic layer with chondroblasts and more collagen. It allows for appositional growth.

What type of cartilage is perichondrium found in?

Hyaline and elastic (but NOT hyaline at articular surfaces)

What type of chondrogenesis must fibrocartilage and hyaline cartilage at articular surfaces undergo?

Interstitial because there is no perichondrium needed for appositional growth

What part of extracellular matrix is found in ALL cartilage?

Chondronectin (like fibronectin to hold stuff together) and aggregated proteoglycans (core protein of aggrecan with chondroitin sulfate and keratan sulfate GAGs connected to hyaluronic acid by link proteins)

What type of collagen is found in hyaline cartilage?

Collagen II

What type of collagen is found in elastic cartilage?

Collagen II

What type of collagen is found in fibrocartilage?

Collagen I

What two fibers/fibrils are found in elastic cartilage?

Elastic fibers and collagen II fibrils

What's the name for benign and malignant cartilage tumors?

Benign: chondroma; malignant: chondrasarcoma

Does cartilage regenerate?

Yes, but it is slow and usually inadequate except young children. This is because it is avascular and hard for it to receive nutrients.

What happens if cartilage doesn't regenerate enough?

Osteoarthritis with pain due to exposed bone.

What do isogenous groups look like in hyaline cartilage and elastic cartilage?

Circular

What do isogenous groups look like in fibrocartilage?

Linear

What type of cartilage forms the cartilage model needed for growth of long bones by endochondral ossification?

Hyaline cartilage

Where is hyaline cartilage found?

Articular surfaces, walls of larger respiratory passages, epiphyseal plates

Where is elastic cartilage found?

External ear, epiglottis, auditory tube, cuneiform and corniculate cartilages of the larynx

Where is fibrocartilage found?

IV disks, articular disks of the knee, mandible, sternoclavicular joints, pubic symphysis