Aging and Cartilage Development

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Where is the ascending limb attached to?

Posterior surface of head

Anterior margin of the squamous tympanic fissure (correct)

Neck of condyle

Capsule

What is the attachment site of the descending limb?

Anterior margin of the squamous tympanic fissure

Behind the disc

Capsule

Posterior surface of head and neck of condyle (correct)

Where does the disc divide?

Behind the ascending limb

At the squamous tympanic fissure

Behind the disc (correct)

Behind the descending limb

What is the attachment site of the disc?

Capsule and the anterior margin of the squamous tympanic fissure Signup and view all the answers

How does the disc divide?

Into ascending and descending limbs Signup and view all the answers

Which part of the disc has some fibers of lateral pterygoid muscle attached to it?

Anterior border Signup and view all the answers

What is characteristic of the looser posterior part of the disc covering?

Vascularized and covered by vascular synovial membrane Signup and view all the answers

Where is the synovial membrane absent?

Over the articular areas of condyle Signup and view all the answers

What is the characteristic of the dense weight-bearing region of the disc?

Synovial membrane is absent Signup and view all the answers

What can be found in the articular areas of condyle, glenoid fossa, and articular eminence?

No synovial membrane Signup and view all the answers

Where do the branches converge?

Into the capsule of the joint Signup and view all the answers

What type of blood vessels pass into the posterior part of the articular disc?

Small arteries, arterioles, and capillaries Signup and view all the answers

What is the function of the articular disc?

To cushion the joint and reduce friction Signup and view all the answers

Where do the small arteries, arterioles, and capillaries pass into?

The posterior part of the articular disc Signup and view all the answers

What is the purpose of the capsule of the joint?

To protect the joint from external damage Signup and view all the answers

What type of cells do fibroblasts develop into with advancing age?

Chondroid cells Signup and view all the answers

What is the result of fibroblasts developing into chondroid cells?

Differentiation into true chondrocytes Signup and view all the answers

What is found in old age?

Small islands of hyaline cartilage Signup and view all the answers

What is the sequence of cell development from fibroblasts?

Fibroblasts to chondroid cells to true chondrocytes Signup and view all the answers

What is the final stage of cell development from fibroblasts?

True chondrocytes Signup and view all the answers

What is the purpose of the ligaments in the temporomandibular joint?

To prevent the condyle from coming in contact with the tympanic plate behind Signup and view all the answers

What is prevented by the ligaments in the temporomandibular joint?

The condyle from coming in contact with the tympanic plate Signup and view all the answers

What happens if the ligaments in the temporomandibular joint fail?

The condyle comes in contact with the tympanic plate behind Signup and view all the answers

Which of the following is a function of the ligaments in the temporomandibular joint?

To limit the range of movement of condyle Signup and view all the answers

What is the result of the ligaments limiting the range of movement of condyle?

Decreased movement beyond the articular eminence Signup and view all the answers

Study Notes

Temporomandibular Joint (TMJ) Structure

Small arteries, arterioles, and capillaries pass through the posterior part of the articular disc.

Articular Disc Attachments

The disc divides into ascending and descending limbs behind.
The ascending limb is attached to the anterior margin of the squamous tympanic fissure.
The descending limb is attached to the posterior surface of the head and neck of the condyle.
Some fibers of the lateral pterygoid muscle attach to the anterior border of the disc.

Disc Covering

The looser posterior part of the disc is vascularized and covered by a vascular synovial membrane.
The synovial membrane is absent in:
- Articular areas of the condyle, glenoid fossa, and articular eminence
- Dense, weight-bearing regions of the disc (central and anterior parts)

With age, fibroblasts develop into chondroid cells, which later differentiate into true chondrocytes.
Small islands of hyaline cartilage may be found in old age.

Ligament Function

The ligaments limit the range of movement of the condyle, preventing it from:
- Coming into contact with the tympanic plate behind
- Passing beyond the articular eminence in front