Cartilage and Bone

A set of practice flashcards covering cartilage and bone topics from the lecture notes.

What are the main functions of cartilage?

>Support and protection of soft tissues

>provide a gliding surface at joints; serve as a model for bone formation

> act as a bone template that ossifies into bone.

SPT

What surrounds cartilage and aids in protection and regeneration?

Perichondrium, a dense connective tissue.

What are the primary cells in cartilage and what do they do?

Chondroblasts secrete matrix below the perichondrium and become chondrocytes; chondrocytes maintain cartilage.

What is the composition of the extracellular matrix in cartilage?

Collagen fibers and a ground substance that is mostly water.

Why doesn’t cartilage regenerate well?

>cartilage is avascular and lacks innervation

>nutrients reach chondrocytes by diffusion from the perichondrium (movement aids diffusion).

Name the three types of cartilage.

Hyaline cartilage, Elastic cartilage, and Fibrocartilage.

Describe hyaline cartilage: features and locations.

>Most common cartilage

>few collagen fibers;

>articular cartilage (lacks perichondrium)

>respiratory tract, nose

> costal cartilage

>bone precursor during development.

Describe elastic cartilage: features and typical locations.

Highly flexible; abundant elastic (and collagen) fibers; found in the ear and epiglottis.

Describe fibrocartilage: features, locations, and function.

Dense collagen fibers that resist tension; located in intervertebral discs, pubic symphysis, and menisci; distributes loads and creates congruent joints.

How can you identify hyaline, elastic, and fibrocartilage in histology images?

Hyaline: purple, glassy ground substance; Elastic: branching elastic fibers; Fibrocartilage: dense collagen fibers.

List the functions of bone.

Support and protection; movement; energy metabolism via hormone secretion; mineral storage (calcium and phosphate); hematopoiesis in bone marrow; energy storage.

What are the components of the bone extracellular matrix and their roles?

Organic osteoid (collagen) provides flexibility and resists tension; inorganic hydroxyapatite provides rigidity and resists compression.

Osteoblasts

form/ build bone (osteoid

From what cells are osteoclasts derived?

Fused bone marrow cells.

What is the difference between osteoblasts and osteocytes?

Osteoblasts build bone; osteocytes maintain bone and reside in lacunae.

What makes bone different from cartilage in terms of vascularization and innervation?

Bone is vascular and innervated; cartilage is avascular and aneural.

How are bones described as biological tissues besides being rigid?

They are flexible and dynamic organs that grow, heal, and remodel.

Name the five classes of bone and give an example of each.

Long bones (humerus); Short bones (talus); Flat bones (sternum); Irregular bones (vertebra); Sesamoid bones (patella).

What are the key features of a long bone’s diaphysis and epiphyses?

Diaphysis is the shaft with periosteum outside; Epiphyses are the ends with articular cartilage.

What lines the medullary cavity and what does it contain?

>Endosteum lines the medullary cavity

>it contains bone marrow and remodeling cells (osteoblasts and osteoclasts).

What covers the outside of a bone?

>Periosteum covers the outside;

What are the two main types of bone tissue and their differences?

>Compact (dense) bone is the hard outer surface;

>Spongy (trabecular) bone is lattice-like and located inside bones.

What is the microstructure of compact bone called and what are its components?

>The Haversian system (osteon) with a central canal, lamellae, lacunae containing osteocytes, canaliculi, and Volkmann’s canals.

How does the microstructure of spongy bone differ from compact bone?

>Spongy bone lacks osteons; it has lamellae with osteocytes in lacunae and trabeculae oriented along lines of stress.

Where is spongy bone found?

>Inside the epiphyses of long bones and between compact bone in flat, short, and irregular bones (the diploë).

What is interstitial growth in bone and when does it stop?

>Growth in length at the growth plate during childhood/adolescence;

> stops when the epiphysis fuses with the diaphysis and the growth plate ossifies.

What is appositional growth in bone?

>Growth in diameter;

osteoblasts add bone matrix at the periosteum; remodeling enlarges the medullary cavity with osteoclast activity.

What are the main aspects of bone remodeling?

>Continuous replacement of bone tissue via osteoclast-mediated resorption and osteoblast-mediated deposition;

>maintains calcium/phosphate homeostasis and adapts to mechanical stress; renewal rates: compact bone ~10 years, spongy bone ~3–4 years.

What is osteoporosis and which bones are commonly affected?

> resorption exceeds deposition

>Deterioration of microscopic bone architecture with low bone mass

>commonly affects vertebrae and the neck of the femur, especially in older, postmenopausal individuals due to estrogen deficiency.

osteoclasts

>resorb/destroy bone

>they coordinate remodeling.

What cover inside of the bone?

Endosteum lines the inside surfaces including the medullary cavity and central canals of osteons.