Lecture – General Skeletal and Bone Histology

What are the main functions of the skeleton?

Structural support, leverage and movement, protection of soft tissues, mineral reservoir, energy storage, and blood cell production.

What is the mineral reservoir in the skeleton primarily made of?

Calcium and phosphate - 98% of body’s calcium is in bones.

What does red bone marrow produce?

Blood cells.

What are the three types of connective tissues in the skeleton?

Connective Tissue Proper, Supporting Connective Tissue, and Fluid Connective Tissue.

What type of specialized connective tissue is cartilage classified as?

Supporting Connective Tissue.

What are chondroblasts?

Cells that lay down cartilage matrix and become chondrocytes when trapped.

What distinguishes hyaline cartilage from other types?

It has few collagen fibers and is the weakest form.

What is the function of osteoblasts?

To lay down new bone material.

What composes the extracellular matrix of bone?

2/3 Hydroxyapatite and 1/3 collagen fibers.

What happens during bone remodeling?

Microfractures attract osteoclasts and osteoblasts to maintain bone health.

What are the two types of growth in bones?

Appositional Growth (width) and Interstitial Growth (length).

How does osteoporosis occur?

An imbalance between osteoclast and osteoblast activity, leading to faster bone breakdown.

Who is more likely to develop osteoporosis?

Elderly women, especially those with low estrogen levels, small frame, or genetic predisposition.

What are the classifications of bone by shape?

Flat bones, long bones, short bones, irregular bones, sesamoid bones, and pneumatized bones.

What is unique about the intramembranous ossification process?

It develops bone between layers of fibrous membranes, typically in the skull.

What occurs in endochondral ossification?

A cartilage model forms first, which is subsequently replaced by bone.

What do osteocytes do?

Maintain and monitor the surrounding matrix of bone.

What is the periosteum?

A connective tissue that lines the outer surface of bone.

What is the role of mesenchymal cells in bone development?

They act as connective tissue stem cells that can differentiate into other connective tissue cells.

What is the significance of the epiphyseal plates?

They allow for lengthwise growth of bones during the growing period.

What is the primary function of fibroblasts in ossification?

To create a dense regular connective tissue membrane that serves as an outline for bone formation.

How long does it take spongy bone to fully replace in the body?

Every 4 years.

How long does it take compact bone to fully replace in the body?

Every 10 years.

What is a fracture hematoma?

A blood clot that forms over a fracture.

What do osteoclasts do in the bone remodeling process?

They break down fractured bone.

What is the primary function of the skeletal system?

To provide structural support and shape to the body.

How many bones are in the adult human skeleton?

There are 206 bones in the adult human skeleton.

What is the axial skeleton composed of?

The axial skeleton consists of the skull, vertebral column, and rib cage.

What connects muscles to bones?

Tendons connect muscles to bones.

What are the two main divisions of the skeleton?

The axial skeleton and the appendicular skeleton.

What role do ligaments play in the skeletal system?

Ligaments connect bones to other bones and provide stability to joints.

What is the purpose of the bone marrow?

Bone marrow produces blood cells and stores fat.

What type of joint allows for the highest range of motion?

Ball-and-socket joints allow for the highest range of motion.

What is the primary mineral found in bones?

Calcium is the primary mineral found in bones.

What is the main characteristic of spongy bone?

Spongy bone has a porous structure that reduces weight while providing strength.