The Skeletal System & Joints Flashcards

Study Notes

Diaphysis

The main shaft of long bones, characterized by a hollow, cylindrical structure made of thick, compact bone.
Provides strong support while minimizing weight.

Epiphyses

Found at both ends of a long bone, composed of cancellous bone filled with marrow.
Bulbous shape enhances muscle attachment and joint stability.

Epiphyseal Line

Located at the junction of epiphysis and diaphysis (metaphysis) in adult bones.
A remnant of the epiphyseal plate which allows for bone lengthening during growth; replaced by bone when growth stops.

Epiphyseal Plate

Composed of four layers:
- Resting cartilage cells for attachment to the shaft.
- Zone of proliferation with active mitosis leading to layer thickening.
- Zone of hypertrophy with enlarged cells undergoing changes with calcium deposition.
- Zone of calcification where dying cartilage cells undergo rapid calcification.

Medullary Cavity

A tube-like, hollow space within the diaphysis filled with yellow marrow in adults.

Compact Bone

One of the two types of osseous tissue forming bones, known as cortical bone.
Functions to support body structure, protect organs, enable movement, and store/release calcium.

Endosteum

A thin epithelial membrane lining the medullary cavity, playing a role in bone growth and repair.

Osteoprogenitor Cells

Stem cell-derived cells involved in bone growth and repair, also known as preosteoblasts.
Found in the bone marrow within cellular layers.

Spongy Bone

Cancellous bone has a lower density but a higher surface area to mass ratio, leading to flexible characteristics.
Located at the ends of long bones and in vertebrae, it is highly vascular and contains red bone marrow for blood cell production.

Osteoclasts and Osteoblasts

Osteoclasts enlarge the medullary cavity, while osteoblasts from the periosteum build new bone externally.
Osteoclasts, known as "bone breakers," resorb bone and release calcium into the bloodstream.

Major Bone Cell Types

Four major types include osteoprogenitor cells, osteoblasts, osteocytes (most common in mature bone), and osteoclasts.

Osteocytes

Mature bone cells responsible for maintaining daily activities of bone tissue.

Resorption

The process involving osteoclasts and osteoblasts working together to increase bone diameter and reshape bones.

Bone Ossification Types

Intramembranous ossification occurs within a connective tissue membrane, forming most skull bones and clavicles.
Endochondral ossification involves cartilage transitioning into bone, critical for the formation of long bones.

Description

Test your knowledge of the skeletal system and its components with these flashcards. Each card covers key terms such as diaphysis, epiphyses, and epiphyseal line, providing definitions and functions for each. Perfect for anyone studying anatomy or preparing for exams.

The Skeletal System & Joints Flashcards

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Questions and Answers

What is the main function of the diaphysis?

What are epiphyses?

Where is the epiphyseal line located?

What is the epiphyseal plate composed of?

What is the function of the medullary cavity?

What is compact bone?

What is the endosteum?

What are osteoprogenitor cells?

What makes spongy bone different from compact bone?

What are the functions of osteoclasts?

What are the four major types of cells in bone?

What characterizes osteocytes?

How does bone grow in diameter?

The intramembranous ossification occurs within a ________ tissue membrane.

Which bones form from intramembranous ossification?