Ch. 6: Bones & Skeletal Tissues

What are the components of the skeletal system?

Bones and joints, which include cartilage, tendons, and ligaments.

What is the human skeleton initially made up of before bone replaces most of it?

Hyaline cartilage and fibrous membranes.

Where are cartilages mainly found in adults?

In regions where flexible skeletal tissue is needed.

What are the three basic types of skeletal cartilage?

Hyaline, elastic, and fibrocartilage.

What is the function of hyaline cartilage?

It provides firm support with some flexibility.

What are articular cartilages?

They cover the ends of most bones at movable joints.

What are costal cartilages?

They connect the ribs to the sternum.

What are respiratory cartilages?

They form the skeleton of the larynx and reinforce respiratory passageways.

What are nasal cartilages?

They support the external nose.

How does elastic cartilage differ from hyaline cartilage?

It contains elastic fibers, making it better suited for repeated bending.

Where is elastic cartilage found in the body?

In the external ears and epiglottis.

What are the properties of fibrocartilage?

It is highly compressible and has great tensile strength.

Where is fibrocartilage found?

In menisci of the knee and intervertebral discs.

What are the functions of bones?

Support, protection, anchorage, mineral storage, blood cell formation, triglyceride storage, and hormone production.

How many bones are in the human body?

206 bones.

How are bones classified?

Into the axial and appendicular skeletons.

What are the four shapes of bones?

Long, short, flat, and irregular bones.

What are long bones?

Bones that are longer than they are wide, such as limb bones except the patella, wrist, and ankle.

What are short bones?

Cube-shaped bones, such as carpals and tarsals.

What are flat bones?

Thin, flattened, and usually curved bones like the sternum, ribs, and skull bones.

What are irregular bones?

Bones with complicated shapes, such as vertebrae and hip bones.

What are the two types of osseous tissue?

Compact bone and spongy bone.

What is compact bone?

Dense, smooth, and solid bone tissue.

What is spongy bone?

Bone with a honeycomb-like structure filled with trabeculae.

What are bone markings?

Features of bones that include projections, depressions, and openings.

What are projections on bones?

Bulges such as heads, trochanters, and spines.

What are depressions and openings in bones?

Features like fossa, sinuses, foramina, and grooves.

What is the diaphysis of a long bone?

The shaft of the bone containing the medullary cavity filled with yellow marrow.

What is the epiphysis of a long bone?

The expanded end area containing red marrow for blood cell production.

What is the periosteum?

The external double-layered membrane with nerve fibers and blood vessels.

What is the endosteum?

The internal connective tissue membrane lining internal passageways.

What are osteogenic cells?

Stem cells that differentiate into bone-forming cells.

What are osteoblasts?

Bone-forming cells that build the bone matrix.

What are osteocytes?

Mature bone cells that maintain the bone matrix.

What are osteoclasts?

Bone-destroying cells that break down bone matrix.

What is an osteon?

The structural unit of compact bone that looks like a tree trunk.

What are lamellae?

Concentric layers of bone tissue.

What is the central canal in bone?

A vertical canal that contains blood vessels and nerves.

What are canaliculi?

Tiny channels that connect osteocytes for communication.

How is spongy bone different from compact bone?

It is less dense, contains trabeculae, and has spaces filled with red or yellow marrow.

What are the organic components of bone?

Bone cells and collagen fibers.

What are the inorganic components of bone?

Mineral salts, mainly calcium-phosphate crystals.

What provides bone with flexibility?

Collagen fibers.

What provides bone with strength?

Mineral salts.

What are the two types of ossification?

Intramembranous ossification and endochondral ossification.

What is intramembranous ossification?

The process where bone develops from a fibrous membrane, forming skull bones and the clavicles.

What is endochondral ossification?

The process where bone forms by replacing hyaline cartilage, forming most bones below the skull.

What is the function of the epiphyseal plate?

It is the growth plate where bones lengthen during childhood and adolescence.

At what age does the epiphyseal plate close in females?

Around 18 years old.

At what age does the epiphyseal plate close in males?

Around 21 years old.

What factors influence bone growth?

Genetics, nutrition, and hormones.

What vitamin is needed for calcium absorption?

Vitamin D.

What vitamin is needed for collagen synthesis?

Vitamin C.

What hormone stimulates epiphyseal plate activity?

Growth hormone.

What hormone regulates growth hormone?

Thyroid hormone.

What hormones promote growth spurts and later cause epiphyseal closure?

Estrogen and testosterone.

What are the two factors driving bone remodeling?

Calcium homeostasis and mechanical/gravitational forces.

What are the two processes involved in bone remodeling?

Bone deposition and bone resorption.

How are fractures classified?

Based on displacement, completeness, direction, and whether they are open or closed.

What are the six types of fractures?

Comminuted, compression, depressed, impacted, spiral, and greenstick fractures.

What are the steps of bone fracture repair?

Hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling.