Osseous Tissue & Bone Physiology – Exam Review Flashcards

Question-and-answer style flashcards covering bone functions, tissue types, anatomy, cells, hormones, growth mechanisms, and fracture types for comprehensive exam preparation.

What are the five primary functions of bone?

Support of soft tissues, protection of organs, assistance in movement via skeletal muscles, hemopoiesis in red marrow, and mineral (Ca2+ & PO43−) storage/release.

Which type of bone marrow performs hemopoiesis and which primarily stores triglycerides?

Red marrow performs hemopoiesis; yellow marrow stores triglycerides.

Where is compact bone typically located and what is its functional unit?

In regions of significant stress such as the diaphysis of long bones; its functional unit is the osteon.

List four characteristics of spongy (trabecular) bone.

Highly porous, located deep to compact bone, lighter in weight, and houses red bone marrow for hemopoiesis.

What connective tissue structure connects bone to bone?

Ligaments.

What connective tissue structure connects skeletal muscle to bone?

Tendons.

What is the periosteum and give two of its functions.

A dense irregular connective tissue membrane surrounding bone; it nourishes bone, contains osteogenic cells for growth, serves as an attachment for tendons/ligaments, and provides passage for vessels and nerves.

What type of cartilage covers the ends of long bones and what is its primary function?

Articular (hyaline) cartilage; it reduces friction and absorbs shock at joints.

Describe the endosteum.

An incomplete cellular layer lining the medullary cavity, central canals, and trabeculae; similar to the osteogenic layer of periosteum.

Where is fibrocartilage found and why is it ideal there?

At symphysis joints (intervertebral discs, pubic symphysis); its dense parallel collagen resists compression between bones.

Name the six bone shape classifications.

Long, short, flat, irregular, sesamoid, and sutural (Wormian) bones.

Give one example of each bone shape classification.

Long – femur; Short – carpals; Flat – sternum; Irregular – vertebra; Sesamoid – patella; Sutural – bones within skull sutures.

Define diaphysis.

The shaft of a long bone.

Define epiphysis.

The proximal and distal ends of a long bone.

What is the metaphysis and what important structure does it contain in growing bones?

Region between diaphysis and epiphysis; contains the epiphyseal (growth) plate.

State two functions of the periosteum related to bone repair and growth.

Provides osteogenic cells for appositional (width) growth and serves in fracture repair.

What fills the medullary cavity of an adult long bone?

Yellow marrow (adipose tissue).

Name the four major bone cell types and give one role for each.

Osteogenic cells – stem cells that produce new bone; Osteoblasts – secrete osteoid and initiate mineralization; Osteocytes – maintain matrix and coordinate remodeling; Osteoclasts – resorb bone matrix.

How does collagen contribute to bone’s physical properties?

Collagen fibers impart tensile strength and allow dissipation of mechanical stress.

List three non-skeletal functions of calcium mentioned in the notes.

Muscle and heart contraction, blood clotting, and cellular exocytosis.

Which hormone is released when blood Ca2+ levels drop and what is its effect on bone?

Parathyroid hormone (PTH); it increases osteoclast activity, releasing Ca2+ from bone into blood.

Which hormone is released when blood Ca2+ rises and what is its effect on bone?

Calcitonin from the thyroid; it inhibits osteoclasts and promotes Ca2+ deposition in bone.

What vitamins are essential for proper bone matrix formation and why?

Vitamin C for collagen synthesis and Vitamin D for calcium absorption and mineralization.

Briefly describe intramembranous ossification and name a bone formed this way.

Bone develops directly from mesenchymal tissue forming ossification centers, producing flat bones such as cranial bones of the skull.

Briefly describe endochondral ossification.

Bone replaces a hyaline cartilage model; primary ossification center forms in diaphysis, secondary centers in epiphyses, leaving articular cartilage and growth plate.

Differentiate interstitial and appositional bone growth.

Interstitial growth lengthens bone at epiphyseal plates; appositional growth increases bone thickness via periosteal osteoblasts.

Where are epiphyseal plates located and what happens to them with age?

Between epiphysis and diaphysis; they ossify and become epiphyseal lines after puberty when growth ceases.

Name four hormones that stimulate bone growth during childhood and puberty.

Human Growth Hormone (hGH), Insulin-like Growth Factor (IGF), estrogen, and testosterone.

How do glucocorticoids affect bone growth?

They slow cell division at epiphyseal plates, potentially inhibiting growth.

List the major effects of thyroid hormones on bone.

Thyroxine supports overall growth; Calcitonin reduces osteoclast activity, promoting calcium deposition in bone.

Define closed fracture.

A fracture in which the skin remains intact (no bone exposure).

Define open (compound) fracture.

A fracture where bone fragments pierce the skin.

What characterizes a transverse fracture?

Fracture line is perpendicular to the long axis of the bone.

What type of fracture results from twisting forces producing a diagonal crack?

Spiral or oblique fracture.

Describe a comminuted fracture.

Bone is broken into multiple fragments; often requires surgical fixation.

What is an impacted fracture?

One bone fragment is driven into another by compressive force.

Define a greenstick fracture and state in whom it is most common.

Partial fracture with one side broken and the other bent; common in children.

During fracture repair, what is the initial soft tissue callus formed from?

Fibrocartilage and collagen fibers bridging the broken ends.

Which bone cell type is primarily responsible for removing the temporary callus and remodeling the bone?

Osteoclasts resorb excess callus, while osteoblasts rebuild compact and spongy bone to original shape.