Anatomy & Physiology: Test 2 Study Guide

Why is bone considered a living organ?

Because it is made of multiple tissue types, contains nerves and blood vessels, and can remodel and repair itself.

Name the four primary tissue types found in bone.

Connective, Nervous, Epithelial, Muscle.

What is the main type of connective tissue in bone?

Bone (osseous) tissue.

Where is nervous tissue found in bone?

Within its nerves.

What is the role of epithelial tissue in bone?

It lines the blood vessels that provide nourishment.

How is muscle tissue involved with the skeletal system?

Skeletal muscle tissue is attached to bones to allow for movement.

How many bones are in the adult human skeleton?

206.

What percentage of a healthy person's body weight is the skeleton?

About 20% (~1/5th).

What are the four components of the skeletal system?

Bones, cartilage, ligaments, and joints.

How often is your entire skeleton replaced?

Every 7

What would happen to the body without the skeletal system?

It would collapse.

Name one organ protected by the skeleton.

The brain (by the skull) or the heart (by the rib cage).

What is one key ability of bone?

It can repair itself after damage.

What is the support function of the skeleton?

To provide a framework that holds up the entire body.

What is the protection function of the skeleton?

To guard the body's vital organs.

How do bones facilitate movement?

They act as levers that are pulled on by skeletal muscles.

What two minerals are stored in bones?

Calcium and phosphate.

What is stored in yellow bone marrow?

Energy in the form of fat.

What is the function of red bone marrow?

Blood cell formation (hematopoiesis).

What is the term for blood cell formation?

Hematopoiesis.

Name one hormone produced by bones.

Osteocalcin.

What does the hormone osteocalcin help regulate?

Insulin secretion, glucose levels, and energy usage.

What determines a bone's function?

Its shape.

What is the defining characteristic of a long bone?

It is longer than it is wide.

What is the primary function of long bones?

To act as levers for movement.

Where are most long bones located?

In the limbs (arms and legs).

Give two examples of long bones.

Humerus and femur.

What is the defining characteristic of a short bone?

It is roughly as wide as it is long (cube

What is the primary function of short bones?

To provide stability and support with little movement.

Give two examples of short bones.

Carpals (wrist bones) and tarsals (ankle bones).

What is a sesamoid bone?

A special type of short bone embedded within tendons.

Give an example of a sesamoid bone.

The patella (kneecap).

What is the defining characteristic of a flat bone?

It is thin, flat, and often curved.

What is the primary function of flat bones?

To provide a large surface area for muscle attachment.

Give two examples of flat bones.

Sternum (breastbone) and scapula (shoulder blade).

What is the defining characteristic of an irregular bone?

It has a complicated, specialized shape.

Give two examples of irregular bones.

Vertebrae and hip bones.

What percentage of bone is water?

About 22%.

What is the dense, smooth outer layer of bone called?

Compact (or cortical) bone.

What is the porous, inner layer of bone called?

Spongy (or cancellous) bone.

What are the properties of bone due to its structure?

Strong, lightweight, and flexible.

What is the basic structural unit of compact bone?

The osteon.

What are the hollow tubes of matrix in an osteon called?

Lamellae.

What runs through the center of an osteon?

The Haversian (or Central) Canal.

What is contained within the central canal?

Blood vessels and nerve fibers.

What are the small gaps between lamellae called?

Lacunae.

What do lacunae house?

Osteocytes.

Does spongy bone contain osteons?

No.

What are the tiny bone struts in spongy bone called?

Trabeculae.

What is the function of trabeculae?

To help resist stress and provide a place for bone marrow.

What type of marrow produces blood cells?

Red bone marrow.

What type of marrow stores fat?

Yellow bone marrow.

What are bone markings?

Surface features where muscles/ligaments attach, where joints form, or where vessels/nerves pass.

What is the function of an osteocyte?

To monitor bone health and direct osteoblast/osteoclast activity.

Where are osteocytes located?

In the lacunae.

What is the function of an osteoblast?

To build and form new bone.

What is the function of an osteoclast?

To break down (resorb) bone tissue.

What type of cell can differentiate into an osteoblast?

Osteoprogenitor (or osteogenic) cell.

What is the process of bone tissue formation called?

Ossification or osteogenesis.

When does the embryonic skeleton begin to form?

At week 8 of embryonic development.

What are the two types of ossification?

Intramembranous and Endochondral.

Which type of ossification forms bone from a membrane?

Intramembranous ossification.

Give an example of a bone formed by intramembranous ossification.

Clavicle (collarbone) or skull bones.

Which type of ossification forms bone by replacing cartilage?

Endochondral ossification.

Where does cartilage remain in a mature long bone?

On the articular surfaces and the epiphyseal plates (during growth).

Why is bone remodeling important?

It prevents calcium from crystallizing and making bones brittle.

What is the first step in the bone remodeling cycle?

Osteocytes detect micro

What cell is responsible for bone resorption?

Osteoclasts.

What cell is responsible for rebuilding bone?

Osteoblasts.

What percentage of the skeleton is replaced each year?

5

What stimulus promotes bone remodeling and strength?

Exercise (stress on the bones).

What is a break in a bone called?

A fracture.

What is the realignment of broken bone ends called?

Reduction.

What is the first stage in bone fracture repair?

Hematoma formation

What type of tissue makes up the soft callus?

Fibrocartilage.

What cells create the bony callus?

Osteoblasts.

What is the final stage of fracture repair?

Bone remodeling.

Hematopoiesis:

The process of blood cell formation, occurring in the red bone marrow.

Cartilage:

A flexible, smooth connective tissue that cushions joints and provides structure.

Ligament:

A tough band of fibrous connective tissue that connects bone to bone, stabilizing joints.

Tendon:

A fibrous cord of connective tissue that attaches muscle to bone.

Joint (articulation):

A point where two or more bones meet.

Intervertebral Discs:

Fibrocartilage pads located between the vertebrae that act as shock absorbers.

Osteon:

The fundamental, cylindrical structural unit of compact bone.

Lamellae:

Concentric rings of calcified matrix that make up an osteon.

Central (Haversian) Canal:

The channel running through the core of an osteon, containing blood vessels and nerves.

Trabeculae:

The tiny, needle

Lacunae:

Small cavities within the bone matrix that house osteocytes.

Osteocyte:

A mature bone cell trapped within the matrix, responsible for maintaining bone tissue.

Osteoblast:

A bone

Ossification:

The process of bone formation.

What does functional classification of joints focus on?

The amount of movement they allow.

What does structural classification of joints focus on?

The material binding the bones together and the presence of a cavity.

What is the general rule between a joint's mobility and its stability?

The more movable a joint, the less stable it is (and vice versa).

Give an example of a very stable, immovable joint.

The sutures in the skull.

Give an example of a very mobile, but less stable joint.

The shoulder (glenohumeral) joint.

What material binds bones in a fibrous joint?

Collagen fibers.

What material binds bones in a cartilaginous joint?

Cartilage.

What key feature do all synovial joints have?

A fluid

How do bones create movement?

Muscles contract and pull on bones across a joint.