Skeletal System – Chapter 8 Review

A set of question-and-answer flashcards that reviews key concepts, structures, and disorders of the skeletal system covered in Chapter 8.

What are the five primary functions of the skeletal system?

Support the body’s framework; protect organs & aid immunity via WBC production; permit movement with muscles; store calcium; perform hematopoiesis (blood-cell formation).

Name the four major bone shape categories and give one example of each.

Long – humerus; Short – carpals; Flat – frontal bone; Irregular – vertebrae.

What is a sesamoid bone? Give an example.

A small round bone embedded in a tendon; example: the patella (kneecap).

What is the diaphysis of a long bone?

The hollow shaft made of hard compact bone.

What occupies the medullary cavity in an adult long bone?

Yellow marrow.

Where is red marrow located in a long bone?

Within the spongy (cancellous) bone of the epiphyses.

What is the articular cartilage and its role?

A thin cartilage layer covering each epiphysis that cushions joints.

Which membrane covers a bone except at joint surfaces?

The periosteum.

Describe the basic structure of flat bones.

A sandwich of compact bone surrounding cancellous (diploë) bone with trabeculae-lined spaces.

What structural feature gives spongy bone its porous look?

Needlelike trabeculae forming a network of open spaces.

What is the structural unit of compact bone?

The osteon (Haversian system).

Define lacunae.

Small spaces between concentric lamellae that house osteocytes.

What channels connect lacunae and deliver nutrients to osteocytes?

Canaliculi.

List the three main types of bone cells and their functions.

Osteoblasts build bone; osteoclasts resorb bone; osteocytes maintain bone matrix.

Name the two basic processes of bone formation.

Endochondral ossification and intramembranous ossification.

During endochondral ossification, where does the primary center of ossification first appear?

In the diaphysis of the cartilage model.

What is the epiphyseal plate and what happens to it at maturity?

A cartilage plate between epiphysis and diaphysis; it is replaced by an epiphyseal line when growth stops.

At about what age is the human skeleton considered mature?

Around 25 years old.

Name the two major divisions of the skeleton and the number of bones in each.

Axial skeleton – 80 bones; Appendicular skeleton – 126 bones.

List the four normal spinal curves.

Cervical, thoracic, lumbar, and sacral curves.

Identify the three common abnormal spinal curvatures.

Lordosis (swayback), kyphosis (hunchback), scoliosis.

How many vertebrae are in the cervical, thoracic, and lumbar regions respectively?

Cervical 7, Thoracic 12, Lumbar 5.

Differentiate true, false, and floating ribs.

True ribs (1–7) attach directly to the sternum; false ribs (8–10) attach indirectly; floating ribs (11–12) have no anterior attachment.

Which two bones form the pectoral (shoulder) girdle?

The scapula and the clavicle.

Which shoulder-girdle bone is most frequently fractured?

The clavicle.

What three bones fuse to form an adult coxal (hip) bone?

Ilium, ischium, and pubis.

Name the largest tarsal bone.

The calcaneus (heel bone).

What are the three arches of the foot?

Medial longitudinal, lateral longitudinal, and transverse (metatarsal) arches.

Give four skeletal differences between males and females.

Male skeleton larger; male pelvis deep & narrow, female pelvis broad & shallow; female pelvic inlet wider; female pubic angle wider.

What are the three functional classes of joints by movement?

Synarthrosis – no movement; Amphiarthrosis – slight movement; Diarthrosis – free movement.

List four common structural features of diarthrotic (synovial) joints.

Joint capsule & ligaments, articular cartilage, synovial membrane, and a joint cavity.

Provide one example for each diarthrotic joint type: ball-and-socket, hinge, pivot, saddle, gliding, condyloid.

Ball-and-socket: shoulder or hip; Hinge: elbow; Pivot: atlas-axis or radius-ulna; Saddle: thumb carpometacarpal; Gliding: intervertebral articular processes; Condyloid: atlanto-occipital joint or knuckle.

What is osteosarcoma and its common sites?

The most common malignant bone tumor, often in the distal femur, proximal tibia, and humerus.

Define osteoporosis and name typical fracture sites.

Loss of bone matrix/trabeculae causing fragile bones; common fractures in wrists, hips, and vertebrae.

How do rickets and osteomalacia differ?

Both involve vitamin D–related mineral loss; rickets affects children before maturity causing bowed legs, osteomalacia affects adults increasing fracture risk.

What characterizes Paget disease (osteitis deformans)?

Faulty bone remodeling leading to enlarged, deformed bones that fracture easily.

What causes osteogenesis imperfecta and how may it be treated?

Insufficient organic bone matrix makes bones brittle; managed with splinting and drugs that reduce bone cell activity.

Define osteomyelitis and its typical treatment.

Bacterial infection of bone; treated with surgical drainage and prolonged IV antibiotics.

Differentiate an open (compound) fracture from a closed (simple) fracture.

Open fractures pierce the skin; closed fractures do not.

With what condition are Heberden and Bouchard nodes associated?

Osteoarthritis (degenerative joint disease).

Distinguish between dislocation, sprain, and strain.

Dislocation: bones in a joint lose proper contact; Sprain: acute ligament injury; Strain: injury to muscle-tendon unit.

What is rheumatoid arthritis?

A systemic autoimmune disease causing chronic synovial inflammation and possible involvement of vessels, eyes, heart, and lungs.

What causes gouty arthritis?

Deposition of sodium urate crystals in joints causing synovial inflammation.

What distinguishes infectious arthritis?

Joint inflammation due to a pathogen, e.g., Lyme arthritis or ehrlichiosis transmitted by ticks.