chapter 6 Flashcards by M A

Which of the following is a primary function of the skeletal system?
A. Hormone production
B. Support
C. Digestion
D. Temperature regulation

Support
Why: The skeletal system supports the body and provides structure.

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Which bone type is thin with parallel surfaces and provides protection?
A. Short bone
B. Irregular bone
C. Flat bone
D. Sesamoid bone

Flat bone
Why: Flat bones protect organs and provide surface area for muscle attachment.

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The shaft of a long bone is called the:
A. Epiphysis
B. Metaphysis
C. Diaphysis
D. Medulla

Diaphysis
Why: The diaphysis is the long central shaft of a bone.

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The femur is classified as a:
A. Short bone
B. Long bone
C. Flat bone
D. Irregular bone

Long bone
Why: Long bones are longer than they are wide; the femur is the longest bone.

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Sutural (Wormian) bones are found:
A. In the wrist
B. In the ankle
C. Between skull bones
D. In the thigh

Between skull bones
Why: Sutural bones are small, irregular bones located between flat skull bones.

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The medullary cavity is located in the:
A. Epiphysis
B. Diaphysis
C. Periosteum
D. Articular cartilage

Diaphysis
Why: The medullary (marrow) cavity is inside the shaft of long bones.

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Which cells are responsible for building new bone?
A. Osteoclasts
B. Osteocytes
C. Osteoblasts
D. Chondrocytes

Osteoblasts
Why: Osteoblasts produce new bone matrix.

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Which bone cells break down bone matrix?
A. Osteoblasts
B. Osteocytes
C. Osteogenic cells
D. Osteoclasts

Osteoclasts
Why: Osteoclasts dissolve bone and release minerals.

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The functional unit of compact bone is the:
A. Trabecula
B. Osteon
C. Canaliculus
D. Lacuna

Osteon
Why: Osteons are cylindrical units that form compact bone.

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Mature bone cells that maintain bone matrix are:
A. Osteocytes
B. Osteoblasts
C. Osteoclasts
D. Fibroblasts

Osteocytes
Why: Osteocytes maintain and monitor the bone matrix.

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Spongy bone differs from compact bone because it:
A. Has osteons
B. Is solid
C. Lacks osteons
D. Has no blood supply

Lacks osteons
Why: Spongy bone is made of trabeculae and does not contain osteons.

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The periosteum functions to:
A. Store fat
B. Cover bone surfaces
C. Produce red blood cells
D. Form cartilage

Cover bone surfaces
Why: The periosteum covers bones and helps with growth and repair.

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Intramembranous ossification forms bones such as the:
A. Femur
B. Mandible
C. Tibia
D. Humerus

Mandible
Why: Dermal bones like the mandible form this way.

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Endochondral ossification begins with a model made of:
A. Spongy bone
B. Compact bone
C. Hyaline cartilage
D. Fibrous tissue

Hyaline cartilage
Why: Most bones form by replacing a cartilage model.

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Lengthwise growth of bones occurs at the:
A. Medullary cavity
B. Epiphyseal plate
C. Periosteum
D. Diaphysis

Epiphyseal plate
Why: The epiphyseal cartilage allows bones to grow in length.

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Parathyroid hormone (PTH) increases blood calcium levels by:
A. Inhibiting osteoclasts
B. Stimulating osteoclasts
C. Decreasing kidney absorption
D. Blocking vitamin D

Stimulating osteoclasts
Why: PTH increases bone breakdown to release calcium.

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The skeletal system includes:
A. Bones only
B. Bones and muscles
C. Bones, cartilage, ligaments, and connective tissues
D. Bones and blood vessels only

Bones, cartilage, ligaments, and connective tissues
Why: The skeletal system includes supportive connective tissues.

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Appositional growth increases bone:
A. Length
B. Density
C. Width
D. Flexibility

Width
Why: Appositional growth thickens bones.

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The first step in fracture repair is:
A. Callus formation
B. Compact bone formation
C. Hematoma formation
D. Spongy bone formation

Hematoma formation
Why: A blood clot forms immediately after a fracture.

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Severe age-related bone loss is called:
A. Osteopenia
B. Osteogenesis
C. Osteoporosis
D. Osteomalacia

Osteoporosis
Why: Osteoporosis is a serious loss of bone mass that weakens bones.

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Calcitonin lowers blood calcium levels by:
A. Stimulating osteoclasts
B. Increasing calcium absorption
C. Inhibiting osteoclasts
D. Increasing calcitriol

Inhibiting osteoclasts
Why: Calcitonin slows bone breakdown.

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Which is NOT a function of the skeletal system?
A. Support
B. Blood cell production
C. Hormone insulin production
D. Mineral storage

Hormone insulin production
Why: Insulin is produced by the pancreas, not the skeleton.

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The periosteum:
A. Lines the medullary cavity
B. Covers outer bone surfaces
C. Is made of cartilage
D. Produces red blood cells

Covers outer bone surfaces
Why: It surrounds the outside of bones except at joints.

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The two layers of the periosteum are:
A. Compact and spongy
B. Inner and outer lamellae
C. Fibrous and cellular
D. Red and yellow

Fibrous and cellular
Why: Outer fibrous layer, inner cellular (osteogenic) layer.

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Perforating (Sharpey’s) fibers: A. Carry nutrients B. Attach periosteum to bone C. Produce osteocytes D. Form cartilage

Attach periosteum to bone Why: They strengthen attachment of tendons and ligaments.

The endosteum: A. Covers bone externally B. Lines internal bone surfaces C. Is thicker than periosteum D. Contains no bone cells

Lines internal bone surfaces Why: It lines the medullary cavity and trabeculae.

Osteoblasts: A. Break down bone B. Maintain bone C. Build bone D. Store calcium

. Build bone Why: They secrete osteoid (new bone matrix).

Osteoclasts: A. Build bone B. Dissolve bone matrix C. Maintain bone D. Form cartilage

Dissolve bone matrix Why: They resorb bone and release calcium.

Osteocytes: A. Are stem cells B. Divide rapidly C. Maintain bone matrix D. Form osteoid

Maintain bone matrix Why: Mature bone cells maintain tissue.

An osteon contains: A. A central canal B. Red marrow C. Cartilage D. Diploë

A central canal Why: The central canal carries vessels and nerves.

Osteogenic cells: A. Are mature bone cells B. Produce osteoblasts C. Break down bone D. Produce collagen only

Produce osteoblasts Why: They are stem cells for bone.

Compact bone contains: A. Trabeculae only B. Osteons C. Red marrow only D. No blood vessels

Osteons Why: Osteons are the structural units

Spongy bone: A. Has osteons B. Lacks trabeculae C. Lacks osteons D. Has no blood supply

Lacks osteons Why: It is arranged in trabeculae.

Spongy bone handles stress by: A. Being solid B. Directing stress along trabeculae C. Avoiding blood flow D. Preventing remodeling

Directing stress along trabeculae Why: Trabeculae align with stress lines.

The diaphysis is the: A. End of bone B. Shaft C. Growth plate D. Joint surface

Shaft Why: Central portion of long bone.

The diploë is: A. A fracture B. Spongy bone in flat bones C. A bone cell D. Compact bone

Spongy bone in flat bones Why: It is between compact layers.

Calcitriol is: A. Inactive vitamin D B. Active vitamin D made in kidneys C. A growth hormone D. A bone protein

Active vitamin D made in kidneys Why: It increases calcium absorption.

The epiphysis is: A. The shaft B. The growth plate C. The end of a long bone D. The marrow cavity

The end of a long bone Why: Wide portion at each end.

Interstitial growth increases: A. Width B. Density C. Length D. Calcium

Length Why: Occurs at epiphyseal plate.

The metaphysis contains the: A. Osteon B. Epiphyseal plate C. Medullary cavity D. Periosteum

Epiphyseal plate Why: Growth occurs there.

Which hormone raises blood calcium? A. Calcitonin B. PTH C. Estrogen D. Vitamin C

PTH Why: Stimulates osteoclast activity.

Appositional growth increases: A. Length B. Width C. Flexibility D. Marrow

Width Why: Adds layers to outer surface.

Calcitonin is secreted by: A. Parathyroid glands B. Thyroid C cells C. Kidneys D. Pituitary

Thyroid C cells Why: Calcitonin lowers calcium.

The first step in fracture repair is: A. Callus formation B. Hematoma formation C. Spongy bone formation D. Remodeling

Hematoma formation Why: Blood clot forms first.

RANKL: A. Inhibits osteoclasts B. Activates osteoclasts C. Forms collagen D. Lowers calcium

Activates osteoclasts Why: It increases bone resorption.

A greenstick fracture: A. Breaks bone completely B. Occurs only in elderly C. Is incomplete, common in children D. Is spiral

Is incomplete, common in children Why: Bone bends and cracks.

A fracture where bone ends shift is: A. Nondisplaced B. Spiral C. Displaced D. Compression

Displaced Why: Bone fragments are out of alignment.

The inorganic portion of bone matrix is mainly: A. Collagen B. Calcium phosphate C. Protein D. Water

. Calcium phosphate Why: Forms hydroxyapatite crystals

Osteopenia: A. Severe bone loss B. Early bone mass reduction C. Increased bone density D. Bone cancer

Early bone mass reduction Why: It can progress to osteoporosis.

Osteoporosis is: A. Mild bone thinning B. Severe bone mass loss C. Infection D. Normal aging

Severe bone mass loss Why: Causes fragile bones.

Hydroxyapatite: A. Makes bone flexible B. Makes bone strong and hard C. Is a bone cell D. Is cartilage

Makes bone strong and hard Why: It is the mineral crystal in bone.

Which of the following is a function of the skeletal system? A) Support B) Protection C) Blood cell production D) All of the above

All of the above Explanation: The skeletal system supports the body, protects organs, and produces blood cells (hematopoiesis).

Which bone is classified as an irregular bone? A) Patella B) Frontal bone C) Vertebra D) Ulna

Vertebra Explanation: Vertebrae have complex shapes and do not fit long, short, or flat categories.

The shaft of a long bone is called the: A) Epiphysis B) Metaphysis C) Diaphysis D) Medullary cavity

Diaphysis Explanation: The diaphysis is the long central shaft of a long bone.

Which cell type secretes the organic bone matrix (osteoid)? A) Osteocyte B) Osteoclast C) Osteoblast D) Chondrocyte

Osteoblast Explanation: Osteoblasts build bone by secreting osteoid.

The region between the diaphysis and epiphysis is the: A) Metaphysis B) Lacuna C) Osteon D) Periosteum

Metaphysis Explanation: The metaphysis contains the epiphyseal plate during growth.

Which bone cell dissolves bone matrix? A) Osteocyte B) Osteoclast C) Osteoblast D) Osteoprogenitor

Osteoclast Explanation: Osteoclasts break down bone during remodeling.

The structural unit of compact bone is the: A) Trabecula B) Lacuna C) Osteon D) Canaliculus

Osteon Explanation: Osteons (Haversian systems) are cylindrical units in compact bone.

The medullary cavity primarily contains: A) Compact bone B) Cartilage C) Marrow D) Osteons

Marrow Explanation: Yellow marrow (fat storage) is in the medullary cavity.

Intramembranous ossification forms: A) Femur B) Vertebrae C) Skull roof bones D) Tibia

Skull roof bones Explanation: Flat bones of the skull form directly from mesenchyme.

Spongy bone is made of interconnecting structures called: A) Osteons B) Trabeculae C) Lamellae D) Medullary canals

Trabeculae Explanation: Trabeculae are thin bone plates arranged along stress lines.

The tiny channels connecting lacunae are called: A) Canaliculi B) Central canals C) Foramina D) Lamellae

Canaliculi Explanation: Canaliculi allow nutrients to pass between osteocytes.

What allows bones to grow in length? A) Periosteum B) Epiphyseal plate C) Osteon D) Medullary cavity

Epiphyseal plate Explanation: Longitudinal growth occurs at the growth plate.

Endochondral ossification begins with a: A) Bone model B) Cartilage model C) Fibrous model D) Calcified matrix

Cartilage model Explanation: A hyaline cartilage model is replaced by bone.

Secondary ossification centers are located in the: A) Diaphysis B) Epiphyses C) Medullary cavity D) Periosteum

Epiphyses Explanation: They form in the ends of long bones.

The most abundant mineral in the body is: A) Sodium B) Potassium C) Calcium D) Phosphorus

Calcium Explanation: Most calcium is stored in bones as hydroxyapatite.

When blood calcium levels rise, which hormone is released? A) Parathyroid hormone B) Growth hormone C) Calcitonin D) Estrogen

Calcitonin Explanation: Calcitonin lowers blood calcium by inhibiting osteoclasts.

A lack of exercise can lead to: A) Thicker bones B) Stronger bones C) Porous, weak bones D) Longer bones

Porous, weak bones Explanation: Bone remodels according to stress; less stress = weaker bone.

Parathyroid hormone (PTH) causes blood calcium levels to: A) Decrease B) Stay the same C) Increase D) Stop circulating

Increase Explanation: PTH stimulates osteoclast activity to raise blood calcium.

When stress is applied to bone: A) Osteoclast activity increases B) Bone becomes brittle C) Electrical signals attract osteoblasts D) Bone becomes thinner

Electrical signals attract osteoblasts Explanation: Stress creates small electrical fields that stimulate bone formation.

If osteoclast activity exceeds osteoblast activity, bones become: A) Denser B) Stronger C) Osteopenic D) Thicker

Osteopenic Explanation: More breakdown than formation reduces bone mass.

During appositional growth, bones: A) Grow longer B) Grow wider C) Become shorter D) Stop remodeling

Grow wider Explanation: Appositional growth increases bone thickness.

Vitamin D is necessary for: A) Collagen production B) Calcium absorption C) Osteoclast inhibition D) Protein synthesis

Calcium absorption Explanation: Vitamin D helps absorb calcium and phosphate from the intestine.

A condition where bone becomes riddled with holes is: A) Osteopenia B) Osteoporosis C) Osteitis D) Osteomalacia

Osteoporosis Explanation: Osteoporosis causes severe bone density loss.

When the epiphyseal plate closes: A) Bones grow faster B) Bones grow wider C) Bones reach adult length D) Cartilage increases

Bones reach adult length Explanation: Closure stops longitudinal growth.

During fracture repair, the thickened healing tissue is called: A) Osteon B) External callus C) Trabecula D) Epiphysis

External callus Explanation: A callus forms around the fracture to stabilize and repair the bone.

chapter 6 Flashcards

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