Skeletal System Quiz

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Questions and Answers

What function of the skeletal system involves safeguarding vital organs?

Support

Blood Cell Production

Movement

Protection (correct)

Which of the following components of the extracellular matrix provides tensile strength to bones?

Minerals

Collagen (correct)

Hydroxyapatite

Connective tissue

What type of bone is typically characterized by being longer than it is wide?

Long bone (correct)

Irregular bone

Flat bone

Short bone

Which type of bone marking is described as an opening or groove?

Foramen (C) Signup and view all the answers

What substance in bones acts as a mineralized 'concrete' providing compression strength?

Hydroxyapatite (A) Signup and view all the answers

What type of bone primarily contains spongy bone and has a generally cube shape?

Short bones (C) Signup and view all the answers

Which part of the bone is composed of compact bone and serves as the shaft?

Diaphysis (C) Signup and view all the answers

What are the small bones located between the flat bones of the skull known as?

Sutural bones (C) Signup and view all the answers

Which cells are responsible for the formation of bone?

Osteoblasts (B) Signup and view all the answers

Which layer covers the external surface of the epiphysis and reduces friction at joint surfaces?

Articular cartilage (A) Signup and view all the answers

What type of growth involves chondrocytes producing new matrix within the tissue?

Interstitial growth (A) Signup and view all the answers

Which of the following is NOT a type of bone classification?

Cubic bones (A) Signup and view all the answers

Where would you expect to find yellow marrow in adults?

In the medullary cavity (C) Signup and view all the answers

What is the primary function of osteoprogenitor cells in bone tissue?

To undergo cell division and develop into osteoblasts (B) Signup and view all the answers

Which component is crucial for the structure of compact bone tissue?

Osteons (C) Signup and view all the answers

What is the role of osteoclasts in bone tissue?

To break down bone tissue (D) Signup and view all the answers

Where is spongy bone primarily located?

In the interior of bones, protected by compact bone (C) Signup and view all the answers

What structure connects lacunae to the central canal in compact bone tissue?

Canaliculi (D) Signup and view all the answers

Which type of lamellae is found between osteons in compact bone?

Interstitial lamellae (D) Signup and view all the answers

What is the main benefit of the structure of trabecular bone?

Allows for nutrient diffusion and reduces bone weight (B) Signup and view all the answers

Which feature of compact bone tissue allows it to resist stresses from weight and movement?

The structure of osteons (C) Signup and view all the answers

What is the primary function of spongy bone tissue?

Reduces overall bone weight for easier movement (B) Signup and view all the answers

Which of the following bones typically contains spongy bone tissue?

Sternum (B), Vertebrae (D) Signup and view all the answers

In intramembranous ossification, which cells first appear at the ossification center?

Osteoprogenitor cells (A) Signup and view all the answers

What occurs immediately after osteoblasts secrete the organic extracellular matrix?

Secretion of extracellular matrix stops (A) Signup and view all the answers

What is formed as a result of the calcification of the extracellular matrix?

Osteocytes (D) Signup and view all the answers

Which development occurs last in the process of intramembranous ossification?

Development of periosteum (D) Signup and view all the answers

What characterizes endochondral ossification?

Bone formation within cartilage (B) Signup and view all the answers

Where does the formation of trabeculae in spongy bone occur?

At the ossification center (D) Signup and view all the answers

What initiates the formation of the primary ossification center in endochondral ossification?

Nutrient artery penetration (C) Signup and view all the answers

Which growth process increases bone thickness?

Appositional growth (B) Signup and view all the answers

What happens to chondroblasts as they become buried in the cartilage extracellular matrix?

They become chondrocytes (C) Signup and view all the answers

Which layer of the epiphyseal plate is responsible for anchoring it to the epiphysis?

Resting cartilage (D) Signup and view all the answers

How do secondary ossification centers differ from primary ossification centers?

They appear in the epiphyses (A) Signup and view all the answers

What type of cartilage makes up the epiphyseal plate?

Hyaline cartilage (A) Signup and view all the answers

During which phase of growth does cartilage lengthen from within?

Interstitial growth (A) Signup and view all the answers

What structure forms after osteoclasts break down spongy bone during medullary cavity development?

Medullary cavity (D) Signup and view all the answers

What is the primary function of chondrocytes in the zone of hypertrophic cartilage?

To contribute to bone elongation (D) Signup and view all the answers

What process do osteoblasts perform to lay down new bone matrix?

Endochondral ossification (A) Signup and view all the answers

At what age does epiphyseal plate closure typically occur in males?

Around age 21 (C) Signup and view all the answers

What is the role of osteoclasts in the zone of calcified cartilage?

Dissolving calcified cartilage (C) Signup and view all the answers

How do periosteal cells contribute to bone growth?

By forming bone ridges that encapsulate blood vessels (A) Signup and view all the answers

What happens to the medullary cavity during bone thickness growth?

It enlarges as osteoclasts destroy tissue (C) Signup and view all the answers

What is indicated by the timing of epiphyseal plate closure?

Bone age and predicted adult height (C) Signup and view all the answers

What is the focus of bone remodeling?

Continuous replacement of old bone tissue (D) Signup and view all the answers

Study Notes

Skeletal System Anatomy and Physiology

The skeletal system's main functions include support, protection, movement, blood cell production, and storage.
It supports the body by providing a framework for tissues.
It protects vital organs like the brain, heart, and lungs.
It acts as levers for muscular action, facilitating movement.
Red bone marrow within bones produces blood cells through a process called hemopoiesis.
Bones serve as a reservoir for minerals (calcium, phosphorus) and fats.

Composition of the Skeletal System

The skeletal system is composed of bones, cartilage, ligaments, tendons, and joints.
These components contribute to the strength, flexibility, and support provided by the skeletal system.

Extracellular Matrix

The extracellular matrix consists of proteins (collagen) and minerals (hydroxyapatite).
Collagen provides tensile strength, similar to steel bars in a framework/concrete.
Hydroxyapatite, primarily calcium phosphate, acts as the mineralized concrete providing compression strength.
Proteoglycans maintain flexibility and water retention within the matrix.

Bone Markings

Bone markings are not smooth, but rather display features indicative of attachment points for muscles, tendons, ligaments, nerves, and blood vessels.
Articulations are points where bones meet.
Projections are parts of the bones that extend above the surface.
Holes, openings, or grooves are indentations in the bone.

Classification of Bones

Long bones: Longer than wide; feature a shaft with ends. Examples include the femur and humerus.
Short bones: Generally cube-shaped; primarily spongy bone. Examples include carpals and tarsals.
Flat bones: Thin and flattened, usually curved with thin layers of compact bone surrounding a layer of spongy bone. Examples include skull, ribs and sternum.
Irregular bones: Irregular shape; do not fit neatly into the other categories. Examples include vertebrae and hip bones.
Sesamoid bones: Small, oval-shaped bones located within tendons. The patella is a common example.
Sutural bones: Small bones located between flat bones of the skull, typically found at the sutures.

Structure of a Bone (Long Bone)

Diaphysis: The shaft of the long bone, mainly composed of compact bone.
Epiphysis: The ends of the bone, primarily composed of spongy bone.
Metaphysis: The regions between the diaphysis and epiphyses; contains the epiphyseal growth plate.
Articular cartilage: Covers the epiphyses, reducing friction at joint surfaces; made of hyaline cartilage.
Periosteum: A fibrous connective tissue membrane covering the outer surface of the diaphysis (shaft).
Perforating fibers (Sharpey's fibers): Secure the periosteum to the underlying bone.
Medullary cavity: A cavity within the diaphysis, typically containing yellow marrow (mostly fat) in adults, and red marrow in areas of blood cell production.
Endosteum: A thin membrane lining the medullary cavity and the internal spaces of spongy bone.

Bone Histology

Osteoblasts: Bone forming cells.
Osteocytes: Mature bone cells residing in lacunae.
Osteoclasts: Bone resorbing cells (breaking down bone tissue).
Compact bone: Dense bone with osteons (Haversian systems).
Spongy bone (Cancellous bone): Trabecular structure housing red bone marrow.

Osteoprogenitor Cells

Undifferentiated cells develop from this stem cell population that are responsible for creating osteoblasts.

Osteoblasts

Builds bone tissue by creating the organic bone extracellular matrix/framework.

Osteocytes

Mature bone cells residing within spaces called lacunae, maintaining cellular function in response to metabolic needs.

Osteoclasts

Break down bone tissue and release minerals into the bloodstream.

Compact Bone Tissue

Osteons (Haversian systems): Cylindrical structural units of compact bone containing concentric lamellae.
Concentric lamellae: Ring-like structural units comprised of mineralized matrix around a central canal.
Central (Haversian) canal: Contains blood vessels and nerves.
Lacunae: Small spaces that house osteocytes.
Canaliculi: Tiny channels connecting lacunae to the central canal.
Interstitial Lamellae: Found between osteons; fragments of older osteons that have been remodeled.
Circumferential Lamellae: Rings of lamellae surrounding the entire outer and inner surface of bone.

Spongy Bone Tissue

Trabeculae Irregular patterns of lamellae;contain osteocytes in lacunae connected by canaliculi;provide structural support with minimal weight.
Bone Marrow: Red bone marrow produces blood cells; yellow bone marrow stores adipose tissue.

Bone Ossification

Intramembranous ossification: Bone forms directly within mesenchyme; common formation for flat bones of the skull.
Endochondral ossification: Bone forms within hyaline cartilage; common formation method for long bones.

Bone Growth in Length

Interstitial growth: Cartilage growth at the epiphyseal side.
Endochondral ossification: Cartilage replacement by bone on the diaphyseal side.
Epiphyseal plate: Central structure for length growth, composed of hyaline cartilage.
Zones of the epiphyseal plate: Resting, Proliferating, Hypertrophic, and Calcified cartilage.

Bone Growth in Thickness

Appositional growth: Bone thickens through the addition of new layers of bone tissue on the outer surface via bone ridges, tunnels, and new osteons.

Bone Remodeling

Continuous process of replacing old bone tissue with new tissue.
Involves bone resorption (osteoclasts) and bone deposition (osteoblasts).

Phases of Bone Fracture Repair

Reactive phase: Formation of a fracture hematoma.
Reparative phase: Fibrocartilaginous and bony callus formation.
Bone remodeling phase: Remodeling to restore the functional structure of the bone.

Healing Time and Factors Affecting Healing

Healing time depends on fracture severity and bone location.
Factors affecting healing include blood supply to the bone, age, and overall health, and nutritional intake (calcium and phosphorus).

Common Fractures

Different types of fractures include open, comminuted, greenstick, impacted, Colles', and Pott's fractures.

Benefits of Bone Remodeling

Strength enhancement
Shape adjustment
Fracture resistance

Factors Affecting Bone Health (Minerals and Vitamins)

Minerals: Calcium, Phosphorus, Magnesium, Fluoride, and Manganese.
Vitamins: A, C, D, K, and B12.

Factors Affecting Bone Health (Hormones)

Insulin-like Growth Factors: Stimulate osteoblasts and promote cell division.
Thyroid Hormones: Promote bone growth by stimulating osteoblasts.
Insulin: Promotes bone growth by enhancing bone protein synthesis.
Sex Hormones: Estrogen and androgen: cause rapid bone growth, promote bone growth by stimulating osteoblasts, and regulate remodeling and resorption in adulthood. They also influence bone development and maturity.
Other hormones: Parathyroid Hormone, Calcitriol (active Vitamin D), and Calcitonin, influence bone remodeling.

Exercise and Bone Health

Moderate weight-bearing exercise stimulates bone growth and strengthening, maintaining bone density.
Exercise helps maintain healthy bones throughout life.

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Description

Test your knowledge on the functions and characteristics of the skeletal system. This quiz covers topics such as bone structure, types, and the role of various components in safeguarding organs. Perfect for students studying anatomy and physiology.