Biology Chapter 6: Bones

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Questions and Answers

What is the primary organic component of the extracellular matrix (ECM) of bone?

Hydroxyapatite

Collagen (correct)

Glycoproteins

Proteoglycans

What function does hydroxyapatite serve in the extracellular matrix (ECM) of bone?

Facilitates cell communication

Resists twisting and stretching

Harden the matrix (correct)

Provides flexibility

Which structure is the structural unit of compact bone?

Lacunae

Canaliculi

Osteon (correct)

Central canal

What is the role of canaliculi in bone tissue?

Connect osteocytes Signup and view all the answers

What characterizes the concentric lamellae within an osteon?

They provide strength by alternating direction of collagen fibers Signup and view all the answers

What covers the expanded ends of long bones?

Articular cartilage Signup and view all the answers

What is the structure that forms the long axis of a long bone?

Diaphysis Signup and view all the answers

What remains as a remnant of the epiphyseal plate in a long bone?

Epiphyseal line Signup and view all the answers

Which type of bone marrow is responsible for hematopoiesis?

Red bone marrow Signup and view all the answers

Which structure lines the inner surfaces of bones?

Endosteum Signup and view all the answers

How many nutrient arteries typically enter a long bone?

One Signup and view all the answers

What does yellow bone marrow primarily consist of?

Adipocytes and blood vessels Signup and view all the answers

Which of the following is true about bone tissue?

It is highly vascularized and innervated. Signup and view all the answers

What are the primary types of osseous tissue found in bones?

Compact bone and spongy bone Signup and view all the answers

Which of the following connective tissues is NOT a component of the skeletal system?

Adipose tissue Signup and view all the answers

How do spongy bone and compact bone differ in terms of structure?

Compact bone has a more organized structure than spongy bone. Signup and view all the answers

Which term describes the primary growth area in long bones where length increases?

Epiphyseal plate Signup and view all the answers

What is the main role of red bone marrow in the skeletal system?

Production of blood cells Signup and view all the answers

Which cell type is primarily involved in bone resorption?

Osteoclasts Signup and view all the answers

What is a key feature distinguishing intramembranous ossification from endochondral ossification?

Intramembranous ossification occurs in flat bones, while endochondral occurs in long bones. Signup and view all the answers

Which component of the bone extracellular matrix is inorganic?

Calcium phosphate Signup and view all the answers

What are interstitial lamellae primarily composed of?

Remnants of resorbed osteons Signup and view all the answers

Where are circumferential lamellae located?

Around the periosteum Signup and view all the answers

Which of the following best describes perforating canals?

Horizontal channels connecting blood supply to the Haversian canal Signup and view all the answers

What type of ossification involves a hyaline cartilage model?

Endochondral ossification Signup and view all the answers

What is a major cause of osteoporosis?

Hormonal factors Signup and view all the answers

What sequence of zones is found in the epiphyseal plate during growth?

Zone of reserve cartilage, Zone of proliferation, Zone of hypertrophy, Zone of calcification, Zone of ossification Signup and view all the answers

What occurs during appositional growth of bone?

Deposition of new bone by osteoblasts Signup and view all the answers

Which process is NOT involved in bone remodeling?

Formation of scar tissue Signup and view all the answers

What happens if the epiphyseal plate is damaged in a bone fracture?

The fractured bone may be shorter than usual as growth concludes Signup and view all the answers

Which step comes first in the fracture healing process?

Hematoma formation Signup and view all the answers

Study Notes

Functions of the Skeletal System

Provides structural support to the body
Protects vital organs, such as the heart and brain
Facilitates movement by serving as attachment points for muscles
Stores minerals, particularly calcium and phosphorus
Houses bone marrow for blood cell production

Types of Connective Tissue in the Skeletal System

Hyaline cartilage: smooth and flexible, reduces friction at joints
Fibrocartilage: tough and durable, found in intervertebral discs and pubic symphysis
Dense regular collagenous connective tissue: forms tendons and ligaments for stability
Dense irregular connective tissue: provides protection and structure in periosteum

Spongy vs Compact Bone

Spongy Bone: Composed of trabecular meshwork; found in interior of bones, lightweight, and allows for flexibility.
Compact Bone: Dense and strong, forms the outer layer of bones, organized into osteons for structural integrity.

Classification of Bones by Shape

Long bones (e.g., femur): elongated structure, major weight-bearing bones
Short bones (e.g., carpals): cube-shaped, provide stability and support, allowing for limited motion
Flat bones (e.g., sternum): thin, flattened, and provide protection, surface area for muscle attachment
Irregular bones (e.g., vertebrae): complex shapes that do not fit into other categories

Definitions and Functions of Bone Structures

Diaphysis: the long central shaft of a bone, supports weight
Epiphysis: the expanded end of a bone, covered with articular cartilage for joint movement
Medullary cavity: hollow space within diaphysis that contains bone marrow
Red bone marrow: site of blood cell production
Yellow bone marrow: stores fat and serves as an energy reserve
Periosteum: fibrous membrane covering bones, contains blood vessels and nerves
Endosteum: membrane lining the medullary cavity, involved in bone growth and repair
Perforating (Sharpey’s) fibers: collagen fibers that anchor periosteum to bone
Nutrient foramen: small openings that allow blood vessels and nerves to enter the bone

Bone Extracellular Matrix Components

Organic components (approx. 33%): osteoid providing flexibility and tensile strength, composed of collagen and ground substance.
Inorganic components (approx. 67%): hydroxyapatite crystals (calcium and phosphorus), providing compressional strength.

Bone Cell Types

Osteoblasts: responsible for bone formation and matrix secretion.
Osteocytes: mature bone cells that maintain bone tissue and communicate with other cells.
Osteoclasts: involved in bone resorption and remodeling.

Compact Bone Structure

Osteons (Haversian systems): structural units containing concentric lamellae and a central canal for blood vessels.
Lamellae: layers of mineralized matrix, oriented to resist twisting forces.
Lacunae: small cavities housing osteocytes.
Canaliculi: connect lacunae, facilitating nutrient and waste exchange.

Spongy Bone Structure

Lacks osteons; contains trabeculae with interspersed osteocytes.
Provides lightweight support and houses red bone marrow.

Osteogenesis & Ossification Processes

Intramembranous ossification: develops from mesenchyme (embryonic connective tissue); forms many flat bones.
Endochondral ossification: develops from hyaline cartilage models; most bones formed this way.

Growth in Length

Epiphyseal plate: contains zones (reserve, proliferation, hypertrophy, calcification, ossification) crucial for lengthening bones.

Implications of Epiphyseal Plate Injuries

Damage can result in stunted bone growth or premature closure, affecting adult height.

Appositional Growth

Involves osteoblasts adding new bone on the outer surface, increasing thickness without changing overall length.

Bone Remodeling Processes

Consists of deposition (bone formation) and resorption (bone loss), maintaining calcium levels and adapting to physical stress.

Blood Calcium Homeostasis Feedback Loop

Low calcium triggers parathyroid hormone release, promoting resorption; high calcium increases calcitonin, promoting deposition.

Osteoporosis

Condition characterized by decreased bone density, increasing fracture risk due to inadequate inorganic matrix; factors include age, sex, and activity level.

Steps in Bone Repair After Fracture

Formation of a hematoma, followed by soft callus formation, bony callus creation, and eventual remodeling into secondary bone.

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Description

Explore the key functions of the skeletal system in this quiz. Understand the types of connective tissues involved and compare spongy versus compact bone. Additionally, learn to classify bones by shape and identify examples within each category.