Questions and Answers
What is the primary function of the skeletal system related to the body's shape?
Which bone is recognized as the longest and strongest in the human body?
What type of bone is primarily composed of spongy bone and is roughly cube-shaped?
Which type of bone includes the vertebrae and facial bones?
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What is the main component of the extracellular matrix of bone?
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What type of bone primarily consists of adipose tissue?
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Which cells are responsible for the formation of new bone tissue?
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What is the primary function of the medullary cavity in long bones?
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What process involves the replacement of hyaline cartilage with bone matrix?
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What change occurs in long bones during appositional growth?
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Study Notes
Overview of the Skeletal System
- Composed of bones, cartilage, tendons, and ligaments.
- Total bones in a baby: 276; adult: 206.
Functions of the Skeletal System (S2PMB)
- Shapes and forms the body.
- Provides structural support.
- Protects vital organs.
- Facilitates movement.
- Stores essential minerals and fat.
- Aids in blood cell production.
Bone Characteristics
- Weakest bone: clavicle (collarbone); softest bone in the human body.
- Bone weight consists of 31% water.
- Longest and strongest bone: femur (thighbone).
Extracellular Matrix Components
- Collagen: robust, ropelike protein providing structure.
- Proteoglycans: large molecules of polysaccharides attached to core proteins.
- Cartilage: contains both collagen and proteoglycans.
- Bone: incorporates collagen and minerals, mainly calcium and phosphate.
- Hydroxyapatite: crystalline structure of calcium phosphate.
Types of Bones
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Long Bones:
- Longer than wide; predominantly made of compact bone; found in limbs.
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Short Bones:
- Cube-shaped; mostly spongy bone; examples include wrist and ankle bones.
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Flat Bones:
- Thin and flattened; examples include skull, ribs, and scapulae.
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Irregular Bones:
- Unique shapes; primarily spongy bone; includes vertebrae and facial bones.
Bone Structure
- Diaphysis: Central shaft of a long bone.
- Epiphysis: Ends of the long bone.
- Epiphyseal Plates: Growth plates indicating bone length increase.
- Articular Cartilage: Covers epiphyses ends to reduce friction.
- Medullary Cavity: Contains bone marrow; features yellow (fat storage) and red (blood cell formation) marrow.
Bone Histology
- Osteoblasts: Cells responsible for bone formation and repair.
- Osteocytes: Mature bone cells found in lamellae.
- Lacunae: Spaces housing osteocytes within lamellae.
- Canaliculi: Tiny channels connecting lacunae.
Classification of Osseous Tissue
- Compact Bone: Dense, smooth texture.
- Spongy Bone: Composed of needle-like pieces with numerous open spaces.
Bone Development
- Embryonic skeleton: primarily hyaline cartilage.
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Ossification Processes:
- Hyaline cartilage model is fully encased in bone matrix by osteoblasts.
- Hyaline cartilage model is digested, creating a medullary cavity.
Bone Growth Mechanisms
- Balanced activity of osteoclasts (bone removal) and osteoblasts (bone deposition).
- Growth Hormone regulates long bone lengthening during puberty.
- Appositional growth results in bone widening and diameter increase.
Bone Remodeling and Repair
- Occurs to maintain structure in response to growth and stress.
- Bone becomes denser and projects form in areas of muscle attachment.
- Repair involves clot formation, callus formation, and remodeling to compact bone.
Calcium Homeostasis in Bone
- Osteoclasts increase blood calcium levels through bone resorption.
- Osteoblasts decrease blood calcium levels by depositing calcium into bone.
Bone Markings
- Projections (Processes): Extensions from bone surfaces for muscle and ligament attachment.
- Depressions: Indentations or cavities within bones for joint formation.
- Examples of projections include tuberosity, crest, and trochanter, while joint-forming features are heads and condyles.
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Description
Test your knowledge on the structure and functions of different bone types, including the diaphysis, epiphysis, and marrow. This quiz covers essential concepts of bone anatomy and growth, focusing on irregular bones and their unique characteristics.
