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What is a primary function of cartilage in the skeleton during the embryonic stage?
What is the main characteristic that distinguishes cartilage as a connective tissue?
Which cells are primarily responsible for maintaining the cartilage matrix?
What is the role of the perichondrium in cartilage?
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Which type of cartilage is commonly found at the ends of bones in movable joints?
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What is a key component of cartilage matrix that contributes to its strength?
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What distinguishes elastic cartilage from other types of cartilage?
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Which type of cartilage is an initial precursor to all other cartilage types?
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What is the principal type of cartilage found in fetuses and infants?
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Where is fibrous cartilage primarily located?
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Which of the following characteristics is true about elastic cartilage?
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What distinguishes the matrix of hyaline cartilage?
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Which of the following structures contains elastic cartilage?
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What best describes the structure of long bones?
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What role does the periosteum play in bone health?
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Which stage of bone healing involves the formation of a soft callus?
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Which factor can hinder the bone healing process?
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What is a common bone disease characterized by reduced bone density?
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What is a characteristic of osteoporosis?
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Which condition is associated with a lack of vitamin D in children?
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What is the primary characteristic of osteomyelitis?
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Acromegaly is characterized by which of the following?
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Which bone cancer is classified as a primary cancer?
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What aspect is essential for effective bone healing?
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Which of the following describes fibrous dysplasia?
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What are the primary causes of bone cancer?
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What is the primary function of osteocytes in bone tissue?
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Which type of bone tissue is described as appearing spongy and containing red bone marrow?
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What role does the periosteum play in bone health?
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Which phase follows the formation of the fibrocartilaginous primary callus in the bone healing process?
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Which factor can potentially delay the healing of broken bones?
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What mineral is primarily responsible for the hardness of mature bone?
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Which characteristic best describes compact bone?
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How does old age impact the healing process of bones?
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What structure serves as the anatomical unit of compact bone?
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Which component is primarily found in the organic matrix of bone?
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What happens to spongy bone during the later stages of healing after a fracture?
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What does the term 'osteoclast' refer to in bone physiology?
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Which type of bone lacks Haversian systems and has a more irregular structure?
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Study Notes
Cartilage: Structure and Function
- Cartilage is a firm, avascular, non-calcified connective tissue.
- It forms the temporary skeleton in embryos and fetuses.
- Cartilage is present on articular surfaces of joints, providing flexibility.
- The temporomandibular joint (TMJ) is a crucial cartilage in the head and neck.
- Cartilage relies on surrounding connective tissue, called the perichondrium, for its nutrition.
- Cartilage consists of cells and a matrix.
- The matrix contains fibers (collagen), intracellular substances, and ground substance.
- Chondroblasts are immature cells that produce cartilage matrix.
- Chondrocytes are mature chondroblasts that maintain the cartilage matrix.
- The ground substance is a highly hydrated gel composed of proteoglycans, chondronectin, and water.
- The type and number of fibers in the matrix vary depending on the type of cartilage.
- The perichondrium is a capsular sheath that surrounds cartilage.
Types of Cartilage
- There are three types of cartilage: hyaline, fibrous, and elastic.
- All cartilage starts as hyaline, but then modifies according to its function.
Hyaline Cartilage
- The most common type of cartilage, especially in fetuses and infants.
- Contains small groups of chondrocyte cells.
- The matrix is smooth and solid, appearing as a bluish-white, glassy tissue.
- Hyaline cartilage is not easily repaired after injury.
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Locations:
- Articulating surfaces of bones.
- Costal cartilages, which attach the ribs to the sternum.
- Cartilages of the larynx, trachea, and bronchi.
Fibrous Cartilage
- Dense, tough, and slightly flexible tissue.
- Contains groups of chondrocytes separated by thick bundles of collagen fibers.
- Collagen fibers are arranged in tight parallel bundles.
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Locations:
- Intervertebral discs.
- Knee and jaw joints.
- Surrounding the rim of the bony sockets of the hip and shoulder joints.
- Pubic symphysis.
Elastic Cartilage
- Contains elastic fibers in the intracellular matrix.
- The least common type of cartilage tissue.
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Locations:
- Pinna of the ear.
- Epiglottis.
- Forming part of the tunica media of blood vessel walls.
Bone Conditions
- Acromegaly is characterized by overgrowth of bones in the face, hands and feet.
- Fibrous dysplasia is an abnormal growth or swelling of bone.
- Rickets occurs when a child's growing bones fail to develop due to a lack of vitamin D.
- Multiple myeloma is a cancer of the plasma cells in bone marrow.
- Osteosarcomas and chondrosarcomas are examples of primary cancers of bone.
- Most cancers found in bone are metastatic, spreading from other organs like the breast, prostate, lung, or kidney.
Osteomyelitis
- Infection of bones, commonly in the long bones of the arms and legs
- Microbes like Staphylococcus Aureus can gain access to bone and spread infection.
- Chronic infection can result when exposed bone becomes infected.
- Bone tumours are frequently linked to other pathologies.
- Cancerous pathology of bones is often metastatic, with malignant cells transferring from primary carcinomas in the breast, lungs and prostate gland.
Functions of Bone
- Support and protection of body structures.
- Framework for movement.
- Blood cell production in the bone marrow.
- Mineral storage, particularly calcium and phosphate.
Development of Bone
- Begins before birth and is complete at approximately 25 years of age.
- Two main types: Intramembranous ossification and Endochondral ossification.
Bone Structure: Cells Present - Osteoblasts
- Bone-forming cells.
- Single nucleus.
- Immature bone cells.
- Become trapped and isolated in lacunae as bone develops.
Bone Structure: Cells Present - Osteocytes
- Develop from osteoblasts trapped in lacunae.
- Mature bone cells.
- Have many processes.
Bone Structure: Cells Present - Osteoclasts
- Bone resorption cells.
- Large and multi-nucleated.
- Can engulf like macrophages.
- Maintain the optimum shape of bone.
- Activity takes place at the bone surface.
- A balance of osteoblast and osteoclast activity maintains normal bone.
Composition of Bone
- Fully developed bone consists of 40-50% inorganic material, 20% water, and 30-40% organic material.
- Inorganic material is comprised of mineral salts, primarily calcium and phosphate.
- Organic material is mainly collagen.
Bone Structure: Matrix
- Inorganic: Crystalline mineral salts and calcium, hydroxyapatite crystals.
- Organic: Mainly collagen.
Bone Structure: Osteon
- Haversian system is the structural and functional unit of bone.
- Each osteon has a central Haversian canal running longitudinally, containing blood vessels, lymph, and nerves.
Types of Bone Tissue: Compact Bone
- Appears solid macroscopically.
- Contains numerous Haversian systems microscopically.
Types of Bone Tissue: Cancellous or Spongy Bone
- Appears spongy macroscopically.
- Contains red bone marrow.
The Structure of Compact Bone
- Strongest form of bone tissue with few spaces.
- Forms the tough outer layer of each bone.
- Approximately 80% of the skeleton is compact bone.
The Structure of Compact Bone
- Concentric rings of flat bone called lamellae make up osteons, surrounding the Haversian canal.
The Structure of Compact Bone
- Spaces between lamellae, called lacunae, contain lymph and osteocytes.
- Canaliculi link lacunae with lymph vessels, providing nutrient transport for osteocytes.
The Structure of Cancellous or Spongy Bone
- Lighter bone tissue with branching bars and plates.
- Makes up the inner structure of short, flat, and irregular bones.
- Does not contain osteons.
- Lamellae are arranged in an irregular lattice of trabeculae, surrounding red bone marrow.
Bone Structure: Periosteum
- Vascular fibrous membrane surrounding the surface of bone.
- Provides nourishment via blood vessels.
- Gives attachment to muscle tendons.
- Assists in bone formation and repair.
Stages of Bone Healing
- Fibrocartilaginous primary callus formation: Occurs in the first months following injury.
- Resorption of dead bone and appearance of spongy bone: The size of the callus is influenced by immobility at the fracture site.
- Gradual replacement of spongy bone by lamellar bone: This bony secondary callus unites the fracture.
- Remodeling: The shape of the bone gradually returns to normal, a process that can take several years.
Factors that can DELAY Bone Healing
- Infection.
- Tissue fragments between bone ends.
- Deficient blood supply.
- Old age.
- Medications like steroids.
- The host response.
Factors that can IMPROVE Bone Healing
- Limited movement/resting of the broken bone.
- Medication
Types of Bone
- Long bones
- Short bones
- Flat bones
- Irregular bones
- Sesamoid bones
Long Bones
- Long shaft or diaphysis.
- Two articular surfaces.
- A central bone marrow cavity.
Short Bones
- Cube-shaped bones.
Flat Bones
- Thin and often curved.
Irregular Bones
- Irregular and complex shapes.
Sesamoid Bones
- Embedded in tendons.
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Description
Explore the fascinating world of cartilage, a vital connective tissue in the human body. Learn about its structure, different types, and crucial roles in joint flexibility and skeletal formation in embryos. This quiz delves into the specific cells involved and the essential matrix that makes cartilage unique.
