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Questions and Answers
Which type of bone serves as a lever, as seen in the long bones of the limbs?
Which type of bone is primarily involved in protecting delicate organs like the brain and spinal cord?
What is the main function of irregular bones in the skeletal system?
Which type of bone is crucial for giving shape to the body and preventing it from being shapeless and flabby?
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What is the primary function of sesamoid bones in the human body?
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Which type of bone primarily functions as a protective shield for organs like the heart and lungs?
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What distinguishes long bones from other bone types in terms of their role?
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What is the main function of flat bones within the skeletal system?
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Which bones are essential for protecting the brain and spinal cord from injury?
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What distinguishes short bones from other types in terms of their primary function?
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Study Notes
Bone Structure and Types
- The outer shaft of long bones consists of compact bone, encased in a periosteum, a connective tissue sheath.
- Ends of long bones feature cancellous (spongy) bone enveloped by a thin layer of compact bone.
- Articular surfaces at the ends of bones are covered with hyaline cartilage for smooth joint movement.
Short Bones
- Found in hands and feet, such as tarsal and carpal bones.
- Roughly cuboidal in shape, consisting of cancellous bone with a thin outer layer of compact bone.
- Covered with periosteum, with their articular surfaces also lined with hyaline cartilage.
Flat Bones
- Located in the vault of the skull, including frontal and parietal bones.
- Comprised of two thin layers of compact bone with a layer of cancellous bone in between.
- Scapulae are categorized as flat bones despite their irregular shape.
Irregular Bones
- Include bones that don't fit into other classifications, like vertebrae, pelvic bones, and certain skull bones.
- Characterized by a thin outer layer of compact bone surrounding cancellous bone.
Sesamoid Bones
- Small nodules found within certain tendons where they glide over bony surfaces.
- Function to improve leverage and protect tendons from wear.
Bone Composition
- Compact bone appears as a dense, solid structure.
- Cancellous bone consists of a network of trabeculae, arranged to withstand stress and strain effectively.
Bone Classification
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Regional Classification:
- Axial Skeleton (80 bones): Includes cranial (8), facial (14), auditory ossicles (6), hyoid (1), vertebrae (26), and thoracic cage (1 sternum, 24 ribs).
- Appendicular Skeleton (126 bones): Comprises the pectoral girdle (4 bones), upper extremities (32 bones), pelvic girdle (2), and lower extremities (30 bones).
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Classification by Shape:
- Long Bones: Found in limbs (e.g., humerus, femur), longer than they are wide, with a tubular shaft (diaphysis) that typically contains a marrow cavity.
- Short Bones: Similar in length and width, mainly provide support and stability.
- Flat Bones: Thin and flat, primarily serve protective roles.
- Irregular Bones: Complex shapes not fitting other categories.
- Sesamoid Bones: Embedded within tendons for mechanical advantage.
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Description
This quiz covers the anatomy of long and short bones, discussing the composition of the outer part of the shaft, the structure of the ends of long bones, and the characteristics of short bones found in the hand and foot.
