Questions and Answers
What is the primary function of intervertebral discs?
Which feature is characteristic of lumbar vertebrae?
What does the sacrum protect?
At what age do the sacral vertebrae begin the process of fusion?
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What is the primary consequence of the dehydration of the nucleus pulposus in intervertebral discs?
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What is the primary reason for shrinking as one ages?
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What characterizes a slipped disc?
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Which condition is defined by the inflammation of the spine?
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Which type of vertebrae allows for significant flexion and moderate lateral flexion?
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What structure forms a fibrocartilaginous joint between adjacent vertebrae?
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At what age range does osteoarthritis typically onset?
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Which type of curvature is characterized by a significant inward curve at the lower back?
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What is unique about cervical vertebrae compared to other types?
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Which condition is associated with the formation of crystals of sodium urate in joints?
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What is a major consequence of osteoporosis?
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Scoliosis is primarily characterized by which type of spinal curvature?
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What is the primary function of the intervertebral discs?
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Which type of vertebrae is located in the lower back?
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What is one of the age-related changes observed in the intervertebral discs?
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Which of the following characteristics is NOT typical of thoracic vertebrae?
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How do cervical vertebrae differ primarily from other types of vertebrae?
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What is a unique feature of lumbar vertebrae compared to thoracic and cervical vertebrae?
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What occurs to the cervical vertebrae as a result of age-related changes?
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What is the primary reason for the development of articular cartilage in the epiphyseal plate during ossification?
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Study Notes
Lumbar Vertebrae
- Lumbar vertebrae increase in size toward the lumbar section to support weight.
- Vertebral body is large, thick, and oval-shaped for weight bearing.
- Spinous process is short and thick, facilitating movement.
- Allows significant flexion, extension, and moderate lateral flexion.
Sacrum and Coccyx
- Sacrum consists of one bone formed from five fused sacral vertebrae by ages 16-18.
- Provides an attachment site for thigh movement muscles.
- Protects reproductive, excretory, and digestive organs.
- Anchors the pelvic girdle to the axial skeleton.
- Sacral foramen are openings allowing sacral nerves to pass through.
- Coccyx formed from three to five small or incomplete vertebrae.
Intervertebral Discs
- Positioned between adjacent vertebrae, forming fibrocartilaginous joints.
- Allow slight vertebral movement and act as ligaments connecting vertebrae.
- Function as shock absorbers for the spine.
- Composed of a fibrous outer ring surrounding a gel-like substance of collagens I and II.
Aging and Height Reduction
- Intervertebral discs act as shock absorbers; dehydration of the nucleus pulposus occurs with age.
- Decreased disc hydration reduces shock absorption capability.
- Height loss with age, evidenced by individuals shrinking over the years (e.g., 5ft 4” to 5ft 1”).
Slipped/Herniated Discs
- Occurs when the outer layer of the disc splits, causing gel to bulge out.
- Can exert pressure on the spinal cord or a single nerve root, leading to pain in affected areas.
Diseases of the Skeletal System
- Arthritis, mainly osteoarthritis and rheumatoid arthritis, involves cartilage erosion, leading to joint pain.
- Osteoarthritis has a later age onset, often unilateral; rheumatoid is typically symmetrical.
- Gout involves sodium urate crystals forming in and around joints.
- Osteoporosis causes loss of bone density, making bones fragile.
- Rickets results from Vitamin D deficiency, leading to soft and weak bones.
- Ankylosing spondylitis involves spine inflammation.
- Scoliosis involves a sideways curvature of the spine.
Curvature Disorders of the Spine
- Lordosis (swayback): Inward curvature at the lower back.
- Kyphosis: Rounded upper back with abnormal curvature (beyond 50 degrees).
- Scoliosis: Sideways spinal curvature.
Bone Development Processes
Intramembranous Ossification
- Begins with mesenchymal cells differentiating into osteoblasts at ossification centers.
- Osteoid is formed, which calcifies and leads to osteocytes.
- Trabeculae form and fuse, creating spongy bone with blood vessels and red marrow.
- Mesenchyme condenses to form the periosteum; compact bone eventually replaces surface spongy bone.
Endochondral Ossification
- Starts with chondroblasts forming a cartilage model.
- Cartilage model grows, chondrocytes calcify, and cavities form as blood vessels enter.
- Osteoblasts invade the primary ossification center in the diaphysis, calcifying the cartilage.
- Medullary cavity develops as osteoclasts break down trabecular bone.
- Secondary ossification centers appear at birth, with ossification proceeding outward.
- Articular cartilage and epiphyseal plates form, allowing lengthwise growth of the bone.
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Description
This quiz covers the anatomy of the lumbar vertebrae, sacrum, and coccyx, highlighting their functions and structural features. It also explores the role of intervertebral discs in the spine's movement and support. Test your knowledge of these crucial components of the human skeletal system.
