Skeletal System

• What are the three distinct layers of the embryo?

  Ectoderm, Mesoderm, Endoderm
• What do mesenchymal stem cells give rise to in osteogenesis?

  Osteoprogenitor cells, Chondroblasts, Osteoblasts, Osteocytes, Osteoclasts
• What is the function of the perichondrium in cartilage?

  • Resists forces when cartilage is compressed
  • Contains blood vessels for nutrient diffusion into cartilage cells
• What type of cartilage is the most abundant?

  Hyaline cartilage
• What is the primary function of fibrocartilage?

  Provides structural support and cushioning
• What are the two groups of bones in the human body?

  Axial skeleton and Appendicular skeleton
• How many bones are in the human body?

  206 bones
• What is the primary function of the axial skeleton?

  Protection and support of body parts
• What is the function of the appendicular skeleton?

  Locomotion and manipulating the environment
• What are long bones characterized by?

  They are longer than they are wide
• What is the function of short bones?

  Provide stability and support with little movement
• What are flat bones primarily used for?

  Protection and muscle attachment
• What are irregular bones?

  Bones that do not conform to other bone shapes
• What are the main functions of bones?

  • Provide framework and support
  • Protect vital organs
  • Act as levers for movement
  • Store minerals
  • Form blood cells
• What are the three levels of bone structure?

  1. Gross anatomical level
  2. Microscopic level
  3. Chemical level
• What is the outer layer of bone called?

  Compact bone
• What is the internal layer of bone known as?

  Spongy bone
• What fills the open spaces between trabeculae in living bone?

  Red or yellow marrow
• What is the role of the endosteum in long bones?

  • Lines the trabeculae of spongy bone
  • Lines the canals that pass through spongy bone
  • Contains osteoblasts and osteoclasts
• Where is haematopoietic tissue found?

  Within the trabeculae cavities of long bones
• What happens to yellow marrow under certain conditions?

  It can revert to red marrow to enhance red cell production
• What is the difference between compact and spongy bone?

  • Compact bone: Dense outer layer, smooth appearance
  • Spongy bone: Honeycomb structure with trabeculae
• How often is spongy bone replaced?

  Every 3 to 4 years
• How often is compact bone replaced?

  Every 10 years
• What happens to bones when they break?

  They undergo remodeling
• What is the structure of the skull?

  • Composed of 22 bones: 14 facial and 8 cranial
  • Encloses and protects the brain
• What is the function of the facial bones?

  Form a framework for the face and contain cavities for sense organs
• What is unique about the hyoid bone?

  It does not articulate directly with any other bone
• What is the function of the hyoid bone?

  Acts as a moveable base for the tongue
• What are the functions of the vertebral column?

  1. Axial support for the trunk
  2. Transmits weight to lower limbs
  3. Surrounds and protects the spinal cord
  4. Provides attachment points for ribs and back muscles
• How many bones make up the vertebral column?

  26 bones
• What are intervertebral discs?

  Cushion-like pads between vertebrae that act as shock absorbers
• Why do intervertebral discs flatten throughout the day?

  Due to compression from body weight and activity
• What is the bony thorax composed of?

  • Thoracic vertebrae
  • Ribs
  • Sternum
  • Costal cartilages
• What is the function of the bony thorax?

  To protect vital organs of the thoracic cavity
• Where is the sternum located?

  In the anterior midline of the thorax
• With which ribs does the sternum articulate?

  With the first two pairs of ribs
• What is located at the posterior end of the sternum?

  The xiphoid process
• What is the function of the xiphoid process?

  Provides attachment for muscles
• What holds the vertebral column in place?

  Ligaments and muscles in the trunk