Anatomical Terminology and Tissue Organization

Anatomical Terminology

• Brachial: Upper arm
• Buccal: Cheek
• Calcaneal: Heel of foot
• Carpal: Wrist
• Cephalic: Head
• Cervical: Neck
• Cranial: Skull
• Crural: Lower leg
• Digital: Fingers or toes
• Dorsal: Back
• Frontal: Forehead
• Gluteal: Buttock
• Hallux: Great toe
• Inguinal: Groin
• Lumbar: Back between ribs and pelvis
• Mammary: Breast
• Mental: Chin
• Nasal: Nose
• Oral: Mouth
• Orbital: Eye
• Palmar: Palm of hand
• Patellar: Kneecap
• Pelvic: Pelvis
• Pubic: Anterior pelvis
• Sural: Calf
• Tarsal: Proximal foot and ankle
• Thoracic: Chest
• Umbilical: Navel

Tissue Organization

• Four major tissue types: Epithelial, Connective, Muscle, Nervous

Epithelial Tissue

• Structure and Types:
  • Simple: Single layer
  • Stratified: Two or more layers
  • Pseudostratified: Appears multi-layered, but all cells touch the basement membrane.
  • Squamous: Flat, irregular shape
  • Cuboidal: Same size on all sides, central nucleus
  • Columnar: Taller than wide, oval nucleus at basal region
• Examples (from lecture):
  • Simple squamous: Alveoli (lungs)

Bone Tissue

• General Functions: Support, protection, movement, hematopoiesis, mineral and energy storage.

• Compact vs. Spongy Bone (structural differences):

  • Compact bone: Solid, dense, outer layer of long and flat bones
  • Spongy bone: Open lattice of trabeculae, inner layer of bones

• Bone Classification by Shape:

  • Long bones: Longer than wide (e.g., femur)
  • Short bones: Nearly equal length and width (e.g., tarsal and carpal bones)
  • Flat bones: Thin surfaces (e.g., frontal bone)
  • Irregular bones: Complex shapes (e.g., vertebrae)

Gross Anatomy of Long Bone

• Diaphysis: Elongated, cylindrical shaft
• Epiphysis: Enlarged, knobby regions at each end
• Metaphysis: Region between diaphysis and epiphysis containing the epiphyseal plate (growth plate).
• Articular cartilage: Thin layer of hyaline cartilage covering the epiphysis, reducing friction and absorbing shock.
• Medullary cavity: Hollow space in diaphysis, containing yellow or red bone marrow.

Bone Cells and their Roles

• Osteocytes: Reside in lacunae, maintains matrix, detects mechanical stress.
• Osteoprogenitor cells: Mesenchymal stem cells in endosteum and periosteum; produce more stem cells or osteoblasts.
• Osteoblasts: Form bone matrix.
• Osteoclasts: Large, multinuclear cells that dissolve bone matrix, releasing calcium.

Hormones Regulating Calcium Levels

• Growth hormone: Promotes bone elongation
• Thyroid hormone: Stimulates bone growth by increasing osteoblast metabolic rate.
• Calcitonin (thyroid): Promotes calcium deposition in bone and inhibits osteoclast activity
• Parathyroid hormone: Increases blood calcium levels by encouraging bone resorption by osteoclasts.
• Sex hormones: Stimulate osteoblasts; promote epiphyseal plate growth and closure.
• Glucocorticoids: Chronically high levels cause bone resorption and loss of bone mass (osteoporosis).