Skeletal System Flashcards

Skeletal System

• General Functions:
  • Supports the body.
  • Facilitates movement.
  • Protects internal organs.
  • Produces blood cells (hematopoiesis) via bone marrow.
  • Stores and releases minerals and fat.
• Adaptability: Bones change based on stresses, including gravity, muscle pulling, diseases and nutrition.
• Components:
  • Bones
  • Cartilage
  • Ligaments
  • Tendons

Bone Classification

Bone Structure:

• Starts as connective tissue and matures to include blood vessels, muscles, and nervous tissue.

Long Bone Features

• Periosteum: Covers the bone.
• Diaphysis: The shaft of the bone.
• Epiphysis: The end point of the bone.
• Epiphyseal Plate: Growth plate.
• Articular Cartilage: Articulates with other bones.

Bone Cells Internal Features

• Compact Bone:
  • 20% of the structure and 80% of the weight.
  • Very dense tissue filled with mineral deposits in a collagen matrix and osteons.
• Cancellous Bone (Spongy Bone):
  • 80% of the structure and 20% of the weight.
  • Lots of open spaces like a sponge, more flexible.

Internal Features

• Marrow Cavity
• Spongy bone lined with endosteum (makes new bones).
• Red Marrow:
  • Made of hematopoietic cells.
  • Food supply for bone cells.
• Yellow Marrow:
  • Made of mesenchymal stem cells that form blood cell components
  • Can be converted to red marrow when the body suffers severe blood loss

Compact vs. Spongy Bone

Bone Growth and Remodeling

• Skeleton is made of cartilage and bone
• Embryonic skeleton is hyaline cartilage
• Young child – most cartilage are replaced by bone
• Most bones develop using hyaline cartilage as the model (flat bones use fibrous membranes).
• Ossification: Process of bone formation.
• Osteoblasts: Bone-forming cells.
• Enclosed hyaline is digested to leave the medullary cavity.
• Two regions remain hyaline cartilage:
  • Articular cartilage
  • Epiphyseal plates

Bone remodeling

Bone Fractures and Repair

Calcium Homeostasis

• Hypocalcemia:
  • Blood has difficulty coagulating.
  • Heart may stop beating or skip beats.
  • Muscles may have difficulty contracting.
  • Nerves may have difficulty functioning.
  • Brittle bones.
• Hypercalcemia:
  • Lethargy.
  • Sluggish reflexes.
  • Constipation.
  • Loss of appetite.
  • Confusion.
  • Coma.

Surface Features of bones

• Result from the bone being attached to ligaments and tendons.
• Ligaments: Bone to bone
• Tendons: Muscle to bone
• Also results from blood vessels and nerves coming in contact with bone.

An Introduction to Bone Markings

• Elevations and Projections
  • Process: Any projection or bump
  • Ramus: An extension of a bone making an angle with the rest of the structure
  • Trochanter: A large, rough projection
  • Tuberosity: A smaller, rough projection
  • Tubercle: A small, rounded projection
  • Crest: A prominent ridge
  • Line: A low ridge
  • Spine: A pointed or narrow process
• Processes formed for articulation with adjacent bones
  • Head: The expanded articular end of an epiphysis, separated from the shaft by a neck
  • Neck: A narrow connection between the epiphysis and the diaphysis
  • Condyle: A smooth, rounded articular process
  • Trochlea: A smooth, grooved articular process shaped like a pulley
  • Facet: A small, flat articular surface
• Depressions
  • Fossa: A shallow depression
  • Sulcus: A narrow groove
• Openings
  • Foramen: A rounded passageway for blood vessels or nerves
  • Canal: A duct or channel
  • Meatus: A passageway through a bone
  • Fissure: An elongated cleft or slit
  • Sinus: A chamber within a bone, normally filled with air