Skeletal System Flashcards
Functions of the skeletal system
Support
Protection: vital organs
Movement
Mineral homeostasis: calcium & phosphorus-hardness
Blood cell production: red blood cells - hematopoiesis
Fat storage: energy generation, stored in yellow bone marrow
What does the skeletal system consist of?
206 bones
Cartilage
Ligaments (bone to bone)
Tendons (bone to muscle)
Types of bone in skeletal system
Shape-
Long bone: humerus, femur (form joints)
Short bone: carpal, tarsal (dissipate stress)
Flat bone: rib, sternum (protection)
Sesamoid bone: patella, hand, foot (develops within tendon, protects, improves movement
Location- Sutural bone (cranial)
Effects of aging on skeletal system
Bone matrix decreases Bone mass decreases Increased bone fractures Bone loss causes deformity, loss of height, pain, stiffness Stooped posture Loss of teeth
*good nutrition & exercise can slow down effects
Bone formation
Ossification (hardening) or osteogenesis (beginnings)
4 situations: Initial formation in the womb Growth during infancy, childhood, adolescence, to adult Remodeling throughout life Repair of fractures throughout life
Histology of bone tissue
Bone matrix: extracellular matrix
Organic: collagen & proteoglycans (45%)
Inorganic: minerals (hydroxyapatite crystals = calcium phosphate + calcium hydroxide)
4 types of cells in bone tissue
Osteogenic: unspecialized-forming
Osteoblast: bone building, manufacture collagen-forming
Osteocytes: mature bone cells-cell
Osteoclast: resorption-destroying
Homeostatic imbalances
Fracture: inability to adapt/withstand stress
Osteoporosis: demineralization of bone
Initial formation of bone
Intramembranous ossification:
Within a membrane model (skull, facial bones)
Fontanels-sutures
Endochondrial ossification: Within a cartilage model Epiphyseal plate (lengthwise growth)
Bone growth- childhood to adulthood
Longitudinal growth:
Epiphyseal plate
Interstitial growth of cartilage in epiphyseal side
Replacement of cartilage on diaphyseal side with bone (endochondral ossification)
Appositional growth:
Thickness
Balance between osteoblast activity on periosteal side & osteoclast activity on endosteal side
Factors affecting bone growth and remodeling-nutrition
Minerals: calcium
Vitamin D: allow adequate amount of calcium to be deposited
Vitamin C: helps form collagen
Vitamin A: balances osteoclast & osteoblast activity
Factors affecting bone growth and remodeling- mechanical
Exercise vs. sedentary
Piezoelectric effect: walking, etc. allows calcium in
Wolf’s law: structure will adapt to stress put on it
Factors affecting bone growth and remodeling-hormones
Growth hormone: regulate activity of epiphyseal plate (excess: gigantism/deficiency: dwarfism)
Thyroid hormone
Calcitonin: produced by thyroid, calcium deposition
Parathyroid hormone: removes calcium; not enough in body
Sex hormones: estrogen-reform bone; birth/testosterone-thicker & heavier
