Bone Basics
Name the 5 functions of the skeletal system. Which two are accomplished by bone marrow?
Protection, support, movement, storage, manufacturing.
Storage and manufacturing are accomplished by bone marrow.
What thin layer covers the ends of a long bone?
Articular Cartilage
Describe the functions of organic and inorganic portions of bone.
Organic- Flexibility
Inorganic- Provides Strength
What 3 types of joints? Give an example of each.
Fibrous- Skull
Cartilaginous- Ribs
Synovial- Knee
Name one portion of the long bone.
Epiphysis, Epiphyseal Plate, Diaphysis
The humerus would be classified as what shape?
Long Bone
Name a structure of compact bone.
osteon, haversian canal, volkmann's canal.
Organic- Flexibility
Inorganic- Strength
What is the purpose of a joint capsule filled with fluid?
Reduces friction on the moving bones
What two hormones regulate blood calcium levels? Which glands secrete them?
PTH and calcitonin. PTH from parathyroid glands, calcitonin from thyroid.
In a long bone, describe where you would find spongy and compact bone.
Compact bone is found around the medullary cavity while spongy bone is found near the epiphyses.
Describe two differences in an infant’s bones and an adult’s (besides size).
An infant would have more cartilage, while an adult would have ossified bones. An infant would also have more red bone marrow than an adult.
What are the 2 major sections of the skeleton? Which one has more bones?
Axial & appendicular. Appendicular has more bones.
Describe the healing of a broken bone using the words callus & hematoma.
When a bone is fractured, a hematoma develops to bring white blood cells to the wound. A callus of cartilage forms, holding the bone together until spongy and compact bone replace it.
Describe how osteoblasts and osteoclasts work together to remodel bone.
Osteoblasts build bone while osteoclasts break it down. They work together to build strength in areas of resistance, while eliminating bone in other areas.
Name the 5 sections of the vertebral column. Which way do they curve?
Cervical (concave), thoracic (convex), lumbar (concave), sacral (convex), coccyx (convex)
What thin layer covers the ends of a long bone?
ossification, calcium
What function do canaliculi and bone canals (Haversian & Volkmann’s) serve?
Canaliculi and bone canals serve to connect bone cells by allowing nutrients to be delivered and waste to be removed.
When standing on your toes, what type of joints are involved?
Gliding (in ankle), hinge (in knee), ball & socket (in hip)
Pediatricians are often particularly concerned about fractures that cross the epiphyseal plate. Explain why.
The epiphyseal plate is the location of growth, so a fracture here could permanently affect the growth of that bone.
An elderly person and a teenager both fall and land on their wrists. The elderly person fractures a bone, while the teenager does not. Explain how differences in bone density and composition could contribute to these different outcomes.
As people age, their bones often lose mineral density, making them weaker and more susceptible to fractures. Younger individuals generally have denser bones with greater flexibility, allowing their bones to withstand more force without breaking.
A disease damages the Haversian canals and canaliculi within compact bone. Explain how this damage could affect the survival of bone cells.
Haversian canals contain blood vessels that deliver oxygen and nutrients to bone tissue. Canaliculi allow nutrients and wastes to move between osteocytes and their surroundings. Damage to these structures could prevent osteocytes from receiving necessary nutrients and removing waste, potentially causing cell death.
A 12-year-old fractures their femur directly through the epiphyseal plate. Although the fracture heals, the injured leg eventually becomes shorter than the other. Explain why this might happen.
The epiphyseal plate is responsible for the lengthwise growth of long bones. If a fracture damages this growth plate, it can interfere with normal bone growth. The injured femur may stop growing or grow more slowly, resulting in one leg being shorter than the other.
A patient experiences damage to the cartilage covering the ends of bones in their knee joint. Predict two problems this patient might experience and explain why.
Pain and inflammation: Damaged cartilage reduces protection between the bones, increasing friction and irritation during movement.
Reduced mobility: Without healthy cartilage, the joint cannot move as smoothly, potentially causing stiffness and difficulty bending or straightening the knee.
A patient's blood calcium level drops significantly below normal. Explain which hormone the body would release, where it comes from, and how the skeletal system helps restore calcium balance.
The parathyroid glands release parathyroid hormone (PTH) in response to low blood calcium. PTH increases bone resorption by indirectly stimulating osteoclast activity, releasing stored calcium from bones into the bloodstream. It also acts on the kidneys and promotes intestinal calcium absorption to help restore normal blood calcium levels.