How can we help?

You can also find more resources in our Help Center.

19 terms

Osseous Tissue and Bone Structure

STUDY
PLAY
Long Bones
Are Long and Thin
Upper Extremedies- humerus, ulna, radius, metacarpals
Lower Extremedies- femur, tibia, fibula
Flat Bones
Are thin with parallel surfaces
Scapula, ribs, sternum, skull
Irregular Bones
Have complex shapes
Vertebrae, pelvis
Sutural Bones (Wormiam)
Are small, irregular bones
Found between the flat bones of the skull
Short Bones
Are small and thick with multiple articulations
Carpals, tarsals
Sesamoid Bones
Are small and flat, develop inside tendons near joint of knees, hands, feet
Patella
Diaphysis
The shaft, a heavy wall of compact bone
The compact bone surrounds a central space called a medullary cavity (location of bone marrow)
Epiphysis
Wide part at each end, composed of a thin exterior layer of compact bone and a large portion of spongy bone
Ends are covered with hyaline (articular) cartilage
Medullary Cavity
The space within a bone that contains the marrow
Osteocytes
Mature bone cell responsible for the maintenance and turnover of the mineral content of the surrounding bone
-live in lacunae, are between layers of matrix called lamellae
-connect by cytoplasmic extensions called canaliculi in lamellae
i. travel between another lacunae or a central canal
-do not divide
-Functions: to maintain protein and mineral context of matrix, to help repair damaged bones, can sense the stress applied to the bone
Osteoblasts
A cell that produces the fibers and matrix of bone
-immature bone cells that synthesize and secrete the organic matrix (osteoid, then hardens by mineral deposition)
-osteoblasts surrounded by bone become osteocytes
Osteoclasts
A cell that dissolves the fibers and matrix of bone
-giant, multinucleate cells secrete acids and protein digesting enzymes to dissolve bone matrix and release stored minerals (osteolysis)
-are derived from the same stem cells that produce macrophages
Osteon
The basic histological unit of compact bone, consisting of osteocytes organized around a central canal and separated by concentric lamellae
-central canal contains blood vessels and connecting each central canal are perforating canals
Ossification
The process of replacing other tissue with bone
-intramembranous and endochondral
Calcification
The process of depositing calcium salts which occurs during bone ossification and in other tissues
Calcitonin
Secreted from the thyroid gland
Decreases calcium ion levels by:
-inhibit osteoclast activity
-increase calcium excretion at kidneys
Therefore, less Ca++ ions enter the blood and losses are accelerated
PTH
Secreted by the parathyroid glands
Increases calcium ions by 3 ways:
-Stimulating osteoclasts
-Increase intestinal absorption of calcium
-Decrease calcium excretion at kidneys
Therefore, more Ca++ ions enter the blood and losses are restricted and homeostasis is maintained
Fracture
A crack or break in a bone from sudden impacts, extreme loads, stresses from unusual directions or pathology
Functions of the Skeletal System
Support
Storage of minerals (calcium and phosphate)
Storage of lipids (yellow marrow)
Blood cell production (red marrow, wbc, rbc)
Protection of internal organs
Leverage for skeletal movement (force of motion)