Chapter 7: Bone Tissue Flashcards
List and describe important functions of bones
support, levers for movement, hematopoiesis, storage for minerals and energy reserves
What is the general gross anatomy of a long bone?
diaphysis, medullary cavity, epiphysis, articular cartilage, epiphyseal plate, epiphyseal line, metaphysics, periosteum, endosteum, perforating fibers
What are the locations and functions of red bone marrow?
children - located in spongy bone and compact bone, in adults - located in axial skeleton; contains reticular tissue and adipocytes; developing blood cells
What are the locations and functions of yellow bone marrow?
contains mostly adipocytes and some red blood cells
What is articular cartilage?
thin layer of hyaline cartilage that covers the joint surface of epiphysis
What is the periosteum?
a tough sheath that covers the outer surface of bone except for the areas covered my articular cartilage
What is the endosteum?
a very thin layer of connective tissue containing osteoprogenitor cells, osteoblasts, and osteoclasts; it covers all internal surface of medullary cavity
What is the difference between the epiphyseal plate and an epiphyseal line?
growth plate; it is a thin layer of hyaline cartilage that provides for the continued lengthwise growth of the bone; in adults it turns into an epiphyseal line
What is the general gross anatomy of a flat bone?
covered by periosteum, has two sides of compact bone with a. spongy inside called the diploë;
How is a flat bone different from a long bone?
no medullar cavity in flat bone
What is an osteon?
functional unit of compact bone tissue
What are lamellae?
layer of bone connective tissue; forms concentric rings
What is the central canal?
a channel located in the center of the osteon where blood vessels and nerves travel through
What is a lacuna?
small space, cavity, or depression.
What are canaliculi?
interconnecting channels within the bone connective tissue that connect with other lacunae; they house osteocytes
Explain the histology of spongy bone
contains no osteons; has trabeculae (crisscrossing bars), bone marrow, and parallel lamellae; nutrients reach osteocytes by diffusion through cytoplasmic processes of osteocytes
What is the location and function of osteoprogenitor cells?
developed from mesenchyme and develops into osteoblasts; when cell divides, one cell remains an osteoprogenitor cell while the other becomes an osteoblast; located in periosteum and endosteum
What is the location and function of osteoblasts?
synthesizing and secreting osteoid; after being entrapped within matrix they produce, they differentiate into osteocytes
What is the location and function of osteoclasts?
located in or adjacent to a resorption lacuna; they are involved in bone resorption
What is the chemical composition of bone?
organic = osteoid, inorganic = hydroxyapatite
What is hydroxyapatite?
crystals that are made up of salt crystal that are primarily calcium phosphate and calcium hydroxide. hydroxyapatite hardens the matrix and accounts for rigidity of bone
Explain the method of intramembranous ossification
- ossification centers form within thickened regions of mesenchyme beginning at the eighth week of development
- osteoid undergoes calcification
- Woven bone and its surrounding periosteum form
- Lamellar bone replaces woven bone, as compact bone and spongy bone form
Explain the method of endochondral ossification
- A hyaline cartilage model of bone forms
- Bone first replaces hyaline cartilage in the diaphysis
- Next, bone replaces hyaline cartilage in the epiphyses
- Eventually, bone replaces hyaline cartilage everywhere, except the epiphyseal plates and articular cartilage
- By a person’s late 20s, all epiphyseal plates typically have ossified, and lengthwise bone growth is complete
What is the process (zones) of long bone growth that occurs at the epiphyseal plates?
- Zone of resting cartilage
- Zone of proliferating cartilage
- Zone of hypertrophic cartilage
- Zone of calcified storage
- Zone of ossification
