Physiology - Exam 3, Deck #1 - Skeletal Flashcards
What are Long Bones?
-Have long longitudinal axes and expanded ends; EX: Forearm and thigh bones
What are Short Bones?
- Are somewhat cubelike with their lengths and widths roughly equal;
- EX. Bones of wrists and ankles
What are Flat Bones?
Are platelike structures with broad surfaces
-EX: the ribs, scapulae, and some bones of the skull
What are Irregular Bones?
Have a variety of shapes and are usually connected to several other bones;
-EX: Vertebrae that comprise the backbone and many facial bones
What are Sesamoid or Round Bones?
-Usually small and nodular and are embedded within tendons adjacent to joints, where the tendons are compressed;
EX. Kneecap or patella
What are the part of a Long Bone?
- Epiphysis (distal/ proximal)
- Diaphysis
- Compact bone
- Spongy bone
- Articular cartilage
- Periosteum
- Endosteum
- Medullary cavity
- Trabeculae
- Marrow (red/yellow)
What is the Epiphysis?
- Expanded portion at each end; articulates (or forms a joint) with another bone;
- Articular cartilage covers
- Largely composed of spongy bone, or cancellous bone, with layers of compact bone on their surfaces
What is Articular Cartilage of long bones?
A layer of HYALINE cartilage which coats the outer surface of the articulating portion of the epiphysis
What is Spongy of Cancellous Bone?
Spongy bone consists of many branching plates called TRABECULAE;
-Trabeculae are most highly developed in the regions of the epiphysis that are subjected to compressive fractures
What is the Diaphysis of Long Bones?
The shaft of the bone which is located between the epiphyses;
-Wall is mostly composed of tightly packed tissue called compact bone, or cortical bone; has a continuous matrix with no gaps
What is the Medullary Cavity of Long Bone
Compact bone in the diaphysis of a long bone forms a semirigid tube with a hollow chamber called the MEDULLARY CAVITY that is continuous with the spaces of the spongy bone
What is found in the Medullary Cavity?
- Endosteum – is a thin membrane containing bone-forming cells; lines the medullary cavity
- Marrow is a specialized type of soft connective tissue that fills the cavity
—Red marrow = hemopoietic – forms red blood cells, white blood cells, blood platelets
—Yellow marrow = stores fat and is inactive in blood cell production
What is the Periosteum of long bones?
The tough, vascular COVERING of fibrous tissue over all of the bone EXCEPT for the articular cartilage area of the epiphysis
What are Processes of long bones?
Bony projections that provide sites for attachment of ligaments and tendons
What are Osteocytes?
- Bone Cells;
- Located in tiny, bony chambers called LACUNAE, which form concentric circles around central canals (Haversian canals)
What are Haversian Canals?
Canals around which osteocytes and lacunae encircle
What are Canaliculi?
Small passageway though which Osteocytes transport nutrients and wastes to and from nearby cells by means of cellular processes
What is the main intercellular material in bones?
- The intercellular material of bone tissue is largely COLLAGEN and INORGANIC SALTS;
- Collagen gives bone its strength and resilience, and inorganic salts make it hard and resistant to crushing
How are the osteocytes (cells) of COMPACT Bone arranged?
- The osteocytes and layers of intercellular material are concentrically clustered around a central canal form a cylinder shaped unit called an OSTEON, sometimes called the Haversian system;
- Many of these units cemented together form the substance of compact bone
What is found in the central canals of Compact Bone?
-Each central canal contains blood vessels and nerve fibers surrounded by loose connective tissue which nourishes bone cells associated with the central canal via GAP JUNCTIONS;
-Central canals pervade bone tissue LONGITUDINALLY
Transverse perforating canals (Volkmann’s canals) interconnect them
What are Transverse Perforation Canals (Volkmann’s Canals) of Compact Bone?
Interconnect the central canals found within compact bone
What is the structure of SPONGY BONE?
- Spongy bone is composed of osteocytes and intercellular material, but the bone cells DO NOT AGGREGATE around central canals;
- The cells lie within the trabeculae and get nutrients from substances diffusing into the canaliculi that lead to the surface of these thin bony plates
What are the 2 ways bones form?
- INTRAMEMBRANOUS bones originate within sheetlike layers of connective tissue
- ENDOCHONDRAL bones begin as masses of cartilage that are later replaced by bone tissue
What is involved Intramembranous Ossification?
- Bones originate within sheetlike layers of connective tissues
- Broad, flat bones
- kull bones (except mandible)
- Intramembranous bones