NCSU BIO 240 Midterm Klesath exam with
complete solutions
Bones - ANSWER--primary organs of the skeletal system
-provides framework of body and attachment site for muscles
Cartilage - ANSWER--component of embryonic, growing, mature bones and joints
-hyaline cartilage is predominant type
Connective Tissue - ANSWER--bone and cartilage outer membrane
-ligaments connect bones, tendons connect muscle to bone
Osteoprogenitor cells - ANSWER-STEM CELLS
-derived by mesenchyme
-found in bone membranes
-these develop into osteoblasts
osteoblasts - ANSWER-MAKE OSTEOID
-found in bone membranes
-secretes osteoid (collagen)
osteocytes - ANSWER-mature bone cells, have spider like extensions
-maintain matrix, monitor stress, allow for communication between different cells in
tissue
-present in, and surrounded by, bone tissue
osteoclasts - ANSWER-big cells that BREAK DOWN MATRIX
-formed by fusing bone marrow cells
-digests all components of matrix (organic and inorganic)
,-calcium is freed from matrix that can then be added to bone
organic bone composition - ANSWER-COLLAGEN
-gives bone tensile strength by resisting stretching, contributes to bone flexibility, can
respond to pressure being place on it
inorganic bone composition - ANSWER-CALCIUM AND PHOSPHATE
-deposited around collagen fibers
-accounts for rigidity of bones
Bone deposition - ANSWER-osteoblasts lay down osteoid and add bone tissue,
secretes collagen fibers after collagen framework is there mineralization occurs (lay
down calcium and phosphate between highly organized collagen)
Bone resorption - ANSWER-Process of osteoclasts breaking down bone, collagen is
broken down (organic portion) by proteolytic enzymes. Calcium and phosphate
(inorganic portions) broken down by hydrochloric acid, which frees these into the blood,
therefore increasing blood levels of calcium and phosphate
Structural unit of compact bone? - ANSWER-osteon
Structural unit of spongy bone? - ANSWER-trabeculae
Compact Bone - ANSWER-located at bone exterior
-appears white, smooth, and solid
-10% of surface area, 80% of bone mass
osteon - ANSWER-functional unit of compact bone composed of concentric lamellae
and a central canal
External concentric lamellae - ANSWER-rings of compact bone that surround the entire
outer compact bone surface; found immediately internal to bone periosteum
Interstitial lamellae - ANSWER-compact bone remains of a partially resorbed osteon
found between newer, complete osteons
, internal circumferential lamellae - ANSWER-Rings of compact bone that line the inner
edge of compact bone tissue, found immediately internal to the endosteum
Central (Haversian) Canal - ANSWER-opening in the center of an osteon, carries blood
vessels and nerves
nutrient foramen - ANSWER-opening in compact bone where vessels and nerves enter
and exit through the periosteum
perforating canals - ANSWER-structures through which blood vessels enter and exit the
bone shaft.
Osteon structure - ANSWER--each osteon contains multiple layers of concentric
lamellae surrounding the central canal
-each lamellae is composed of inorganic crystals deposited between collagen fibers
-within each concentric lamellae the collagen fibers are parallel
-90 degrees from collagen fibers in adjacent lamellae
Osteocytes - ANSWER--osteoblasts surrounded by bone matrix become osteocytes
-osteocytes are located between concentric lamellae
-the osteocyte cell body is housed in small open spaces called lacunae
-cellular processes extend from osteocyte cell body and travel within then concentric
lamellae through thin, small spaced called canaliculi
Arrangement of osteocytes - ANSWER--innermost layer of osteocytes extend cellular
processes to the central canal blood supply
-these osteocytes connect to adjacent osteocytes through extensions by gap junctions
found at their cellular processes
-nutrients and minerals are shared from cell to cell through this system which also
allows for cellular communication within the osteon
periosteum - ANSWER-a double layer sheath that covers and protects outer surface of
compact bone
Perforating (Sharpey's) fibers - ANSWER-Tufts of collagen that fuse the periosteum to
the outer compact bone layer
complete solutions
Bones - ANSWER--primary organs of the skeletal system
-provides framework of body and attachment site for muscles
Cartilage - ANSWER--component of embryonic, growing, mature bones and joints
-hyaline cartilage is predominant type
Connective Tissue - ANSWER--bone and cartilage outer membrane
-ligaments connect bones, tendons connect muscle to bone
Osteoprogenitor cells - ANSWER-STEM CELLS
-derived by mesenchyme
-found in bone membranes
-these develop into osteoblasts
osteoblasts - ANSWER-MAKE OSTEOID
-found in bone membranes
-secretes osteoid (collagen)
osteocytes - ANSWER-mature bone cells, have spider like extensions
-maintain matrix, monitor stress, allow for communication between different cells in
tissue
-present in, and surrounded by, bone tissue
osteoclasts - ANSWER-big cells that BREAK DOWN MATRIX
-formed by fusing bone marrow cells
-digests all components of matrix (organic and inorganic)
,-calcium is freed from matrix that can then be added to bone
organic bone composition - ANSWER-COLLAGEN
-gives bone tensile strength by resisting stretching, contributes to bone flexibility, can
respond to pressure being place on it
inorganic bone composition - ANSWER-CALCIUM AND PHOSPHATE
-deposited around collagen fibers
-accounts for rigidity of bones
Bone deposition - ANSWER-osteoblasts lay down osteoid and add bone tissue,
secretes collagen fibers after collagen framework is there mineralization occurs (lay
down calcium and phosphate between highly organized collagen)
Bone resorption - ANSWER-Process of osteoclasts breaking down bone, collagen is
broken down (organic portion) by proteolytic enzymes. Calcium and phosphate
(inorganic portions) broken down by hydrochloric acid, which frees these into the blood,
therefore increasing blood levels of calcium and phosphate
Structural unit of compact bone? - ANSWER-osteon
Structural unit of spongy bone? - ANSWER-trabeculae
Compact Bone - ANSWER-located at bone exterior
-appears white, smooth, and solid
-10% of surface area, 80% of bone mass
osteon - ANSWER-functional unit of compact bone composed of concentric lamellae
and a central canal
External concentric lamellae - ANSWER-rings of compact bone that surround the entire
outer compact bone surface; found immediately internal to bone periosteum
Interstitial lamellae - ANSWER-compact bone remains of a partially resorbed osteon
found between newer, complete osteons
, internal circumferential lamellae - ANSWER-Rings of compact bone that line the inner
edge of compact bone tissue, found immediately internal to the endosteum
Central (Haversian) Canal - ANSWER-opening in the center of an osteon, carries blood
vessels and nerves
nutrient foramen - ANSWER-opening in compact bone where vessels and nerves enter
and exit through the periosteum
perforating canals - ANSWER-structures through which blood vessels enter and exit the
bone shaft.
Osteon structure - ANSWER--each osteon contains multiple layers of concentric
lamellae surrounding the central canal
-each lamellae is composed of inorganic crystals deposited between collagen fibers
-within each concentric lamellae the collagen fibers are parallel
-90 degrees from collagen fibers in adjacent lamellae
Osteocytes - ANSWER--osteoblasts surrounded by bone matrix become osteocytes
-osteocytes are located between concentric lamellae
-the osteocyte cell body is housed in small open spaces called lacunae
-cellular processes extend from osteocyte cell body and travel within then concentric
lamellae through thin, small spaced called canaliculi
Arrangement of osteocytes - ANSWER--innermost layer of osteocytes extend cellular
processes to the central canal blood supply
-these osteocytes connect to adjacent osteocytes through extensions by gap junctions
found at their cellular processes
-nutrients and minerals are shared from cell to cell through this system which also
allows for cellular communication within the osteon
periosteum - ANSWER-a double layer sheath that covers and protects outer surface of
compact bone
Perforating (Sharpey's) fibers - ANSWER-Tufts of collagen that fuse the periosteum to
the outer compact bone layer
