BIOL 235 Midterm 1 Questions and Answers
(Updated Study Guide) 2026
• bone -✓✓organ made up of several different tissues working together
(bone tissue, cartilage, dense connective tissue, epithelium, adipose
tissue, nervous tissue)
• skeletal system -✓✓entire framework of bones and their cartilages
• basic functions of skeletal system -✓✓support [soft tissues, attachment
of tendons]
protect [important internal organs from injury]
assistance in movement
mineral homeostasis [storage and release]
blood cell production [red bone marrow]
triglyceride storage [yellow bone marrow]
• long bone -✓✓has greater length than width
• diaphysis -✓✓is the bone's shaft or body—the long, cylindrical, main
portion of the bone
• epiphyses -✓✓the proximal and distal ends of the bone
• metaphyses -✓✓the regions between the diaphysis and the epi- physes.
In a growing bone, each metaphysis contains an epiphyseal (growth)
plate, a layer of hyaline cartilage that allows the diaphysis of the bone to
grow in length
• epiphyseal line -✓✓the cartilage in the epiphyseal plate is replaced by
bone; the resulting bony structure is known as the ______
,• articular cartilage -✓✓thin layer of hyaline cartilage covering the part
of the epiphysis where the bone forms an articulation ( joint) with
another bone. Articular cartilage reduces friction and absorbs shock at
freely movable joints.
• periosteum -✓✓tough connective tissue sheath and its associated blood
supply that surrounds the bone surface wherever it is not covered by
articular cartilage. It is composed of an outer fibrous layer of dense
irregular connective tissue and an inner osteogenic layer that consists of
cells
• medullary cavity (aka marrow cavity) -✓✓hollow, cylindrical space
within the diaphysis that contains fatty yellow bone marrow and
numerous blood vessels in adults. This cavity minimizes the weight of
the bone by reducing the dense bony material where it is least needed
• osteoprogenitor cells -✓✓unspecialized bone stem cells derived from
mesenchyme, the tissue from which almost all connective tissues are
formed. They are the only bone cells to undergo cell division; the
resulting cells develop into osteoblasts. Osteoprogenitor cells are found
along the inner portion of the periosteum, in the endosteum, and in the
canals within bone that contain blood vessels
• osteoblasts -✓✓bone-building cells. They synthesize and secrete
collagen fibers and other organic components needed to build the
extracellular matrix of bone tissue, and they initiate calcification
• osteocytes -✓✓mature bone cells, are the main cells in bone tissue and
maintain its daily metabolism, such as the exchange of nutrients and
wastes with the blood. Like osteoblasts, osteocytes do not undergo cell
division
• osteoclasts -✓✓huge cells derived from the fusion of as many as 50
monocytes (a type of white blood cell) and are concentrated in the
, endosteum. On the side of the cell that faces the bone surface, the
osteoclast's plasma membrane is deeply folded into a ruffled border.
Here the cell releases powerful lys- osomal enzymes and acids that
digest the protein and mineral com- ponents of the underlying
extracellular bone matrix
• compact bone tissue -✓✓the strongest form of bone tissue. It is found
beneath the periosteum of all bones and makes up the bulk of the
diaphyses of long bones. Com- pact bone tissue provides protection and
support and resists the stresses produced by weight and movement.
80% of skeleton
• osteons/haversian systems -✓✓repeating strucutural units in compact
bone tissue. Each osteon consists of concentric lamellae arranged around
an osteonic (haversian or central) canal
• concentric lamellae -✓✓circular plates of mineralized extracellular
matrix of increasing diameter, surrounding a small network of blood
vessels and nerves located in the central canal
resemble growth rings of trees
• lacunae (plural) -✓✓small spaces between concentric lamellae
containing osteocytes
• canaliculi -✓✓small channels radiating out from lacunae, contain
extracellular fluid, connect lacunae with one another
• interstitial lamellae -✓✓areas between neighboring osteons, also have
lacunae with os- teocytes and canaliculi. Interstitial lamellae are
fragments of older osteons that have been partially destroyed during
bone rebuilding or growth
• interosteonic (Volkmann's/perforating) canals -✓✓canals that penetrate
compact bone as patways fo blood vessels and nerves from periosteum
(Updated Study Guide) 2026
• bone -✓✓organ made up of several different tissues working together
(bone tissue, cartilage, dense connective tissue, epithelium, adipose
tissue, nervous tissue)
• skeletal system -✓✓entire framework of bones and their cartilages
• basic functions of skeletal system -✓✓support [soft tissues, attachment
of tendons]
protect [important internal organs from injury]
assistance in movement
mineral homeostasis [storage and release]
blood cell production [red bone marrow]
triglyceride storage [yellow bone marrow]
• long bone -✓✓has greater length than width
• diaphysis -✓✓is the bone's shaft or body—the long, cylindrical, main
portion of the bone
• epiphyses -✓✓the proximal and distal ends of the bone
• metaphyses -✓✓the regions between the diaphysis and the epi- physes.
In a growing bone, each metaphysis contains an epiphyseal (growth)
plate, a layer of hyaline cartilage that allows the diaphysis of the bone to
grow in length
• epiphyseal line -✓✓the cartilage in the epiphyseal plate is replaced by
bone; the resulting bony structure is known as the ______
,• articular cartilage -✓✓thin layer of hyaline cartilage covering the part
of the epiphysis where the bone forms an articulation ( joint) with
another bone. Articular cartilage reduces friction and absorbs shock at
freely movable joints.
• periosteum -✓✓tough connective tissue sheath and its associated blood
supply that surrounds the bone surface wherever it is not covered by
articular cartilage. It is composed of an outer fibrous layer of dense
irregular connective tissue and an inner osteogenic layer that consists of
cells
• medullary cavity (aka marrow cavity) -✓✓hollow, cylindrical space
within the diaphysis that contains fatty yellow bone marrow and
numerous blood vessels in adults. This cavity minimizes the weight of
the bone by reducing the dense bony material where it is least needed
• osteoprogenitor cells -✓✓unspecialized bone stem cells derived from
mesenchyme, the tissue from which almost all connective tissues are
formed. They are the only bone cells to undergo cell division; the
resulting cells develop into osteoblasts. Osteoprogenitor cells are found
along the inner portion of the periosteum, in the endosteum, and in the
canals within bone that contain blood vessels
• osteoblasts -✓✓bone-building cells. They synthesize and secrete
collagen fibers and other organic components needed to build the
extracellular matrix of bone tissue, and they initiate calcification
• osteocytes -✓✓mature bone cells, are the main cells in bone tissue and
maintain its daily metabolism, such as the exchange of nutrients and
wastes with the blood. Like osteoblasts, osteocytes do not undergo cell
division
• osteoclasts -✓✓huge cells derived from the fusion of as many as 50
monocytes (a type of white blood cell) and are concentrated in the
, endosteum. On the side of the cell that faces the bone surface, the
osteoclast's plasma membrane is deeply folded into a ruffled border.
Here the cell releases powerful lys- osomal enzymes and acids that
digest the protein and mineral com- ponents of the underlying
extracellular bone matrix
• compact bone tissue -✓✓the strongest form of bone tissue. It is found
beneath the periosteum of all bones and makes up the bulk of the
diaphyses of long bones. Com- pact bone tissue provides protection and
support and resists the stresses produced by weight and movement.
80% of skeleton
• osteons/haversian systems -✓✓repeating strucutural units in compact
bone tissue. Each osteon consists of concentric lamellae arranged around
an osteonic (haversian or central) canal
• concentric lamellae -✓✓circular plates of mineralized extracellular
matrix of increasing diameter, surrounding a small network of blood
vessels and nerves located in the central canal
resemble growth rings of trees
• lacunae (plural) -✓✓small spaces between concentric lamellae
containing osteocytes
• canaliculi -✓✓small channels radiating out from lacunae, contain
extracellular fluid, connect lacunae with one another
• interstitial lamellae -✓✓areas between neighboring osteons, also have
lacunae with os- teocytes and canaliculi. Interstitial lamellae are
fragments of older osteons that have been partially destroyed during
bone rebuilding or growth
• interosteonic (Volkmann's/perforating) canals -✓✓canals that penetrate
compact bone as patways fo blood vessels and nerves from periosteum
