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73 Cards in this Set

  • Front
  • Back
6 functions of bone tissue and skeletal system
Assistance in movement
Mineral homeostasis
Blood cell production
Triglyceride storage
In certain bones, a connective tissue called ____________ produces red blood cells, white blood cells, and platelets, a process called _________
Red bone marrow

Triglycerides stored in adipose tissue of ___________ is an important chemical energy reserve.
Yellow bone marrow
In the newborn, all bone marrow is ______ and involved in ________

bone shaft or body. Long, cylindrical main portion of bone
distal and proximal ends of bone
regions in a mature bone where diaphysis joins the epiphysis.
In growing bone, each metaphysis includes an ____________, a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length
epiphyseal plate
When bone growth in length stops, the cartilage in epiphyseal plate is replaced by bone a becomes the ____________
epiphyseal line
thin layer of hyaline cartilage covering epiphysis where bone forms articulation with another bone
articular cartilage
tough sheath of dense regular connective tissue that surrounds bone surface when it is not covered by articular cartilage
space within the diaphysis that contains fatty yellow bone marrow in adults.
medullary OR marrow cavity
thin membrane that lines medullary cavity. Contains single layer of bone forming cells and small amount of connective tissue
Bone matrix is about 25%_____, 25%_____, and 50% ________
25% water

25% collagen fibers

50% crystallized mineral salts
process of mineral salts being deposited in framework formed by collagen fibers of the matrix
The combination of _________ and ____________ is responsible for the hardness of bone
crystallized salts

collagen fibers
A bones hardness depends on ____________, a bone's flexibility depends on _____________
crystallized inorganic mineral salts

collagen fibers
4 types of cells in bone tissue



unspecialized stem cells derived from mesenchyme, only bone cells to undergo cell division
osteogenic cells
After cell division, daughter cells of osteogenic cells develop into
synthesize and secrete collagen fibers and other organic components needed to build the matrix of bone tissue, and they initiate calcification.
As osteoblasts surround themselves with matrix, they get trapped in their secretions and become _______
main cells of bone tissue and maitain it's daily metabolism, such as exchange of nutrients and waste with the blood. Do Not undergo cell division
derived from fusion of as many as 50 monocytes, concentrated in endosteum, plasma membrane that faces the bone surface is folded into a ruffled border, release powerful lysosomal enzymes and acids that break down bone
The breakdown of bone matrix by osteoclasts is called _____
About 80% of skeleton is ____ bone and 20% is ____ bone

forms external layer of all bones and bulk of diaphysis of long bones, arranged in units called osteons or Haversian systems
compact bone tissue
blood vessels, lymphatic vessels, and nerves from the periosteum penetrate the compact bone through transverse _________
perforating (Volkmann's) canals
concentric rings of hard, calcified matrix found in compact bone, surround the central (Haversian) canals
concentric lamellae
between the lamellae are small spaces called _______, which contain osteocytes
lacunae (little lakes)
Radiating in all directions from the lacunae are tiny _________, which are filled with ECF.
Canaliculi (small channels)
Inside the canaliculi are slender fingerlike processes of _________. Neighboring osteocytes communicate via ___________

gap junctions
Osteons in compact bone tissue are aligned in the same direction along __________
lines of stress
Lines of stress in bone are not _______. They change over time in response to _________

physical stress
The areas between osteons contain _________, which also have lacunae with osteocytes and canaliculi
interstitial lamellae
Lamellae that encircle the bone just beneath the periosteum are called _______, and lamellae that encircle the medullary cavity are ______
outer circumferential lamellae

inner circumferential lamellae
bone that does not contain osteons, consist of irregular latticework of thin columns of bone called _______
spongy bone

______ bone tissue makes up most of the bone tissue of short, flat, and irregularly shaped bones.
The spongy bone tissue of hip bones, ribs, breastbone, backbones, and the ends of long bones is the only site of ________ in adults
Near center of the epiphysis, a large nutrient artery passes through a hole in compact bone called the _____________
nutrient foramen
One or two _______ accompany nutrient artery in diaphysis, numerous ______ and ______ exit with their respective arteries in the epiphysis, and many small _____ exit with arteries in the periosteum
nutrient veins

epiphyseal and metaphyseal

The process by which a bone forms is called ______ or ______
ossification OR osteogenesis
2 methods of bone formation
endochondral ossification

intramembranous ossification
method of bone formation that occurs directly on or within loose fibrous connective tissue membranes
Intramembranous ossification
Replacement of cartilage by bone
endochondral ossification
4 phases of intramembranous ossification
Development of center of ossification- osteoblast secrete matrix

Calcification of the matrix

Formation of trabeculae

Development of the periosteum
Connective tissue that is associated with the blood vessels in trabeculae differentiates into ____
red bone marrow
Bones that develop by intramembranous ossification
flat bones of skull, mandibles, soft spots
5 stages of endochondral ossification
Development of cartilage model- chondroblasts produce hyaline cartilage model

growth of cartilage model- chondrocytes hypertrophy, burst, increase of pH triggers calcification

Development of primary ossification center

Development of secondary ossification center

Formation of articular cartilage and epiphyseal plate
Interstitial growth results in _____ of bone, whereas ______ results in increase of thickness

appositional growth
Once perichondrium starts to form bone it is called ____
_____ is a layer of hyaline cartilage in the metaphysis of a growing bone
epiphyseal plate
4 zones of epiphyseal plate that increases bone length
Zone of resting cartilage- cells anchor epiphyseal plate to epiphysis

Zone of proliferating cartilage- chondrocytes divide to replace.

Zone of hypertrophic cartilage- lengthening results from cell divisions in proliferating zone and maturation of cells in hypertrophic zone

Zone of calcified cartilage- calcified cartilage is replaced by bone
The diaphysis of a bone increases in length bc of activity of the _____
epiphyseal plate
The epiphyseal plates close at around ___ - ___ years of age
When the epiphyseal plate fades, it leaves a bony structure known as ____
epiphyseal line
Bone grows in thickness due to addition of new bone tissue by _____ around the outer surface of a bone. Known as ____ growth
periosteal osteoblasts

appostional growth
Sex steroids, especially ______ shut down growth at the epiphyseal plates
During childhood, the most important hormones that stimulate bone growth are ____ and ____
IGF- insulinlike growth factor

hGH- human growth hormone
ongoing process where osteoclasts carve out tunnels in old bone and osteoblasts rebuild it. Can take only 2 to 3 months, or last much longer
bone remodeling
The breakdown of matrix by osteoclasts is
bone resorption
One way that estrogens slow resorption of bone is by promoting ______ of osteoclasts
apoptosis (programmed death)
series of microscopic fissures in bone that forms without any evidence of injury to other tissues. Standard x-rays normally fail to reveal, but show clearly in bone scan
stress Fx.
5 steps of repair of a bone Fx
Formation of Fx hematoma- blood clots, blood capillaries grow, phagocytosis cleans up debris

Fibrocartilaginous callus formation- repair tissue that bridges the broken ends of the bone. Takes about 3 weeks

Bony callus formation- osteogenic cells develop into osteoblasts. Fibrocartilage converted into spongy bone

Bone remodeling- dead portions of bone are resorbed by osteoclasts. Compact bone replaces spongy bone
For bones to unite, the ends of the Fx bone must be brought into alignment, a process known as _____
Bone id body's major calcium reservoir, storing ___% of body calcium
The most important hormone that regulates calcium exchange between bone and blood is ____, secreted by ______
PTH (parathyroid hormone)

parathyroid gland
If blood Ca decreases, parathyroid gland cells detect the change and increase production of _______. The gene for PTH in _________ cell detects increased production of _____, resulting in increased _____ being released into the blood. The presence of more ____ increases number and activity of ______, which liberates Ca to move into blood and increase levels to normal.
cAMP (cyclic adenosine monophosphate)

parathyroid gland cell




_____ acts on the kidneys to decrease loss of Ca in urine, and stimulates formation of ______, a hormone that promotes absorption of Ca from GI tract.
PTH (parathyroid hormone)

When blood Ca rises above normal, parafollicular cells in thyroid gland secrete _____.
_____ inhibits activity of osteoclasts, speeds up Ca uptake by bones, and accelerates Ca deposition into bones
calcitonin (CT)

During middle of fourth week of development upper limbs appear as small elevations called ______. End of fourth week _______ appear. The ______ consist of masses of general mesoderm covered by ________.
upper limb buds

lower limb buds

limb buds

About 22 to 24 days after fertilization, mesodermal cells form a solid cylinder of cells called the ______, which plays a critical role in inducing, through chemical signals, __________ cells to develop into specialized tissues and organs.

unspecialized embryonic cells
loss of calcium and other minerals from bone matrix