Chapter 6: Bone Tissue Flashcards
how many important functions does the skeletal system have?
six
the skeletal system has six important functions:
1. Provides ________ by acting as a structural framework a point of attachment for tendons and ligaments.
2. _________ the internal organs (brain, chest, etc.).
3. Assist body ____________ (in conjunction with muscles).
4. Store and release salts of ________ and ______________.
5. Participate in _______ ____ ____________ (hematopoiesis)
6. Store ___________ in adipose cells of yellow marrow.
support, protect, movements, calcium, phosphorus, blood cell production, triglycerides
T/F: bone is a dynamic tissue – it is always remodeling (building up and breaking down).
true
a highly vascularized connective tissue with a hard mineralized extracellular matrix
bone
how many arrangements is bone found in in the body?
two
what two arrangements is bone found in in the body?
compact and spongy
T/F: the skeletal system is made up of one type of tissue.
false
also known as osseus tissue
bone
name the two major tissues of the skeletal system.
bone and cartilage
the skeletal system is associated with ___________, ________, and _______.
ligaments, tendons, joints
which is stronger: compact or spongy bone?
compact bone
bone that is good at providing protection and support
compact bone
compact bone forms the ____________ of long bones.
diaphysis
compact bone forms the _________ ______ of all bones.
external layer
bone that is lightweight and provides tissue support
spongy bone
give two other terms for spongy bone.
trabecular or cancellous bone
spongy bone forms much of the __________ and the __________ _______ of long bones.
epiphysis, medullary cavity
poorly vascularized, connective tissue with a matrix, composed of chondroitin sulfate and various fibers
cartilage
how many types of cartilage are there?
three
cartilage consisting of a gel-like ground substance and appears bluish white in the body, is found in the embryonic skeleton, at the end of bones, and in the nose and in respiratory structures; it is flexible, allows movement, provides support, and is usually surrounded by a perichondrium
hyaline cartilage
cartilage that is found in the pubic symphysis, invertebral discs, and menisci (cartilage pads) of the knee joint; it contains chondrocytes scattered among clearly visible bundles of collagen fibers
fibrous cartilage
cartilage that maintains the shape of organs such as the epiglottis of the larynx, auditory tubes, and external ear; its chondrocytes are located within a threadlike network of elastic fibers, and it has a perichondrium
elastic cartilage
how many types of cells does bone contain?
four
what are the four types of bone cells?
osteoprogenitor cells, osteoplast, osteocytes, osteoclasts
bone stem cells able to differentiate into other types of cells
osteoprogenitor cells
bone building cells that synthesize and secrete, collagen, fibers and other organic components
osteoblasts
mature osteoblasts (maintenance)
osteocytes
bone cells that remodel bones and cause them to release calcium through a process called bone resorption
osteoclasts
the removal of minerals and collagen fibers from bone by osteoclasts
bone resorption
besides bone and cartilage, the skeletal system contains other important tissues. name four of them.
epithelium (endothelium (form capillary walls)) nerves (periosteum, especially tender), red marrow (hematopoiesis), yellow marrow (fat storage)
what percentage of bone is made of water?
25%
what percentage of bone is made of organic proteins?
25%
what percentage of mineral salts (hydroxyapatite crystals) is bone made of?
50%
what is the organic constituent of bone?
collagen fibers
in bone, collagen, fibers provide _________ and _______ _________.
flexibility, tensile strength
name the inorganic constituents of bone.
calcium phosphate, calcium carbonate (both hydroxyapatite crystals), magnesium, fluoride, sulfate
name the nine parts of a long bone.
diaphysis, epiphyses (2), metaphyses (2), articular cartilage, periosteum, medullary cavity, endosteum
bone shaft
diaphysis
both ends of the bone at the joints
epiphyses
region between diaphysis and epiphysis
metaphyses
cartilage covering both epiphyses
articular cartilage
connective tissue surrounding the diaphysis
periosteum
hollow space within diaphysis
medullary cavity
thin membrane lining the medullary cavity
endosteum
a space within the diaphysis of the long bones that contains fatty yellow, bone marrow in adults
medullary cavity
a membrane that lines the medullary cavity
endosteum
the endosteum is composed of ______, ___________ connective tissue and contains ____________ and ____________.
dense, irregular, osteoclasts, osteoblasts
thin layer of hyaline cartilage covering the epiphysis of bones
articular cartilage
found where the bone forms in articular (joint) surface – where one bone moves against another bone
articular cartilage
a dense a regular connective tissue membrane that surrounds cartilage
perichondrium
cells that form cartilage
chondrocytes
T/F: many of the major bones are formed from cartilage (the remainder do not go through a cartilaginous stage).
true
tough sheath of dense, irregular, connective tissue on the outside of the bone
periosteum
the periosteum contains one of the four types of bone cells….which one does it contain?
osteoblasts
the periosteum contains one of the four types of bone cells….which one does it contain?
osteoblasts
bone cells that help the bone grow in thickness (oppositional growth), but not in length
osteoblasts
the periosteum also assists with _________ _______ and serves as an attachment point for ________ and ____________.
fracture repair, tendons, ligaments
layer of hyaline cartilage in the metaphysis of a growing bone that consists of 4 zones
epiphyseal growth plate
in adolescents, through the end of active growth, the epiphysis of the long bones contains hyaline cartilage and forms an ___________ ______ ______.
epiphyseal growth plate
the growth plate is always actively dividing and causing the bone to ________ from each end.
elongate
T/F: in adults, the epiphyseal cartilage is no longer present, and elongation of bones has stopped
true
the calcified bone that replaces the cartilage/epiphyseal growth plate in adults
epiphyseal line
the epiphyseal line is visible __________ and on __-____.
externally, x-rays
T/F: compact bone contains calls osteons.
true
T/F: compact bone contains units called osteons.
true
the basic unit of structure in adult compact bone, consisting of a central canal with its concentrically arranged bone lamellae, bone lacunae, osteocytes, and bone canaliculi; also called a haversian system
osteons
circular plates of mineralized/calcified extracellular matrix of increasing diameter, surrounding a small network of blood vessels and nerves located in the osteonic canal
concentric bone lamellae
fragments of older osteons that have been partially destroyed during bone rebuilding or growth
interstitial bone lamellae
the circumferential bone lamellae that line the medullary cavity
inner circumferential lamellae
the circumferential bone lamellae directly deep to the periosteum
outer circumferential lamellae
small spaces between the lamellae which house osteocytes
lacunae
small channels filled with extracellular fluid connecting the lacunae
canaliculi
blood and lymphatic vessels are found in the _______ ________ ______.
osteon’s central canal
a minute passageway by means of which blood vessels and nerves from the periosteum penetrate into compact bone
volkmann’s canals
do spongy bones have osteons?
no
irregular latticework of thin plates of spongy bone tissue; fibrous cord of connective tissue serving as supporting fiber by forming a septum extending into an organ from its wall or capsule
trabeculae
trabeculae of spongy bone support and protect the ____ _____ _______ and are oriented along lines of stress (helps bones resist stresses without breaking)
red bone marrow
T/F: hematopoiesis (blood cell production)occurs in spongy bone
true
within each trabecula of spongy bone are _________.
lacunae
as in compact bone, _______ contain osteocytes that nourish the mature bone tissue from the blood circulating through the trabeculae.
lacunae
the interior of long bones is made up primarily of
_______ bone.
spongy
the use of spongy bone lessens overall bone _______.
weight
periosteal veins are accompanied by __________ _____.
periosteal arteries
the use of spongy bone lessens overall bone weight
periosteal arteries
periosteal arteries (accompanied by nerves) enter the diaphysis through __________ ______.
Volkmann’s canals
enters the center of the diaphysis through a nutrient
foramen
nutrient artery
hole in which the nutrient artery enters and they nutrient vein exits
nutrient foramen
the __________ and _________ also have their own arteries and veins.
metaphyses, epiphyses
accompany the blood vessels (this is often the case) in bone
nerves
the periosteum is rich in ________ ______, and is therefore, sensitive to tearing or tension
sensory nerves
the process of forming new bone
ossification or osteogenesis
bone formation occurs in four situations:
* Formation of bone in an ________
* Growth of bones until ___________
* Remodeling of ______
* Repair of __________
embryo, adulthood, remodeling, fractures
how many different methods can ossification occur through? name them.
two. intra-membranous and endochondral
ossification begins around the ___ ______ ___ _________ __________
6th week of embryonic development
ossification that produces spongy bone that may subsequently be remodeled to form compact bone
intra-membranous ossification
ossification whereby cartilage is replaced by bone; forms both compact and spongy bone
endochondral ossification
which method of ossification is simpler?
intra-membranous ossification
method of ossification that is used in forming all bones of the skill and the clavicle
intra-membranous ossification
with intra-membranous ossification, bone forms from ___________ _____ that develop within a membrane – without going through a cartilage stag
mesenchymal cells
T/F: intra-membranous ossification has many ossification centers.
false
the method of ossification that is used in the formation of most bones, especially long bones
endochondral ossification
endochondral ossification involves the replacement of _______.
cartilage
how many primary centers of growth come with endochondral ossification? how many primary centers of growth come with endochondral ossification?
one primary and two secondary
growth from within, as in the growth of cartilage; also called endogenous growth.
interstitial growth
how many major events does growth in length of long bones involve?
two
the growth in length of long bones involves two major events:
1. growth of ________ ___ ____ ___________ ______
2. replacement of cartilage by _____ ______ in the epiphyseal plate
cartilage on the epiphyseal plate, bone tissue
name the four zones of the epiphyseal growth plate.
resting cartilage, proliferating cartilage, hypertrophic cartilage, calcified cartilage
zone where the cells do not function in bone growth, they anchor the epiphyseal plate to the epiphysis of long bone.
zone of resting cartilage
zone where slightly larger chondrocytes arranged like stacks of coin
zone of proliferating cartilage
with the zone of proliferating cartilage, the chondrocytes undergo interstitial growth as they ______ and _______ ____________ ______.
divide, secrete extracellular matrix
zone that consists of large maturing chondrocytes arranged in columns
zone of hypertrophic cartilage
zone responsible for the transition from cartilage to bone
zone of calcified cartilage
in the zone of calcified cartilage, lysis of _____________ & ____________ begin in order to lay down matrix.
chondrocytes, osteoblasts
this zone becomes ‘new diaphysis’ that is firmly attached to the rest of the diaphysis.
zone of calcified cartilage
____________ dissolve the calcified cartilage, and ____________ invade the area, laying down bone matrix
osteoclasts osteoblasts
the activity of the epiphyseal plate is the way bone can increase in length.
epiphyseal plate
results in adults when the epiphyseal plates close and bone replaces all the cartilage
epiphyseal line
bones grow in thickness at the outer surface by ____________ ______.
appositional growth
T/F: bone forms before birth and continually renews itself.
true
name the two methods by which the ongoing replacement of old bone tissue by new bone tissue can occur.
bone deposition and bone resorption
the addition of minerals & collagen fibers to bone by osteoblasts
bone deposition
removal of minerals & collagen fibers from bone
by osteoclasts
bone resorption
T/F: old bone is never destroyed, therefore there’s no need for new bone to form throughout an individual’s life
false
as osteoblasts deposit _____ on the outer surface,
osteoclasts widen the __________ ______ from within (bone formation)
bone, medullary cavity
what age is ossification contributing to bone length usually complete by?
18-21 years
T/F: bones can still continue to thicken and are capable of repair even after the epiphyseal growth plates have closed.
true
a balance must exist between the actions of __________ and ___________.
osteoclasts, osteoblasts
if too much new tissue is formed, the bones become abnormally _____ and _______.
thick, heavy
if too much new tissue is formed, a person can develop one of two conditions…name them.
acromegaly and gigantism
occurs after closing of the epiphyseal plate
acromegaly
occurs before the closing of the plate
gigantism
excessive calcium loss weakens the bones, as occurs in ___________ (especially women in menopause).
osteoporosis
a vitamin d deficiency may cause bones to become too “soft”, as seen in the bone diseases, _______ and ____________
rickets, osteomalacia
name the three factors affecting bone growth.
minerals, vitamins, hormones
bone contains large amounts of _________ and _____________. additionally, smaller amounts of ____________, ________, and ____________ are required for bone growth and remodeling
calcium, phosphorus, magnesium, fluoride, manganese
vitamin that stimulates activity of osteoblasts
A
vitamin that is needed for synthesis of collagen
C
vitamin that is essential to healthy bones because it promotes the absorption of calcium from foods in the gastrointestinal tract into the blood
D
active form of vitamin D
calcitriol
vitamins needed for the synthesis of bone proteins
K and B12
hormones are key contributors to normal bone ____________.
metabolism
name the two hormones most important to bone growth during childhood.
human growth hormone and insulin-like growth factor
hormone secreted by the anterior lobe of the pituitary gland; promotes general growth of all body tissues, including bone, mainly by stimulating the production of insulin-like growth factors.
human growth hormone
hormone secreted by the liver, bones, and other tissues on stimulation by growth hormone; promotes normal bone growth by stimulating osteoblasts and by increasing the synthesis of proteins needed to build new bone
insulin-like growth factor
secreted by thyroid gland; promote normal bone growth by stimulating osteoblasts
thyroid hormones
secreted by the pancreas; promotes normal bone growth by increasing the synthesis of bone proteins
insulin
name the two sex hormones responsible for affecting bone growth.
estorgen and testosterone
sex hormone secreted by the ovaries in women
estrogen
sex hormone secreted by the testes in men
testosterone
sex hormones stimulate the osteoblasts and promote the sudden “_______ _____” that occurs during the teenage years
growth spurt
sex hormones shut down growth at the ___________ _______ around age 18–21, causing lengthwise growth of bone to end
epiphyseal plates
sex hormones contribute to bone remodeling during adulthood by slowing bone __________ by osteoclasts and promoting bone __________ by osteoblasts.
resorption, deposition
hormone secreted by the parathyroid glands that promotes bone resorption by osteoclasts, enhances recovery of calcium ions from urine, and promotes formation of the active form of vitamin D (calcitriol)
parathyroid hormone (PTH)
hormone secreted by the thyroid gland that inhibits bone resorption by osteoclasts
calcitonin (thyrocalcitonin)
PTH stimulates osteoclastic activity and raises serum _______ levels.
calcium
T/F: calcitonin (thyrocalcitonin), and to a lesser extent hGH and the sex hormones, stimulate osteoblastic activity and lower serum calcium level
true
Vitamin D is needed for the absorption of the ____ and _____ ions from the small intestine, and reabsorption of those same ions in the kidneys
Ca2+, PO4–
bones store ____ of the body’s calcium.
99%
the parathyroid gland secretes parathyroid
hormone (PTH) when _______ levels drop.
calcium
___________ are stimulated to increase bone
resorption and calcium is released. PTH also stimulates the production of ________ by the kidneys to increase calcium absorption in the intestines.
osteoclasts, calcitriol
when broken ends of the bone protrude through the skin
open (compound) fracture
when broken ends of a bone do not break the skin
closed (simple) fracture
the bone is splintered, crushed, or broken into pieces at the site of impact, and smaller bone fragments lie between the two main fragments
comminuted fracture
partial fracture in which one side of the bone is broken and the other side bends, similar to the way a green twig breaks on one side while the other side stays whole, but bends; occurs only in children, whose bones are not fully ossified and contain more organic material than inorganic material
greenstick fracture
fracture that is all the way through the bone
complete fracture
fracture where one part is shoved up into the another
impacted fracture
type of broken bone that twists around your bone and looks like a corkscrew
spiral fracture
type of broken bone that runs horizontally perpendicular to your bone
transverse fracture
when the pieces of bone move so much that a gap forms around the fracture when your bone breaks
displaced fracture
means the pieces of your bone moved so much that a gap formed around the fracture when your bone broke
Pott fracture
fracture of the distal end of the lateral forearm bone (radius) in which the distal fragment is displaced posteriorly.
Colles fracture
the vertebral body of one or more vertebrae fractures and becomes compressed into a wedge-shape. May be caused by injury, trauma, or more commonly in individuals with osteoporosis.
vertebral compression fracture
a break in a bone
fracture
the healing process of a fracture involves __ different phases in __ steps.
3, 4
name the three phases of fracture repair.
reactive, reparative, bone remodeling
name the four steps of fracture repair.
fracture hematoma forms (reactive), fibrous cartilage forms (reparative), bony callus forms (reparative), bone remodeling
an early inflammatory phase of fracture repair
reactive phase
phase that includes the formation of a fibrocartilaginous callus first and a bony callus second
reparative phase
the last phase of fracture repair
bone remodeling phase
under mechanical stress, bone tissue becomes stronger through deposition of ________ ____ and production of ________ _____ by osteoblasts. unstressed bones, on the other hand, become weaker
mineral salts, collagen fibers
astronauts in space suffer rapid loss of bone densit
bone density
the main mechanical stresses on bone are those that result from the pull of ________ _______ and the pull of _______ (weight-bearing activities)
skeletal muscles, gravity
from birth through __________, more bone is produced than is lost during remodeling. in adults, the rates are the same.
adolescence
older individuals, especially post-menopausal women, experience a decrease in _____ ____ when resorption outpaces deposition.
bone mass
a decrease in bone mass occurs as the level of ____ _________ diminishes during middle age (especially in women after menopause). bone resorption by osteoclasts outpaces bone deposition by osteoblasts.
since female bones are generally smaller and less massive than males to begin with, old age has a greater adverse effect in females.
sex hormones
what are the two principal effects of aging on bone tissue?
loss of bone mass and brittleness
the loss of calcium from bones is one of the symptoms in ____________.
osteoporosis
collagen fibers give bone its tensile strength, and ________ _________ decreases with age. the loss of tensile strength causes the bones to become very brittle and susceptible to fracture.
protein synthesis
a condition where bone resorption outpaces formation and 80% of those affected are women
osteoporosis
name the two conditions that can occur due to inadequate calcification of extracellular bone matrix
rickets and osteomalacia
condition that affects children and leads to bowed legs and deformations in skull, rib cage, or pelvis
rickets
condition that affects adults and causes painful/tender bones and fractures with minor trauma
osteomalacia
degeneration of articular cartilage, leads to friction of bone against bone
osteoarthritis
infection of bone often caused by Staphylococcus aureus
osteomyelitis
condition where the reduced bone mass below normal
osteopenia
bone cancer that primarily affects osteoblast
osteosarcoma
