Bones and Skeletal Tissue Flashcards
what is the process of cartilage becoming bone called
ossification
what is skeletal cartilage made of
highly resiliant, molded cartilage tissue that consists primarily of water
what does skeletal cartilage eventually turn into
bone
is skeletal cartilage vascular or avascular
avascular
is skeletal cartilage innervated or not
not innervated
what is perichondrium
a layer of dense connective tissue that surrounds cartilage
what are the 2 purposes of perichondrium
- helps cartilage resist outward expansion
- helps cartilage getoxygen and nutrients through blood vessels
what is cartilage made of
chondrocytes
what are chondrocytes
cells encased in cavities (lacunae) within jelly-like extracellular matrix
when born, what is the human skeleton made of
cartilage
does all cartilage turn to bone
no, only in places that do not require flexibility
what is the most abundant type of cartilage
hyaline cartilage
what is the purpose of hyaline cartilage
support, flexibility, and resiliance
what kind of fibers are hyaline cartilag made of
collgen fibers
where can you find hyaline cartilage
- connects the ribs to the sternum
- the tip of the nose
what kind of fibers is elastic cartilage made of
elastic fibers
where can you find elastic cartilage
- external ear
- epiglottis
what is the epiglottis
what directs food into the esophagus, rather than into the lungs
how does the epigotis prevent food from going into the lungs
it is a flap that covers the glotis (the opening to the tranchea)
what kind of fibers is fibrocartilage made of
thick collagn fibers
where can you find fibrocartilage
- vertebral discs
- menisci of knee
because fibrocartilage is made of thick collagen fibers it has… (strength)
great tensile strength
what are the two ways cartilage grows
- appositional growth
- interstitial growth
in what direction does appositional growth expand the cartilage
widening it
in what direction does interstitial growth expand the cartilage
lengthening it
what is the calcification of cartilage
the deposition of calcium into cartilage
what is calcification a synonym for
ossification
how does appositial growth work
cartilage forming cells deposit matrix on the pheriphery (edge of cartilage)
how does interstitial growth work
chondrocytes in the lacunae divide and secrete the new matrix
what are the 7 important function of bones
- support
- protection
- movement
- mineral and growth factor storage
- form blood cells
- triglyceride (fat) storage
- hormone protection
what do bones support
- the body
- soft organs
what do bones protect
- brain
- spinal cord
- vital organs
how do bones help with movement
they are levers for muscle action
what minerals do bones store
- calcium
- phosphorus
- growth factors
how are blood cells formed in the bones
hematopoiesis occurs in red bone marrow cavities of certain bones
what is the purpos of fat storage in the bones and where is it stored
fat is used for enery and found in yellow bone marrow
how many bones are in the human skeleton
206
what are the 2 groups the human skeleton is divided into
- axial skeleton
- appendicular skeleton
what is the axial skeleton group
the long axis of the body
what bones are found in the axial skeleton group
- skull
- vertebral column
- rib cage
what is the appendiculr skeletal group
upper and lower limbs
what is a girdle
a set of bones that attach
how are limbs of the appendicular skeleton group attachd to the axial skeleton group
girdles
what are the 4 different bone shapes
- long bones
- short bones
- flat bones
- irregular bones
what shape are long bones
longer than they are wide
what bones in the body are long bones
limbs
what shape are short bones
cube-shaped
what bones in the body are short bones
wrist, ankle, and patella
what are sesamoid bones
short bones that form within tendons
what is an example of sesamoid short bones
the patella
does everyone have the same number of short bones
no, it is different in everyone
what is the shape of flat bones
thin, flat, slightly curved
what are examples of flat bones
- sternum
- scapulae
- ribs
- most skull bones
what shape are irregular bones
complicated shapes
what are examples of irregular bones
- vertebrae
- hip bones
why are bones considered organs
because they contain different types of tissues
what is bone tissue called
osseous
what are the 3 levels of bone structure
- gross
- microscopic
- chemical
what is the gross structure of bones
you can see it with your naked eye
what is the microscopic structure of bones
you can see it under a microscope
what is the chemical structure of bones
calcium phosphates
what is compact bone
the dense outer layer on every bone that appears smooth and solid
what is sponge bone
made up of a honeycomb of small, needle-like pieces of bone called trabeculae
what are the open spaces between trabeculae filled with
red or yellow bone marrow
what are the boney spines of spongey bone called
trabeculae
what is the structure of short, irregular, and flat bones
- one thin layer of spongey bone (dipole) covered by compact bone
- compact bone sandwiched between connective tissue membrane
- bone marrow scattered throughout spongey bone. no defined marrow cavity
- hyaline cartilage covers area of bone that is part of a movable joint
what are the thin plates of spongey bone in short, irregular, and flat bones called
diploe
what covers the outside of compact bone in short, irregular, and flat bones
the periosteum
what covers the inside portion of compact bone in short, irregular, and flat bones
endosteum
what 3 physical characteristics do all long bones have (gross anatomy)
- shaft (diaphysis)
- bone ends (epiphyses)
- membranes
what is the diaphysis of a long bone
tubular shaft that forms the long axis of a bone
what is the diaphysis of a long bone made of
compact bone surrounding central medulary cavity that is fulled with yellow marrow (in adults)
what is yellow bone marrow
fat tissue
what is the epiphyses of a long bone
the ends of a long bone. articular cartilage covers articular (joint) surface
what is the epiphyses of a long bone made of
compact bone externally and spongey bone internally
why do people get taller
their long bones get longer
what is between the diaphysis and epipysis (full grown adult)
the epiphyseal line
what is between the diaphysis and epipysis (still growing child)
epiphyeal plate
what occurs at the epiphyseal plate
bone growth
what is hematopoiesis
blood cell production (found in childern)
what characteristic is only found in long bones
a shaft
what are the 2 types of membranes found in bones
- periosteum
- endosteum
what are the characteristics of the periosteum membrane of bones
- outer membrane
- white
- double layer
- covers external surfces except joints
what is the osteogenic layer of the periosteum mebrane of the bone
the inner layer abutting bone and contains primative osteogni stem cells (bone generating cells)
what does the periosteum membrane of the bone contain
nerve filbers and blood vessels that continue on to the shaft through nutrient foramen opening
what does the endostenum membrane of the bone cover
the trabeculae of spongy bone
where can you find the endostenum mmbran of the bone
between compact bone and spongey bone (inner part of bone)
what quality do endostenum and periostenum membranes of the bone share
they both contain osteogenic cells that generate other types of bone cells
where can red bone marrow be found in adults
the heads of femur and humerus
in newborns, wher is red bone marrow found
in medullary cavities and all spongy bone
what happens to yellow bone marrow if the person bcomes anemic
it turns to red bone marrow
what are the 3 types of bone markings
- projection
- depression
- opening
what is a projection bone marking
an outward bulge of the bone
what causes a projection bone marking
increased stress from muscle pull or a modification for joint
what is an example of a projection bone marking
the head of the femur
what does a deprssion bone marking look like
a bowl or grove-like cutout
what is the purpose of depression bone markings
serve as a passageway for vessels and nerves or serves a role in joints
what is an example of a deprssion bone marking
where the femur meets the hip bone
what is an opening bone marking
a hole or canal in the bone
what is the purpose of an opening bone marking
serves as a passageway for blood vessels and nerves
what is an example of an opening bone marking
where the spinal cord meets the skull
what are the 5 major cells of bone tissue
- osteogenic cells
- osteoblasts
- osteocytes
- bone-lining cells
- osteoclasts
what is the stem cell for bones
osteogenic cells
what is another name for osteogenic cells
osteoprogenitor cells
where can you find osteogenic cells
in the periosteum and the endosteum
which of the major cells of bones are mitotically active
osteogenic cells and osteoblasts
what is the parent cell of most bone cells
osteogenic cells
all bone cells derive from osteogenic cells except…
osteoclasts
what is the purpose of osteoblasts
to form and deposit bone by secreting unmineralized bone matrix called osteoid
what is osteoid made of
collagen and calcium binding proteins
what makes up 90% of bone protein
collagen
what are osteocytes
mature bone cells in the lacunae that do not divide
what is the purpose of osteocytes
to maintain the bone matrix and act as stress or strain sensors as well as communicate information to osteoblasts and osteoclasts
osteocytes are not actively involved in…
depostion (making) or resorption (dstroying) of bone cells AKA bone remodeling
what is the purpose of bone-lining cells
help maitain the matrix
what are bone lining cells
flat cells on the bones surface (they line the bone)
what is it called when bone-lining cells are on the external bone surface
periosteal cells
what is it called when bone-lining cells are on the intrnal bone surface
endosteal cells
what are osteoclasts drived from
hematopietic stem cells that become macrophages (blood cells)
what is the structure of osteoclasts
giant, multinucleated cells with ruffled boarders
what is the purpose of an osteoclasts ruffled boarders
to increase surface area for enzyme degradation of bone
what is the purpose of osteoclasts
break down bone (resorption)
do osteaclasts or osteoblasts work first
osteoclasts
what is nother word for compact bone
lamellar bone
what does compact bone (lamellar bone) consist of
- osteon (haversian system)
- canals and canaliculi
- interstitial and circumferential lamellae
where are interstitial lamellae found
lodged between osteons
where are circumferential lamellae found
the circles that go all around the bone (not part of osteons)
what is an osteon
the structural unit of compact bone
what do osteon cylanders consist of
several rings of bone matrix called lamellae
osteon cylinders run _____ to the long axis of the bone
parallel
what do lamellae contain
collagen fibrs that run in different directions in adjacent rings
what do lamellae help to resist
stress and twisting
where are bone salths found
between collagen fibers
what is another word for the cetral canal of a bone
haversian canal
where do central canals run
through the core of the osteon
what does the central canal contain
blood vessels and nerve fibers
what is another work for perforating canals of the bone
volkmann’s canals
where do perforating canals run
perpendicular to the long axis of the bone
what are lacunae
small cavities that contain osteocytes
what are canaliculi
hairlike canals that connect lacunae to each other and to the center canal
how do osteoblasts maintain contact with eachother and osteocytes
projections
what kind of lamellae are not part of the osteon
interstitial lamellae
what are interstitial lamelae
they fill gaps between osteons OR are remnants of osteons cut by bone remodeling
what kind of lamellae helps long bones resist twisting
circumferential lamellae
where is circumferential lamellae
deep to periosteum but superficial to endosteum
what layers of lamellae extend around the entire surface of the diaphysis
circumferential lamellae
what kind of bone helps the bone to resist stress
spongey bone
what do trabeculae do to the bone
they confer strength to the bone
bone is made up of both _______ and ________ compounds
organic and inorganic
are organic compounds mineralized or not
non-mineralized
what bone cells are organic components
- osteogenic cells
- osteoblasts
- osteocytes
- bone-lining cells
- osteoclasts
- osteoids
what secretes osteoids
osteoblasts
what are osteoids made of
ground subtance and collagen fibers
what do osteoids provide the bone with
high tensile strength and flexibility
what causes the resiliance of bones
sacrificial bonds in or between collagen molecules
what is the purpose of sacraficial bonds
to be sacraficed in order to hlp protect the rest of the bone
what are inorganic comonents of bones
hydroxyapatites
what are hydroxyapatites
mineral salts
what do hydroxaptits (mineral salts) consist of
calcium phosphate crystals in and around collagen fibers
what are hydroxyapatites (mineral salts) responsible for
hardenss and resistance to compression of the bone
what is ossification
the formation of bone tissu
what are the 2 typs of ossification
- endochondral ossification
- intramembranous ossification
what kind of ossification forms the majority of the skeleton
endochondrial ossification
what are the bones formed from endochondrial ossification called
cartilage (endochondrial) bones
how are bones formed through endochondrial ossification
by replacing hyaline cartilage
what are some examples of bones formed through intramembranous ossification
some flat bones of the skull and clavicle
how are bones formed through intramembranous ossification
it develops from fibrosis membrane
what are bones formed by intermembranous ossification
membrane bones
where does endochondral ossification begin
the primary ossification center in the center of the shaft
in endochondral ossification, what must happen before ossification
the breakdown of hyaline cartilage
endochondral ossification forms essentially all bones below (interior) to…
the base of the skull
what are the 5 main steps in the process of ossification
- bone collar forms around diaphysis of cartilage model
- central cartilage in diaphysis calcifies and develops cavitis
- periosteal bud invated cavities and causes spongey bone
- the diaphysis elongate and the medullary cavity
- epiphyses ossifys
what is the diaphysis
the shaft of the long bone
once the epiphyses ossifies hyaline cartilage only remains in…
epiphyseal plates and articular cartilage
what are the 4 major steps involved in the ossification of the bony skeleton
- ossification centers formed when mesenchymal cells cluster and become osteoblasts
- osteoid is secreted by osteoblasts, then calcified (calcium phosphate is deposited)
- woven bone is formed when osteoid is laid down around blood vessels, resulting in trabeculae
4.lamellar bone replaces woven bone, and red marrow appears
does intermembranous ossification have a primary and secondary ossification center
no, intermembranous ossification only has one ossification center
what kind of growth leads to a bons increase in thickness
postnatal bone growth
what kind of growthleads to a bones increase in length
interstitial growth
in order or interstitial growth to be possibl, what must be present
epiphyseal cartilage in the epiphyseal plate
why does the epiphyseal plate maintain a constat thickness
the rate of cartilage growth on one side is blanced by bone replacement on the other side
what are the 5 zones of the epiphyseal plate (superficial (proximal) -> deepest (distal))
- resting (quiescent) zone
- proliferation (growth) zone
- hypertophic zone
- calcification zone
- ossification (osteogenic) zone
what is another name for the resiting zone of the epiphyseal plate
quiescent zone
what is taking place in the resting (quiescent) zone of the epiphyseal plate
the cells are inactive
what is anoher name for the proliferation zone of the epiphyseal plate
the growth zone
what is taking place in the proliferation (growth) zone of the epiphyseal plate
cells are actively mitotic (dividing). the new cells move upward, pushing the epiphsis away from the diaphysis, lengthening the bone
where is the proliferation (growth) zone of the epiphyseal plate found
the diaphysis side of the epiphyseal plate
are the cells costest to the diaphysis older or younger
older
what happens in the hypertrophic zone of the epiphyseal plate
the cartilage lacunae enlarge and erode, causing the chondrocytes (cells) that have been produced in the proliferatin zone to enlarge
what happens in the calcification zone of the epiphyseal plate
the cartilage matrix is calcidied and starts to deteriorate, causing the chondrocyts (cells) to die
what happens in the ossification zone of the epiphyseal plate
-deteriorated chondrocytes leave long spicules
- spicules are eroded by osteoclasts and covered with bone by osteoblatss
- the cartilage is replaced by spongey bone
what do you call the epiphyseal plate when it is no longer active
epiphyseal line
what happens when the epiphysis and diaphysis fuse
the epiphyseal plate becomes inactive (epiphyseal line)
when do females stop growing
around 18
when do males stop growing
around 21
what causes bones to thicken
- stress
- exercise
- added weight
how do bones thicken through appositional growth
- osteolasts remove bone on endosteal surface
- osteoblats bneith periosteum secrete bone matrix on external bone
what is the most important hormone in stimulating epiphyseal plate activity
growth hormone
what does the thyrid hormone do
modulates activity of growth hormone, ensuring prper proportions
what does testostrone (males) and estrogen (females) promote
growth spurts
is bone active
yes, bone is actively being recycled
what does bone remodeling considt of
bone resorption (osteoclasts) and bone deposition (osteoblats)
where does bone remodeling occure
the surface o the periosteum and endosteum
are osteoblats or osteoclasts active first
osteoclasts
what do osteoclasts do
break down the bone by degrading organic and inorganic components. they secrete lysosomal enxymes (digest matrix) and acidity (converts calcium salts so soluble form)
what do osteoclasts phagocytize
deminderaized matrix and dead osteocytes
where are products digested by osteoclasts digested
into interstitial fluid and into the blood
after osteoclasts demineralize the matrix and dead osteocytes what happens to the osteoclasts
they leave
what deposits new bone matrix
osteoblasts
what is the osteoid seam
the new matrix deposited by osteoblasts
what is the calcification front
the boarder between old bone and new bone
what are the theories for what causes bone deposit
- mechanical signals
- increased concentrations of calcium and phosphate ios for hydroxyapatite formation
- matrix proties that bind and concentrate calcium
- appropriate amount of enzyme alkaline phospates for mineralization
what is hypocalcemia
low levels of calcium in the blood
what is the process of negative feedback in response to hypocalcemia
- stimulates the parathyroid gland
- release of parathyroid hormone (PTH)
- activates osteoclasts
- releases calcium
- normalization of calcium levels
what is the process of negative feedback in response to hypercalcemia
- stimulates parafolicular cells of thyroid gland
- release of calcitonin
- activates osteoblasts
- deposits bone
- calcium used in blood
what is hypercalcemia
calcium levels in blood are too high
what can hypocalcemia cause
hyperexcitability
what can hypercalcemia cause
nonresponsiveness and calcium stones
what does wolf’s law state
bones grow or remodel in response to demands placed on them
what effect does handedness have on the bones
you dominant arm will have thicker and stronger bones
where are curved bones the thickest
where they are most likely to buckle
what do trabeculae form along lines of stress
trusses
why are bones of a fetus and bedridden people featureless
the lack of stress on the bones
what are the 3 causes of bone remodeling
- stress
- injury
- imbalance in calcium
what are examples of stress that can lead to bone remodeling
- weight gain
- exercise
- handedness
during youth, what is the primary cause of fractures
trauma
in old age what is the primary couse of fractures
a weakness in the bones due to bone thinning
what do nondisplaced fractures look like
the bones are still aligned
what do displaced fractures look like
the bones are not aligned
what is a complete break of the bone
it is brokn all the way through
what is an incomplete break of the bone
it is fractured
what happens to the skin in an open (compound) fracture
the skin is penetrated
what happens to the skin in a closed (simple) fracture
the skin is swollen but not broken
what does a comminuted fracture look like
the bone is shattered. 3+ pieces
when are comminuted frctures common
with age, for those whose bones are more brittle
what do compression fractures look like
the bon is crushed
when are compression fracturs common
in weight bearing people
what are the 2 ways to heal a compression fracture
- fusion
- metal bars and pins
what does a spiral fracture look like
the break goes all around the bone
when are spiral fractures common
when excessive twisting is applied to the bone
what is an epiphyseal fracture
when the epiphysis seperates from the disphysis along the epiphyseal plate
what are depressed fractures
when the broken portion of the bone is pushed inwards
where are depressed fractures common
the skull
what are greenstick fractures
when one side of the shaft breaks and the other side bends
who are greenstick fractures common in
children
what is another word for the realignment of fractured bones
reduction
what is open reduction
a physician manipulates to correct the position
what is closed reduction
surgical pins or wires secure the ends
what is imoalization of the bone
prevent it from moving by cast or sling to help with the healing of the bone
what are the 4 major steps in repairing the bone
- hematoma formation
- fibrocartilage callus formation
- bony callus formation
- bone remodeling
what is hematoma formation
when a mass blood clot (hematoma) leads to swelling and pain
what is fibrocartilaginous callus formation
- fibroblasts secrete collagen fibers to span break and connect broken ends
- fibroblasts, cartilage, and osteogenic cells begin the reconstructon of bones
what is bony callus formation
the callus isconverted to bony (hard) callus of spongey bone
what is bone remodeling
- excess material on diaphysis exterior and within medullary cavity is removed
- compact bone is laid down to reconstruct shaft walls
wht are 2 major bone diseases
- osteomalacia (adults)/ rickits (children)
- osteoporosis
what is osteomalacia
- bones are poorly mineralized
- calcium salts arent adequatley deposited
- pain upon bearing weight
what is rickets
- osteomalacia in children
- results in bowed legs and other bone deformities
- caused by vitamine D deficiency, exclusive breastfeeding, lack of sun exposure, anti-seizure medications or lack of calcium
what i the main symptom of rickets
growth delay
what skeletal deformaties are caused by rickets
- bowed legs
- rachitic rosary
- widening of epiphyseal junctions
what are the treatments of rickets
- correct undrelying condition
- vitamin d supplements
- mineral supplements
when giving rickets patients vitamin d supplements, what is the concern
if they take too much they could get hypercalcemia or nephrolithiasis (calcium stons in kidneys)
what is osteoporosis
when bone density drops
are women or men more likely to get osteoporosis
women
how do you treat osteoporosis
- calcium
- vitamin d supplements
- weight bearing exercise
- hormone replacement therapy
what is the best way to prevent osteoporosis
high calcium diet while young
