Flashcards in chapter 6 osseous tissue Deck (125):
what chemical makes up most of the substance of cartilage, and what characteristic does it give the cartilage?
water - resilience and flexibility (springy)
the dense irregular CT surrounding cartilage is called what? What does this do for the cartilage?
perichondrium - resists outward expansion
The cartilage itself does not have two things found in most tissues. What are they, and how does cartilage compensate for this?
blood vessels and nerves - diffusion from perichondrium
mature cartilage cells, immature cartilage cells
spaces where the cartilage cells reside
What limits the thickness of cartilage?
diffusion only carries materials over short distances
What type of cartilage is the most common and forms the embryonic skeleton?
Why do we not see the fibers in hyaline (glass) cartilage?
only fine collagen
Name 4 types of hyaline cartilage in the body.
1. articular cartilage
2. costal cartilage - ribs
3. respiratory cartilage - larynx, trachea
4. nasal cartilage
What is the flexible (bendable) cartilage, and where is it found?
elastic cartilage - ear and epiglottis
the cartilage with the highest tensile strength that will withstand the most compression
What makes fibrocartilage so tough?
thick collagen fibers
What makes elastic cartilage so flexible?
Give two places to find fibrocartilage.
1. intervertebral discs
2. knee menisci
Why is cartilage better for the embryonic skeleton than bone?
flexible matrix allows mitosis so it can grow
Name and explain the two types of cartilage growth.
1. appositional - growth from perichondrium (outside)
2. interstitial from the matrix (inside)
When does cartilage growth usually stop?
the process of depositing calcium in a tissue
What part of the skeleton consists of the skull, vertebrae, sternum and ribs? What does this part of the skeleton do?
axial skeleton - protects, supports and holds body parts.
What part of the skeleton consists of the skull, vertebrae, the shoulders and arms, hips and legs? What does this part of the skeleton do?
appendicular skeleton - locomotion (movement)
Name, and describe the 4 main types of bones.
long bones - longer than they are wide
short bones - boxy
flat bones - thin
irregular bones - complicated shapes
humerus, radius, ulna, metacarpals and phalanges, femur, tibia, fibula, metatarsals
carpals and tarsals
scapula, ribs and most skull bones
vertebrae, coxal bones
a bone that forms within a tendon - give an example
sesamoid - patella
a bone that forms in the sutures of the skull
Name the 6 major functions of the skeletal system.
1. supportive framework
2. protects soft organs
3. levers for movement
4. stores minerals and growth factors - calcium bank
5. makes blood cells in red marrow - hematopoiesis
6. stores fats (triglycerides) in yellow marrow
What are the two major functions of bone markings?
1. place for attachment of muscles, ligaments and tendons
2. pathways for blood vessels and verves
the solid bone made of osteons (Haversian systems)
the honeycomb bone made of trabeculae
another name for spongy bone
Where is compact bone found?
outside and diaphysis (shaft)
Where is spongy bone found?
inside and epiphyses (ends)
What are the spaces between the trabeculae filled with?
the shaft of the bone
the expanded ends of the bone
epiphysis - proximal and distal
the hollow, center of bone
medullary cavity or marrow cavity
the type of marrow found in the medullary cavity of adults
yellow marrow - fat
the thin cartilage that covers bones where they join
the growth region of the epiphysis - Of what material is it composed?
epiphyseal plate (metaphysis) - hyaline cartilage
a growth plate that has finished growing - Of what material is it composed?
epiphyseal line - bone
the outer covering of bone
the inner lining of bone - covers trabeculae
mature bone cells, immature bone cells
bone stem cells that mature into osteoblasts
osteoprogenitor cells (osteogenic cells)
white blood cells that dissolve bone
the holes where blood vessels enter bone - what are these blood vessels called
nutrient foramina - nutrient vessels
the threads that adhere the periosteum to thebone
perforating (Sharpey's) fibers
What is the term for the spongy bone in flat bones?
Where in a bone does hematopoiesis (blood production) occur?
What is the difference in the location of red marrow in newborns and adults? Why is this true?
more red marrow as a newborn - need to make more blood cells during growth
in adults - more yellow marrow - however, yellow can convert to red if anemic
What bones can we analyze red marrow in adults?
sternum and hip (coxal)
Name and describe the three types of lamellae.
1. concentric lamellae - share a central canal (1 osteon)
2. circumferential lamellae - around entire bone
3. interstitial lamellae - old osteons that are being remodeled
another name for compact bone
lamellar bone - made of lamellae
another name for an osteon
another name for a central canal
What is the difference between compact and spongy bone at withstanding stress?
compact - best at stress in one direction
spongy - good at stress from multiple directions
How do osteons handle torsion (twisting stress)?
the collagen fibers within the different lamellae have their fibers running in different directions, and the calcium salts align accordingly
the blood vessels that connect adjacent central canals - run perpendicular to the central canals
another name for perforating canals
the tiny, hairlike canals that connect adjacent osteocytes
What cell junction connects the osteocytes at the canaliculi?
What causes an osteoblast to mature into an osteocyte?
It surrounds itself with matrix and becomes trapped in a lacuna.
How are the trabeculae aligned within spongy bone?
along lines of stress
the organic part of the matrix of bone
Of what 2 materials is osteoid composed?
What property does this material provide bone?
1. ground substance of proteoglycans and glycoproteins
2. collagen fibers
This gives bone its tensile strength (flexibility)
What is the inorganic component of bone?
What property does this material provide bone?
hydroxyapatite - mineral salts like calcium phosphate
This gives bone its hardness
Why do the bones need the proper balance or organic and inorganic elements?
too hard and they become brittle
too flexible and they bend
the process of bone formation (2 terms)
ossification or osteogenesis
Before week 8 of embryonic development, of what two materials is the skeleton composed?
1. fibrous membranes
2. hyaline cartilage
What are the two types of ossification, and what is the difference between them?
1. intramembranous ossification - in a membrane
2. endochondral ossification - in a cartilage model
Which type of ossification is most common? Give some example bones for this type.
endochondral - all long bones like the humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals
How does endochondral bone formation begin?
a periosteal bone collar forms around the perimeter of the cartilage model
Where does the bone begin forming in the cartilage model, and what is this area called?
diaphysis - primary ossification center
Where does bone formation continue within the cartilage model (after the diaphysis), and what is this area called?
When do these new areas form?
epiphysis - secondary ossification center
These form shortly after birth.
As the bone gets longer and wider at the diaphysis, it takes bone away from where and deposits it where? What is the result
takes away - endosteum
deposits - periosteum
The medullary (marrow) cavity enlarges and the bone stays light.
What is the difference between the primary and secondary ossification?
secondary doesn't make a marrow cavity
- it remains spongy bone
The hyaline cartilage remains in two places following secondary offification. What are they?
1. articular cartilage
2. epiphyseal plate between the diaphysis and epiphysis
From what embryonic germ layer does bone originally form? What cells are formed from this that create the membranes and cartilage?
mesoderm - mesenchyme (embryonic stem cells for CT)
Around what age is the skeleton usually fully ossified? What are some of the last bones to ossify?
age 25 - carpals
Bone formation exceeds bode resorption through what age?
Osteoblasts and clasts should work equally through what age range?
young adults - as long as active and eating a balanced diet
Many people start losing bone mass around what age?
"normal" bone loss
when bone loss reaches disease proportions and a person has pathologic fractures
Why do women lose more bone mass than men?
menopause - changing levels of sex hormones
What happens to bone with aging?
1. less complete osteon formation
2. less complete mineralization of bone
3. diminished blood supply
4. more nonviable (dead) bone
5. fractures heal more slowly
What can help bone repair in elderly?
ultrasound and electrical stimulation
a congenital type of dwarfism with defective cartilage and poor endochondral bone growth - short limbs but membranous bones (skull) forms normally
an abnormal projection from a bone often due to overgrowth in aging bones
pain in a bone
inflammation of bone
brittle bone disease due to inadequate collagen fibers
OI - osteogenesis imperfecta
inflammation of bone and bone marrow caused by bacteria entering the bone from either a compound fracture or a infection spreading from near the bone
a bone cancer - often aggressive - can metastasize to lungs
a fracture in a diseased bone
placing sustained tension on a body region to keep it in alignment
What kind of fractures are most common in people with osteoporosis?
1. compression fractures of the spine - hunched over
2. "hip" fracture - broken femur at the hip
What are the typical treatments for osteoporosis?
1. calcium supplements
2. vitamin D supplements
4. hormone replacement therapy - controversial due to side effects (stroke, heart attack, breast cancer)
How does genetics play a role in osteoporosis?
a specific gene has been found to reduce serotonin which inhibits osteoblasts
What are some other factors that contribute to osteoporosis?
1. petite body frame to start with
2. insufficient exercise or immobility
3. poor diet
4. abnormal vitamin D receptors
5. smoking (reduces estrogen levels)
7. thyroid problems - hormones
8. carbonated beverages - leach minerals from bone
a disease of excessive and haphazard bone deposition and resorption making very thick bone in some areas and too much spongy bone in others
a condition of soft and painful bones - poorly mineralized
due to poor diet of Ca or not enough vitamin D to absorb it
osteomalacia in children - get really bowed legs
any break in a bone
a fracture across the long axis of a bone
a fracture along the long axis of a bone
a fracture that is out of alignment and will need to be set
a fracture that remains in alignment
a fracture that breaks through the skin
compound or open
a fracture that doesn't break through the skin
simple or closed
a fracture of the growth plate - what is the concern
epiphyseal fracture - bone might stop growing
a common sports fracture caused by twisting
a crushing fracture - often of vertebrae
a fracture in a young bone where it bends
a fracture with many shattered pieces
a broken bone is pushed inward - common in the skull
a common wrist fracture upon falling - breaks radius at thumb
an ankle break where the medial and lateral malleolus are broken
the realignment of a broken bone
What is the difference between an open and a closed reduction?
open - surgical
closed - nonsurgical
What are the steps in fracture repair?
1. fracture hematoma - clots
2. fibrous callus forms
3. bony callus forms
when bone is replaced and reshaped
Why is it necessary?
remodeling - old bone salts get brittle.
Why does calcium need to be removed from bones?
We need certain calcium levels in our blood for muscle and nerve function so we sometimes borrow from the bones.