Bones/skeletal tissue Flashcards
(32 cards)
3 types of cartilage + location?
Hyaline: most carrtilage except..
Elastic cartilage (“E..”): external ear, epiglottis, eustacian tube
Fibrocartilage: knee meniscus, pubic symphysis, intervertebral discs
Cartilage: vascular or avascular? (so what?)
Avascular: hard to repair
Appositional growth vs interstitial growth of cartilage?
length vs thickness?
Appositional: occurs at surface, adds protuberances
Interstitial growth: expanding cartilage from within (increase overall size of cartilage)
Cartilage calcification:
Why?
How?
Why: to replace cartilage with bone (as a result of injury/aging)
How: oxygen supply cut off, calcium phosphate deposited into eroded matrix, chondrocytes die + leave space for bone
2 textures of bone + functions
Spongy (cancellous/trabecular)
Compact
Spongy: filled with bone marrow (makes new blood cells)
Compact: outer layer, dense (smooth looking without microscope)
Inner membrane of bone:
Outer membrane of bone:
Endosteum
Periosteum
Lamellae
purpose
orientation (to previous layer)
Purpose: weight-bearing
90 deg. to previous layer
Canaliculi: connect what to eachother and to what
Connect lacunae to eachother and to central canal
Which orientation are trabeculae aligned in (in spongy or compact bone?)
Trabeculae: spongy bone, direction of physical stress
Diaphysis vs Epiphysis
What type of bone
Where is each on the bone?
What type of marrow in each
What divides them
yellow vs red marrow?
Both in long bones
Diaphysis: shaft, Epiphysis: head
Diaphysis: yellow marrow
Epiphyses: red marrow
Epiphyseal line
How can you tell if a bone is adult or child?
Epiphyseal PLATE: child, still room for development
Epiphyseal LINE: adult, bone is ossified.
Where do nutrients enter the bone?
Nutrient foramina
Osteoblasts vs osteoclasts
Osteoblasts: synthesize osteoid (mitotically active) - build bone
Oosteo clasts: reabsorb/break dwon bone matrix
2 types of cells produced by osteoblasts?
Difference
Osteocytes: mature bone cells in lacunae
Bone lining cells: mature cells on bone surface
Both maintain bone matrix
Is bone primarily organic or inorganic?
Primary inorganic substance (what is it composed of, function)
Inorganic
Hydroxyapatites: calcium phosphare (hardness/resistance to compression
How much of the body’s calcium is in bone?
99%
what are the 3 stages of bone development (ossification)
- bone formation (prenatal)
- post-natal bone growth (until early childhood)
- bone remodelling/repair (lifelong)
Bone formation (prenatal):
Endochondral ossification: how? which bones?
Intramembranous ossification: how? which bones?
Endochondral: bone replaces hyaline cartilage model (bones inferior to skull)
Intramembranous: bone developd from fibrous membrane (skull bones-flat)
Endochondral bone formation:
When does it occur
How
Where is bone collar laid down first?
Prenatally
Hyaline cartilage model, as cartilage matrix deterioriates, osteoblasts produce osteoid
Bone collar first laid down on outside of bone
Postnatal bone growth
Occurs until when?
Interstitial vs Appositional bone growth
Does thickness of bone change?
Until early childhood
Intersitital: cartilage calcification, FOR BONE LENGTH
Appositional: osteoblasts add rings to outer surface while osteoclasts break down inside FOR BONE THICKNESS
Thickness doesn’t change, only diameter increases
Bone remodeling
How much bone mass is recycled weekly (%)
How often is spongy bone replaced (years)
How often is compact bone bone replaced (years)
5-7% weekly
Spongy bone: every 3-4 years
Compact bone: every 10 years
Important nutrients for bone deposit (when injured or added strength is needed)
Protein
Vit C, D, A
Calcium
Phosphurus
Magnesium
Manganese
Remodeling control: how do you know…
If remodeling will happen
Where remodeling will happen
If: hormones
Where: physics (mechanical/gravitational forces)
What do these hormones do?
Growth hormone (GH)
Thyroid hormone (T3/T4)
Sex hormones (est/test)
GH: growth at epiphyseal plate (height increase)
T3/T4: modulate GH activity
Sex hormones: growth spurts, close epiphyseal plate when growth is finished
