A. functions
- support
- movement
- protection
B. types of skeletons
- hydrostatic skeleton
- exoskeleton
- endoskeleton
B. types of skeletons
1. hydrostatic skeleton
- “water stabilized skeleton”
- “water controlled skeleton”
- soft, squishy
- no bones
- water contained under pressure
- pressurized water base
ex: jellyfish, worms
B. types of skeletons
2. exoskeleton
- “outside skeleton”
a) most jointed
b) must be shed to allow growth
ex: crabs ready to grow split their exoskeleton and pump up their body hydrostatically, and overtime their epidermis will begin to harden into a new exoskeleton
c) muscles on inside
- opposite orientation than humans
animal examples: crabs, clams, insects, snails
B. types of skeletons
3. endoskeleton
- “inside skeleton”
a) usually jointed
b) made of
- bone/cartilage in chordates
- protein/silicon in sponges
- calcite in echinoderms
c) living, grows with body
- endoskeleton’s can be protective
but most of the time with your soft
parts on the outside, but the
advantage of that is that the
endoskeleton can revive
- bones, not fully fused until
adulthood
- bones grow with the body
- can’t shed
- when bones are growing with the
body, they start off as cartilage
d) muscles on outside of skeleton
animal examples: humans, dogs, cats, horses, fish, birds, reptiles, amphibians
C. structure of bones
- bone cells build bones
- bone tissue types
- bone marrow
- blood supply
- joints
C. structure of bones
1. bone cells build bones
- the bone cells that build bones are
actually called osteoblasts - bone cells living in bone are called
osteocytes, they live in holes in the
bone called lacunae (means lagoon) - produce matrix (protein and
calcium)
C. structure of bones
2. bone tissue types
- ends of long bones are called
spongy bones - spongy bones is a important sight
for blood cell production for red and
white cells - the advantage of spongy bone is it
provides spaces and passage ways
for blood cell production - having spongy at the end of the
bone means that any shock coming
from the other side of the joint will
be absorbed - compact bone (hard) has few spaces
in it, it’s very rigid and strong
C. structure of bones
3. bone marrow
- marrow is the soft parts of the bone
inside the bone - the red marrow is the spongy bone
at the end of long bones of center of
plate-like bones, where blood cells
are produced - the yellow marrow is the fat storage
- having the bone be hollow makes it
stronger - having less bone makes the bone
more lightweight making it
advantageous, allowing the
organism to move better
C. structure of bones
4. blood supply
- bones are living organs so they have
to have a blood supply - bones are highly vascular and have
lots of blood vessels running
through them
C. structure of bones
5. joints
- typically aligned with cartilage
- points of articulation (something moving against something else)
a) must prevent slippage of bones
i. grooves
ii. ligaments (hold joint and bones
together)
b) must reduce friction
i. cartilage (shock absorption and
reducing friction)
ii. lubricant (synovial fluid)
D. functions of vertebrate bones
- structural support
- attachment for muscles
- protection
- blood cell production
- calcium and fat storage
- endocrine (osteocalcin)
- allow to resist gravity
- calcium can be pulled out
