I. Skeletal System

Question 1

A. functions

Answer 1

1. support
2. movement
3. protection

Question 2

B. types of skeletons

Answer 2

1. hydrostatic skeleton
2. exoskeleton
3. endoskeleton

Question 3

B. types of skeletons
1. hydrostatic skeleton

Answer 3

• “water stabilized skeleton”
• “water controlled skeleton”
• soft, squishy
• no bones
• water contained under pressure
• pressurized water base

ex: jellyfish, worms

Question 4

B. types of skeletons
2. exoskeleton

Answer 4

• “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

Question 5

B. types of skeletons
3. endoskeleton

Answer 5

• “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

Question 6

C. structure of bones

Answer 6

1. bone cells build bones
2. bone tissue types
3. bone marrow
4. blood supply
5. joints

Question 7

C. structure of bones
1. bone cells build bones

Answer 7

• 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)

Question 8

C. structure of bones
2. bone tissue types

Answer 8

• 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

Question 9

C. structure of bones
3. bone marrow

Answer 9

• 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

Question 10

C. structure of bones
4. blood supply

Answer 10

• 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

Question 11

C. structure of bones
5. joints

Answer 11

• 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)

Question 12

D. functions of vertebrate bones

Answer 12

1. structural support
2. attachment for muscles
3. protection
4. blood cell production
5. calcium and fat storage
6. endocrine (osteocalcin)

• allow to resist gravity
• calcium can be pulled out