Anatomy

Question 1

What is the function of a skeleton?

Answer 1

Support
Protection of internal organs
Movement (along with muscles)

Question 2

What are the 3 types of skeleton?

Answer 2

hydrostatic
exoskeleton
endoskeleton

Question 3

Describe a hydrostatic skeleton + example

Answer 3

• No hard parts → fluid filled sac under pressure
• Organs situated internally and are protected by fluid
• Muscles act on sac to make it change shape
  e.g octopus

Question 4

Describe an exoskeleton + example

Answer 4

• external → hard outer casing for protection and support
  e.g crab

Question 5

Describe an endoskeleton + example

Answer 5

Internal - bones e.g humans

Question 6

What are most invertebrate mollusks exoskeletons made of?

Answer 6

Calcium carbonate

Question 7

What are arthropods exoskeletons made from?

Answer 7

Chitin

Question 8

What are the advantages of an exoskeleton?

Answer 8

• Punching power
• Ability to withstand high water pressure (e.g deep sea spider crab)
• Protection against desiccation (e.g stops scorpion losing water in desert)

Question 9

What are the disadvantages of an exoskeleton?

Answer 9

Lack of ability to grow → exoskeleton must be shed and replaced by ecdysis
Energetically costly
Leaves individual vulnerable until new skeleton hardens

Question 10

What are the disadvantages of an exoskeleton?

Answer 10

Lack of ability to grow → exoskeleton must be shed and replaced by ecdysis
Energetically costly
Leaves individual vulnerable until new skeleton hardens

Question 11

what is the process of shedding and replacing an exoskeleton called?

Answer 11

Ecdysis

Question 12

What are the disadvantages of an exoskeleton?

Answer 12

Lack of ability to grow → exoskeleton must be shed and replaced
Energetically costly
Leaves individual vulnerable until new skeleton hardens

Question 13

Describe the muscles in an exoskeleton

Answer 13

Muscles situated on the inside of the skeleton
Muscles work in teams to make a an appendage move

Question 14

What is the endoskeleton of cartilaginous fish made from?

Answer 14

Cartilage
- Made if collagen fibers embedded in a solid gel matrix = flexibility

Question 15

What is the skeleton of all terrestrial vertebrates made from?

Answer 15

Hard ossified bone
- Framework of collagen filled in with calcium phosphate = strength

Question 16

Describe the living structure of bone

Answer 16

Red yellow bone marrow (blood cells)
Yellow (fatty tissue)
Compact bone (tightly packed layers = strength)
Spongy bone (porous - max strength/min weight)
Periosteum (outer layer of bone)

Question 17

What are the 3 cells invloved in bone formation?

Answer 17

• Osteoclasts
• Osteoblasts
• Osteocytes

Question 18

Describe osteoclasts and the role they play in bone formation

Answer 18

• Large cells
• Multiple nuclei
• Dissolve bone to free Ca and minerals to be recycled into new bone

Question 19

Describe osteoblasts and the role they play in bone formation

Answer 19

• Small cells
• Single nuclei
• Work in teams to form bone - lay down Ca and minerals

Question 20

Describe osteoblasts and the role they play in bone formation

Answer 20

• Formed from differentiated osteoblasts
• New bone builds around them
• Connected by branches
• Sense pressure/ cracks in the bone and direct repair

Question 21

Skeletal morphology is ______ _______ across different vertebrates

Answer 21

highly conserved