Anatomy Flashcards
What is the function of a skeleton?
Support
Protection of internal organs
Movement (along with muscles)
What are the 3 types of skeleton?
hydrostatic
exoskeleton
endoskeleton
Describe a hydrostatic skeleton + example
- 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
Describe an exoskeleton + example
- external → hard outer casing for protection and support
e.g crab
Describe an endoskeleton + example
Internal - bones e.g humans
What are most invertebrate mollusks exoskeletons made of?
Calcium carbonate
What are arthropods exoskeletons made from?
Chitin
What are the advantages of an exoskeleton?
- 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)
What are the disadvantages of an exoskeleton?
Lack of ability to grow → exoskeleton must be shed and replaced by ecdysis
Energetically costly
Leaves individual vulnerable until new skeleton hardens
What are the disadvantages of an exoskeleton?
Lack of ability to grow → exoskeleton must be shed and replaced by ecdysis
Energetically costly
Leaves individual vulnerable until new skeleton hardens
what is the process of shedding and replacing an exoskeleton called?
Ecdysis
What are the disadvantages of an exoskeleton?
Lack of ability to grow → exoskeleton must be shed and replaced
Energetically costly
Leaves individual vulnerable until new skeleton hardens
Describe the muscles in an exoskeleton
Muscles situated on the inside of the skeleton
Muscles work in teams to make a an appendage move
What is the endoskeleton of cartilaginous fish made from?
Cartilage
- Made if collagen fibers embedded in a solid gel matrix = flexibility
What is the skeleton of all terrestrial vertebrates made from?
Hard ossified bone
- Framework of collagen filled in with calcium phosphate = strength
Describe the living structure of bone
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)
What are the 3 cells invloved in bone formation?
- Osteoclasts
- Osteoblasts
- Osteocytes
Describe osteoclasts and the role they play in bone formation
- Large cells
- Multiple nuclei
- Dissolve bone to free Ca and minerals to be recycled into new bone
Describe osteoblasts and the role they play in bone formation
- Small cells
- Single nuclei
- Work in teams to form bone - lay down Ca and minerals
Describe osteoblasts and the role they play in bone formation
- Formed from differentiated osteoblasts
- New bone builds around them
- Connected by branches
- Sense pressure/ cracks in the bone and direct repair
Skeletal morphology is ______ _______ across different vertebrates
highly conserved
