Support Systems Flashcards
Hollow tubes
They are structurally stronger than a solid tube of the same mass
Turgor pressure
The hydrostatic pressure within a plant cell vacuole that puts pressure on the cell wall, creating structure and rigidity
What is the purpose of lateral roots?
Absorption of water and dissolved minerals
What is the purpose of primary roots?
Anchorage and stability
What is a hydrostatic skeleton?
A capsule of fluid surrounded by 2 layers of muscle- circular and longitudinal
How do hydrostatic skeletons allow movement ?
Segmental contraction of muscles and anchorage by bristles drives the body forwards- burrowing
What animals have a hydrostatic skeleton?
Earthworm
What is an exoskeleton?
A hard outer surface that provides protection of soft tissues. Often calcified
What animals have exoskeletons?
Mollusks- clams, mussels.
Arthropods- insects, crabs.
‘Artho’
Joint
‘Podia’
Foot
What are the advantages of an exoskeleton?
- Strong and light
- Mineralisation= hard and protective
- Thin and flexible at joints
What are the limitations of an exoskeleton?
- Crushed easily
- They outgrow the skeleton
What is an endoskeleton?
It provides a rigid system for muscle contraction and protection of vital organs
What are the two types of endoskeleton?
- Cartilaginous
- Bony
Features of a cartilaginous endoskeleton
- Thin- allows for diffusion of oxygen
- Light
- Efficient and flexible
Features of a bony endoskeleton
- Rigid support against gravity
- Develop from a cartilaginous skeleton
- Dynamic- respond to physiological loading
What are the advantages of bones not being solid?
- Reduces weight
- Strength- they resist compression and tension
What are the middle of bones called?
The central medullary cavity
Where is red marrow found?
At the ends of bones
Where is yellow marrow found ?
In the middle of bones
