Support Systems Flashcards
(10 cards)
Types of skeletons
- Hydrostatic skeletons
- exoskeletons
- endoskeletons
Hydrostatic Skeletons
Definition
fluid-filled, closed chambers inside the body, that provide support against which muscles can contract to bring about movement.
Animals that have hydrostatic skeletons
- coelenterates e.g. jellyfish
- annelids e.g. earthworms
- nematodes e.g. roundworms
Disadvantages of hydrostatic skeletons
- lack well developed skeletal defense mechanisms
- have a restricted range of movement
- are confined to areas near or in water as they lose water so readily
- cannot reach any great size, whether they live on land or in the water
What exoskeletons are made of
name and definition
Chitin: a polysaccharide that is light and quite strong
Advantages of an exoskeleton
- external structure that supports the animal and protects its internal organs from injury
- has muscles attached to knobs and plates so it allows for movement
- has joints where the exoskeleton is thin and flexible, enabling the animals to move more easily
- is often covered with a layer of wax called a **cuticle **that reduces loss of water from the body, preventing the animal from drying out
disadvantages of exoskeletons
- because of their rigidity, ecoskeletons limit mobility
- they also growth
Ecdysis
A new exoskeleton is regenerated by the underlying epidermis.
2. after the exoskeleton is shed, the arthropod pumps up its body by the intake of air or water to expandthe new exoskeleton to a larger size
3. dehydration of the cuticle the takes place which causes it to harden into an exoskeleton
Endoskeletons
Found inside the body, made bone and/or cartilage
Advantages of an endoskeleton
- supports body, giving it shape
- is made up living tissue that can grow
- protects innternal organs
- provides anchors for muscles for movement
