Summary Grade 11 life science notes on the human/animal support and movement system

Types of skeletons
Hydro skeletons
 Fluid filled cavity surrounded by muscle
 Provides support against which muscles can contract
 Pressure from fluid and muscle contractions change animals shape
and bring about movement
 Invertebrate animals with soft bodies (jellyfish)

Advantages
 Don’t need special support system as they usually live-in water

Disadvantages
 Can’t preform fast movements
 Can only occur in aquatic or moist environments
 Limit’s size
 No large degree of protection

Exoskeleton
 External / outside of body
 Occurs in invertebrate animals (largest group of arthropods)
 Consists of polysaccharide and chitin (sometimes hardens)

Advantages
 Supports and protects tissue and organs
 Attachment for muscles (fast movement)
 Joints for movement is where exoskeleton is thin and flexible
 Prevents desiccation (drying out)

Disadvantages
 Limit’s size (the larger they grow the heavier the skeleton gets
limiting movement)
 Limits growth as chitin does not expand (animals cans shed but new
one is weak)
 Impermeable to gasses so they have respiratory organs with
openings for respiration




Endoskeleton
 Internal
 Consists of bone and cartilage

, Advantages
 Living bone and cartilage grow with organism
 Protects important organs
 Structured support and shape
 Attachment of muscles for movement
 Joints between bones make the body flexible

Disadvantages
 Vulnerable to desiccation (drying out)


Important
 Vertebra animals: vertebral column meaning they have an
internal skeleton consisting of bone and cartilage
 Invertebrate animals: do not have vertebral columns which
means they have no internal skeletons




Human skeleton
Functions