11.2 Movement Flashcards
What are exoskeletons?
External skeletons that surround and protect most of the body surface of animals such as crustaceans and insects
How do bones and exoskeleton facilitate movement?
By providing an anchorage for muscles and by acting as levers
How do bones and exoskeleton facilitate movement?
By providing an anchorage for muscles and by acting as levers
How can levers change?
They change in the size and direction of forces
What are the 3 main components of a lever?
- effort force (muscle)
- fulcrum (pivot point)
- resultant force (body weight)
What determines the class of lever?
The relative position of the eoffrt force, fulcrum and resultant force
What is the difference between a first, second and third class lever?
What is the effort force, resultant force and pivote point for each?
What is the class of each of these levers?
How does a grasshoppers leg acts as a third class lever?
Fulcrum is at the body end
effort force is between the fulcrum and the resultant force
How does a grasshoppers leg acts as a third class lever?
Fulcrum is at the body end
effort force is between the fulcrum and the resultant force
When skeletal muscles work in pairs, what does that tell us?
They are antagonistic
What does antagonistic muscles produce?
opposite movements at a joint
How are biceps and triceps antagonistic muscles?
the triceps extend the forearm while the biceps flex the forearm
In a pair of antagonist muscles, which is the agonist and which is the antagonist?
Agonist - one that is contracting
Antagonist - one that is relaxing
How many pairs of appendages does a grasshopper have?
3
What is the hindlimb of a grasshopper specialized for?
Jumping
What are the 3 main parts of a grasshoppers hindlimb?
- below the joint is referred to as the tibia
- at the base of the tibia is another join below which is the tarsus
- above the join is the femur
Where are relatively massive muscles found on the hindleg of a grasshopper?
femur
What happens to the muscles of a grasshopper when they jump?
- flexor muscles contract
- brings the tibia and tarsus into a position where they resemble the letter Z
- the femur and tibia are brough closer
- this is refered to as flexing
- the extensor muscles relax during this phase
- the extensor muscles will then contract extending the tibia and producing a powerful propelling force
When flexing, what muscles contract and relax?
Flexor muscle contract
Extensor muscle relax
What is an example of a synovial joint?
The human elbow
Where can you find a joint?
The point where bones meet
What do joints allow for?
Allow the bones to move in relation to each other - this is called articulation