Animal Lesson 8 Flashcards
(59 cards)
Hardened support structures can be what?
external, internal, or absent
What do hardened support structures do?
Keeps the body up right
Hydrostatic skeleton
fluid held under pressure in a closed body compartment to make it feel hard against the body. E.g., worms, jellyfish, sea anemone.
Jellyfish
Not competely enclosed. With special epithelial muscular cells around they can close off opening and become really hard.
Endoskeleton
hardened internal skeleton. E.g., sponges (why they stay up right), echinoderms (made up of ossicles that are intertwined on the inside), chordates (us made up of bone and cartage).m
Exoskeleton
hardened external skeleton. Soft part attached inside of their exoskeleton to protect themselves and create movement. E.g., arthropod cuticles (insects and hardshell fish) and mollusc shells.
How do worms crawl?
Peristaltic Crawling
Long and skinny worm shape
Longitudinal muscle relaxed (extended). Circular
muscle contracted.
Short and fat worm shape
Circular muscle relaxed. Longitudinal muscle
contracted.
Steps of how warms crawl
Head is contracted then it extends forward, graple onto the bottom and then squeezing the individual segments together and bringing the back of its body back this way.
Bristles
Part of worm graple to the ground.
Main part of worm
Segments with fluid in a closed cavity through whole body.
The two muscles of the worm
An example of antagonist muscle pairing. They work in opposite direction, if both happen at same time because you won’t move.
Can animals with a hydroskeleton jump?
Yes they can. They use hydrostatic pressure.
Endoskeletons and exoskeletons generate movement using what?
muscles attached to the hard parts of a skeleton.
What are the bicep and tricep attached to in humans?
Bicep attached to the inside part of lower arm bone. Tricep attached to the other side underneath the elbow.
Antagonistic muscles
generate opposite movements across a joint. When one contracts, the other must relax.
Flexion of human arm
Biceps contract and pulls arm bone towards it while tricep is relaxed.
Extension of human arm
Tricep contracts and shortens and pulls bone from outside outwards. While the bicep is relaxed.
Bicep is a what?
Flexor
Tricep is a what?
Extensor
Grasshopper leg movement
Leg comes in when flexor muscle (that’s inside the extensor) contracts. Leg extends out when the extensor muscle contracts.
Vertebrate skeletal muscle example of hierarchical organization
Skeletal muscle composed of Muscle fibres (each a multinucleated muscle cell) composed of Myofibrils composed of Thin (actin) + thick (myosin) filaments.
Bundle of muscle fibres are kept together by what?
A membrane