Locomotion and Support Flashcards
How did locomotion and support evolve?
mutually
What is required for locomotion in water to prevent damage?
Flexibility and support
What is Reynolds number, and what does it describe?
ratio of intertial force to viscous force
behavior of a cylinder in water
What does a high Reynold’s water mean (4)?
at higher numbers, inertial force predominates and determines the behavior of water flow around an object
must expend more energy to move
inertia carries it forward when it stops swimming
changes laminar to turbulent water flow (less efficient)
What does a low Reynold’s number mean (2)?
at low numbers, viscous force predominates and determines the behavior of water
stops immediately when movement stops
What is ameboid locomotion? (2)
uses gel-like ectoplasm surrounding a fluid endoplasm
movement is facilitated by changing the cell state
How does amoeboid movement work (3)?
-pseudopods develop on the surface to creep
innermost endoplasm moves forward while outermost remains stable
as it advances, ectoplasm becomes rigid at tip of pseudopodium
What is a lobopod?
wide, blunt-tipped psuedopods in protists and eukaryotic cells
What exhibits ameboid locomotion?
protists and amoeboid cells
How are cilia and flagella related?
homologous in structure
What group lacks cilia?
arthropods
What is cilia, where does it arise, and what does it do?
cilia is shorter and occurs in patches
arises from kinetosome/ basal body
propulsive force
What do large animals do to move using cilia/ flagella at low Reynold’s numbers?
large animals secrete mucus to lower Reynolds number
- allows movement of fluid over cilia/ flagella
What is the structure of flagella?
long flexible rod covered by plasma membrane extension
What is an axoneme?
9 paired microtubules running length of cilia
What are dynein arms?
two rows of projection that directs adjacent doublets
What are radiospokes?
protein complexes that drive movement; attach to central doublet
How do microtubules work in a flagella, and what does it do?
microtubules slide up and down one another, bending it
microtubules provide support/ endoskeleton
What can cilia and flagella be used for?
can be used to make feeding/ gas exchange currents, line digestive tract, sex cells, sensory structures
What are mastigonemes?
branches on flagella that increases surface area for propulsion
How does cilia differ from flagella?
simpler and more consistent
How does cilia move (2)?
- coordinated beating is due to hydrodynamic constraints by surrounding water layer
- some are under neural control (reversing stroke)
What do skeletons do?
maintains shape, provides support, serves as attachment for muscles, transmit forces of muscle contractions for work, and extend related muscle
What can skeletons be hade of?
hard tissue, secreted skeleton, or turgid fluids/ tissues (hydrostatic skeleton)
What is a hydrostatic skeleton based on?
incompressibility and ability to assume any shape for liquids
How does a hydrostatic skeleton work? (3)
fluids transmits pressure change rapidly and unidirectionally
muscles can only perform work contracting
as muscle contracts, hydrostatic skeleton extends to create pressure
What does the coelom do in the hydrostatic skeleton?
coelom in muscle layers allows fluid to move to one side when contracted
What is peristalsis? (2)
moves by contracting posterior circular muscles
opposite end must be anchored when extending and moving
What is peristalsis seen in?
seen in feeding proboscis and tube feet
What is hydrostatic movement?
diagonal muscle fibers intersecting to prevent twisting
What is required for the hydrostatic skeleton?
volume of fluid should be constant (sphincter muscles prevents fluid from leaving holes)
How do organisms increase precision of the hydrostatic skeleton?
more precise through segmentation
What is a rigid skeleton?
capacity to grow larger, more precise or controlled movement, defense, and speed
What is a skeleton from the mesoderm called vs the ecoderm?
mesoderm- endoskeleton (spicules/ bones)
ectoderm- exoskeleton
How did the rigid skeleton originate?
a byproduct (nitrogenous waste and organic molecules led to chitin) or calcium for calcareous shells
What is an articulate skeleton?
exoskeleton of arthropods, clams, braciopods, and endoskeleton of echinoderm
What is a nonarticulating skeleton?
snail exoskeleton and endoskeleton of sea urchins and sand dollars
What are skeletons often made from?
collagen
What is cuticle?
extracellular matrix secreted by the epidermis
What is the cuticle made of, and how is it strengthened (2)?
glycocalyx matrix, collagen, keratin, chitin, and cellulose
may be mineralized to form spicules or shells
may be layered with different structure and composition
What is tanning?
strengthening of cuticle by adding calcium and pigments
What does the cuticle do (2)?
provides defense and prevents dessication
wax on surface can decreas water permeability
What is muscl instertion?
where muscle is anchored for movement
What are flexor muscles?
movement of limb toward body
What are extensor muscles?
contraction extends away from body
What are protractor and retractor muscles?
anterior and posterior movement of limbs
What are adductor and abductor muscles?
moves body part toward or away from a point of reference
How can unattached muscles be found? (2)
but form masses of muscle fiber (snail foot)
no origin and insertion but can act on each other
