Locomotion Flashcards
What is locomotion?
- The act of moving from one place to another
- Integrates anatomy with physiology
- Translates cellular contraction into whole animal movement
Flow of locomotion?
Sensory system –> CNS –> Motor neurons; cardiovascular system; respiratory system; digestive system –> Muscles; skeleton; blood vessels (musculoskeletal system)
Locomotor functions of skeletal system?
- Structural support for appendages
- Storage of energy in elastic devices
- Biomechanical levers
- Convert force of muscle contraction into movement
What are some types of skeletal systems?
-Hydrostatic
Fluid-filled chambers (ex. Earthworm, squid)
-Exoskeleton
External skeleton – in arthropods
-Endoskeleton
Internal skeleton – in vertebrates
How do most invertebrates move?
- Most invertebrates move by crawling (insects are an exception)
- Simple muscles work with hydrostatic skeleton
- Some- Alternate contractions of circular and longitudinal muscles produce peristaltic waves of contraction
How does a nematode move?
Contract- off ground
Relaxed- on ground
Only longitudinal muscle
How does a worm move?
Longitudinal muscle contraction= scrunched up
Circular muscle contraction= elongated
How does a squid move?
- Layers of muscle arranged around a hollow chamber
- Muscle fibers arranged in two dimensions within the body wall: Circular fibers and Radial fibers
- Mantle muscles contract- jet period- water outflow
- Relax- water influx
How do echinoderms move?
- Most sea stars and sea urchins use their tube feet for gas exchange
- Tube feet inflated by water
- Water is sucked in through madreporite and stored in bulbs
- bulb contracts- pushes water into tube feet
What has an exoskeleton?
Insects
- Exoskeleton is made up of chitin
- Muscles connect to the cuticle via myotendon junctions
How do ants move?
With half their legs on the ground (3/6)
What has an endoskeleton?
Vertebrates
What is an endoskeleton made of? Evolutionary trends?
- *Skeletons made of
- cartilage only
- bone and cartilage
- *Evolutionary trends
- More robust skeletons for tetrapods
- Birds and bats have secondarily reduced skeletons for flight
What connects bone?
- *Connective tissue – parallel fibers of collagen
- *Interconnect elements of the musculoskeletal system
- Ligaments (Bone to bone)
- Tendons (Bone to tendon)
What are two main fiber (muscle) types in fish? What is each used for?
1. White 85% of muscle in body Glycolytic, fatigues quickly High intensity, burst swimming 2. Red Oxidative, slow to fatigue Slow, steady cruising
What did tetrapods (four legs) transition to land require?
- *Complex locomotor muscles and neuronal control
- Muscles composed of heterogenous fiber types
- Increased complexity because of many different types of movement: Standing, walking, running, hopping, flying
What are 3 elements of levers? What depends on these position?
Fulcrum
Weight (load)
Force (effort)
-Mechanics of a lever
What does Lfa, Lwa, and MA mean?
- Lfa- length of force arm- distance between the force and the fulcrum
- Lwa- length of the weight arm – distance between the fulcrum and the weight
- MA- Mechanical advantage – ratio of the force arm to the length of the weight arm
What are the 3 different classes of levers? Examples of each? Most common in animals?
Class:
1. Fulcrum placed between the effort and load. The movement of the load is in the opposite direction of the movement of the effort. Lfa > Lwa
Ex: Skull
2. Load between the effort and the fulcrum. Movement of the load is in the same direction as that of the effort. Lfa > Lwa
Ex: Ball of foot
3. Effort between the load and the fulcrum. Both the effort and load are in the same direction. Lfa < Lfw
Ex: Bicep
What lever do cheetahs vs lions have? How does this effect their speed?
-Cheetah: shorter LFA
less force, but fast
-Lion: longer LFA
more force, but slow
What are antagonistic muscles and locomotor module?
- Antagonistic muscles - separate muscles that induce flexion and extension
- Locomotor module - all muscles responsible for a type of movement
How do birds fly?
Upstroke= Supracoracoideus flexing
Downstroke=Pectoralis flexing
Trade off muscles flexing. As pectorals flexes it pulls the wings down but also creates a pull on the supra muscle which responds by flexing
How is ATP stored?
- Muscles have an ATP store
- Larger storage in creatine phosphate
Compare glycolysis with aerobic metabolism.
**Glycolysis** 2 ATP per molecule of glucose Fast ATP production No oxygen dependence Carbohydrates only Stored fuel **Aerobic metabolism** 36 ATP per molecule of glucose Slow ATP production Dependence on oxygen Carbohydrates, lipids, and amino acids Stored and mobilized fuel
What does high intensity activity use large quantities of?
- Uses large quantities of glucose
- Stored in muscle cell as glycogen
- Produces lactic acid (Increases pH)
What does muscle exhaustion occur as a result of?
-Energetic shortfalls
-Ion disturbances
pH imbalance
How does the body recover from exhaustion?
- Replenish energy stores
- Reestablish ion gradients
How is lactate used during recovery? What was it produced by?
- Lactate produced by glycolysis removed during recovery
- Oxidized by mitochondria in aerobic muscle
- Converted back to glucose in the liver
What is oxidative phosphorylation?
- Allows long-term steady-state activity
- More mitochondria increases aerobic capacity
- Low mitochondria content in glycolytic muscles
- High mitochondria content in oxidative muscles
- Highest in flight muscles of insects and hummingbirds
What metabolic transitions occur during migration of salmon?
Start- lots of fat
Middle- lots of protein; break down digestive tract for protein
End- Lots of carbs
What’s perfusion? What controls it?
How much blood is entering an organ
Smooth muscles in arterioles
Whats vasomotion? Vasoactive agents?
- Vasomotion - cycling between constriction and dilation at rest- increase in activity increases dilation duration
- Vasoactive agents - chemicals that alter contractility of arteriole smooth muscle; may be released locally- NTs and metabolic end products
Whats angiogenesis? Triggered by what?
- Synthesis of additional blood vessels
- Triggered by persistent regional hypoxia- causes cells to proliferate and penetrate tissues
Whats myoglobin? 2 roles?
- Oxygen-binding heme protein in aerobic muscle
- Two major roles:
1. Intracellular oxygen storage
2. Transport of oxygen – facilitates diffusion by binding to free oxygen
What are 2 main environmental factors influence locomotion?
- Gravity
2. Fluid properties of surrounding medium
What are 2 effects of boundary layers on locomotion?
- Viscous effects - cost of carrying the boundary layer
2. Inertial effects - cost of moving an object from rest
What have large boundary layers?
Zooplankton, insects, etc
Does gravity affect terrestrial animals more than aquatic animals? Why?
- Yes.
- Terrestrial animals compensate with complex and substantial musculature
- Aquatic animals benefit from a body density that approximates that of the environment - buoyancy
What increases buoyancy? Examples?
- Lipid stores
- Animals accumulate lipids that increase buoyancy
- Zooplankton – have large lipid droplets
- Sharks – steroid compound (squalene) in livers
- Marine mammals – thick blubber layer
Whats a swim bladder? How did it arise?
- Gives buoyancy control.
- Likely arose as a primitive lung; buoyancy was a secondary function
- Derived from an outgrowth of the GI tract
What’s metamorphosis? Examples?
-Aquatic to terrestrial transition
Ex. Frogs – tadpole adapted to moving in water; Adult adapted for land – limbs, diverse musculature
What are two metazoan invasions of terrestrial environment?
- Invertebrates
- Vertebrates
What does velocity affect?
- Cost of transport
- COT vs. speed is typically U-shaped
- Preferred velocity is typically close to minimum COT
- Animals alter style of movement to minimize COT
What does jumping require?
Jumping requires long legs and rapidly contracting muscle
Whats true flight? 2 examples.
Whats gliding?
- Remain airborne for long periods
- Flapping or hovering
- Soaring
- Descend towards the ground
How do 3 different environments affect locomotion?
Locomotion on land – most energetically expensive
Locomotion in air – lift minimizes the effect of gravity
Locomotion in water – most energetically efficient
How does body size affect locomotion?
- Smaller animals have higher mass specific cost of transport
- Water – drag increases with surface area (x^2); Power increases with volume of muscle (x^3)
- Land – smaller animals need more uneconomical fast twitch fibers to move appendages faster.
