Flashcards in Locomotion and Exercise Deck (93):
What are the two kinds of fluid flow?
Which kind of flow increases the cost of locomotion?
How can animals reduce drag? (2 ways)
What are two types of drag?
1) Friction drag
2) Pressure drag
What part of the object determines how much friction drag there is? What is the main determinant of how much friction drag there is? What is one application of reducing this?
- BOUNDARY LAYERS
- Viscosity of the fluid
- Swimsuit designs reduced friction drag
What does a Reynolds number describe? How is it defined?
The Reynolds number describes whether inertial effects or viscous effects dominate.
Re= velocity of movement* linear dimension of object* density of fluid/ viscosity of fluid
A large Reynolds number means...
That inertial effects dominate
The cost of locomotion is greatly increased under ______________
Turbulent flow conditions
If we have a swimmer and a flier who are the same size, what has a higher reynolds number?
Swimmers have higher Reynolds numbers
What is an importantly law that governs flight (name and state it)? How do wings take advantage of this?
Bernoulli's Principle: A faster moving liquid produces less pressure than the same fluid moving at a slower speed.
Wings take advantage of this with their shape (longer surface on top makes fluid travel faster=less pressure above)
What do we call the shape of a wing?
What is one metric that we use to measure bird wings (name and define)
Wing aspect ratio: A ratio of wingspan to wing surface area
What can we say about the wing aspect ratio of birds depending on bird size. Why is this?
Larger birds have a higher aspect ratio (longer, narrower wings) because it is more efficient for soaring. Little birds have a lower aspect ratio (shorter, wider wings) because its more maneuverable.
What is another metric describing wings and weight?
Wing loading: the weight of a bird divided by the area of its wing.
Discuss the advantages and disadvantages of wing loading, with an example for high and low
High wing loading and aspect ratio is advantageous for soaring because of low metabolic cost (albatross). Lower wing loading and aspect ratio is advantageous for thermal soaring birds because they need to have a tighter turning radius to stay in the updraft (vulture)
Name 4 adaptations/behaviors of birds that swim:
1) Increased muscle mass (heavier)
2) Exhale before diving
3) Patting down feathers to expel air and reduce volume
4) Higher wing loading (shorter wings b/c easier to generate thrust in water than in air)
Name 2 adaptations/behaviors of fish that fly:
1) Large pectoral/pelvic fins
3) high aspect ratio and high wing loading
How do fish increase their buoyancy? Why is this advantageous?
With swim bladders! It is energy efficient to have buoyancy.
What fills the swim bladder? What is this connected to? What empties the swim bladder? What is this connected to?
Gas gland fills (connected to liver). Oval window empties (connected to heart).
How does the gas gland fill the swim bladder?
Metabolism of GLUCOSE results in LACTATE formation, CO2 production, and a PROTON increase, resulting in more O2 coming off of hemoglobin and entering the swim bladder.
So, we'd say the gas gland has a high/low pH
What is the world's fastest fish? How fast can they swim?
Sailfish. 68 m.p.h.
What are three important musculoskeletal factors that influence locomotion? With examples
1) Arrangement/distribution of fibers with different functional properties (e.g. red oxidative fibers along side of fish, white glycolytic above and below)
2) Selective activation of different muscle types (red vs. white fibers)
3) Attachment of muscles and organs to skeleton (e.g. turtles are very efficient)
Why are turtles so efficient?
The top shell keeps the shoulder in place, and the bottom shell holds the gut up. They also use lots of slow muscle!
What are the three types of levers? Which is fastest, and which most powerful? What differentiates the three types?
Class I lever (fastest), Class II lever, Class III lever (most powerful)
The key metric is the ratio between the length of weight from the fulcrum and the length at which force is applied from the fulcrum
What differentiates lions and cheetahs?
Lion has the muscle attached farther from the fulcrum, so more of a powerful joint, whereas cheetah muscle is attached close to the fulcrum, so it is a faster lever.
What is a humans, dog's, and cheetah's top speed?
What are two things that determine speed?
1) Leg strength (force generated)
2) Leg swing speed
What are three adaptations that allows cheetahs to run fast?
1) Rotary gallop (legs churn in a circular motion)
2) Flexible back (allows for long stride and longer foot contact with ground)
3) Leg swing speed (very fast!)
Describe a cheetah's legs
Light lower leg to reduce swing speed, but powerful upper leg to generate force
What is the most important factor for force generation?
How long the foot is in contact with the ground
Describe the factors that affect a sprinter's speed
1) Leg swing speed is even across the board for most humans: not something we can really change
2) Hitting the ground harder (generates more force). Mostly from the calf
3) Exert the same force over a longer period (maximize the time that feet are in contact with the ground)
What is one adaptation that spiders have evolved to save energy? How does it work?
Elastic sclerite: stretches when leg bends, then recoils with the stored energy!
What do kangaroos do to conserve energy?
Change in gait (4 legs to 2) takes advantage of elastic energy storage in the tendons of the legs
How does a horse optimize energy output as it wants to move faster?
Walking, trotting, and galloping all have an optimum speed. It chooses the one which is most energetically favorable (metabolic optimum) for a desired speed.
How do snakes move?
By making selective friction/contact with the surface
How do seals minimize energy?
By gliding whenever possible
What can we say about oxygen consumption and locomotion? How about oxygen consumption and animal speed?
Oxygen consumption increases with speed of locomotion.
Smaller animals require higher oxygen consumption to reach a given speed.
Rank the three forms of locomotion from least energetically favorable to most
Running, Flying, Swimming
Describe 5 cardiovascular changes that occur during exercise:
1) 3-10x increase in blood flow to skeletal muscle
2) Small increase in Mean Arterial Pressure (MAP)
3) Increase in systolic arterial pressure
5) 2-6x increase in cardiac output, due to 2-3x increase in heart rate and 50% increase in stroke volume
What is one cardiovascular thing that doesn't change during exercise
Diastolic blood pressure
Describe five main changes in blood flow during exercise
1) Blood flow to brain decreases
2) Blood flow to skeletal muscle increases
3) Blood flow to skin increases slightly (for cooling)
4) Blood flow to abdominal organs and kidney decreases
5) Blood flow to heart increases
What is not an issue during exercise? What is the rate limiting step during exercise?
Ventilation is not an issue (can increase alveolar ventilation rate by 20x), as we are able to dramatically increase ventilation. However, cardiovascular delivery of O2 to tissues is an issue!
What causes a "stitch in your side"?
Hypoxia of the diaphragm muscle
What causes a "second wind"?
The adjustment to anaerobic metabolism
Do CO2 levels rise or fall during exercise?
Do proton levels rise or fall during exercise?
What is VO2 Max?
The maximal rate of oxygen consumption (aerobic capacity)
What are the units for VO2 max? What are the figures for average people and elite athletes? How long can you maintain 35% and 75% of VO2 max?
Avg: 20-50 mls/min/kg
Elite: 80 mls/min/kg
8-10 hrs (35%), 1-2 hrs (75%)
What are the two main differences between an elite endurance athlete and an average person?
1) A bigger heart (left ventricular hypertrophy, leads to a low resting heart rate)
2) Muscles' ability to use that oxygen (due to more mitochondria, indicated by VO2 max)
What is the highest VO2 max ever recorded?
What can we say about post exercise oxygen consumption?
It is higher, to make up for all the oxygen that was just used up
Describe how heat production, heat loss, and core temperature adjust to exercise
Heat production increases rapidly and then stays constant. Heat loss and core temperature gradually increase until they also levels off.
What are two key muscle fiber types and when are they used?
white glycolytic fibers: used for rapid, powerful movements
red oxidative fibers: used for long endurance movements
What happens to muscle fibers as we train?
The types of fibers adjust to our training
Name one nervous system change that occurs during exercise
- Sympathetic nervous system activity increases
Name five metabolic changes that occur during exercise:
1) Insulin levels decrease (lets blood glucose levels rise)
2) Glucagon secretion increases (more glucose in blood)
3) Glucose uptake by muscles increases
4) Metabolic rate increases
5) Lactic acid levels increase
Discuss energy sources during a marathon
First 90 min- use glycogen stores. Then, start to use fat, which requires more O2 for breakdown. This is why people get winded and hit the wall later on
What is the main source of ATP in short distance events?
Anaerobic glycolysis and creatine phosphate
What is the main source of ATP during long distance events
Aeobic catabolism using glycogen and glucose, then using lipids
What are four changes that occur with endurance training?
1) More oxidative fibers
2) increase in mitochondrial density
3) more lipid droplets
4) increase in oxidative enzymes used in TCA cycle! (succinate dehydrogenase and cytochrome oxidase)
What metric do we see rise with endurance training?
What are two changes to the muscle fibers that occur with endurance training?
Fast glycolytic fibers convert to fast oxidative fibers. Capillary density increases around all fiber types.
What is one molecule that we see more of with more endurance training?
VEGF (Vascular Endothelial Growth Factor)
What is one way that we measure the muscle fiber types that are present?
Look for alteration in MYOSIN HEAVY CHAIN ISOFORMS
Why would somebody interested in increasing white muscle fibers train endurance?
Because when you stop training there is a DETRAINING OVERSHOOT, which leads to the presence of more white fibers than before you started training
Name four things that strength training does affect but endurance training doesn't
2) fiber diameter
3) number of myofibrils
4) glycolytic enzymes
Name two things that endurance training effects but strength training doesn't
1) oxidative enzymes
2) cardiovascular system
What is one thing that increases for both strength and endurance training?
Name two things that strength and endurance training have opposite effects on
1) capillary density (endurance up)
2) mitochondrial density (endurance up)
What do we call muscle loss because of non-use?
What is remarkable about hibernating bears?
They don't demonstrate as much atrophy as expected
What do we call age related loss in muscle mass, strength and function?
What can we say about the relationship between distance and peak age?
Longer distance has later peak age
What do we call synthetic testosterone?
What can we say about steroids vs. their naturally occurring counterparts?
They have very similar structures
What class of steroids is related to testosterone?
When were anabolic steroids first produced? When were they first banned in the Olympics?
What does anabolic mean?
It means they build up muscle tissue
What does androgenic mean?
It means that they promote the development of masculine trains
What are the results of taking anabolic steroids? What are two therapeutic uses
Leads to increased body weight, lean muscle mass, and muscle strength.
Used to treat chronic wasting conditions and stimulate bone growth
Why can it be hard to predict the effect of steroids?
Because they are usually taken as a cocktail with multiple different substances ("stacking")
When is the most dangerous time to take steroids? Why?
Most dangerous during puberty, because sex hormones are very important for brain development
Name a few bad effects of anabolic steroids
Atrophied testes, impotence
Left ventricular hypertrophy and increased risk of heart attack
More depression and suicide
Stunted bone growth in adolescents
What do endurance athletes do to cheat?
Blood doping: increases the number of red blood cells in the blood stream. This increases the hematocrit (normally 45%)
What are the two types of blood doping where cells are injected?
AUTOLOGUS blood doping: athletes own red blood cells are harvested for later use
HOMOLOGOUS blood doping: cells from a compatible donor are used
What are the risks of blood doping?
2) Strain on heart
What is a substance that can be injected for blood doping and how does it work?
EPO (ERYTHROPOIETIN): naturally occurring hormone that can stimulate the production of red blood cells. Can raise hematocrit to 70%.
What is high hematocrit called?
What is a newer way to achieve blood doping? (Name and describe)
Repoxygen: Viral gene therapy, upregulates endogenous EPO production
What is one gene that seems to indicate good athletic performance? What protein does it encode (and what are this protein's effects)? Describe the gene and the evidence
ACTN3 gene encodes for Alpha-Actinin 3, a protein in fast twitch muscles that stabilizes ACTIN FILAMENTS and helps anchor Z-DISKS.
3 Alleles: RR, RX, and XX. XX results in absence of actinin protein. XX less common in power Olympians than the general pop, but more popular in endurance Olympians than the general pop.
What is one gene mutation that leads to larger, more powerful muscles at a younger age?
Mutation inactivating MYOSTATIN (a protein that puts the breaks on muscle growth)