Physiology Flashcards
How does water enter an animal’s system
1) Preformed water (food and drink)
2) Metabolic water production
How do electrolytes enter an animal’s system
1) Preformed water (food and drink)
How does water leave an animal’s system
1) Respiration
2) Cutaneous water loss
3) Feces
4) Urine
How do electrolytes leave an animal’s system
1) Feces
2) Urine
How do freshwater fish osmoregulate?
1) They are hyperosmotic
2) They are at risk of hypervolemia and hyponatremia
3) They produce dilute urine
4) They uptake electrolytes in the gills
How do marine fish osmoregulate?
1) They are hypoosmotic
2) They are at risk of hypovolemia and hypernatremia
3) They actively drink seawater
4) They produce concentrated urine
5) They excrete electrolytes through chloride cells in the gills
How do elasmobranchs osmoregulate?
1) They have TMAO and urea in their blood which increases blood osmolality
2) Therefore, they are hyperosmotic
2) They are at risk of hypervolemia and hyponatremia
3) Concentration of saltwater is higher in water than in their blood which is why they need a rectal salt gland
How do marine reptiles osmoregulate?
1) They produce uric acid which, although requires a lot of water, allows some urine to pass backwards into the hindgut for water resorption
2) They have a salt gland that allows them to drink sea water while maintaining osmotic balance.
How do marine birds osmoregulate?
1) They produce uric acid which, although requires a lot of water, allows some urine to pass backwards into the hindgut for water resorption
2) They have a salt gland that allows them to drink sea water while maintaining osmotic balance.
How do marine mammals osmoregulate?
1) Very concentrated urine (reniculate kidney)
2) Apneustic breathing
3) Nasal turbinates
4) Lipid rich diet
5) Lipid-dense milk (when lactating)
Nitrogenous waste in different organisms
1) Ammonia = most aquatic animals (fish)
2) Urea = mammals, most amphibians, sharks
3) Uric acid = birds, insects, reptiles
Which marine mammals drink seawater?
1) Sea otters, common bottlenose dolphin, hooded seal, harp seal (while feeding)
2) Galapagos fur seal, short-beaked common dolphin, and short-finned pilot whale while fasting
Surface area scaling
Volume ^2/3
Mass ^ 1
Length^2
Volume
Length^3
Mass ^ 1
Fundamental variables of scaling relationships and derived variables
1) Mass
2) Length
3) Time
Derived
1) Density
2) Velocity
3) Acceleration
4) Force
5) Stress
6) Work
7) Power
8) Mass specific power
9) Biomass density
10) Production
11) Productivity
Equation for scaling of body mass
Y=aMsub(b)^b
a = proportionality constant
b = mass exponent
In log form:
log(Y) = log(a) +b*log(Msub(b))
Things that scale with body mass
1) Blood volume of mammals
2) Lung volume of mammals
3) Resting metabolic rate: Mass^.75
3) Mass-specific metabolic rate: Mass^-.25
4) VO2max: Mass^.75 (.81)
5) Specific net transport cost ^-.25
Scaling of metabolic rate
1) Total Metabolic Rate: Mass^.75
2) Mass-Specific Metabolic Rate: Mass^-.25
Environmental implications of scaling of metabolic rate
1) Small mammals degrade more energy per unit mass than large mammals
2) Therefore, a given energy supply will run
out more quickly for small animals
3) Or, looked at per unit time, a given energy supply will support a much smaller biomass of mice than of large moose or elephants
4) So larger species are better at getting and using energy than smaller species from similar taxa (better competitors)
Oxygen consumption and locomotion
1) For running animals on land, oxygen consumption increases with speed of running and the slope of this line is greater for small animals
2) Cost of travel is smaller for larger animals (relatively)
3) But minimum total cost of transport increases with increasing body size
Environmental implications of locomotory scaling
1) Informs optimal foraging theory
2) Using maximum and average speeds for animals of a given body size allows us to estimate range over which they can operate as the distance from a central point like a nest.
3) Has implications for territory size and habitat quality
4) For any given migration time, flying animals will be able to complete a much longer distance than walkers or swimmers of similar size, so to achieve the same distance in the same time, walkers or swimmers would have to be much larger.
Mammalian Dive Response
1) Breathing ceases
2) Bradycardia
3) Blood flow to peripheral tissues and organs reduced
Diving metabolism
1) Hypometabolism: thought to be related to anaerobic metabolism (ATP produced without oxygen, but only 2 ATP produced per molecule of glucose, lactic acid is byproduct)
2) Aerobic metabolism (38 ATP produced per molecule of glucose)
Challenges of Diving
1) HPNS (most animals do not dive deep enough to experience this)
2) Collapse/compression of air spaces (surfactant)
3) Oxygen toxicity, nitrogen narcosis, and decompression sickness (breathhold dive and collapse lungs)
4) Foraging without breathing (Bradycardia, hypoxia resistance)
Q10
1) temperature sensitivity of enzymatic interaction
2) the factor at which the rate of a reaction increases for a 10 degree increase in temperature
Heatshock proteins
1) Proteins that are induced during stress that make the animal more resilient to other types of stressors
Cryoprotectants
1) Protect cells from injury during drastic temperature changes (typically alcohols or sugars)
2) Function as colligative cryoprotectants in which the osmotic concentration of body fluids is increased so that only a limited percentage of total body water can turn into extracellular ice
3) Function as noncolligative cryoprotectants that protect the membranes and preserve subcellular structures from long-term damage
Partial endothermy
1) Small birds and animals (hummingbirds, tiny rodents)
2) Normally high metabolic rate is turned down seasonally or every night to reduce energy expenditure
3) Temporary torpor
Facultative endothermy
1) bumble bees
2) When ecotothermic animals “turn on” endothermic heat generation system in some parts of their body
Regional endothermy
1) some fish and some reptiles
2) Localized areas of musculature routinely operate at much higher temperatures than the rest of the body
3) Allow faster or more sustained movements in cold environments
Regional heterothermy
1) birds and mammals in cold environments
2) extremities are much cooler
Inertial homeothermy/endothermy
1) Animals that have no specific strategy for raised metabolic rate
2) Essentially ectothermic and bradymetabolic animals can still have high and constant body temperature if they are large
3) Have a very high thermal inerta because of scaling effects (SA:V)
Blubber advantages and disadvantages
Advantage 1) Low maintenance 2) Doesn't compress at depth Disadvantage 1) Requires energy
Fur advantages and disadvantages
Advantage 1) More insulative per unit area Disadvantage 1) High maintenance 2) Does not work at depth 3) Cannot be used as energy store
What are the basic requirements that energy is used for?
1) Basal Metabolism
2) Activity (e.g. locomotion)
3) Thermoregulation
4) HIF
What is excess energy allotted to?
1) Growth
2) Storage
3) Reproduction
4) Repair
What happens to chemical reactions at increasing temperatures?
1) Rates of reactions increase with increasing temperature
2) This occurs until the temperature becomes too high and proteins begin to denature (unfold)
acclimation versus acclimitization
1) Acclimation is the process of responding to a single stressor (occurs in the lab)
2) Acclimatization is a phenotypic response to a change in environment (e.g. acclimatize to high altitude but this is reversed when brought back to sea level)
What is the risk of very low temperatures?
1) Freezing of intracellular fluids
What are biphasic effects of temperature increase on the rate of biological processes
1) As temperature increases, rate of progress of reactions increases as activity rates increase
2) Then the optimal temperature is reached
3) From the optimal temperature there is a rapid decline in rate of progress because of destructive effects of high temperature
Metabolic heat production
h*(Tb-Ta)+E h = heat transfer coefficient E = Evaporative heat loss OR hconduction*(Tb-Ta)+hconvection*(Ts-Ta)+hadvection*(Ts-Ta) + E + S S = Heat storage
Steady state condition at which body temperature is maintained
Heat loss (Q) must equal metabolic heat production
What scales allometrically?
1) Blubber mass
2) Volume
3) Blood volume
4) Skeletal mass
5) Heart mass
6) Oxygen stores
What scales as mass to the 3/4
1) Metabolic rate
2) Brain mass
3) Power from muscles
What scales as mass to the -1/4
1) Mass-specific metabolic rate
2) Heart rate
What is the scaling of conductance
-.5
What is the scaling of insulation (fur)
.17
What is the Meeh coefficient
1) Scales with the SA relationship
2) More spherical animals have a lower Meeh coefficient, but animals like bats and sugar gliders with extra membranes in wings and gliders have a higher Meeh coefficient
