Animal Physiology - Exam 1 Flashcards
All invertebrates are __________.
ectotherms
Ectotherm body temperature and metabolic rate are ____________ correlated.
positively
Endotherm body temperature is relatively constant except for ______
when the environmental temperature is low, then metabolic rate will be high. (engaging homeostatic regulation)
Homeostasis
The tendency of organisms to maintain a relatively constant internal environment despite variable external conditions
Between a fish and the external environment, which has a greater fluctuation of oxygen concentration over time?
External environment
Homeostatic loop
way of controlling systems via feedback
Set point
the point at which homeostasis is set
The _______ feedback loop is the most common and it’s purpose is to _______ the variable ____ the setpoint.
Negative; return: to (restores homeostasis)
The _______ feedback loop is rare but effective and it’s purpose is to ________ the variable ____ the setpoint
positive; move; away from (disrupts homeostasis, establishes new setpoint or dynamic biological action)
_______: a collection of specialized cells of the same type that come together to function and focus on common cellular activity on a _______ scale.
Tissues; smaller
_______: are made of multiple tissues coming together and work on a _______ scale
organs; larger
________: series of connected but individual organs are coming together for a larger function
organ systems (ie: digestive)
Organ systems involved in control are:
nervous, endocrine
Organ systems involved in support and movement:
skeletal, muscular
_______ and ______ are other functions of organ systems
maintenance; reproduction
Body systems are _________
integrated
What are the components of body fluid?
- intracellular fluid (ICF)
- extracellular fluid (ECF)
- in a dynamic state
Intracellular fluid?
- is 40% of body weight
- is the fluid inside the cytoplasm of cells
Extracellular fluid?
- is 20% of body weight
- is composed of blood plasma and interstitial fluid
Interstitial fluid?
- 15% of body weight
- is the fluid between the cells and the blood vessels
What does it mean that body fluid is in a dynamic state?
the 3 types of fluid (intracellular, interstitial, blood plasma) are in constant exchange
Adaptation
Evolution through natural selection which leads the organism to match the demands of its environment physiologically, anatomically and behaviorally - irreversible. (populations evolve, not individuals)
Acclimatization
persistent spectrum of changes due to prolonged exposure to naturally occurring environmental conditions - is reversible.
Acclimation
persistent spectrum of changes because of a long exposure to experimentally-induced environmental conditions - is reversible. (only 1 variable changed, temp?)
Variables with relative stability?
- temperature (endotherms!)
- [O2] [CO2]
- ECF volume and pressure
- nutrients
- waste products
- water, salts
- pH
- fertility
________ conform within the environmental temperature
ectotherms
line of conformity
a 1:1 relationship between variables
Zone of stability
where homeostasis is maintained
What can thermal classification of animals be based on?
- source of body heat
- nature of their body temperature (Tb) relative to the environment (Te)
ectotherms
obtain heat from the external environment
endotherms
produce heat metabolically or actively radiate heat
heterotherms
show characteristics of both an ectotherm and an endotherm
Poikilotherms
variable internal body temperatures that fall within a wide range of environmental temperatures; also wide homeostatic range for body temperatures.
Homeotherms
maintain constant body temperatures with narrow homeostatic range for body temperature.
Heterotherms
can switch between homeo- and poikilotherm
Homeostatic range
the range between low and high body temperature levels - the normal range that sustains life
Some major differences between ecto- and endotherms
- resting metabolic rate (endotherms ^ @low temp)
- total energy expenditure at rest
- response to changes in temperature
A(n) _________ increases its metabolic rate to maintain its body temperature in cold conditions
endotherm
Between endo- and ectotherms, which type spends more metabolic energy?
Endotherms across almost all temperatures.
What is true for endo-, ecto-, and heterotherms?
they can use behavior to influence body temperature and metabolic rate
Examples of behavioral thermoregulation
- a lizard maintaining a specific body temperature in the day and night by its location
- an elephant splashing water over itself to release heat faster
_________ metabolic rate _______ with increasing body size
unscaled; increases
Metabolic rate =
0.1M^(3/4)
Mass vs. metabolic rate graph is a ______ _______, which means:
biological truism; the relationship stays constant across organisms in species
_____ -specific metabolic rates are highest in _____ endotherms
Mass; small
A mouse will…in comparison to an elephant
burn through energy more quickly to maintain temperature. It is losing heat every second
What is the significance of being able to fly?
A bird can find new niches to hunt/mate/live instead of being constrained to travel on foot like a t-rex
freshwater aquatic invertebrates are important…(hint: relates to pH)
bioindicators of environmental health
The _____ is very sensitive to acidic conditions, this organism will tell us early of a change in _____.
midge; pH
At rest, what is the extracellular and intracellular concentration of potassium. This favors…
5 mM; 148 mM; efflux from the cell
At rest, what is the extracellular and intracellular concentration of sodium, this favors..
142 mM; 10mM; influx into the cell
At rest, calcium concentration favors ______.
influx
At rest, Chloride concentration favors _______.
influx
How to calculate change in concentration
the difference in concentration:
out-in across the membrane for a specific ion/solute
electrochemical equilibrium influenced by
- degree of membrane permeability to ions and water
- membrane impermeability to large charged molecules (ex: anions)
What will happen if impermeable anions (A-) are added to one side of the membrane
- the electrochemical equilibrium of each ion species changes.
- There will be more negatively charged ions on the outside of the cell.
The inside of the cell is generally _____, so K+ movement is _______.
negative; restricted to keep negative charges from being too great
Partition coefficient is measured by
K = [solute] lipid/ [solute] water
If K is high, what does it mean?
The solute is more permeable across the cell membrane
Partition coefficient measures
the membrane permeability of a non-electrolyte based on if it can cross a membrane (dissolve and diffuse)
Permeability constant across a membrane is directly related to
K, so P is dependent on K.
Dm is
diffusion coefficient of solute (rate of diffusion substance through membrane)
x is
diffusion distance
If x is high, P will be
low
If P is high, K is
high
if Dm is high, P will be
high
Fick’s diffusion equation is
J = dQs/dt, the rate of diffusion by the quantity [Q] of solute [s] diffusing per unit time
Fick’s law is
Diffusion rate (J) is directly proportional to change in concentration gradient (deltaC s) x total diffusional surface area (SA) x solubility of substance (S s) / diffusion distance (X) x the sqrt of molecular weight (MW s)
If MW goes up, J will
go down (inversely related)
if deltaC s goes up, J will
go up (deltaC s = concentration gradient of substance; difference between C1 and C2 across the membrane) (directly related)
if A goes up, J will
go up (directly related)
If X goes up, J will
go down (inversely related) (X = diffusion distance or membrane thickness)
If S s goes down, J will go
down (S s = solubility of the substance, molecule or ion)
If J goes down, what will happen to each component
sqrt of MW up, X up, SA down, S s down, deltaC s down
Osmosis
the movement of water through a semipermeable membrane from a less concentrated to a more concentrated solution
Solutes exert ________ ______: a force that _____ water _____ the cell, based on ____ ___
osmotic pressure; draws; into; concentration differences
fluid exerts ______ ______: a force that _____ water _____ the cell, based on _____ ______.
hydrostatic pressure; pushes; out of; pressure differences
Hydrostatic force
the force exerted by the fluid per unit area of the contact surface
What does [A-] mean when looking at it with other concentrations
the molar equivalent of negative charges carried by other molecules and ions
Donnan equilibrium
when the ion concentration is equal between the inside and outside of the cell
T/F: the cell is in Donnan equilibrium
False, the charges must be unequal to balance other charges present in the cell.
Living cells are at a _____ _____, not equilibrium because energy is ________ for maintenance
steady state; required
Cells ______ regulate their intracellular volume
dynamically
What will happen if Na+ levels are not maintained at equilibrium because of some metabolic inhibitor added
the cell will no longer be able to pump Na+ out, this means that water will influx via osmotic pressure which increases cell volume and eventually this will cause the cell to burst
Leaky membrane channels are
always open
An example of a resting channel
a resting K+ channel is always open, so K+ is constantly lost
Gated membrane channels are
open only under specific conditions
A voltage-gated channel is
a channel that opens (briefly) in response to change in the membrane potential (in volts)
A ligand-gated channel is
a channel that opens (closes) in response to a specific extracellular neurotransmitter
A signal-gated channel
a channel that opens (closes) in response to a specific intracellular molecule
A mechanically-gated channel
a channel that opens when there is applied pressure from the environment
What transports polar molecules (like glucose/amino acids) across membranes
Carriers
Carriers are _____ ______ that possess a _____ _____ for the molecules or ions being transported. This is NOT a ______.
specific proteins; binding site; channel
Carriers can be ________ because there is a ______ amount in the cell membrane
saturated; limited
Uniporters
can only flux one molecule or ion
Coupled transporters
flux of more than one molecule/ion: symporter or antiporter
symporters
unidirectional
antiporters
bidirectional (both molecules/ions must be present to work)
Uniporters, symporters and antiporters are(hint: type of transport)
types of facilitated transport because there is a protein present
Passive diffusion through a membrane looks like what on a graph?
a straight, positive linear line that changes in height of slope based on membrane permeability
Passive transport through channels looks like what on a graph?
a straight, positive linear line that levels at close to end of the height of extracellular concentration of the substrate
Carrier-mediated transport (passive or active) looks like
A straight, positive linear line that levels out much faster, which tells us that there are a limited number of carriers available in the membrane and they will be become saturated at a certain point
Vmax is
when the rate of diffusion reaches its maximum
Channels are
selective for their ions
An ion with a large radius has a
low strength of hydration shield
channels are selective based on
- size of the ion (must be the right size to remove H2O molecules attached-takes energy to remove H2O)
- charge of the ion (to cause conformational change when it binds to the carbonyl on the a-helices in the channel)
A channel/carrier reduces energy of activation (deltaG) for diffusion with:
- creating a aqueous (hydrophobic) environment within the membrane for the solute
- promotion of dehydration (loss of H2O) with the solute binding to the amino acid side chains (helps ion pass through narrow channel IF right size)
An ion with a small radius, like Na+, has a
stronger hydration shield
Epithelial tissues are
- semi-permeable tissue
- a selective barrier between outside environment and inside of body
- composed of sheets of epithelial cells connected via tight junctions
- line cavities + hollow organs (like small intestines)
Epithelial tissues do form _____ which affects the _______/________ of _________, ________ and _____
barriers; transport/movement; water, solutes; cells
What part of the digestive system has the most carriers?
the small intestines
_______ _____ facilitate regulation of substance flux across body compartments
epithelial tissues
The _____ ______ in epithelial cells limit __________ path
tight junctions; paracellular
_________ path of ______/________ substances is ________ by the type of transporters in the membranes of the cells
transcellular; ionic/hydrophobic; regulated
In what direction does current in (frog) skin move?
+ to -
What is an example of charge moving transcellularly
Na+ passively and slowly moves into a cell from the external environment, this means through the active transport pump (ATP), cells will be pushing Na+ out the epithelial cell into the interior of the body. This allows for net movement of sodium into the body.
transcellular movement/path
when there is selective transport through the cell. Occur through membrane-bound proteins on the cell.
paracellular movement/path
where substances move through the space between two cells. Depends on how tight the junctions are.
Active transport
requires energy to move substances against an electrochemical gradient
Active transport can be in ______ directions and it can transport _____ molecule (s)/ion (s)
either or both; one or more
________ active transport ______ direct participation of ______
primary; requires; ATP
_________ active transport (_________): energy comes from a _______ __________ gradient that is established by:
secondary; cotransport; ion concentration; primary active transport
What is the most important protein in physiology
the Na+-K+ ATPase transporter
T/F: the Na+-K+ pump is found in all animal cells
true
T/F: the Na+-K+ pump is a symporter
False, an antiporter
what role does Na/K ATPase play in Na+ ion gradient in the cell?
balances rate of active transport of Na+ with Na+ leak
What happens to Na/K ATPase if the cell is metabolically blocked
it is inhibited
The potent neurotoxin on the newt’s skin is
tetrodotoxin
the Na+/K+ pump facilitates ________ separation of cell membrane. it also _______ different [__] and [___] across the plasma membrane
charge; restores; K+; Na+
Once ______ ______ ______ uses _____ to create ion gradients; other _______ can then be transported ________ with the ion, _______ the _______ concentration gradient
primary active transport; ATP; substrates; secondarily; AGAINST; substrate’s
Co-transport with Na+ renders:
substrate transport against its concentration gradient energetically favorable
T/F: other solutes can drive secondary active transport
True
Neurons are _____ cells
excitable
_______/_______ potentials are present and can ______ changes in cellular activity
electrical; chemical; enable
Application of ______ _____ to any cell will affect its activity
electrical stimulation
the receiving end of the neuron contains
the dendrites
where does the 1st change in membrane charge occur?
in the dendrites
what is part of integration in a neuron?
dendrites to the axon hillock
what is part of the spike initiation in a neuron?
the axon hillock
what is part of the impulse conduction of the neuron?
the axon (myelin sheath) until the axon terminals
the axon terminals are involved in:
transmitter secretion/release
Dendrite to the end of myelin sheath is:
electrical signals
axon terminals convert into
chemical signals
Neurons ________ to form ______ (simple or complex) to _______ signals throughout body
connected; circuits; transmit
neurons are
conductive
can be stimulated with a completed circuit and a stimulus
The cell’s membrane potential is denoted by:
the type of charge that is lining up next to the membrane. On the outside, positive charges are gathering, on the inside, negative charges are gathering
Voltage difference (Vm) is _____ _____ across the membrane
relatively stable and negative
another name for this relatively stable voltage reflecting cell’s inactive state is:
the resting potential
Vm quantitatively dependent on:
- different ion concentrations inside and outside the cell
- selective permeability of ion channels
What will happen across a cell membrane only permeable to K+ if K+ concentrations are equal?
there will be no net current (=movement)
with _______ concentration, ____+ current (_____) formed
unequal; K; flux
Loss of + charge across membrane?
- charge inequity across membrane that creates electromotive force (emf) opposite conc. gradient
large enough emf?
K+ movement stops, with unequal concentrations still and equilibrium potential (mV) established for K+
- this is when the electrical gradient and concentration gradient are equal in magnitude
What is the equation for the equilibrium potential for a specific ion?
E ion = 58 or 62/Z times log ([ion]out/[ion]in)
58 in nernst is
room temp
62 in nernst is
body temp
T/F: the membrane is equally permeable to all ion species
False
T/F: nernst does take permeability into account
False
What will happen if there is high K+ concentration outside the cell
diffusion will decrease
K+ will begin to influx
this is not normal cell behavior
What does the Goldman equation take into account?
It takes into account the permeability of each ion in addition to each ions deltaC
What is the Goldman equation
Em (membrane potential) = 58 or 62 times log (PK+ [K+]out/PK+[K+]in) + (PNa+[Na+]out/PNa+[Na+]in) + (PCl-[Cl-]in/PCl-[Cl-]out)
PK+ at rest?
100
PNa+ at rest?
3
PCl- at rest?
10
At cell birth, what is the cells membrane potential?
the cells membrane potential is very negative and it will attract K+ because it is already losing K+ through passive diffusion
What happens if a cell is too negative?
it will resist work
The cell is continually losing ______ charged ions, __+, which generates a ________ charged internal electrical gradient
positively; K+; negatively
what other ion can move through leaky K+ channels down it’s own electrochemical gradient to help offset the highly negative intercellular charge
Na+
Voltage is equal to
current times resistance
Passive electrical response
a shift in membrane potential produced when an electrical current is applied to and flows across the cell membrane
- slow, smooth changes
What is happening in the membrane during passive electrical responses
- no ion channels open or close
- ionic current occurring through K+ channels (static)
- resting K+ channels always open in the membrane
hyperpolarize
cell’s potential becomes more negative relative to resting
depolarize
cell’s potential becomes more positive relative to resting
Current moving upward is _____ ___ a cell
efflux out of
Current moving downward is ___ ___ a cell
influx into
The membrane operates as a ______ ______ to yield ______ membrane properties
simple; circuit; passive
Ic is
- Capacitative current as a stored potential across only phospholipids
- builds rapidly + 1st then discharges
Ir is
resistive current through ion channels only
- fewer channels than membrane SA so more limited
- can be rapid based on channel type
delta Vm is
membrane potential = change in current times resistance present
Resistance is ______ affected by membrane permeability
directly
Capacitors _____ charges
store
conductors _____charges
move
Membrane conductance is a measure of what
The movement of charge across the membrane
Conductance is _______ to permeability because it is determined by ______ and their _______
unequal; ions; concentration
Resistance (R) is equal to
1 over conductance (G)
- conductance and resistance are inversely related
High conductance yields a
weakly resistive membrane (can’t store charge, very low potential)
Resistance _____ flow of current
hinders
increased delta C means _________ resistance
decreased
a small separation of charges across a membrane means
increased resistance
an increase Resistance means
a decreased cross-sectional area (# of open channels)
increased distance (x) traversed by current (membrane thickness) means
increased R
