Exam 1 (Chapters 1 & 5) Flashcards
what two fluids are found in the ECF?
plasma, interstitial fluid
what fluid is found in the ICF?
cytosol
what three ions are high in the ECF?
what two ions are high in the ICF?
ECF: Na+, Cl-, Ca2+
ICF: K+, A- (lg. anions)
which type of control, local or long distance, involves the nervous and endocrine system?
long distance control
what does the feedback loop do?
modulate the response loop to stop it from getting out of range
which type of feedback, (+) or (-), is homeostatic? which one is the majority of feedback loops?
(-) feedback is homeostatic and is the majority
what does (-) feedback do to the initial stimulus?
opposes / deceases the response of the initial stimulus
what does (+) feedback do the initial stimulus? what is the common example?
enhances / increases the response of the initial stimulus
-carries it further away from homeostasis
-OXYTOCIN!
what is feedforward control?
predicts change and gets ahead of the problem
-starts a response loop prior to the stimulus
sight/smell of food -> watery mouth, increase of stomach acid
exercise -> increase O2 before the deficit
how do circadian rhythms (biorhythms) control hormones?
they have repeatable / predictable day & night cycles
-decrease in body temp. late at night
how does acclimatization and acclimation control hormones? what is the difference b/w the two?
adaptation of physiological processes due to environmental conditions
-moving to a place w/ higher altitude causing the set point of RBC numbers in blood to change
ACCLIMATIZATION: natural setting
ACCLIMATION: artificial, lab setting
what is osmotic equilibrium?
fluid conc. are the same in ICF & ECF (both 300mOsM)
-no net movement
-body is normally in osmotic equilibrium
what is chemical disequilibrium?
ICF & ECF having different concentrations of ions
-ECF: high in Na+, Cl-, Ca2+
-ICF: high in K+, A-
what is electrical disequilibrium?
different distribution of charges in ICF & ECF
-ECF: slightly positive (cations)
-ICF: slightly negative (anions)
what is osmosis?
movement of water across the membrane
-moves in response to a concentration / solute gradient
-water moves to HIGHER concentration
what is osmotic pressure? what is it comparing?
pressure that opposes the movement of water by osmosis
-comparative number
-STOPS water movement through pressure
compares SOLUTIONS
what is osmolarity?
number of particles per liter (OsM/L)
what is molarity?
number of moles per liter (M)
which ion dissociates? which two don’t dissociate?
NaCl dissociates (1M -> 2mOsM)
Urea & Glucose do NOT dissociate (1M -> 1mOsM)
what does tonicity compare?
comparing solution to cell volume
-no unit!
which one is reciprocal, tonicity or osmolarity?
osmolarity
-can compare solution A to solution B and can compare B to A
Tonicity: can only compare solution to cell
what does isosmotic mean?
same number of particles
what does hyperosmotic mean? which is higher, ICF or ECF?
one solution has a greater number of particles
-ECF is higher in particles
what does hyposmotic mean? which is higher, ICF or ECF?
one solution has fewer number of particles
-ICF is higher in particles
what is constant value in mOsM of the ICF? is it always penetrating or nonpenetrating?
300mOsM
-nonpenetrating
what does isotonic mean?
no net gain / loss of H2O in the cell
what does hypotonic mean? which direction does water move?
cell swells / gains H2O
-water moves INTO cell (ICF-NP is bigger)
what does hypertonic mean? which direction does water move?
cell shrinks / loses H2O
-water moves OUT of cell (ECF-NP is bigger)
what are penetrating solutes? what is the common penetrating solute?
the freely diffuse across the plasma membrane
-NO water movement needed
UREA
what are nonpenetrating solutes? what are the two common nonpenetrating solutes?
cannot cross plasma membrane freely (TRAPPED)
-needs water to move it
NaCl, GLUCOSE
what is the exception to the rule: “osmolarity does NOT predict tonicity”?
a hyposmotic solution can predict a hypotonic cell
-when ICF-NP is bigger than ECF-NP, water always moves IN
T/F, the body is electrically neutral?
TRUE
-body electrically neutral (for every cation, there is a matching anion) but ions not equally distributed
what is a conductor?
the material in which attracted ions can move through freely
-WATER
what is an insulator?
the material in which attracted ions CANNOT move through freely
-ion movement is stopped due to the phospholipid bilayer
what are three law of conservation factors that lead to a resting membrane potential?
-opposite charges attract
-like charges repel
-separating attracted charges requires energy
what does the term “RESTING” mean? what about “POTENTIAL”?
resting: normal steady homeostatic state
potential: charge difference
-comes from difference in charge or concentration
-stored in electrochemical gradient
what are potassium (K+) leak channels?
always opened (non-gated) channels that allow K+ out of the cell in small amounts
-makes ICF more (-) and ECF more (+)
what gradient drives K+ leak channels? what ions attract and repel K+ to keep the ICF & ECF regulated?
electrochemical gradient (electrical and chemical gradient)
-attracted to A- in the ICF
-repelled by Na+ in the ECF
what three things make the resting membrane potential?
Na+/K+ pump
K+ leak channels
A- in the ICF
how does the Na+/K+ pump create the RMP?
3 Na+ OUT
2 K+ IN
-makes ECF more (+), ICF more (-)
how do K+ leak channels create the RMP?
K+ exits ICF making the ECF more (+), ICF more (-)
how do A- (anions) create the RMP?
creates a more negative ICF
which has a bigger impact on the RMP, K+ or Na+? why?
K+
-the equilibrium potential for K+ is closer to K+ than Na+
E(Na) = +60mV
E(K) = -90mV
RMP = -70mV
what is equilibrium potential?
the potential to stop movement
what is depolarization do to the RMP?
makes the membrane potential more (+)
what two things leads to a depolarization of the cell?
opening Na+ channels
removing K+ leak channels (traps K+ in the cell)
what is hyperpolarization do to the RMP?
makes the membrane potential more (-)
what two things lead to a hyperpolarization of the cell?
opening Cl- channels
opening K+ channels
what is repolarization?
returning back to the resting RMP (-70mV)
when are beta cells at rest? (glucose, ATP, K+ channels, insulin secretion)
glucose is low
ATP is low
K+ channels are open
insulin NOT released
what is the sequence of events that occurs when beta cells are active?
glucose is HIGH
1) aerobic respiration generates lots of ATP
2) ATP closes K+ channels (leads to depolarization)
3) Ca2+ voltage-gated channel opens and Ca2+ enters cells
4) the Ca2+ intracellular signal causes the exocytosis / release of insulin hormone by beta cells
