Exam 1 Flashcards
What is steady state?
maintaining same internal environment
* same in ; same out
What is equilibrium?
balanced opposing forces
lowest energy state
* does not involve time
What is homeostasis?
ability of the body to rapidly adjust and adapt to fluctuating environmental conditions while maintaining constant
What is an example of positive feed back?
hemorrhagic shock
What is an example of negative feedback?
mild hemorrhage
What is meant by a “feed-forward” mechanism?
anticipate changes and prompt thee system to act before anything happens
What are 4 the major characteristics of a homeostatic system?
- network of feedback loops
- hierarchy of feedback loops
- redundancy
- adaptability
What is negative feedback?
responds to an altered output by RESTORING itself towards a predetermined set point
What is positive feedback?
responds to disturbance by moving variables FARTHER AWAY from the initial set point
What 2 things are needed to maintain homeostasis?
- control (direct manipulation)
- regulation (end result)
Positive feedback promotes _____________
instability
In negative feedback, the stimulus INCREASES or DECREASES?
decrease stimulus
In positive feedback, the stimulus INCREASES or DECREASES?
increase stimulus
What are 3 examples of exceptions to positive feedback loops promoting instability?
- blood clotting cascade
- childbirth
- action potentials
What is the normal body temperature?
36.8 - 37.9
What is the main way body heat is produced?
metabolism
What are 3 ways body heat are produced?
- metabolism
- food intake
- muscular activity
What are 5 ways body heat is lost?
- radiation
- conduction/convection
- evaporation of sweat
- respiration
- urination/deification
What is the main way body heat is lost?
radiation
If you are warmer than your environment you _______ heat
loose (to environment)
If you are cooler than your environment you will _______ heat
gain (from environment)
How is body temperature lost/gained from radiation?
transfer of heat to and from skin by electromagnetic waves
How is body temperature lost/gained from conduction?
transfer of heat between skin and air (touch)
How is body temperature lost/gained from convection?
transfer of heat by MOVEMENT of air or water over body
How is body temperature lost from evaporation?
evaporation of water from skin and breathe
Where is temperature regulated in brain?
hypothalamus
Anterior hypothalamus is responsible for what temperature?
heat
Posterior hypothalamus is responsible for what temperature?
cold
When its hot outside do your blood vessels dilate or constrict?
dilate
Is hunger activated by HOT or COLD?
cold
Is increased voluntary activity activated by HOT or COLD?
cold
Is increased epinephrine/norepinephrine activated by HOT or COLD?
cold
Is vasoconstriction activated by HOT or COLD?
cold
Is horripilation activated by HOT or COLD?
(goose bumps) cold
Is vasodilation activated by HOT or COLD?
hot
Is apathy and inertia activated by HOT or COLD?
hot
Is anorexia activated by HOT or COLD?
hot
Fever is due to __________ activating the hypothalamus
cytokines
What does the hypothalamus secrete to induce a fever?
prostaglandins
How do prostaglandins cause a fever?
increases hypothalamic set point by inhibiting warmth sensitive neurons
- body temp is now seen as too low and mechanisms to increase temp are set into place
What do antipyretics target?
prostaglandins synthesis (COX1/2)
What is diffusion?
net movement of substance from area of high concentration to low
What is a concentration gradient?
difference in solute concentration between compartments
How do you find the net rate of movement?
rate of diffusion from compartment 1–> 2 MINUS rate of diffusion from compartment 2 —> 1
Diffusion is _________ proportional to the surface area of the barrier and _________ proportional to the thickness of the barrier
directly
inversely
What is the driving force for net diffusion across the membrane?
concentration gradient
What is flux?
rate of diffusion per area (Js)
What is Fick’s 1st Law?
Js = Ps x change in Cs
FLUX = permeability of solute across barrier x concentration gradient
Why is Fick’s Law sometimes written with a negative in front of the equation?
moving from high to low concentration (downhill)
Diffusion is better for short or long distance?
short
What kind of things use simple diffusion?
gases
ethanol
urea
What kind of things use facilitated diffusion?
water
ions
sugars (glucose)
What kind of things use active transport?
Na/K pump
Facilitated diffusion uses MM kinetics causing the graph to be _________. Why?
hyperbolic
transport proteins can become saturated
Carrier require conformational changes or are always open?
require changes
What is secondary active transport?
the transport of a solute in the direction of its increasing electrochemical potential coupled to the facilitated diffusion of a second solute (usually an ion) in the direction of its decreasing electrochemical potential.
What is an example of secondary active transport?
glucose takes advantage of Na+ transport so glucose can travel against its own gradient
* glucose movement coupled with Na transport
What are 3 basic types of secondary transporters?
uniport
symport
antiport
Pores are generally open or closed?
open
Channels are generally opened or closed?
intermittently open (gated and selective)
Carrier are generally opened or closed?
closed
What is the difference between osmolaRity and osmolaLity?
osmolaRity: mOsm/kg
osmolaLity: mOsm/L
What is osmolarity?
number of osmotically active particles in solution
Osmolarity is based soley on the __________
solute concentration
What is osmotic pressure?
pressure required to stop movement of water from one compartment to another
What is an ideal v. non-ideal membrane?
ideal: only permiable to H2O
non-ideal: permiable to H2O and solute
What is the osmotic pressure if the membrane is permeable to water and all solutes?
0
What does it mean if a membrane reflects solute?
non-permiable membrane
What value indicates a reflection coefficient for a non-permiable membrane?
1
What does it mean if a membrane doesn’t reflects solute?
permeable membrane
What value indicates a reflection coefficient for a permiable membrane?
0
What is normal plasma osmolarity?
300 mOsm
How do you calculate osmolarity?
molarity x particles
(concentration) x (number of particles broken down into)
What is tonicity?
measure of the water gradient that exists between two solutions
tonicity depends on what 2 factors?
solute concentration
permeability of membrane
What value is considered hyperosmotic?
> 300 mOsm
What value is considered hyposmotic?
< 300 mOsm
A solution with lesser osmotic strength than solution inside the cell and solute is not permeable across membrane will cause cell to _____ and is considered a __________ solution
swell
hypotonic
* Water moves in the direction of higher osmotic pressure
A solution with greater osmotic strength than solution inside the cell and solute is not permeable across membrane will cause cell to _____ and is considered a __________ solution
shrink
hypertonic
* Water moves in the direction of higher osmotic pressure
Osmolarity of a solution is no an accurate predictor of its _______. Why?
tonicity
easily membrane permeable solutes (glycerol/urea), when placed in hypertonic solution (500 mOsm of glycerol = hyperosmotic solution), the cell will swell
What is a diffusion dipole?
K+ (small molecule) leads Ac- (large molecule) through the membrane
What happens when a membrane is permeable to only one ion and not the other?
the resting membrane potential will equal the equilibrium potential for that ion
ex: resting potential = difference in K+ inside and outside
What is the Nerst equation and what does it tell you?
Eion = 60/charge x log [outside]/[inside]
(equilibrium potential) potential at equilibrium conditions where there is no current and no concentration gradient
What is the membrane potential?
charge difference between inside and outside of cell
What is equilibrium potential?
potential (charge) at which ion will not cross barrier anymore because charge on that side is sufficient (no more gradient)
At Nerst’s equilibrium potential for an ion, there is no movement because…
chemical and electrical driving forces are equal and opposite
Do all cells have membrane potential?
yes
What is a reversal potential?
outside current exceeds equilibrium potential so the flow of ions would go AGINST its concentration gradient
Does the action potential ever actually reach E na?
No
What is the positive feedback loop in an action poteential?
depolarization/influx of Na
What breaks the positive feedback loop in an action potential?
closure of Na channels
Na channels are _______ dependent activation
K channels are ________ dependent activation
Na: voltage dependent
K: voltage dependent
What is the normal resting membrane potential?
-70 mV
What is the usual Na+ potential?
+60 mV
What is the usual K+ potential?
-90 mV
What are the basic steps of action potential?
- depolarization
- action potential
- repolarization
- refractory period
- rest
What happens during depolarization?
- Na+ channels open
- Na enters cell
- cell becomes more positive
What happens right after depolarization?
action potential (Na channels close)
What happens during repolarization?
- K+ channels open
- K+ leaves cell
- cell becomes more negative
Does the cell become more positive or negative during depolarization?
positive
Does the cell become more positive or negative during repolarization?
negative
What happens during hyperpolarization?
membrane potential moves to resting potential (-70 mV) but over shoots it
What is the absolute refractory period?
no stimulus can trigger another action potential
What is the relative refractory peroid?
larger than normal stimulus can trigger a new action potential
What prevents backward conduction of action potential?
refractory period
How does the action potential propogate?
spreads to nearby section of axon (domino affect)
What does myelin do?
stops leakage of current
increases action
Why is myelin not continuous?
allows for Na and K channels
* Node of Ranvier
and speed
What is the origin of membrane potentials?
the K+ that leaks from the inside of the cell to the outside via leak K+ channels and generates a negative charge in the inside of the membrane
Velocity of action potential os determined by what 3 factors?
- diameter/resistance of neuron
- size of stimulus
- degree of mylenation
How is the threshold reached to trigger an action potential?
a stimulus raises the intracellular potential to a threshold level and Na+ channels open instantaneously
How is an action potential an all or nothing process?
because unless this trigger is reached, an action potential will not happen
Na channels are _______ dependent inactivation
K channels are ________ dependent inactivation
Na: time dependent
K: voltage dependent
Whats the autonomic nervous system?
involvuntary
Whats the somatic nervous system?
voluntary
What are the 2 branches of the autonomic nervous system?
sympathetic
parasympathetic
What is the sympathetic nervous system?
fight or flight
What is the parasympathetic nervous system?
rest and digest
How does the autonomic v. somatic NS effect path differ?
autonomic: indirect path (ganglion)
somatic: direct path
Somatic nervous system always release _______ at neuromuscular junction to induce muscle contractions
acetyl choline
What are pre-ganglionic neurons?
cell bodies in spinal cord and is controlled by higher brain centers
What are post-ganglionic neurons?
send their axons directly to effector organs
Does the sympathetic NS use acetylcholine or norepinephrine?
both
Does the parasympathetic NS use acetylcholine or norepinephrine?
acetylcholine
What receptor does the sympathetic and parasympathetic NS use use to recept pre-ganglionic acetylcholine?
nicotinic receptor
What receptor does the sympathetic NS use to recept post-ganglionic norepinephrine?
adrenergic receptor
What receptor does the parasympathetic NS use to recept post-ganglionic acetylcholine?
muscarinic receptor
Both sympathetic and parasympathetic pre-ganglionic neurons secrete _________
acetylcholine
Parasympathetic post-ganglionic axons release __________
acetylcholine
sympathetic postganglionic axons release ___________
norepinephrine
What is the exception involving sympathetic axons that do not secrete norepinephrine but acetylcholine instead?
sweat, muscle hairs, and blood vessels
* in F/F there is a rise in body heat causing you to sweat to lower your temperature
also increased vasodilation for muscles to get more blood
SYMPATHETIC Pre-ganglionic nerves leave spinal cord from ______ to _____
throacic to lumbar
SYMPATHETIC PRE-ganglionic axons are short/long and myleinated/unmyleinated
short
myleinated
SYMPATHETIC POST-ganglionic axons are short/long and myleinated/unmyleinated
long
unmyelinated
Sympathetic ganglia are located close to spinal cord or target organ?
spinal cord
PARASYMPATHETIC Pre-ganglionic nerves leave spinal cord at ______ and _____
cranial
sacral
PARASYMPATHETIC PRE-ganglionic axons are short/long and myleinated/unmyleinated
myleinated
long
PARASYMPATHETIC POST-ganglionic axons are short/long and myleinated/unmyleinated
unmyelinated
short
Parasympathetic ganglia are located close to spinal cord or target organ?
target
What is the special nerve for the parasympathetic NS?
CR X
vagus nerve
Where is the vagus nerve located?
across diaphragm
What is dual innervation?
organs have both sympathetic and parasympathetic responses
What organ does not have dual innervation?
only has sympathetic b/c could not handle the change in dilation
Norepinephrine and epinephrine activates what receptor type?
adrenergic receptor
What kind of receptor is adrenergic recptors?
GPCR
What are the 2 types of adrenergic receptors?
alpha and beta
Norepinephrine activates mainly ____ adrenergic receptors
alpha
epinephrine activates mainly ____ adrenergic receptors
alpha and beta equally
alpha 1 adrenergic receptors are G___
Gq (activate)
alpha 2 adrenergic receptors are G___
Gi (inhibitory)
beta 1 adrenergic receptors are G___
Gs (activate)
acetylcholine activates what kind of receptor?
cholinergic receptors
What are the 2 types of cholinergic receptors?
muscarinic
nicotinic
Where are muscarinic receptors found?
all effector cells stimulated by postganglionic neurons
Where are nicotinic receptors found?
cell bodies of postganglonic neurons
What are nicotinic receptors stimulated by?
acetylcholine
What are muscarinic receptors stimulated by?
aceetylcholine
Nicotinic receptors are ______ channels
ligand gated ion
what is autonomic tone?
balance between the sympathetic and parasympathetic divisions of the autonomic nervous system
What part of the brain is important for the autonomic NS?
hypothalamus
What does the pituitary gland do?
control endocrine (under hypothalamus)
What gland secretes mpost of the bodies epinepherine? and cortisol
adrenal gland (stress response)
What receptor is used in the stress response?
nicotinic receptor
What are the 4 fluid compartments of the body?
- ICF
- ECF
- plasma
- specialized fluid
What is the 60:40:20 rule?
60% x body weight = water
40% x body weight = ICF
20% x body weight = ECF
How do you calculate the amount of plasma in the body
ECF x 25%
What is oncotic pressure?
osmotic pressure exerted by solute in blood capillaries
What is the hydrostatic pressure?
blood pressure on walls
What are starling forces?
forces responsible for moving fluid in and out of capillaries
What is the NET filtration pressure at the arterial end?
10 mmHg
What is the NET filtration pressure at the venous end?
-7 mmHg
What end of the capillary does fluid leave?
arterial
What end of capillaries does fluid enter?
venous
How does edema happen?
increase in pressure on the venous end of capillaries causes decrease in fluid absorption leading to pooling in tissue
lower concentration = ____ osmotic pressure
lower
higher concentration = _____ osmotic pressure
If only one ion can pass then what happens to the concentration of ion at equilibrium?
no change in concentration
increased/decreased membrane potential = more negative
increased
increased/decreased membrane potential = more positive
decreased
For ATPase, ___ Na in or out and ____ K in or out
3 Na – out
2 K – in
What is the partition coefficent?
the more soluble in lipid a solute is the easier it passes the membrane
tight junctions are selectively ________
permeable
apical side is located…
outside
basal side is located ….
inside
what is transcellular epithelial transport?
transport through the cells
what is paracellular epithelial transport?
transport between cells (junctions)
What is a leaky epithelia?
periable to ions
What is a tight epithelia?
not permeable to ions
Can water do para and/or trans-cellular transport?
yes (follows solute)
