Lab Exam Flashcards
Diffusion is a _____ process dependent on a solute ______.
Diffusion is a passive process dependent on a solute concentration gradient.
Molecular weight is ______ to molecular size
Proportional becuase molecular weight is grams per mole and a mole is 6.626x10^23
How does solute concentration affect the rate of diffusion?
Higher concentration gradient the higher the rate
How does molecular weight affect the rate of diffusion?
Smaller molecules has a higher rate of diffusion because it has a higher rate of velocity.
KE=1/2mV^2
If KE is constant a lower mass will have a larger velocity.
What is the driving force behind diffusion?
Kinetic Energy of the colliding particles
What does MWCO stand for? what does a large MWCO mean?
Molecular Weight Cut Off. a large MWCO means that it is a large pore.
fastest to slowest diffusion of urea glucose albumin NaCL
NaCl> urea> glucose> NaCl
Why do some solutes require a carries protein to pass through the membrane?
They are too big or a lipid insoluble (hydrophilic / polar)
whats the difference in facilitated diffusion vs. smile diffusion?
Facilitated requires a carrier protein while simple diffusion is just diffusion through the membranes it self
How does the number of protein carriers affect the rate of diffusion?
The more protein carriers the faster rate of diffusion. # of transporters is the rate limiting factor!
Explain what happens when protein carriers are saturated?
When the protein carriers are saturated all of the channels are being used so this is the max rate of diffusion. A low number of protein carriers will take it longer to reach equilibrium.
What is osmosis?
Osmosis is the diffusion if H20
How does water diffuse in terms of concentration of water?
Water travels from a higher concentration of water to a lower concentration of water. In other words is travels from low solute to high solute concentration
What is and what creates osmotic pressures?
It is the pressure that opposes the flow of water. It is created by the non diffusing particle. The larger concentration of non diffusing particles the smaller the osmotic force because it wants water to flow towards the system
What determines what passes through during filtration?
the size of the molecules
What type of pressure highly effects filtration rate?
Hydrostatic pressure
What type of physiology changes will affect the hydrostatic pressure?
Increase in BP or afferent capillary vasodilation will increase the hydrostatic pressure = increase filtration rate
Why does filtration rate increase with an increase of hydrostatic pressure but the filtrate concentration doesn’t?
Both water and solute are traveling at a higher rate so the concentration would still be the same.
Why is the Na+/K+ ATPase an active transporter?
It is an active transport because it uses ATP to move Na+and K+ against the concentration gradient
What is the resting membrane potential and what affects it?
It the voltage difference between the inside and the outside of the cell. It is influenced by the permeability and the concentration difference between the inside and the outside
how does the cell body and axon differ in terms of resting membrane potential
it is the same
Why doesn’t Na+ change the resting membrane potential as much K+
K+ is more permeable to the membrane therefor changes the resting potential more.
What affects the conductance of K+ and Na+
Conductance is simply the movement of K+ and Na+ across the membrane. It is affected by the open channels for the ion and the concentration gradient.
Explain how the the conductance of Na+ and K+ changes throughout an AP
@ rest K+ is more permeable
when depolarization occurs Na+ channels open, increasing the conductance of Na+ ions
AP are initiated @
Axon hillock, trigger zone
TTX vs Lidocaine
TTX blocks irreversibly and lidocaine blocks Na+ reversibly over time.
Lidocaine can block the AP to nocireceptors = no pain
What is inactivation of Na+ channels
Inactivation occurs at the top of AP and will cause absolute refractory period where a new AP is unable to propagte
What is the difference between absolute refractory period and relative refractory period
Absolute refractory period is due to inactivated Na+ channels so no AP propagation. In relative refractory some of the Na+ channels already “closed” because of repolarization so another AP is possible with a greater stimuli
what happens to the threshold when the intervals between stimuli is decreased?
The threshold becomes higher bc it takes a higher stimuli to propagate an AP bc there is less Na+ channels able to open and a lot of K+channels are open to depolarize the cell
What affects the conduction velocity of a neuron?
The mylenation and axon diameter
conduction is measure in meters/second
Describe the difference between A, B, C fibers
A is the fastest conductor bc it is the largest in diameter and most mylenated
whats inside the neurotransmitter vesicle and how is it released?
Its release is dependent on an action potential large enough to open up the Ca2+ ion channels. The influx of Ca2+ ions will release the vesicle of ACH and ACH will bind to open Na+ channels
How does the neurotransmitter reach the ion channels it will bind to?
Diffusion
How does having a small amount of Ca2+ extracellularly / Mg2+ extracellularly / normal ECF Ca2+ differ?
Mg2+ blocks Ca2+ channels so there will be no ACH release
Low ca2+ going in will result in less vesicles of ACH released
Under normal ECF Ca2+, whats the difference between a small stimuli and large stimuli?
A large stimuli will cause more release of ACH (through more exocytosis of vesicles, the vesicles contain the same amount of ACH every time)
Describe why Mg2+ blocks the ca2+ channels
Mg2+ has the same charge as Ca2+ so it is attracted to the same channel but Mg2+ is larger than Ca2+ so it ends up clogging the channel
Explain how a synaptic potential can be “graded”
If there is a a larger number of presynaptic release of ACH vesicles then there is an AP larger in frequency being transmitted into the new axon
Interneurons respond to neurotransmitter stimuli with a
Graded potential
interneurons are receptors?
then the receptors will trigger another neuron and this neuron will propagate an AP?
Describe the activity between a sensory neuron to a receptor neuron and onto an efferent nueron
The sensory neuron will release Ach vesicles onto the receptor neuron which will propagate a graded AP. The higher the stimuli the more ACH releases by sensory the larger the graded potential which will send a higher frequency of AP onto the next neuron
How does volume and pressures change in respiration
Inspiration: diaphragm and external intercostals contract which causes volume to increase so pressure decreases
Expiration: diaphragm and external intercostals relax to decrease the volume so pressure increases
What the volumes of TV, ERV, IRV, VC, TLC
TV = .5L ERV = 1-2L IRV = 2-3 L VC= 3-5L TLC=4-6L
What is the FVC?
FCV is the forced vital capacity which is the amount of air that can be expelled during an expiratory after a forced inspiratory
What is FEV1?
FEV1 is the amount of air expired at one second of a FVC
What is the difference between obstructive and restrictive airways?
Obstructive hinders air flow which can be seen in asthma / COPD
Restrictive reduces volumes and capacities as seen in Emphysema (loss of recoil)
How does FEV1 and FVC change in obstructive vs. Restrictive airways?
In obstructive airways the lung capacity is not changed so FVC is the same although it might take a longer time to inspire and expire but it is hard to expire so FEV1 is decreased
In restrictive airways the FVC decreases bc there is a decrease in lung capacity bc it does not extend as much and a decrease in FEV1 bc its hard to expire due to loss of recoil
What is FEV1% (compare and contrast obstructive and restrictive) and what does a lower FEV1% mean?
Obstructive: only FEV1 decreases so there is a decrease in the ratio, this mean that there is a higher airway resistance
Restrictive: both FEV1 and FVC decrease which makes the ratio stay the same so there is a normal airway resistance
Describe how pneumothorax leads to atelectasis
Pneumothorax is the result of a hole in the inter pleural space that will atmospheric pressure and interplueural pressure.
without the interplueral being less than the lung the collapsing force of the lung (from recoil and surface tension) the lung will collapse = atelectasis
describe how surface tension adds to the collapse force
Surface tension is the water lining the lungs and they try to hydrogen bond to each other while having adhesive forces to the wall.
How does the negative interpleural lung pressure result in inhibiting lung collapse?
since the interpleural pressure is less than the lung pressure the lung pushes out. Its like creating a suction to keep the lungs open
How does surfactant affect air flow?
Surfactant decreases surface tension so it allows more airflow into the alveoli. The increase airflow is because the diameter is larger therefor has less resistance
describe why a puncture to one side of the interpleural does not result in the collapse of both lungs?
both lung cavities are separate so one puncture does not result in both sides equalizing to the atm
What is laminar flow?
It describes how the flow in the middle vessel is the fastest bc there is no friction
What is the main way to regulate blood flow?
The main way is through local vasodilation / vasoconstriction of arterioles
What kind of graph does changing the radius of the vessels vs flow look like?
It looks like an exponential graph bc in terms of resistance radius affects it to the fourth power
Describe how a large diameter can also increase resistance?
In large vessels there can be a decrease of laminar flow bc the liquid “tumbles”back
How does viscosity affect the flow?
Viscosity increases resistance so it decreases flow. It popsicles it is not to the power of anything but after data collection we can see that viscosity decreases the flow exponentially
What components of the blood increases viscosity?
Proteins, platelets, blood cells
What physiological changes would result in higher viscosity of blood?
Dehydration, (polycethmyia too much RBC)
How does blood pressure affect flow rate
the greater the pressure (gradient) the faster the flow. The relationship is linear.
Pressure is created by the ventricles contractin
How will the heart react to an increase in flow rates?
It will beat faster so that the BP remains constant
How does a long diastolic period affect the cardio system
A long diastole will result in a longer filling time so more EDV which results in a higher SV.
What parameters can we change to keep BP constant?
We can change to SV, HR, and Resistance
Describe the intrinsic and extrinsic factors of SV
SV is intrinsically affected by EDV and after load. SV in extrinsically affected by ANS
Whats the difference between skeletal AP and a cardiac AP
A cardiac AP is longer due to Ca2+ plateau during phase 2. This is to prevent tetany of cardiac muscle
In terms of phases of the cardiac AP when is the absolute refractory period and the relative refractory period
The absolute refractory period starts at phase 1 and all the way half way through phase 3
The relative refractory period is from phase 3 and on
Whats a extrasystole and when can it happen vs not happen
Extrasystole is another AP propagation during the relative refractory period so this can only happen during diastole
Why is it important that the heart does not reach tetny
The heart needs a long enough diastole so that it can fill the ventricles before it contracts
Why is the wave larger in the force transducer for a ventricle contraction vs a trip contraction
the ventricle has more muscle mass so it has a greater force generated
Describe the height of the extrasystole as shown in the force tranducer
The extrasystole will either be smaller or the same height as the original ventricular systole…
it will be smaller if there was a low EDV bc low contraction force
It will be the same if there was a normal EDV
Describe how the SNS and PNS input affect the heart
SNS increases inotropy(contractility) and chronotropy (HR)
PNS decreases Chronotropy but does not affect Contractility
What does the vagus nerve do and what is it capable of?
It conducts PNS signals and too much PNS signal can cause the heart to stop
What is vagal escape?
this is when the heart beats again after it stops due to too much PNS signals because other pacemakers take over to generate the HR
it is done by an ectopic pacemaker
Map out the pacemaker cells and note which one is the main pacemaker
SA–> AV–> bundle of his –> purkinje fibers
The SA node is the main pacemaker and it has the faster AP propagation @100x per minute
Describe why the SA node propagates 100AP per minute but the normal HR @ rest is 70/min?
Its because @ rest we are getting more PNS signaling which decreases our heart rate
In terms of the AP how does PNS affect it?
the HR is slower so phase 4 (funny channels) rises slower
Cholinergic vs. Adrenergic modifiers of the heart and explain how it acts in GPCR
Cholinergic = Acetylcholine = acts as a Ginhibitor -> HR decreases
Adrenergic = Epi and Nepi = acts as a Gstimulator ->HR and contractility increases
Epinephrine
SNS, Binds to b1 adrenergic
Pilocarpine
Acetylcholine agonist = decreases HR
Atropine
Acetylcholine antagonist = increases HR
Digitalis
Increases contractility and decreases HR
the increase of contractility is due to Digitalis decreasing the activity of the Na+/K+ atpase. This decreases the activity of the Na/Ca exchanger which means there is more Ca2+ left inside the cell
Na/Ca wants to push out Ca by taking in Na but theres already enough Na inside
Digitalis decreases HR by increasing vagal activity
How will Ca2+ blockers affect the heart
It would decrease contractility due to tropomyosin biding
It would decrease HR bc Ca2+ is needed for AP
What will happen if there is an increase of K+ extracellularly of a heart?
It will increase HR bc K+ outside will decrease the amount of K+ flowing out so the restingmembran potential is higher and therefore closer to the threshold
What will happen when there is an increase of Na+
Nothing! bc Na+is already plentiful so it won’t affect the amount of Na+ coming in during AP so no change in HR
Na+ is not needed in contracting so no change in contractility
How does ca2+ blockers help hypertensive patients
Ca2+ blockers decreases contractility (SV) and HR which would decrease BP
Explain why an increase in stimulus would increase the force stimulated by muscles and what does it mean when maximal voltage is reached?
the higher the stimuli voltage the more motor unit is recruited so there is a higher force
The maximal voltage is the voltage @ which an increase will not cause the force to increase
What is the 3 phases of a muscle twitch and what occurs in each one?
Latent: a motor neuron is releasing ACH vesicles in the NMJ which results in Na+ channels opening and depolarization opens the Ryanodine receptor
Contraction: Ca2+ binds to myosin and cross bridges form
Relaxation: SERCA pumps pump Ca2+ back in the sarcoplasmic reticulum
Describe two ways to increase the force produced
Wave summation will reach max tension. This is because the muscle is being innervated more frequently and there is residual ca2+ which results in more cross bridge and a larger force
Recruiting more motor units can also increase the force produced (spatial summation)
Tetany is?
Sustained muscle contraction due to frequent stimuli
What is fatigue
the inability to to maintain the force due to a decrease in ATP or n increase in ADP, PI, Lactic acid. When there is a decrease in ATP there are less active cross bridges which results in less force
Describe how rest time affects fatigue?
The longer rest time the longer the muscle can hold a force. In other words the longer the rest time the slower fatigue will kick in. Bc at rest ATP is replenished and ADP and Pi is decreased
What is an isometric contraction
This is a contraction at which the muscle length is constant bc the amount of force made is equal to the amount of force need to hold something
Describe what the passive force is?
It is the force from titan wanting to recoil. It increases as muscle length increases
What happens when you vasoconstrict the afferent arteriole?
The pressure decreases because less blood is flowing and as a result the filtration rate is lower
What happens when you vasoconstrict the afferent arteriole
The pressure increases bc less blood is able to leave the glomerulus so there is an increase in pressure and an increase in filtration rate
Describe why glucose reabsorption is “secondary active transport”
It uses the Na+ from the outside of the cell to come bring in glucose through a cotransporter. It is a secondary transporter because it uses the Na+ that the Na+/K+Atpase transported out
Describe why some glucose will end up in the urine if there is too much glucose?
Glucose needs transporters to be moved out of the lumen back into the blood so it cane saturated when there is too much and the excess can be urinated. Note that the number of glucose transporters cannot be altered
Where is glucose reabsorbed?
In the PCT
Where does aldosterone come from and what does it do
Aldosterone comes from the adrenal cortex and it increases the reabsorption of Na+ and as a result will increase reabsorption of H20 in the DCT
Where does ADH come from and what does it do?
It comes from the posterior pituitary gland and it increases the aquaporins which increases the reabsorption of water in the collecting ducts
ANP
ANP acts to decreases BP by increasing urine volume
1) dilating the afferent arteriole
2) excrete H2O and Na+ in collecting duct
How does ADH affects the osmolarity of urine
It results in a hyper osmotic urine bc there is a large solute concentration
Describe how ANP affects the osmolarity of urine
It results in a hypo osmotic urine bc there is a lot of H20
