Term
| What is the hierarchy of protein structure? |
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Definition
1) Primary
2) Secondary
3) Tertiary
4) Quaternary |
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Term
| What bonds contribute to tertiary protein structure? |
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Definition
Disulfide bonds between Cysteine residues;
Ionic bonds between charged sidechains;
Hydrophobic interactions among nonpolar sidechains;
Hydrogen bonds among distant amino acid residues. |
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Term
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Definition
Equilibrium is a steady state when the forward reaction rate is equal to the reverse reaction rate.
A + B <-> C + D |
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Term
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Definition
(change in net energy) ΔG°'=-RT(K'eq) Keq=[products]/[reactants] If Keq is: >1 (more reactants than products): bias towards product 1 (products=reactants): no bias <1 (more products than reactants): bias toward reactant If ln(Keq): >0: product 0: no bias <0: reactant If ΔG°': negative: product 0: no bias positive: reactant Rxn type: exergonic: spontaneous rxn towards product endergonic: requires energy for rxn
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Term
| Why do exergonic reactions require a boost? |
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Definition
| Even exergonic rxns require a boost because reactions consist of unstable intermediates, each of which has its own Keq. The Keq of the total rxn is only the net of all the small rxns that take place. |
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Term
| What are the mechanisms in which an enzyme can catalyze a rxn? |
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Definition
Hold the substrate in the proper orientation so that the reactant groups are closer together enhancing the probability of the rxn;
React with the substrate to form an unstable intermediate which readily undergoes a second rxn to form the products;
Side groups within the active site may act as H+ donors or acceptors in acid/base rxns;
binding event can place an internal strain on a susceptible bond that increases the probability of breaking the bond. |
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Term
| How do enzymes speed up the rate of rxns? |
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Definition
| Lowering activation energy. |
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Term
| Without an enzyme, what would happen in a rxn? |
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Definition
| The net energy (Gibb's energy) change will not change, and the final equilibrium state (Keq) will not change, but the products will be made slowly. |
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Term
| Enzymes have an active site that is...? |
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Definition
| specific for a certain substrate (recall lock and key model). |
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Term
| What are allosteric sites? |
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Definition
| Sites on the enzyme where other molecules may bind and modify the activity of the enzyme. |
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Term
| Many mammals have optimal rxn rates around __ degrees. |
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Definition
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Term
| At a higher temperature, a greater % of molecules will be above the activation energy, so... |
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Definition
| rxn will proceed faster, so the rxn will produce more product as you elevate temperature. |
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Term
| What are enzymes sensitive to? |
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Definition
| Temperature, salinity, pH |
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Term
| How can you compare enzymes? |
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Definition
Turnover number- number of substrate molecules transformed by a single molecule of enzyme per unit time under optimal conditions.
mol substrate/mol enzyme/min
Using this, we can compare enzymes which are both functioning at their optimal conditions (not standard conditions like in chemistry) so we can compare very different enzymes (different optimal temperatures) to eachother. |
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Term
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Definition
| The maximum rate at which a rxn can occur. |
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Term
Vmax vs. [substrate] graph:
What happens at low, intermediate, and high [substrate]? |
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Definition
low [substrate]: slow rxn rates
intermediate [substrate]: increased rxn rates
high [substrate]: leveling off of rxn rate because all the active sites on the enzyme are saturated |
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Term
| What does Km (the Michaelis constant) mean? |
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Definition
In terms of affinity, Km shows us how well an enzyme can deal with its substrate (at V1/2).
High Km: a lot of substrate required to get a rxn going, therefore low affinity;
Low Km: starts activities at a low substrate concentration, therefore high affinity |
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Term
| Changes in enzyme concentration (in terms of rxn rate vs. [substrate])... |
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Definition
| do not affect the Km, but affect the Vmax. |
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Term
| What are the important points of a Lineweaver-Burke plot? |
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Definition
| A Lineweaver Burke plot is a double reciprocal plot in which the x-axis is 1/[S] and the y-axis is 1/Vo. The x-int is -1/Km and the y-int is the (inverse of) 1/Vmax. The slope is Km/Vmax. |
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Term
| What is competitive inhibition? |
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Definition
The inhibitor blocks the substrate from binding to the active site of the enzyme (usually has similar structure to substrate). It binds reversibly to the enzyme, and high [S] can overcome the inhibition.
On the Lineweaver Burke plot, there is no change in Vmax (y-int) because Vmax can still be reached at high [S]-same amount of product, but there is an increase in Km (actually a decrease because it is inverse- less affinity) because the enzyme cannot bind to the substrate is much at V1/2. |
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Term
| What is noncompetitive inhibition? |
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Definition
The inhibitor DOES NOT bind to the active site, unlike competitive inhibition. The inhibitor binds to an allosteric site, which changes the folding of the enzyme to prevent the active site from working. This binding is reversible. The substrate CAN still bind to the enzyme but no product can be produced.
On the Lineweaver Burke plot, there is no change in Km because the enzyme can bind to the substrate just as well as normal- same affinity, but there is an increase in Vmax (actually a decrease, because it is the inverse- less product) it cannot produce as much product. |
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Term
| What is allosteric activation? |
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Definition
| it increases the sensitivity of the enzyme (increases the affinity) by binding to an allosteric site. |
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Term
| What is covalent activation? |
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Definition
| it is the phosphorylation of an enzyme, using ATP and kinase, which increases the amount of product produced without affecting the affinity. |
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Term
| What are the three types of pumps? |
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Definition
Contractile pumps- contractile chamber (heart)
External pumps- skeletal muscles can act as pumps by compressing the vessel walls
Peristaltic pumps- rhythmic wave of contraction |
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Term
| What is the difference between an open and closed circulatory system? |
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Definition
Open- circulating fluid enters a low pressure sinus once in the circulatory cycle and comes into direct contact with the tissue and mixes with extracellular fluids
Closed- circulating fluid remains within blood vessels at all points in the circulatory system |
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Term
| How does an open circulatory system work? |
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Definition
| Blood is pumped by the heart through the aorta series of arteries into the hemocoel; the hemolymph in the hemocoel bathes the organs; blood then reenters the heart from the hemocoel through the efferent vessels (in arthropods, through the ostia); the pressure of the hemolymph is very low |
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Term
| How does a closed circulatory system work? |
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Definition
arterial blood and venous return are connected by fine vessels that form capillary beds, which perfuse the tissues to provide oxygen and nutrients
found in vertebrates, some invertebrates (earthworms and cephalopods- squids and octopuses) |
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Term
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Definition
flows away from the heart
a - away - artery |
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Term
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Definition
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Term
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Definition
| chamber of the heart that receives blood |
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Term
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Definition
| chamber of the heart that pumps blood out |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| recovery system of fluid from the tissues to the venous system (through the thoracic duct) |
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Term
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Definition
| point in the cardiac cycle when the heart is relaxed -> low BP |
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Term
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Definition
| point in cardiac cycle when the heart is contracting -> increasing BP |
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Term
| basic circulatory plan: water breathing fish |
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Definition
| heart (deO2) -> gills (blood becomes oxygenated) -> body (receives oxygenated blood) -> |
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Term
| basic circulatory plan: air breathing tetrapod |
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Definition
| lungs (blood becomes oxygenated) -> LHS -> body (receives oxygenated blood) -> RHS -> |
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Term
| detailed circulatory plan: water breathing teleost fish |
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Definition
| atrium -> sinus venosus -> ventricle -> bulbus (NOT CONTRACTILE) -> afferent branchial artery -> gills (blood becomes oxygenated) -> efferent branchial artery -> dorsal aorta -> arterio-arterial anastomosis -> tissues (receives oxygenated blood) -> vein -> |
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Term
| What have some fishes evolved in order to deal with hypotoxic conditions? |
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Definition
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Term
circulatory system: air breathing teleost fish (electric eel)
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Definition
blood is oxygenated at the ABO, and flows meets the deoxygenated venous blood before returning to the heart, creating parially oxygenated blood, which is then pumped by the heart back to the ABO but also to the gills, where CO2 is removed, and then systemically again. gills are non-functional ABO is in the mouth |
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Term
| circulatory system: African Lungfish (Protopterus) |
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Definition
| the heart consists of 3 chambers, the atrium, ventricle, and bulbus cordis, all with a spiral fold to separate O2 and deO2 blood. the O2 blood that has been oxygenated at the lungs is then pumped through the heart to the gill arches, through the dorsal aorta, and to the tissues, which receive the O2. The de02 blood then goes through the other side of the heart towards the gills, where CO2 is released. Then, if the fish is submerged, the pulmonary artery which leads to the lung is closed and the blood flows through the ductus and back towards the tissues. However, if the fish is breathing air, the ductus is closed and the blood flows through the pulmonary artery to be oxygenated and then pumped back to the heart. |
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Term
| circulatory system: amphibian |
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Definition
| the heart is divided into 2 chambers, the LA and RA. the LA receives oxygenated blood from the lungs and pumps it through the artery to the tissues, where it becomes deO2 and goes back to the heart. on the way, however, it becomes partially oxygenated by mixing with oxygenated blood from the skin. this partially oxygenated blood is pumped through the RA through the pulmocutaneous artery to the lungs and the skin. the blood that is oxygenated in the lungs is then pumped to the tissues again, but the blood that is pumped to the skin meets up with the deoxygenated blood from the tissues again, partially oxygenating it, before being revieved into the RA and pumped back to the skin or lungs. |
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Term
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Definition
have 3 chambers: have 2 atria (LA and RA) and 1 ventricle
RA- deO2
LA- O2
spiral fold keeps O2 and deO2 blood somewhat separated; flow is regulated by resistance through blood vessels in the lungs |
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Term
| heart: non-crocodillian reptiles (ex: turtles) |
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Definition
partially subdivided ventricle allows some separation of pulmonary and systemic flow (horizontal septum)
flow separation is also maintained by differential pressure within the circulatory system |
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Term
| non-crocodilian reptile modes of circulation: normal |
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Definition
| present during normal breathing; low pulmonary resistance -> blood from RHS enters pulmonary artery; O2 blood from the LA goes through the left and right aorta |
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Term
| non-crocodilian modes of circulation: holding breath |
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Definition
R-L shunt
present during diving and breath holding; breath hold increases pulmonary resistance (b/c blood doesn't need to go to the lungs as it cannot be oxygenated at this time); deoxygenated blood is directed from pulmonary circulation to systemic circulation |
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Term
| non-crocodilian modes of circulation: active |
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Definition
L-R shunt
during periods of high activity; oxygenated blood is shunted from systemic circulation to pulmonary circulation (because blood needs to be oxygenated during activity); provides further enrichment of blood for the cardiac tissue |
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Term
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Definition
4 full chambers: 2 atria, 2 ventricles
fully divided septum separates pulmonary and arterial flow
RHS of the heart is pulmonary, LHS is systemic
aorta is split
right aorta- perfuses brain and muscles
left aorta - perfuses gut |
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Term
| crocodilian heart: normal, rest |
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Definition
weak R-L shunt
blood is weakly directed away from pulmonary and to systemic
low systemic BP (right aorta), so some deO2 blood from the RA goes through the left aorta and then through the formaen of panizza, mix with oxygenated blood in the RA |
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Term
| crocodilian heart: hold breath |
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Definition
strong R-L shunt
blood is strongly directed away from pulmonary to systemic
valve closes at the pulmonary artery, so blood is recirculated from RV to the aortas |
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Term
| crocodilian heart: normal, active |
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Definition
no shunt
blood pressure high in LV; O2 blood flows through the right and left aorta; deO2 blood flows exclusively through the pulmonary artery |
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Term
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Definition
| open duct between the pulmonary artery and the aorta (L-R shunt) because, in utero, no need for blood to go to lungs. after birth, the duct should close normally, but if it is not closed, then there is a L-R shunt due to low pulmonary vascular resistance, causing pulmonary hypertension. |
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Term
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Definition
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Term
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Definition
| duct that bypasses the liver (fetal liver not as active as in utero) |
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Term
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Definition
layer of proximal vessels
very flexible, important for arteries close to the heart because it dampens BP changes |
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Term
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Definition
layer of proximal vessels
contractile layer of smooth muscle |
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Term
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Definition
layer of proximal vessels
highly variable |
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Term
| endothelium (layer of proximal vessels) |
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Definition
| may allow small soluble substances to pass through |
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Term
| How does linear velocity vary across the circulatory system? |
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Definition
| Linear velocity decreases in the capillaries even though the vessels are getting finer |
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Term
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Definition
v- velocity is a linear measure (cm/s)
Q- flow is a measure of how much volume of blood moves through a vessel (cm3/s)
A- area is the cross sectional area of the vessel (cm2)
velocity is greatest when the total cross sectional area is the least. velocity is lowest when total cross sectional area is the greatest. |
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Term
v1/v2 = A2/A1
(v1)(A1)=(v2)(A2) |
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Definition
| works given that the flow will be constant as blood passes through a larger blood vessel (inelastic tube) |
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Term
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Definition
elements in a series are additive
Rt= R1+R2+R3
elements in parallel are additive of the inverse (ie if a branch branched off into 3 branches and then came back together into one so the 3 branches had been parallel)
1/Rt = 1/R1+1/R2+1/R3
which means the number of tubes will dictate how much pressure drop there will be |
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Term
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Definition
p=density of the liquid
Pd=pressure
v=velocity
arterial side: as one descends from the arteries -> arterioles etc, there is a pressure drop as resistance decreases (flow constant)
venous side: as one goes through the venous returns, velocity increases again as cross sectional area decreases but due to flexibility of the veins (in contrast to muscular arteries) the resistance of the veins is low, therefore the pressure remains low |
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Term
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Definition
Q=(P1-P2)∏r4/8ζL ζ = viscosity, L = lengt (do not have to memorize) 2 major assumptions: 1) tube is rigid 2)flow is not turbulent predicts: flow decreases as viscosity increases, flow decreases as the length of the tube increases, flow dramatically decreases as the radius decreases |
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Term
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Definition
silent
exhibits a parabolic velocity profile (velocity is 0 at the wall of the tube (boundary layer) and maximal at the centre)
circulatory system is designed for laminar flow to minimize turbulence |
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Term
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Definition
noisy
generates eddies and requires more energy to move through the vessel |
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Term
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Definition
| describes the amount of potential for turbulence in a given system. higher reynold's number means more likely to have turbulence. Re>1000 means turbulence will likely occur. |
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Term
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Definition
| the forces from the movement of blood through the arteries, the veins, and through the capillary bed; tend to push water OUT OF the lumen (inside of the capillary) and into the interstitial space; affected by vascular tone (amount of flexibility) |
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Term
| colloidal osmotic pressure (aka oncotic pressure) |
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Definition
| caused by the differences in solute concentrations (between capillaries and tissues, mostly albumin protein); albumin in the plasma has a strong negative charge, which helps the lumen to retain Na+ (Gibbs-Donnan effect); retained Na+ will also tend to draw water out of the interstitium into the lumen of the capillary |
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Term
| Starling-Landis Hypothesis |
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Definition
| blood plasma loses volume (fluid) in the initial segment of the systemic capillaries because hydrostatic pressure out of the lumen exceeds osmotic pressure into the lumen; about halfway through the capillary bed, the 2 pressures are equal; towards the end of the capillary bed, the hydrostatic pressure falls and is exceeded by the osmotic pressure |
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Term
| What do lymphatic ducts do? |
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Definition
| they help to return fluid back to the systemic circulation. lymph returns to circulation at the back of the neck. |
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Term
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Definition
| filter lymph fluid, have lymphocytes which can kill pahtogens |
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Term
| Why are lymphatics important in infections or injury? |
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Definition
| infections/injury cause an inflammatory response under the influence of histamine, which increases the permeability of capillaries and therefore causes local tissue swelling. lymphatics help to reduce fluid accumulation in affected areas. the reason lymph nodes become swollen when you have a serious infection is because they are working harder to reduce fluid accumulation. |
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Term
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Definition
| a filarial worm invades and blocks the lymph ducts that drain tissue areas, leading to extensive local swelling |
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Term
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Definition
| caused by flooding of the alveoli by fluid and is very dangerous as it prevents adequate gas exchange in the lungs. lymphatics are very important in clearing out alveolar fluid. during sepsis (blood infection), the permeability of pulmonary capillaries to fluid goes up, which can lead to this condition. |
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