Term
What percent of the TBW is extracellular fluid (ECF) and intracellular fluid (ICF)? |
|
Definition
|
|
Term
|
Definition
Percentage of blood volume made up of cells |
|
|
Term
How do you calculate Total Blood Volume (TBV)? |
|
Definition
TBV= Plasma Volume x 100 / (100-hematocrit) |
|
|
Term
How do you calculate volume of distribution? |
|
Definition
Volume = amount of tracer / concentration of tracer |
|
|
Term
For what particles does simple diffusion work for? |
|
Definition
Small (<200MW) and uncharged |
|
|
Term
Why does facilitated diffusion require no energy? |
|
Definition
It only transports particles down their concentration gradient |
|
|
Term
Why is water transfer via aquaporins faster than osmosis? |
|
Definition
Aquaporins are facilitated diffusion, which is faster than simple diffusion. |
|
|
Term
Why does active transport require energy? |
|
Definition
You transport against the concentration gradient. |
|
|
Term
What is the action of Na+/K+ ATPase? |
|
Definition
3 Na+ out of the cytosol and 2 K+ into the cytosol |
|
|
Term
What is the critical task that the Na/K ATPase performs in terms of osmolarity? |
|
Definition
It reduces the number of osmotic particles inside the cell so that it does not swell and burst. |
|
|
Term
How do secondary active transporters get their energy? |
|
Definition
They use the electrochemical gradient set up by another transporter. |
|
|
Term
What is a cotransport (symport) vs. a countertransport (antiport/exchange)? |
|
Definition
Cotransport have both solutes moving in the same direction.
Countertransport has the solutes moving in opposite directions. |
|
|
Term
What causes osmotic pressure? |
|
Definition
When two compartments separated by a semipermiable membrane have different concentrations of impermeable solutes. |
|
|
Term
When do behaviors of fluids in solution become more ideal? |
|
Definition
When they become closer to dilute |
|
|
Term
What is the major player in determining osmalarity in extracellular fluid? |
|
Definition
|
|
Term
What is the normal osmolarity in body fluids? |
|
Definition
|
|
Term
|
Definition
Tendancy of an external solution to resist expansion |
|
|
Term
What is an isotonic solution? |
|
Definition
145mM NaCl (290mOsm/L).
No change in RBC volume |
|
|
Term
What is a hypertonic solution? |
|
Definition
300 mM NaCl (600 mOsm/L)
Water comes out of the RBC by osmosis into plasma, shrinking it. |
|
|
Term
What is a hypotonic solution? |
|
Definition
50mM NaCl (100 mOsm/L)
RBC swells because water leaves plasma and enters the cell, leading to hemolysis when plasma is <200mOsm/L |
|
|
Term
When does hypernatremia/dehydration occur? |
|
Definition
Na+ concentration in serum is >146 mM.
Electrolyte imbalance due to lack of free water. |
|
|
Term
When does hypoatremia occur? |
|
Definition
When serum Na+ is below 135 Na+ mmol/L
Life-threatening at 120 mmol/L |
|
|
Term
What are the subunits of myosin-II? |
|
Definition
6 subunits:
one pair heavy, 2 pairs of light chains. |
|
|
Term
What is the function of Titin? |
|
Definition
It's the molecular spring that keeps the thick filament centered |
|
|
Term
What are the parts of the thin filament? |
|
Definition
Actin, tropomyosin, troponin |
|
|
Term
What subunit of troponin binds to Ca? |
|
Definition
|
|
Term
How many thin filaments surround a thick filament? |
|
Definition
|
|
Term
Where does actin bind on myosin (thick filament)? |
|
Definition
|
|
Term
Where does Calcium come from in muscles? |
|
Definition
The sarcosmic reticulum, especially near the terminal cistern near the T system |
|
|
Term
What pumps the Calcium into the SR at a high rate? |
|
Definition
SERCA, active transporter of Ca-ATPase |
|
|
Term
What helps sequester the Calcium in the terminal cisterns of the SR? |
|
Definition
|
|
Term
How many Ca are pumped into the SR by SERCA per ATP? |
|
Definition
|
|
Term
What causes the relaxation of a muscle fiber? |
|
Definition
SERCA pumping of a into the SR (ATP-dependent process) |
|
|
Term
What is an isometric contraction? |
|
Definition
"Same length"
Generates force with constant muscle length |
|
|
Term
What is an isotonic contraction? |
|
Definition
"same tension"
length decreases as the muscle shortens, force remains constant. |
|
|
Term
What type of contraction can do work? |
|
Definition
|
|
Term
|
Definition
A single contraction caused by a single AP |
|
|
Term
|
Definition
Muscle contraction has APs with frequency high enough to produce continuous maximal contraction in muscle |
|
|
Term
|
Definition
Total tension minus Passive Tension |
|
|
Term
Where is active tension maximal? |
|
Definition
Where there is a max overlap of thick and thin filaments allowing the most cross-bridges to form. |
|
|
Term
What are Type I muscle fibers? |
|
Definition
Slow twitch (Red Muscles) |
|
|
Term
What are type II muscle fibers? |
|
Definition
Fast twitch muscles (white muscles) |
|
|
Term
How to single-unit smooth muscles function? |
|
Definition
They funciton as a syncytium - muscle fibers electrically connected to each other via gap junctions. |
|
|
Term
What is myogenic activity? |
|
Definition
When single-unit smooth muscle produce phasic contractions. |
|
|
Term
How do type II smooth muscles initiate contraction? |
|
Definition
Neurotransmitter release (neurogenic not syncytial) |
|
|
Term
What innervates a multiunit subunit? |
|
Definition
|
|
Term
Where does the calcium for contraction come from for smooth muscle? |
|
Definition
|
|
Term
Where does Ca bind to in smooth muscle? |
|
Definition
Calmodulin to phosphorylate myosin |
|
|
Term
What allows persistant partial contraction of smooth muscle (tonus)? |
|
Definition
|
|
Term
What is the purpose of Alpha-1 adrenergic recptor activation and what activates it? |
|
Definition
NE
It increases IP3 and Ca to increase muscle contraction/BP |
|
|
Term
What is the purpose of Beta-2 adrenergic recptor activation and what activates it? |
|
Definition
Epinephrine
Increases cAMP to relax muscle and decrease peristalsis/BP |
|
|
Term
What causes the steady influx of Ca and Na in pacemaker cells? |
|
Definition
|
|
Term
What channel do pacemaker cells lack that ventricular cells do have? |
|
Definition
|
|
Term
What channels do ventricular cells possess that are not in SA nodal cells? |
|
Definition
Fast voltage-dependent Na channels that opens with depolarizations
Potassium channel called the K1 potassium channel that is open at voltages between -90 mV and -50 mV.
|
|
|
Term
At what rate do SA nodal cells fire without modulation? |
|
Definition
|
|
Term
At what rate do AV nodal cells fire without modulation? |
|
Definition
|
|
Term
At what rate do Bundle of His cells fire without modulation? |
|
Definition
|
|
Term
What type of blockage is marked by a >0.18 sec (180 msec) delay between atrial and ventricular depolarization? |
|
Definition
|
|
Term
What is it called when every other P wave is followed by a QRS complex? |
|
Definition
2:1 Second degree blockage |
|
|
Term
What type of blockage is determined by an AV node being incapable of conducting impulses? |
|
Definition
|
|
Term
How much stronger is the Left Ventricle pump vs the Right Ventricle? |
|
Definition
5 times stronger due to resistance |
|
|
Term
How are the systemic and pulmonary circuits arranged vs the vascular beds? |
|
Definition
Systemic/Pulmonary: Series
Vascular beds: Parallel |
|
|
Term
What is the relationship of velocity, CSA, and flow? |
|
Definition
|
|
Term
|
Definition
|
|
Term
Where is the most time spent by blood in the vascular cycle? |
|
Definition
|
|
Term
Where does the biggest drop in pressure occur in the circulatory system? |
|
Definition
Between the small arteries and the arterioles |
|
|
Term
How does the mean pressure vs maximal puslatile pressure change across the circulatory tree? |
|
Definition
The mean pressure always decreases, but the maximal pulsatile presure can actually be higher past the aorta. |
|
|
Term
Where is most of the blood found in the circulatory tree? |
|
Definition
On the venous side under low pressure. |
|
|
Term
How do the artery and vein paths of the circulatory tree differ in terms of pressure and volume storage? |
|
Definition
Aorta/large arteries: Pressure storage
Veins: Volume storage |
|
|
Term
|
Definition
The ratio between change in volume and change in pressure |
|
|
Term
How do you measure Cardiac Output in terms of pressure and resistancef? |
|
Definition
|
|
Term
How will raising pressure on the left side of the circulatory system affect blood flow? |
|
Definition
Raising the diastolic pressure will diminish the driving pressure through the pulmonary circuit leading to lung edema |
|
|
Term
How does the resistance of a vessel relate to the radius of the vessel? |
|
Definition
|
|
Term
How does flow rate of a vessel relate to it's radius? |
|
Definition
|
|
Term
What is critical closing pressure? |
|
Definition
If driving pressure drops 20-25 mmHg, blood flow stops completely because the intrinsic sympathetic tone causes the small vessels to close. |
|
|
Term
How does constriction/dilation affect critical closing pressure? |
|
Definition
Constriction: Increases CCP
Dilation: Decreases CCP |
|
|
Term
How does increased hematocrit affect viscosity? |
|
Definition
|
|
Term
How does a radius <200um affect viscosity? |
|
Definition
It results in fluidization of RBC and streamlined flow |
|
|
Term
How does velocity affect viscosity? |
|
Definition
At slow speeds viscosity increases |
|
|
Term
Where does blood flow fastest in a vessel? |
|
Definition
|
|
Term
When does turbulent flow occur in straight vs braches of vessels? |
|
Definition
Branches: Re > 1000
Straight: Re > 2000 |
|
|
Term
Why does Re increase during constriction of a vessel? |
|
Definition
The velocity of a vessel that's half the size will have a velocity 4 times greater, so Re is two times larger (turbulence more likely) |
|
|
Term
How does radius affect wall size of a vessel? |
|
Definition
A small radius requires a thin wall to maintain pressure, while a large radius requires a thicker wall to maintain pressure |
|
|
Term
What is the average length of a small artery? |
|
Definition
|
|
Term
How do the walls of the right and left ventricles and the sizes of the ventricles compare in the heart? |
|
Definition
Walls: Left ventricle 3 xs thicker than right
Size: Equal |
|
|
Term
What type of motion do myocytes enact? |
|
Definition
Oblique/Circumferential motions |
|
|
Term
What causes the differences in pressure between the Left and Right ventricles of the heart? |
|
Definition
The different wall thicknesses and radii
Left is 3xs thicker, 2xs larger radius = 120 mmHg
Right is 3xs thinner, 2xs smaller radius = 20 mmHg |
|
|
Term
How does contraciton of cardiomyocytes affect the heart? |
|
Definition
It increases wall tension, τ |
|
|
Term
How does concentric hypertrophy affect the heart (thickened walls)? |
|
Definition
More pressure can be generated, but volume inside the ventricle decreases => decrease in stroke volume |
|
|
Term
How does Dilated/eccentric hypertrophy affect the heart (radius increase)? |
|
Definition
Thickness decreases of the wall => pressure decreases.
More blood can be accomadated, but enough pressure can't be generated. |
|
|
Term
What happens to the excitation wave if the AV node pathway is blocked? |
|
Definition
The wave will not propagate |
|
|
Term
What are the low pressure and high pressure valves? |
|
Definition
Low pressure: AV Valves
High Pressure: Semilunar Valves |
|
|
Term
What causes the influx of extracellular Calcium during long cardiac contractions? |
|
Definition
Dihydropyridine receptors (L-type Ca receptors) |
|
|
Term
How can you increase the uptake of Ca into the SR? |
|
Definition
Beta-adrenergic agonists (phosphorylates phospholamban) |
|
|
Term
What are the preload and afterload for the heart? |
|
Definition
Preload: End diastolic volume
Afterload: Aortic pressure |
|
|
Term
What is the total force generated in contraction? |
|
Definition
Sum of active fores generated by contractile elements plus the passive force due to extension of muscle elastic elements. |
|
|
Term
How does stretch relate to force in the heart? |
|
Definition
The greater the stretch, the more forceful the contraction |
|
|
Term
What is the resting length of cardiac muscle sarcomeres? |
|
Definition
70% optimum length required for force generation |
|
|
Term
|
Definition
Influence of agents that alter contractility |
|
|
Term
What are positive inotropes? |
|
Definition
Increase contractility (noradrenaline, digitoxin) |
|
|
Term
What are negative inotropes? |
|
Definition
Decrease contractility (acetylcholine, Ca Channel blockers) |
|
|
Term
How do cardiac glycosides affect the heart? |
|
Definition
They inhibit the Na-K pump causing increased cytosolic Na, and increased Ca to improve contractility through SR load increase. |
|
|
Term
How are cardiomyocytes connected to each other? |
|
Definition
|
|
Term
What is contractility a measurement of? |
|
Definition
The amount of Ca available in the cytosol |
|
|
Term
How does excitation-contraction of skeletal muscle differ from cardiac muscle? |
|
Definition
It does not require an influx of extracellular Ca |
|
|
Term
How much tension does the cardiac muscle develop in order to double the systolic pressure within the ventricle? |
|
Definition
|
|
Term
What are the steps in atrial contraction? |
|
Definition
Atrial contraction
Isovolumetric ventricular contraction
Ventricular ejection
Isovolumetric ventricle relaxation
Ventricular filling |
|
|
Term
What is the End Diastolic Volume? |
|
Definition
Total blood contained in each ventricle. |
|
|
Term
|
Definition
|
|
Term
What causes the first heart sound? |
|
Definition
|
|
Term
What valves are opened for ventricular ejection? |
|
Definition
|
|
Term
What causes the second heart sound? |
|
Definition
Sharp closure of the semilunar valve |
|
|
Term
What is the normal stroke volume at rest? |
|
Definition
|
|
Term
|
Definition
|
|
Term
What are systolic and diastolic pressures? |
|
Definition
Systolic: Peal pressure reached during systole
Diastolic: Lowest pressure during diastole |
|
|
Term
|
Definition
Period during which the ventricle is contracting |
|
|
Term
How does shortening of diastole affect the heart at high rates? |
|
Definition
|
|
Term
|
Definition
Period of ventricular relaxation |
|
|
Term
|
Definition
It's the period between closure AV valve closes to the closure of the semilunar valve |
|
|
Term
What is overall heart rate shortening due to - systole or diastole? |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
Reflection of backward AV valve bending during isovolumetric ventricular contraction and impact of adjacent arteries with sudden increase in pressure from aortic valve opening |
|
|
Term
|
Definition
Association of slow rise in pressure as the atria and great veins fill. |
|
|
Term
What will an incompetence in the tricuspid valve cause? |
|
Definition
Regurgitation of blood through the valve during systole that would have an abnormal increase between c and v waves during rapid ejection. |
|
|
Term
How do you calculate MAP? |
|
Definition
|
|
Term
|
Definition
|
|
Term
When is the greatest change in volume in the heart? |
|
Definition
During rapid ventricular ejection and rapid filling |
|
|
Term
When is the least change in volume in the heart? |
|
Definition
Isovolumetric ventricular contraction/relaxation (no change) |
|
|
Term
What is the ejection fraction (EF)? |
|
Definition
|
|
Term
How do right and left ventricular SV compare? |
|
Definition
|
|
Term
What are the heart sounds caused by? |
|
Definition
The closure of the valves resulting in vibration of the valves, the heart, and the large arteries near them. |
|
|
Term
When is a third heart sound normal to be found? |
|
Definition
|
|
Term
What causes a fourth heart sound to be heard? |
|
Definition
|
|
Term
What causes a splitting of the second heart sound? |
|
Definition
The semilunar valves close with a delay of each other (pulmonary valve closes slightly later than aortic) |
|
|
Term
What causes an accentuation of splitting (physiological splitting)? |
|
Definition
Deep inspiration so that pulmonary valve closure is further delayed by larger blood amount being ejected. |
|
|
Term
What causes pathological splitting? |
|
Definition
A diseased left ventricle causes contraction to be less vigorous so the aortic valve closes after the pulmonary.
Inspiration leads to lessened splitting. |
|
|
Term
What are the effects of valve stenosis? |
|
Definition
Orifice of the valve is narrowed so that the velocity increases and flow is turbulent. |
|
|
Term
What is valve incompetence and what are the effects? |
|
Definition
Incomplete closure of the valve causes a leaky valve. |
|
|
Term
When are soft systolic murmors common? |
|
Definition
Children and anemic patients due to low viscosity. |
|
|
Term
What are the P, QRS Complex, and T waves representative on the ECG? |
|
Definition
P wave: depolarization of atria and initiates atrial contraction.
QRS Complex: Depolarization of ventricle and precedes ventricle contraction.
T wave: precedes ventricular contraction. |
|
|
Term
What is the end-systolic pressure-volume relationship (ESPVR)? |
|
Definition
The max pressure that can be developed by the ventricle at any given left ventricular volume.
Defines the max pressure generated at any given inotropic state. |
|
|
Term
What does the width of a pressure-volume loop show? |
|
Definition
|
|
Term
What does the height of a pressure-volume loop show? |
|
Definition
|
|
Term
What is the preload on the pressure-volume loop? |
|
Definition
Volume at which the mitral valve closes |
|
|
Term
What is the afterload on the pressure-volume loop? |
|
Definition
Pressure at which the aortic valve opens |
|
|
Term
How does the External/Internal work ratio compare to cardiac performance? |
|
Definition
The larger the ratio, the better the performance. |
|
|
Term
How is pumping effected if cardiac muscle compliance decreases? |
|
Definition
|
|
Term
How is pumping effected if cardiac muscle contractility increases? |
|
Definition
|
|
Term
How is pumping effected if aortic pressure increases? |
|
Definition
|
|
Term
How is pumping effected if venous pressure increases? |
|
Definition
|
|
Term
End diastolic volume increases causes what? |
|
Definition
|
|
Term
If diastolic pressure is 90 and systolic pressure is 135, what will your MAP be? |
|
Definition
|
|
Term
How does CO in women compare to men? |
|
Definition
|
|
Term
How many L/min and mL/sec of blood are pumped? |
|
Definition
|
|
Term
What are the long-term CO factors? |
|
Definition
Ventricular geometry
Ventricular compliance
Electrical Coordination of contraction |
|
|
Term
What are the short-term CO factors? |
|
Definition
Preload
Afterload
Contractility
HR |
|
|
Term
|
Definition
PP = SV/Aortic Compliance |
|
|
Term
What happens to pulse pressure when arteries are less compliant? |
|
Definition
|
|
Term
How does inhalation affect intrathoracic pressure, RA pressure, Pressure difference, and venous return? |
|
Definition
intrathoracic pressure = decreases
RA pressure = decreases
Pressure difference = increases
venous return = increases |
|
|
Term
What is the Mean Systemic Filling Pressure (MSFP)? |
|
Definition
Pressure values after circulation has been stopped and pressure has equalized between arteries, capillaries, veins, and cardiac chambers. |
|
|
Term
How will a 1L infusion of saline affect your MSFP? |
|
Definition
|
|
Term
How will decreasing the compliance of veins affect the MSFP? |
|
Definition
This makes the veins "less flacid," so that the circuits are more "full" and the MSFP increases |
|
|
Term
How does gravity affect "gauge" pressure above and below the heart? |
|
Definition
Above the heart: subtracts gauge pressure
Below the heart: adds gauge pressure |
|
|
Term
What happens to a vessel if pressure is negative inside the flexible vessel and positive outside of it? |
|
Definition
|
|
Term
What will happen to a vessel if the pressure is negative inside and the integrity of the vessel is damaged? |
|
Definition
An air embolism will occur |
|
|
Term
How does mean system filling pressure compare to mean arterial pressure and venous pressure? |
|
Definition
Always:
Lower than MAP
Higher than Venous Pressure |
|
|
Term
How is MAP calculated with an elevated HR? |
|
Definition
|
|
Term
What is the value of the mean circulatory filling pressure and how does saline addition affect it? |
|
Definition
7 mmHg
It increases it since it's more "full." |
|
|
Term
What is the difference between contraction, contractility, and contractile? |
|
Definition
Contraction: shortening and creating force
Contractility: Cardiac muscles contracting depending on Ca
Contractile: Protein/fiber/etc ability to contract |
|
|
Term
How will Increased Blood volume affect CO and Venous pressure? |
|
Definition
|
|
Term
How will an increase in heart contractility affect CO and VP? |
|
Definition
CO increases, CVP decreases |
|
|
Term
How will a hemorrhage affect CO and VR? |
|
Definition
Vascular volume significantly decreases so CO and VR drop |
|
|
Term
How does adipose accumulation affect CO and BV? |
|
Definition
Linearly increases BV and CO |
|
|
Term
How does hypertention affect obese people? |
|
Definition
It's a double burden - increase in afterload and preload |
|
|
Term
What ventricle is thicker in fetuses and newly borns? |
|
Definition
Right ventricle wall because it has been working harder in the womb. |
|
|
Term
|
Definition
Maintenance of constant blood flow to an organ despite changes in pressure gradient across the organ bed. |
|
|
Term
What are the major determinants of coronary blood flow? |
|
Definition
1. Perfusion Pressure
2. Myocardial Extravascular Compression
3. Local Myocardial Metabolism
4. Neurohormonal Influenecs |
|
|
Term
What is reactive hyperemia? |
|
Definition
Increase in blood flow in response to prior decrease in blood flow |
|
|
Term
How do you calculate Cerebral Perfusion Pressure (CPP)? |
|
Definition
CPP = MAP - ICP (Intracranial Pressure) |
|
|
Term
What are the most common vasodilator signals in the cerebral circulation? |
|
Definition
CO2 and pH
(increased CO2 and H+ causes cerebral vasodilation and increased blood flow) |
|
|
Term
How does low O2 concentrations affect the lungs? |
|
Definition
It causes pulmonary vasoconstriction |
|
|
Term
What does a reflection coefficient of 0 and 1 mean? |
|
Definition
0: freely permeable to the barrier
1: barrier is impermeable to the substance |
|
|
Term
What is the typical oncotic pressure of blood? |
|
Definition
|
|
Term
What is oncotic pressure? |
|
Definition
Pressure created by proteins in the blood plasma that tends to pull water into the circulatory system. |
|
|
Term
What pressure opposes oncotic pressure? |
|
Definition
|
|
Term
What are the typical hydrostatic pressure at the arterial and venous ends of the capillaries? |
|
Definition
Arterial end: 30 mmHg
Venous end: 15mmHg |
|
|
Term
What is the oncotic pressure and the hydrostatic pressure of the interstitial fluid? |
|
Definition
Oncotic: 3-6 mmHg
Hydrostatic: -1 and -5 mmHg |
|
|
Term
What pressure drives fluid movement of the blood? |
|
Definition
|
|
Term
How do lymphatic vessels differ from blood capillaries? |
|
Definition
They lack tight juncitons between endothelial cells and are permeable to proteins |
|
|
Term
How do you determine the net movement of blood? |
|
Definition
Hydrostatic pressure (P) - Oncotic pressure (Π)
If positive = net movement OUT capillary
If negative = net movement IN capillary |
|
|
Term
What happens if Hydrostatic pressure is greater than oncotic pressure? |
|
Definition
Filtration (movement OUT) |
|
|
Term
What happens if Hydrostatic pressure is less than Oncotic pressure? |
|
Definition
|
|
Term
What will increased capillary hydrostatic pressure cause? |
|
Definition
Increased filtration in the arteries |
|
|
Term
What will increased Venous Hydrostatic Pressure cause? |
|
Definition
Increased venous filtration (since absorption won't occur in the venous system and pressure won't drop as much across) |
|
|
Term
How will blocked lymph affect filtration and absorption? |
|
Definition
Intersitial Oncotic pressure would increase, thus the overall oncotic pressure drops and filtration will increase |
|
|
Term
How will a decrease in plasma protein affect filtration and absorption rates? |
|
Definition
Overall oncotic pressure will decrease since capillary oncotic pressure drops, thus overall filtration increases. |
|
|
Term
How will a increase in plasma protein affect filtration and absorption rates? |
|
Definition
Overall oncotic pressure will increase since capillary oncotic pressure increases, thus causing absorption to increase. |
|
|
Term
What NT is released by preganglionic sympathetic and parasympathetic neurons? |
|
Definition
|
|
Term
What receptors are on postganglionic sympathetic and parasympathetic neurons? |
|
Definition
|
|
Term
What is the primary NT released by postganglionic sympathetic neurons? |
|
Definition
Norepinephrine (but not always) |
|
|
Term
What is the NT released by postganglionic parasympathetic neurons? |
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Definition
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Term
What is the effector organ receptor sympathetic neurons? |
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Definition
alpha or beta (but not always) receptors |
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Term
What is the effector organ receptor parasympathetic neurons? |
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Definition
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Term
What blocks postsynaptic nicotinic receptors? |
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Definition
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Term
What blocks muscarinic receptors? |
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Definition
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Term
Where are α1 receptors present? |
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Definition
Postsynaptic sites in smooth muscle innervated by adrenergic sympathetic nerves |
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Term
Where are β1 receptors present? |
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Definition
postsynaptic sites of some adrenergic nerves like the heart. |
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Term
What usually stimulates β2 cells? |
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Definition
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Term
What will stimulating β1 receptors of the heart cause? |
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Definition
Increased HR and contractility |
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Term
What will β2 receptor stimulation cause? |
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Definition
relaxation of bronchioles, and vasodilation in arterioles with β2 receptors (like skeletal muscle arterioles) |
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Term
What will a cholinergic activation of the heart cause? |
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Definition
Decreased HR via cholinergic muscarinic receptors |
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Term
What will Adrenergic activation of the heart cause? |
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Definition
Increased HR and contractility due to norepinephrine release from sympathetic fibers activating β1 receptors |
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Term
What will cholinergic activation of blood vessels cause? |
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Definition
Little, if any, endogenous parasymp innervation of blood vessels |
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Term
What will adrenergic activation of the blood vessels cause? |
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Definition
Constriction via symp activating α1 receptors
Dilation via circulating epinephrine activating β2 in arterioles with β2 receptors. |
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Term
What will cholinergic activation of the lung bronchiole system cause? |
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Definition
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Term
What will adrenerigic activation of lung bronchiole muscles cause? |
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Definition
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Term
What will adrenergic activation of sweat glands cause? |
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Definition
Secretion (Ach but sympathetic) |
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Term
What type of system dominates heart rate control? |
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Definition
Cardioinhibitory parasympathetic control |
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Term
How do parasympathetic neurons influence SA cells? |
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Definition
They release Ach that activates muscarinic cholinergic recptors to activate potassium channels and decrease rate of depolarization. |
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Term
Without the normal cardio-inhibitory parasympathetic activity, what would be your HR? |
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Definition
100-120 bpm (following SA node cells) |
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Term
Aside from decreasing rate of depolarization, how else does parasympathetic activity influence the heart? |
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Definition
Decreases conduction velocity between cells
Decreases excitability of latent pacemakers |
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Term
How does norepinephrine affect SA node cells? |
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Definition
β1 adrenergic receptors are activated causes influx of Na and Ca through the If Channel
(increases depolarization rate -> increased HR) |
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Term
How does sympathetic stimulation affect SA Node Cells? |
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Definition
Decreases the threshold for Ca Channels -> increased excitability
(HR increases)
β1 adrenergic receptors increases depolarizatation rate (HR increases)
and increases Ca flow through voltage gated Ca channels |
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Term
How does parasympathetic stimulation affect SA Node Cells? |
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Definition
Ach released to muscarinic cholinergic receptors that activate potassium channels to hyperpolarize the cell and decrease rate of depolarization |
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Term
What will an increase in parasympathetic activity cause? |
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Definition
A stop of the HR for as long as 4 seconds. |
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Term
What will applying atropine do to the heart? |
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Definition
Muscarininc blocker: Raises the HR to 100-120 bpm.
Mimics a lack of parasympathetic inhibition. |
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Term
What will applying propanolol to the heart cause? |
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Definition
Blocks β1 receptors: slows the HR and decreases cardiac contractility and excitability.
Mimics a loss of sympathetic activity |
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Term
What nerve fibers densely innervate smooth muscle cells in arterioles? |
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Definition
Postganglionic Sympathetic Fibers that release Ach |
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Term
What will a decrease in sympathetic activity in the arterioles cause? |
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Definition
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Term
What is respiratory sinus arrhythmia (RSA)? |
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Definition
The heart beats more rapidly during inspiration and more slowly during post-inspiration |
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Term
What is the main cause of respiratory sinus arrhythmia (RSA)? |
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Definition
Inhibition of parasympathetic preganglionic cardiac neurons during inspiration |
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Term
How does the Valsalva Maneuver affect the heart? |
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Definition
Decreases CO and BP
Decrease in baroreceptor discharge
Sympathetic increases, Parasympathetic decreases
HR and contractility increase |
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Term
How does the standing from supine position affect the heart? |
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Definition
Decreases baroreceptor discharge and parasympathetic.
HR and contractility increases and so does vasoconstriction due to sympathetic activity. |
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Term
How does horrhagic and septic shock affect the heart? |
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Definition
Bradycardia and vascular resistance decrease causing BP to drop |
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Term
How does the diving reflex affect cardiac function? |
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Definition
Bradycardia and increased parasympathetic activity |
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Term
How does hypertension affect barorecptors? |
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Definition
They cause resetting due to accomodation. |
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Term
What causes the Cushing reflex and how does it affect the heart? |
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Definition
Low levels of cerebral blood flow.
Causes dramatic increase in sympathetic heart and arteriole activity to increase arterial pressure. |
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Term
What are the purposes of the baroreflexes from sustained exercise? |
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Definition
Restore lowered BP, HR/contractility are increased, CO increases |
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