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107 Cards in this Set
- Front
- Back
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The diffusion of water across a semipermeable membrane
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Osmosis
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The movement of molecules across a selectively permeable membrane with the aid of membrane transport proteins
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Facilitated Diffusion
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THe spontaneous movement of molecules across a lipid bilayer from high to low concentration
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Simple Diffusion
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How is the speed of Simple Diffusion across a membrane measured?
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Flux = KpA(Co - Ci)
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Gases such as oxygen and carbon dioxide, steroids, and fatty acids are all examples of nonpolar molecules. By what mechanism are they transported across a biological membrane? Why?
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Simple Diffusion
Because they are nonpolar, so they diffuse fairly rapidly |
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Which mechanism of transport do ions such as Na+ and Cl- use to pass through the membrane?
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Facilitated diffusion if along the concentration gradient, or Active transport
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What is ficks first law of diffusion proportional to and inversely proportional to?
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Proportional:
Area or membrane Concentration difference across the membrane. Inversely Proportional: Thickness of the membrane. |
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How is water diffused through the membrane in Osmosis, despite its polar nature?
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Aquaporins
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What does Osmotic pressure depend on?
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The water concentration.
It will prevent more flow from one beaker to the other, if the beaker is too small to accommodate more water. |
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Tonicity has got to do with
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The solute, not solvent.
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Hypertonic cells have higher or lower solute compared to the medium/solvent?
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Higher solutes. Placing it into a medium, the water will flow into the cell causing it to burst.
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What will block active transport?
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Inhibition of ATP
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List the 4 primary active transport proteins
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All Plasma membranes: Na+/K+ ATPase = Na out and K in.
Ca2+ transport H+ Transport H+/K+ transport |
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Primary ion found in extracellular fluid?
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Na+
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What does the phosphorylation of the transporter (the phosphate coming from the breakdown of ATP) do to the transporter?
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Alters the affinity of the binding site
Alters the rate of conformational change |
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Two main properties of neurons
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Irritability - ability to respond to stimuli
Conductivity - ability to transmit an impulse |
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How is the interior and exterior charged in a resting neuron?
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Interior is negative
Exterior is positive |
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What is the reason for the maintenance of the difference in electrical charge established by the diffusion of ions?
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The Na+/K+ Pump
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How many Na+ are moved out the cell and how many K+ are moved into the cell during the active transport of the Na+/K+ pump?
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3 Na+ are moved out and 2 K+ are moved in
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Where is the trigger zone of the neuron?
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Axon Hillock
This is where the threshold stimulus is activated, causing a brief permeability to Na+ ions to rush into the cell causing Depolarization. |
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When the interior of the membrane becomes less negative due to the influx of Na+, and the exterior becomes less positive, what is this phenomena called?
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Depolarization
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When do the K+ channels begin to open? (pushing K+ out the cell)
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When the Depolarization phase reaches 0mV
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The movement of K+ out the cell, decreasing the charge from +35mV, what is this phase termed?
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Repolarization
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What reestablishes the resting membrane potential?
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The K+ flowing out the cell during repolarization
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During repolarization, can a strong stimulus initiate anything?
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Yes, called the relative refractory period
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When is the Absolute refractory period occurring?
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When the sodium gates are open and the membrane is totally insensitive to any additional stimuli.
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Which phase is termed "all or nothing"
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The depolarization phase of the action potential.
This does not have to happen in every neuron in a nerve. |
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What 3 things can elicit a nerve impulse (action potential)
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1. Chemicals
2. Touch 3. Electric Shock |
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What is the instrument that measures the voltage changes over time?
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Oscilloscope - the voltmeter
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All neurons in a nerve are termed
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Compound nerve action potential
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A higher voltage will depolarize more neurons in a nerve? True or false
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true
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What are some environmental things that can inhibit a nerve impulse
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1. Deep Pressure
2. Cold Temperature 3. Local anesthetics - Lidocaine, Ether 4. Alcohol 5. Curare |
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Sodium channel antagonist that prevents sodium channels from opening
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Lidocaine
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A plant extract that paralyzes prey, an alpha toxin that binds to ACh binding sites on the postsynaptic cell membrane, blocking synaptic transmission by preventing neural impulses to flow from neuron to neuron.
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Curare
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What does the speed of transmission of an impulse depend on
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Conduction velocity of the axon - diameter, size, myelination
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What is used in conjunction with the Oscilloscope to amplify the depolarization of the exterior of the membrane to facilitate the recording of the event?
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Bio-amplifier
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Autorhythmicity is a property found in which type of muscle?
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Cardiac muscle (and some smooth muscle which isn't excitable)
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What is the heart rate dependent on? Which cells do these act specifically?
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SNS - Norephinephrine
PNS - Acetylcholine Act on the pacemaker cells. |
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Age, physical fitness, and emotional state can alter what in terms of the heart?
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Resting Heart Rate (average is 70bpm)
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Where does the heart receive the Sympathetic input from?
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Several nerves extending from the spinal cord
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Where does the heart receive the Parasympathetic input from?
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A single pair of Vagus nerves
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How many phases are in the cardiac action potential?
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Phase 0: Depolarization opens Na+ channels to increase membrane potential
Phase 1: Inactivation of Na+ channels to decrease the membrane potential slightly. Simultaneously, K+ channels close, Ca2+ channels open to buffer the fall of the membrane potential caused by the inactivation of Na+ channels. Phase 2: "Plateau Phase" Remains depolarized. K+ stay closed, Ca2+ stay open. Phase 3: THe internal potential falls gradually when the other K+ channels continually remove K+ from the cell, and this causes the Ca2+ to start closing until the Ca2+ stops flowing into the cell, allowing for the resting potential to be reached. Phase 4: The period of resting potential until the next depolarization. |
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What ions are present in large quantities inside and outside the cardiac cell?
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Outside: Na+ and Ca2+
Inside: K+ |
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What is the resting potential of the cardiac membrane dependent on?
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The ratio of extracellular and intracellular concentrations of Potassium
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State the proportionalities of Flow rate
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Flow = delta Pressure gradient / Resistance
(Pressure gradient - difference between the pressures at the two ends of the pipe.) |
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For the blood, what is the pressure gradient referring to?
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The difference in the pressures between the arteries and veins that results when the blood is pumped into the arteries
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What are the main factors determining Resistance?
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Blood vessel radius, length, and blood viscosity
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How does the Radius of the blood vessel affect the resistance?
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Smaller radius = greater resistance
Due to the frictional drag between the blood and the vessel walls. |
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How is radius affected?
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Vasodilation or vasoconstriction
Lipid deposits. |
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What is the single most important factor in determining blood flow Resistance?
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Blood vessel radius
(diameter) |
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How does blood vessel length affect resistance?
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Longer vessel = greater resistance
Due to friction between the blood and vessel walls |
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What is viscosity primarily determined by?
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Levels of Hematocrit (fractional contribution of RBCs to the total blood volume)
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Describe the two types of blood flow that can be seen as the fourth factor in determining resistance?
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Laminar Flow - calm, smooth blood flow along the length of the vessel. Most blood flows this way.
Turbulent Flow - quick and rough flow. |
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Which equation expresses the relationships between blood pressure, vessel radius, vessel length, and blood viscosity on Laminar blood flow?
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Poiseuille's Equation
Proportional to: Pressure gradient difference, Radius^4. Inversely: Viscosity, Vessel length |
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What is the body's main method to controlling blood flow throughout the body?
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Via contraction or relaxation of the smooth muscle found in the tunica media of an artery.
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Which vessels are very important to mediate in order to maintain arterial blood pressure?
What is released in response to rapid blood flow in these vessels? |
Resistance vessels: Small arteries and arterioles that regulate blood flow throughout the body.
They can release Nitric Oxide (vasodilator) in response to rapid flow, reducing shear stress. |
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Blood consists of two main parts:
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Plasma - proteins, nutrients, solutes
Formed Elements - RBC, WBC, Platelets |
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Viscosity in: Anemia and Polycythemia
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Anemia = low RBC count = low viscosity
Polycythemia = high RBC count = high viscosity |
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Increasing resistance does what to flow?
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Reduces flow
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When does the flow of blood go through the atrioventricular valves into the ventricles?
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During Diastole
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What is the blood volume called in the ventricles at the end of diastole called?
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EDV
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When either the Atria or Ventricles begin to contract, this is called?
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Systole
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When does the pressure within the ventricles rise due to the force of the myocardial walls on the enclosed blood, at the same time closing the AV valves?
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At the start of Systole
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The contraction observed in the ventricles at the start of systole, before the opening of the semilunar valves, is termed?
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Isovolumetric Contraction
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What needs to occur during Systole in order to open the Semilunar valves?
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The pressure during the isovolumetric contraction needs to keep rising to force the opening of the semilunar valves, then the pressure can fall. This is termed Ventricular Ejection
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After Ventricular Ejection, when the ventricular pressure falls below the aortic pressure, what happens?
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Semilunar valves close.
Systole ends. |
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At the end of Ventricular Ejection, a volume of blood approximately equal to that ejected during systole remains. This volume is referred to as:
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End Systolic Volume
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The amount of blood each ventricle pumps per minute
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Cardiac Output
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Which law states that when the rate at which blood returns to the heart changes, the heart will adjust its output to match the change in inflow?
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Frank-Starling Law
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How does exercise lead to an increase in the stroke volume of the heart?
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As more blood is returned to the heart, the amount of blood pumped to the body per contraction per ventricle (stroke volume) increases.
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A “normal” stroke volume is:
Normal heart rate: Normal Cardiac output: |
A “normal” stroke volume is: 70 ml
Normal heart rate: 75 beats per minute Cardiac output: 5 liters per minute. (This is the approximate volume of blood in the body) |
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What is the difference between the EDV and ESV
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Stroke Volume
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Starling’s Law tells us that when more blood than normal is returned to the heart by the venous system...
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...the heart muscle will be stretched, resulting in a more forceful contraction.
This, in turn, will cause more blood than normal to be ejected by the heart, raising stroke volume. |
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The heart is composed of three major types of cardiac muscle:
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Atrial muscle
Ventricular muscle Specialized Excitatory and Conductive muscle fibers |
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What is the difference in time span of Atrial and Ventricular Cardiac muscle vs. Skeletal muscle
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The atrial and ventricular types of muscle contract in much the same way as skeletal muscle, except that the duration of contraction is much longer.
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How is the contraction of the Specialized Excitatory and Conductive muscle fibers?
What compensates for this? |
The Specialized Excitatory and Conductive muscle fibers contract only feebly because they contain few contractile fibrils.
Instead, they exhibit either automatic rhythmical electrical discharge in the form of action potentials or conduction of the action potentials through the heart, providing an excitatory system that controls the rhythmical beating of the heart. |
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In addition to the atrial muscle fibers contracting slightly quicker than the ventricular muscle fibers to allow filling, special importance of this system is that it allows all portions of the ventricles to contract almost simultaneously, which in turn benefits the heart in what way?
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It is essential for most effective pressure generation in the ventricular chambers.
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This rhythmical and conductive system of the heart is susceptible to damage by heart disease, especially by what?
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Ischemia of the heart tissues resulting from poor coronary blood flow.
The result is often a bizarre heart rhythm or abnormal sequence of contraction of the heart chambers, and the pumping effectiveness of the heart is often severely affected, even to the extent of causing death. |
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What are the Internodal pathways in the heart responsible for?
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They conduct the impulse from the sinus (S-A) node to the atrioventricular (A-V) node.
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What is the A-V bundle responsible for?
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It conducts the impulse from the atria into the ventricles.
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Purkinje Fibers are responsible for ?
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They conduct the cardiac impulse to all parts of the ventricles.
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This ability of the heart to generate its own contractions is called
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Autorhythmicity
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Heart Rate and Strength of contraction are modified by what?
(Despite it's ability to generate it's own impulses) |
Sympathetic and Parasympathetic divisions of the ANS
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What increases the:
Rate of Sinus Nodal discharge Rate of conduction and excitability in all portions of the heart Force of contraction of all the cardiac musculature |
Norepinephrine
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What decreases the:
Rate of rhythm of the Sinus Node Excitability of the A-V junctional fibers between the atrial musculature and the A-V node, thereby slowing transmission of the cardiac impulse into the ventricles. |
Acetylcholine
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A small portion of the current spreads all the way to the surface of the body, and this is measured by the?
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ECG
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What does the frontal plane (parallel) of the ECG leads consist of?
What about the Transverse (perpendicular) plane? |
Frontal Plane:
3 Augmented limb leads 3 Standard Leads Transverse Plane: 6 Chest Leads |
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What is another name for the 3 Standard Leads?
Why are they called this? List the 3 Leads and explain them. |
Bipolar Leads.
They record differences in potential between a positive and negative recording electrode. I - RA(-) to LA(+) II - RA(-) to LL(+) III - LA(-) to LL(+) |
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What is it called when the 3 Standards leads form a shape over the body?
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Einthoven's Triangle.
The amplitudes from these leads have a mathematical relationship to one another. |
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What is another name for the 3 Augmented limb leads?
Why are they called this? List the 3 leads and explain them. |
Unipolar Limb Leads.
They consist of one positive lead recording the potential difference between a signal recording electrode and a combination of other electrodes that form a composite negative electrode. aVR - RA(+) to LAL(-) aVL - LA(+) to RA/LL(-) aVF - LL(+) to RA/LA(-) |
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How is the view of the heart for the Augmented Limb Leads in relation to the Standard Leads?
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They are at a right angle to the Standard Leads
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What are the 6 chest leads recording?
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The electrical potential of the cardiac muscle immediately beneath the electrode. This is able to be done because the heart surfaces are close to the chest wall.
Relatively small abnormalities in the ECG recording can be identified through the individual chest leads. V1 V2 V3 V4 V5 V6 |
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Identify the part of the ECG:
1. Results from the Atrial Depolarization, occurs at the beginning of Atrial contraction 2. Results from the Ventricular Depolarization AND Atrial Repolarization 3. Results from Ventricular Repolarization 4. Ventricular Contraction 5. Period when the Ventricles are Depolarized 6. Period between the beginning of Atrial and Ventricular Excitation |
1. P-wave
2. QRS Complex 3. T-wave 4. Q-T Interval (Beginning of Q wave to end of T wave) 5. S-T Segment (End of S wave to start of T wave) 6. P-R Interval (Beginning of P wave to start of QRS) |
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In a normal heart, the average direction of the vector (direction of electrical potential generated by current flow through the heart) during spread of the depolarization wave through the ventricles, is called the ?
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Mean QRS Vector
(is about +59°, but it ranges from 0° to +90°) |
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Which Deviations are characterized by a mean electrical axis of:
-> 0° to -90° -> +90° to +180° Abnormal conditions that can cause axis deviation include: |
Left axis deviation: 0° to -90°
Right axis deviation: +90° to +180° Abnormal conditions that can cause axis deviation include: hypertrophy and position of the heart within the body. |
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List as many functions of the circulatory system:
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Transport: waste, nutrients, oxygen, hormones.
Maintain: Appropriate environment for all tissues for optimal survival and function of cells. |
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What is the main control for the rate of blood flow through most tissues?
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The tissue demand for nutrients and oxygen.
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What is the reason for the alternating pressures between the systolic pressures (120mmHg) and diastolic pressures(80mmHg)?
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The pulsatile nature of the pumping heart
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What is the pressure in the vena cava when blood is systemically returned to the right atrium of the heart?
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0mmHg
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What is the measurement used for the average of all the arterial pressures measured by millisecond over a period of time?
But, it is not defined as the absolute average, why? |
Mean Arterial Pressure (MAP)
It is not the average because the arterial pressure is nearer to the diastolic pressure than it is to the systolic pressure during the greater portion of the cardiac cycle. |
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What is the pulse pressure?
What is it indicating? |
The difference between the Systolic and Diastolic Pressures.
It indicates the changes in pressure during the contraction of the heart. |
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What is:
The force exerted by the blood against any unit area of the vessel wall? |
Blood Pressure
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What is the method to measure blood pressure called?
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The indirect Auscultatory method (using a stethoscope and a sphyngomanometer)
Values are not accurate, but within 10%. |
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What are the sounds called that are heard during the Auscultatory Method?
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Korotkoff Sounds
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What is the normal Pulse Pressure?
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40mmHg
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What is the normal MAP?
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70-100mmHg
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What is the formula to calculate MAP?
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MAP = Diastolic Pressure + (Pulse Pressure/3)
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