Cardiac Flashcards
Hyperplasia
Increase in number of cells
Hypertrophy
Increase in cell mass - cell number stays the same
Dysplasia
Abnormal organization of cells; change in number, mass or location of cells; often related to cancer
G-protein messenger system
Second messenger system; allows for dramatic magnification of signal
Crenation
When cells lose water and become shriveled
Hemolysis
Death/destruction of RBCs
Oncotic/Colloid osmotic pressure
Osmotic pressure across a semi-permeable membrane; capillary dynamics
Diffusion potential
Potential difference created by an ion crossing a membrane while moving down its concentration gradient
Equilibrium potential
Charge at which ions stop crossing a membrane
Resting membrane potential
Equilibrium potential for a cell membrane; ~-70 mV
Diffusion coefficient
Part of what determines membrane solubility; based on solute’s shape and size
Flow
(pressure)/(resistance)
Resistance
(viscosity)(length)/(radius^4)
Systolic pressure
Pressure when heart is contracting
Diastolic pressure
Pressure when heart is at rest
Pulse pressure
(Systolic) - (Diastolic)
Mean arterial pressure
Diastolic + 1/3(Pulse pressure)
Stroke volume
Blood ejected in one cardiac cycle
Cardiac output
(Stroke volume)(Heart rate)
Normal = 5 to 5.5 l/min
Anomsia
Inability to smell
Chorea
Jerky, arrhythmic movements
Sign of extrapyramidal pathology
Akinesia
Inability to easily perform voluntary movements; hesitation and jerkiness
Sign of extrapyramidal pathology
Athetosis
Slow, continuous, writhing movements of lips, tongue and extremities
Sign of extrapyramidal pathology
Ptosis
Droppy eye
Miosis
Constricted pupils
Mydrosis
Dilated pupils
Anhydrosis
Absence of or decreased perspiration
Compliance
Volume/pressure - venous compliance is higher than arterial
Laminar flow
Flow through a circular vessel is faster and smoother; non-laminar flow in blocked arteries is more turbulent and can be auscultated as bruits
Dichrotic notch
Upward tick in aortic pressure after ventricular ejection is complete; caused by rebound of elastic arterial walls
Aortic mean pressure
100 mmHg
Large artery mean pressure
100 mmHg
Arteriole mean pressure
50 mmHg
Capillary mean pressure
20 mmHg
Vena cava mean pressure
4 mmHg
Right atrium mean pressure
0-2 mmHg
Pulmonary artery mean pressure
15 mmHg
Pulmonary capillary mean pressure
10 mmHg
Pulmonary vein mean pressure
8 mmHg
Left atrium mean pressure
2-5 mmHg
Preload
Ventricular volume just before systole (end diastolic volume) - maximum volume
Affected primarily by venous side
Phases of cardiac action potential
Phase 0 - upstroke
Phase 1 - repolarization
Phase 2 - plateau
Phase 3 - repolarization (contains supranormal period)
Phase 4 - decaying membrane potential (determines heart rate)
SA node doesn’t have a plateau (Phase 1 and 2)
Intrinsic firing rates of the heart
AV - 70-80 bpm
SA - 40-60 bpm
Bundle of His - 40 bpm
Purkinje fibers - 15-20 bpm
Atrial kick
Atrium contracts - provides 15-20% of heart volume and increases contractility by stretching heart
SA node arrest (ECG rhythm)
Missed beat - no P, QRS or T
SA node never fired
May be caused by burst of parasym.
Junctional beat
Extra beat w/out a P wave
Someplace below SA node depolarizes
Juncitonal rhythm
No P wave before QRS complex
HR is set at AV or Bundle
Ryanodine
Most common receptor in calcium-induced calcium release mechanisms
Funny channels
Slow Na+ leak channels that create an unstable membrane potential
Sym and Parasym innervation of heart
Sym - atria and heart
Parasym - atria only
Frank-Starling Law
As EDV increases, contractility increases (to a point)
Ventricular Hypertrophy
Increased size of heart cells
Afterload
Pressure that the heart works against to pump blood - pressure in the aorta
Affected more by arterial side
Atropine
Anti-cholinerginic/parasympathetolytic
Starling forces
Capillary dynamics - how the combination of intravenous and extracellular oncotic and hydrostatic forces move water back and forth across capillary beds
Frank-Starling Law
EDV or pressure/CO or force
More in, more out (until you move past the apex)
Ejection fraction
Percentage of blood ejected w/ each heart beat
Normal = 55% = 70 mL