Term
the basic types of activites required by the heart to impart potential and kinetic energy to blood |
|
Definition
excitation, condiction, & contraction |
|
|
Term
T/F in a normal heart excitation, conduction, & contraction are inseperately linked |
|
Definition
|
|
Term
Heart tissue that express excitability |
|
Definition
atrial m., ventricular m., conductive tissue, and pacemaker cells |
|
|
Term
specialize in contracting (doing work) |
|
Definition
atrial and ventricular muscle |
|
|
Term
capable of spontaneous depolarization |
|
Definition
|
|
Term
specialize in propagqating impulses from one area of the heart to another and can also depolarize spontanteously at a slower rate |
|
Definition
|
|
Term
pacemaker, transitional cells, purkinje cells, atrial and ventricular muscle cells are able to work together because... |
|
Definition
they display slightly different physiologic properties that alow them to preform cyclic activities |
|
|
Term
|
Definition
|
|
Term
|
Definition
transmit impulses throught the heart |
|
|
Term
|
Definition
the larger the cardiac cell size |
|
|
Term
|
Definition
|
|
Term
|
Definition
few myofibrils or mitochondria and a little glycogen
Have no intercalated disks |
|
|
Term
P cells are the macemakes cells that conduct at a velocity of |
|
Definition
|
|
Term
transmit impulses from P cells to other cells in the heart |
|
Definition
|
|
Term
Containnumerous myofibrils and mitochondria but lack well adaptive T-tubules. 20-30 microns long & make side to side (end to end) contacts via intercalated disks |
|
Definition
|
|
Term
|
Definition
have a well developed sarcoplasmice reticulum and t tubles. 100 microns in length. abundant myofibrils and mitochondria. COnduct at a velocity of 1m/sec |
|
|
Term
Cardiac cells are excited by cells that have |
|
Definition
inherent cyclic discharge rhythems |
|
|
Term
Cardiac cells form a network called __ because they can receive electrical impulses directly from other cells |
|
Definition
|
|
Term
Cardiac cells have what kind of syncytium? |
|
Definition
|
|
Term
intercalated disks are located at... |
|
Definition
|
|
Term
the functional specializations of intercalated disks |
|
Definition
desmosomes
fascia adherens
nexuses |
|
|
Term
These are sparce in sinoatrial & atrioventricular nodal cells but plentiful in Perkinje cells where conduction is rapid |
|
Definition
|
|
Term
The type of action potential produced in the SAN & the AVN |
|
Definition
|
|
Term
The tyoe of action potential that occurs in the atrial muscle cells, ventricular muscle cells & the purkinje system |
|
Definition
|
|
Term
Functions as the pacemaker of the heart by virtue of its high rate of spontaneous depolarization |
|
Definition
|
|
Term
Spontaneous discharges of the pacemaker does not alter what in other cells? |
|
Definition
inherent rate of discharge |
|
|
Term
Transmembrane poteneials (TMP) of SAN have no __ but do have ___ |
|
Definition
stable resting membrane potential; MRP |
|
|
Term
Maximum repolarization potential (MRP) |
|
Definition
|
|
Term
When __ is reached, the cells begin to hypopolarize & will eventually give rise to anothr action potential |
|
Definition
|
|
Term
___ has a long refractory periods which prevent the ventricles from being restimulated prematurely |
|
Definition
|
|
Term
The AV nodes properties are helpful in cases of.. |
|
Definition
|
|
Term
|
Definition
|
|
Term
AV node provides pacing at about __ of the SAN |
|
Definition
|
|
Term
The __ of the spontaneous change during pacemaer potential is one of the determinates of heart rate. |
|
Definition
|
|
Term
The slow decrease in TMP is brought about by ___ |
|
Definition
a decline in the outward potassium current |
|
|
Term
__ increases towards the end of the pacemaker potential |
|
Definition
|
|
Term
What increases during the rising phase of the action potential? |
|
Definition
|
|
Term
There is an absence of fast __ channels but a presence of __ __ chennels. |
|
Definition
|
|
Term
T/F The rising phase is caused promarily by calcium? |
|
Definition
|
|
Term
Increases potassium and thus will slow the heart rate |
|
Definition
|
|
Term
increases intracellules concentrations of calcium and sodium thus increasing the heart rate |
|
Definition
|
|
Term
The resting potential of fast action potentials is much more __ than slow action potentials |
|
Definition
|
|
Term
|
Definition
rapid initial depolarization characterized by a reversal potential |
|
|
Term
The reversal potential is almost soel caused by |
|
Definition
sodium influx through voltage-gated fast sodium channels |
|
|
Term
|
Definition
initial rapid repolarization that begins to return the potential towards zero |
|
|
Term
|
Definition
rapid decrease in conductance of the membrane to sodium and increase towards potassium |
|
|
Term
|
Definition
slow phase of repolarzation resulting in a plateau caused by slow influx of calcium and sodium |
|
|
Term
During the Phase 2 plateau, the cell membrane is more permeable to __ |
|
Definition
|
|
Term
Because of the Phase 2 shorter plateau, what can beat faster than the ventricles |
|
Definition
|
|
Term
|
Definition
a final rapid repolarization which returns the membrane to its resting potential |
|
|
Term
|
Definition
decrease influx of calcuim and an increase in outward flow of potassium |
|
|
Term
During what phase is calcium pumped back into the sarcoplasmic retculum or out into the extracellular fluid? |
|
Definition
|
|
Term
|
Definition
|
|
Term
During what phase is the excess sodium pumped out of the cell? |
|
Definition
|
|
Term
|
Definition
atrial & ventricular muscle cells & Purkinje fibers |
|
|
Term
__ eliminates the fast responses of muscle cells and Purkinje fibers and converts them to the slow type of action potential |
|
Definition
|
|
Term
|
Definition
|
|
Term
___ are calcuim antagonists and partially block the slow enterance of calcium. Can stabelize the heart in cases of arrythmias |
|
Definition
|
|
Term
True or False: The calcium that influxes during the AP is enough for contraction |
|
Definition
False; some must be brought in fromt he S.R. |
|
|
Term
Ways the rate of discharge in a pacemaker cells can change |
|
Definition
slope of diastic depolarization
threshold potential
resting potential |
|
|
Term
tachycardia is a possibe effect of__ |
|
Definition
|
|
Term
Stimulating __ will result in bradycardia, a negative chronotropic response. |
|
Definition
|
|
Term
|
Definition
negative chronotropic effect |
|
|
Term
Which statent about the features of cardiac cells is false?
A. the full polarity of the resting potential is not as great as other cells
B. The oversoot of the action potential is more
C. The time course of the action potential is slower |
|
Definition
|
|
Term
The transmission velocity in the atrial muscle, bundle of His & ventricular muscle is about... |
|
Definition
|
|
Term
Conduction velocity in the AV node is about (not in the Perkinje systern)... |
|
Definition
|
|
Term
In the Purkije systern the AV conduction velocity is about... |
|
Definition
|
|
Term
Conducton velocity depends on all of the following except:
A. Fiber diameter
B. Rapidity of depolarization
C. Rapidity of repolarization
D. Amplitude of the action potential |
|
Definition
|
|
Term
There is no wave for __ in the ECG due to this being simultaneous with another depolarization |
|
Definition
|
|
Term
cardiac muscle is different than skeletal muscle physiologically because.... |
|
Definition
cardiac action potentials are longer |
|
|
Term
The peak force of the muscle twitch in cardiac muscle is reached simultaneous with... |
|
Definition
the AP is reaching the end of repolarization |
|
|
Term
What, in cardiac muscle, not only initiates but modulates a mechanical event? |
|
Definition
|
|
Term
Because electrical & mechanical events are very near the same duration in cardiac cells, cardiac muscles cannot __ |
|
Definition
|
|
Term
___ strengthens the contractile process in the heart by interfering with the sodium-potasium movement in the cell-membrane |
|
Definition
|
|
Term
Tension and length are very hard to measure in cardiac muscle, so they may be replaced with |
|
Definition
cardiac output & end-diastolic volume |
|
|
Term
|
Definition
the ability of the heart to self-regulate in response to changing loads of inflowing blood |
|
|
Term
|
Definition
any agent which alters the force of contraction without changing the degree of strech on cardiac fibers |
|
|
Term
__ regulation occurs when filling of the heart increases cardiac metabolism & hence the force of contraction |
|
Definition
|
|
Term
__ regulation areises from a changing fiber length |
|
Definition
|
|
Term
True/False The heteromteric means expresses the Frank-Starling Law |
|
Definition
|
|
Term
__ of the energy requiremements of the heart are derived from non-esterfied fatty acids & the remainder by glucose |
|
Definition
|
|
Term
The heart does not need neural input to finction, but it is innervated by nerve terminals of the __ |
|
Definition
ANS (both sympathetic and parasympathetic) |
|
|
Term
These nerve terminals of the ANS contain:
A. granular vesicles = adrenergic
B. agranular vesicles = cholinergic |
|
Definition
|
|
Term
|
Definition
|
|
Term
__ innervation to hte heart increases te rate & force of contraction
A. sympathetic
B. parasympathetic |
|
Definition
|
|
Term
The phenomenon caused by isoproterenol may be regulated by __ |
|
Definition
increased intracellular levels of cyclic AMP, the second messenger for many beta actions |
|
|
Term
The parasympathetic activities of the heart are directed promarily towards __ |
|
Definition
|
|
Term
The parasympathetic system has very little effect on cardiac __ |
|
Definition
|
|
Term
Acetylcholine decreases the slow inward current due to calcium influx but more importantly, increased __, thus decreasing the effects of vagal stimulation. |
|
Definition
|
|
Term
increased extra cellular potassium limits he efffect of __ on __ muscles
A. Ach, atrial
B. APM; Purkinje
C. Ach; Purkinje
D. Ach; Ventricular |
|
Definition
|
|