Study PhysioMid2 Flash Cards

 
Pile Management Card
PhysioMid2

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Can the rate of Autorhythmic cells be modified by neural input?
Yes. it is influenced by Sympathetic or Parasympathetic stimulation
What would increasing K+ permeability do to the membrane potential of the cell?
Hyperpolarize
What determines heart beat rate?
Frequency of A.P/activity of pacemaker cells
what is the threshold for pacemaker potential?
-40mV
Do pacemaker cells generate their own AP?
Yes
Do pacemaker cells generate their own rhythm?
Yes
What is the pacemaker potential (b/c they don't have resting since they don't rest) start in mV?
-60mV
What is the other name for Myocardial Autorhythmic Cells?
Pacemaker cells
What is the mV for a resting membrane potential for a myocardial contractile cell?
-90mV
Can skeletal muscles exhibit summation and tetanus?
Yes
Who has a longer Refractory period? Skeletal or Cardiac muscle fiber?
Cardiac muscle fiber
How can you prevent tetanus in the heart?
(sustained contraction)
by the refractory period being as long as the contraction period allowing the heart to relax between contractions so the ventricles can fill with blood.
The plateau in the Action Potential of a Myocardial Contractile cell is caused by what?
Ca+ channels opening and : K+channels closing.
Do Myocardial contractile cells need Ca2+ :
Yes. they need Ca2+ to initiate contraction
Do Myocardial contractile cells have a :
T-tubules
Yes
Do Myocardial contractile cells have a :
Mitochondria?
Yes. Consumes 70-80%of the oxygen delivered to it by the blood.
Do autorhythmic cells contribute to contribute to the contractile force of the heart?
No.
The signal for myocardial contraction comes from what?
Autorhythmic cells or Pacemaker cells.
Cardiac muscle cells contract with or without nervous stimulation?
Without nervous stimulation
Cardiac muscles have what hormonal influence?
Epinephrine
Do cardiac muscles have a fiber arrangement of sarcomeres?
Yes
Are cardiac muscles striated?
Yes
Do Cardiac muscle contain mitochondria?
Yes
Ventricular muscle are arranged in what kind of arrangement?
This allows it to what?
Spiral arrangement. Which allows ventricular contraction to squeeze the blood upward toward the apex.
Gap junctions
allow electrical signals to pass rapidly from cell to cell.
Intercalated disks contain Desmosomes that do what?
transfer force from cell to cell
The chordae tendinae prevent
the valve from being pushed back into the atrium
Cardiac muscle cells are also called?
Structure?
Attached to each other by?
Myocardial muscle cells
Branched
Intercalated disks
Semilunar valves prevent what?
blood that has entered the arteries from flowing back into the ventricles during ventricular relaxation.
What if there is a hole in the septum
Deoxygenated and oxygenated blood mixing, less blood pumped into circulation by ventricles.
What is a heart murmur?
Unusual noises made by heart valves
Superior and Inferior vena cava flow into what?
Right Atrium
Right side pumps into which circulation
Pulmonary circulation
Left side of heart pumps into which circulation
Systematic Circulation
systematic circulation
takes blood away from the hearts
pulmonary circulation
takes blood to and from the lungs
Cardiac output
volume blood leaving either ventricle in time
Velocity=
V=Q(flow rate)/A(cross sectional area)
Resistance
1/r^4
Velocity
length/time
Flow rate
mL/min
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