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25 Cards in this Set
- Front
- Back
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Diff between pulmonary and system circuits.
What do vessels do? Describe 3 types |
To and from lungs
to and from rest of body Carry blood through circuits, blood away from heart to heart permit exchange |
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Compare musculature between ventricles
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Left has more and its walls are thicker
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Which side of the heart is more muscular and why?
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Left, pumps blood with greater pressure
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Function of chordae tendineae?
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Prevents backflow into left atrium
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Blood coming from lungs goes through which valve first?
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Bicuspid
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Semi-lunar (pulmonary and aortic) valves do what?
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Prevent blood from flowing from aorta dn pulmonary artery back into atria
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Role of connective tissues and fibrous skeleton in heart?
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Connective:
physical support, elasticity, distribute force of contraction, prevent overexpansion Fibrous skel: stabilizes valves, isolates atrial and ventricular cells |
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Role of intercalated discs, and gap junctions?
Where does calcium enter from? |
Physcial coupling, electrical coupling
ECF and SR |
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What are the two classes of cardiac muscle cells? Give examples
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Muscle cells of Conducting system (modified cardiac muscle cells): internodal PW cells, AV bundle, bundle branches, purkinje fibers
Contractile cells |
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Describe path of electrical signal in a heart beat
On an ECG, where is a good spot to look for where electrical signal originates?Where atria contracts? Ventricles contract? |
SA Node-->internodal PWs (small delay)-->AV node-->AV bundle-->Bundle branches-->Purkinje fiber
Right before the hill starts going up small round lump before spike spike |
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What is depolarization of the heart due to?
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Slow influx of Na+ ions
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Describe ionic paths in skeletal and cardiac APs? How do the two APs compare?
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Rapid depol by entry of Na+ (Na+ ch. open)
Na+ ch close, Ca++ open PLATEAU Ca++ enters Ca++ closed, K+ open REPOLARIZATION K+ loss Cardiac much loooonger action potential and contraction |
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What is cardiac output? How is it calculated?
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Amoutn of blood pumped by each ventricle in one minute
HRate (beats/min) x Stroke volume (ml/beat) |
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Describe how stroke volume changes during different phases of contraction.
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Medium-high at Ventricular diastole, highest at end-diastloic volume, lower at ventricular systole, lowest at end-systolic volume
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Describe factors affecting heart rate
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Autonomic innervation: cardiac reflexes, tone, SA node
Hormones, Epi, norepi, thyroid hormone venous return |
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Heart rate describes what?
End-diastolic volume? End-systolic volume? Stroke voluime? |
How fast
Fill volume Empty volume How much |
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What does the cardiac reflex detect?
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blood pressure, dissolved gas concentrations
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How does norepi increase heart rate?
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increases rate of depol
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What is the role of the SA node? How is it modified? Give examples.
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Establish baseline
ANS: atrial reflex, stretch Parasymp stimuln: hyperpolarizes so slower depolarization and lower heart rate Symp stimuln: deduced repolarization, more rapid depol |
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What would stretching of the atria indicate? Hear response? How?
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increased blood return to heart, beat faster, increased symp activity, increased depol of atrial cells
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What does the Farnk-Starling principle state?
What are factors affecting end systolic volume? Describe them |
More in-more out
Preload: more blood in-->more stretch-->more force Contractility: how much force? Afterload: resistance to emptying heart |
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What is end diastolic volume?
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Fill volume
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What does inotropic mean?
Effect of symp stimln on it? How? Para stimln? How? |
Contractility of muscle tissue
Positive, release NE (more force, more pumped blood) Negative, ACh, less blood pumped |
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Effect of exercise on cardiac output?
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increase
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What is cardiac reserve?
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Diff between resting and maximal cardiac output
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