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PHYS3
Heart I
| Question | Answer |
|---|---|
| What is the pericardium? | A fibrous sac that encoloses the heart |
| Mycoardium: | Walls of the heart |
| What are they made of? | Cardiac muscle cells |
| What lines the inner surface of the myocardium? | Endothelium |
| What is endothilium AKA? | Endocardium |
| What are the valves located between each atrium and ventricle called? | AV valves |
| What is their purpose? | prevent hte backflow of blood |
| What is the right AV valve? | Tricuspid |
| Left? | Bicuspid |
| What is the purpose of the pulmonary and aortic valves? | Prevent backflow of blood from pulmonary trunk into the right ventricle and fromt he aorta into the left ventricle |
| Where does blood flow in order? | Venca cava, right heart, pulmonary ciruclation, left heart, aorta, and sytemic circulation |
| How is cardiac muscle arranged? | Layers that are tightly bound together |
| Is it similar to smooth and skeletal muscle? | Yeah, it is a combo of both of their characterisitcs |
| CARDIAC MUSCLE CHARACTERISTICS | CARDIAC MUSCLE CHARACTERISTICS |
| What are the four main characteristics? | Striated, intercalated disks, gap junctions join cells and a conduction system |
| What does it mean for them to be striated? | Actin and myosin filaments are present |
| What are intercalated disks? | They attach myofibrils to keep cells together |
| What is the purpose of gap junctions? | Permit APs to be conducted from cell to cell |
| Are they present in skeletal muscle? | Nope |
| CONDUCTING SYSTEM | CONDUCTING SYSTEM |
| How are teh conducting cells in contact with other cardiac muscle fibers? | Uh...see above, gap junctions |
| What is the heart innervated by? | Sympathetic and parasympathetic nerve fibers |
| What specific parasympathetic nerve innervates the heart? | Vagus nerve |
| What do sympathetic fibers release? | NE |
| What do parasympathetic fibers release? | Ach |
| RECEPTORS ON CARDIAC MUSCLE | RECEPTORS ON CARDIAC MUSCLE |
| NE Receptors are: | Beta adrenergic |
| What other messenger released from the adrenal gland can have such a similar effect to NE? | EPI |
| What about receptor types of Ach? | Muscarinic type |
| What arteries supply the myocardium? | Coronary arteries |
| What do they branch from? | The aeorta |
| HEARTBEAT COORDINATION | HEARTBEAT COORDINATION |
| What must cardiac muscle cells do for their contraction to occur? | They must have APs |
| What are the sinoatrial node? | The conducting system cells where depolarization occurs to get the heart to beat |
| SEQUENCE OF EXCITATION | SEQUENCE OF EXCITATION |
| What is the sequence of excitation starting from the SA node? | SA noce-->both atria-->AV node |
| Where is the AV node located? | Base of right atrium |
| What occurs at the AV node that is unique? | There's a delay |
| See figure 12-11, P. 207 | P. 397 ANALYZED BELOW |
| What are the components of atrial excitation? Label start and end | SA (start) and AV node (end) |
| What are the components of the ventricular excitation? | Atrial relaxation (start) |
| What is theresting membrane potential? | -90 mV |
| With an AP, the membrane permeability of what 3 elements changes? | Potasium, sodium, calcium |
| At rest, what is amount of sodium and calcium in cell? | Low sodium, low calcium |
| At rest, what is the potasium allows in membrane potential? | low patisum at rest |
| What happens when the sodium allowance increases? | Depolarization |
| What does this force calcium channels to do? | Calcium channels open and remain open for a while |
| Why do they remain open for a while? | There's a slow permeability for the Caclium, so it has to come in slowly |
| What heppens when theCalcium channels eventually close? | Repolarization |
| What node geneartes the current that leads to the depolarization of all other cardiac muscle cells? | The SA node |
| What does it therefore exhibit; what is the term for this characteristic? | Pacemaker potential |
| What is the pacemaker potential? | brings the membrane potenitaial to the threshold and initiates an AP |
| What happens when the potasium is released from the cell? | Negative membrane potential |
| What is autamacity and which node does it apply to? | It is when the SA node can be self excited |
| With no humaral or neural input, what is the number of depolarizations of the SA node in a minute/ | 100 |
| THE ELECTROCARDIOGRAM | THE ELECTROCARDIOGRAM |
| What is the EKG? | Tool for evaluating the electrical events in the heart |
| What are its components? | P, T, QRS waves |
| What is the P-wave? What does it look like? | atrial depolarization; kinda of an isolated spike, first one |
| QRS wave: | Ventricular depolarization; complex |
| T-wave: | Ventricular replarization; little spike at end |
| EXCITATION CONTRACTING COUPLING | EXCITATION CONTRACTING COUPLING |
| What is needed for excitating coupling? Where is ti released form? | Calcium from the SR |
| What does it combine with? | tropinin |
| What is the major signal for calcium releases in the SR? | calcium entering the PM in an AP |
| What is this phenomena called? | Calcium induced calcium release |
| How can you increase the force of an AP? Why can you do this? | Increase CAclium, you can do this becasuse not all tropnin is saturated with calcium, so adding more calcium-->more binding-->greater force |
| Where does the calcium bind on the SR? | Calcium receptors on the surface of SR |
| Where does calcium flow? | into cystol |
| How many AP does a cardiac muscle undergo at a time? | Only ONE |
| Why? What is tetnus and why can't the cardiac muscle undergo this? | summartion of contraction; can't undergo it b/c it has a very long refractory period |
| What is a refractory period? | period during and after an AP when an excitatble membrane can't be re-excited |
| Can skelatal muscle undergo tetnus? | yep |
Created by:
talkglitter2486