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The Heart
The Heart Part 2
| Question | Answer |
|---|---|
| Pulmonary circuit carries blood where? | too and from lungs |
| systemic circuit carries blood where? | too and from anywhere in body but lungs |
| systole is what kind of motion in the heart? | squeeze |
| is systole de or repolarization? | depolarization |
| diastole is what kind of motion in the heart? | relaxing |
| Is diastole de or repolarization in the cell? | repolarization |
| When the heart is about to beat is the cell positive or negative? | negative |
| when the systole comes, what happens to the cell? | influx of positivity |
| depolarization makes the cell more pos or neg? | more positive |
| Name the two ions on the outside of the cell: | Na+ and Ca+ |
| What keeps a cell very negative? | big proteins and chlorides stuck in the cell bc can't go through the lipid bilayer- K- doesn't exert much of a charge compared to these |
| What tells the signal to be sent to squeeze? | depolarization |
| Repolarization makes the cell more pos or neg? | neg |
| What is Rhythmicity? | regular heart beat |
| What is Automaticity? | heart contracts spontaneously via pacemaker cells w/o nervous stimulation |
| Characteristics of Cardiac monocytes: | Small size Will synchronize to one another Single, central nucleus Branching interconnections between cells Intercalated discs connect them |
| What connects and allows for ion movements between intercalated discs? | gap junctions |
| What is responsible for conveying force of attraction? | intercalated discs |
| Who propagates action potentials? | intercalated discs |
| 2 types of cardiac myocytes: | conductive and contractile cells |
| Conductive cells= | ELECTRICITY MESSENGERS |
| Contractile cells= | SYSTOLE |
| conductive cells form what: | the nodes and electrical branches |
| contractile cells produce what: | the actual muscle contraction |
| contractile cells are what dependent: | Calcium |
| Cardiac action potential phases range from what to what? | 0-4 |
| Phases of cardiac action potential: | 0- depolarization 1- brief early repolarization 2- Plateau 3- repolarization 4- refractory |
| Inside the contractile cell is negative or positive? | negative |
| Outside the contractile cell is negative or positive? | Positive |
| Name some of the positive ions: | Na+ & Ca+ |
| What keeps the inside of the cells negative? | large proteins |
| Most of the time the cell is polarized or depolarized? | polarized |
| What happens when the cell depolarizes? | Inside becomes positive and outside becomes more negative |
| About how many times per minute is the squeeze/depolarization signal from a nerve sent to the cardiac myocytes? | 60/100 |
| What is systolic blood pressure? | squeeze/top number/depolarization |
| What is diastolic blood pressure? | relax/down (bottom number)/repolarization |
| What's the name for the type of signal that makes a signal jump? | saltatory conduction |
| In what phase of contraction is there an Influx of Na+ through voltage-gated sodium channels? | depolarization |
| In what phase of contraction is there a Slow Ca+ channels open at -40 mV and begin slow influx of Ca+? | depolarization |
| In what phase of contraction do the Fast Na+ channels close? | depolarization |
| In what phase of contraction do Voltage-gated potassium channels open; small shift to restore (-)? | brief (early) repolarization |
| In what phase of contraction is balance established between slow influx of Ca+ and slow efflux of K+ (both channels open) causes long duration of next phase? | plateau |
| In what phase of contraction is there an influx of Ca+ triggers Calcium-induced Calcium Release from stored Ca+ in SR. Causes cardiac mm contraction half way through the plateau phase. | plateau |
| In what phase of contraction do Slow Ca+ channels close? | plateau |
| In what phase of contraction is there a K+ efflux (flow out of cell) continues to flow out of cell since Ca+ channels are closed and no longer balance movement of K+? | Repolarization |
| In what phase of contraction do Slow K+ channels finally close, leading to return of resting membrane potential to -70 mV? | Repolarization |
| In what phase do Sodium-potassium pump restores balance, pumping Na+ out and drawing K+ in. Ca+ returned to sarcoplasmic reticulum? | Repolarization |
| In what phase is there complete repolarization past normal negative resting potential; no AP’s may be fired at -90 mV? | Refractory |
| What triggers the contraction of a cardiac myocyte? | Action Potential |
| T/F: The nervous system can/can not stimulate the cardiac myocyte contraction? | False, they can however control the rate at which the contractions happen. |
| Cells of what signal the action potential? | SA node |
| Action potential is essentially what? | A brief reverse in the polarity of the cell membrane (controlled by pumps embedded within) |
| What cells of the AV node fire action potentials? | pacemaker |
| At what number does the AP begin? | -60 |
| At what number does the AP hit threshold? | -40 |
| What is pacemaker potential? | happens at threshold, slow influx of Na+ ions |
| Pacemaker cells do or do not have a true resting potential? | do NOT |
| When do Ca+ channels open? | @ threshold |
| What happens as a result of the Ca+ influx? | "rising"/depolarization |
| How are the ion concentrations restored? | pumps |
| When is the cell at resting membrane potential? | -90 |
| slow calcium channels open when? | -40 |
| the similar influx and efflux of what two ions keeps the membrane relatively stable during the plateau? | Ca+ and K+ |
| When does the SR release large amounts of Ca+? | after plateau phase |
| What is calcium induced calcium release? | When the SR releases a large amount of Ca+ |
| Where does the conduction pathway of the heart start? | SA (sinoatrial) Node |
| 2nd step to conduction pathway of the heart: | Internodal tracts and Bachman's Bundle |
| 3rd step to conduction pathway of the heart: | Atrioventricular node |
| 4th step to conduction pathway of the heart: | Atrioventricular (AV) bundle of His |
| 5th step to conduction pathway of the heart: | Left and Right bundle branches |
| 6th step to conduction pathway of the heart: | Purkinje Fibers |
| Is Potassium negative or positive? What kind of effect does it have on the cell? | +1; makes cell more negative because "the positive people have left and thus, the environment/party has become more negative" |
| Depolarization results in what action in the heart? | Systole/squeeze |
| Repolarization results in what action in the heart? | Diastole/relax |
| What is the name for making a signal jump from node to node? | saltatory conduction |
| True or false: when using saltatory conduction, the signal loses strength as it moves? | false, strength of the signal remains the same all the way down |
| Systole should occur at what number? | 120mmHg |
| Diastole should occur at what number? | 70mmHg |
| Systole makes the cell more negative or more positive? | pos |
| Diastole makes the cell more negative or positive? | neg |
| Cardiac cycle relies on what? | Electricity |
| True/false: the signal for the heart goes through the spinal chord? | False, while it can influence the speed of it... it beats btw 60/100 bpm on its own- the heart generates its own electricity |
| The Sinoatrial (SA) node is _____________ firing | Always |
| The cardiac pacemaker has the highest rate of _______and therefore sets the pace | spontaneous depolarization (fastest automiticity) |
| What is Sinus rhythm: | normal electrical pattern established by the SA node |
| What is a node? | Group of conductive cells gathered in the heart |
| Nodes are sometimes or always in a state of slow depolarization? | Always |
| Action potential results as a result of what? | Spontaneous repolarization |
| What slows the signal from internodal tracts takes-100 msec to pass through? What does this delay allow for? | small diameter of AV cells; Atria to contract before the ventricles |
| What is the function of the AV bundle of His? | connects atria to ventricles electrically |
| Where are the Left and Right Bundle Branches? | |
| What do the Left and Right Bundle Branches send their signal through? | send impulses through the moderator band to papillary muscles of the right ventricle |
| What are purkinje fibers? | fast conductors that reach all ventricular myocytes |
| What is/happens during the first phase of the cardiac cycle? | Atrial Systole: Atrial depolarization + Contraction (signaled by the P wave) |
| What is/happens during the second phase of the cardiac cycle? | Early ventricular systole: Isovolumetric ventricular contraction + LUB (S1) |
| What is/happens during the third phase of the cardiac cycle? | Late ventricular systole: Ventricular ejection |
| What is/happens during the fourth phase of the cardiac cycle? | Early ventricular diastole: Isovolumetric ventricular relaxation + DUB (S2); Dicrotic wave produced from pressure change |
| What is/happens during the fifth phase of the cardiac cycle? | Late ventricular diastole: passive ventricular filling |
| What causes the "LUB"? | Slamming shut of the tricuspid and bicuspid valves |
| What causes the "DUB"? | Slamming shut of the semilunar valves |
| What is different in the phases of cardiac contraction and the neuron firing? | plateau phase because the heart has to have time to refill |
| What is the electrical pathway of the heart not following proper order called? | fibrillation |
| Who drives this whole cardiac cycle? | The brain who wants constant oxygen and sugar |
| How is pacemaker potential different than normal cardiac contraction? | No plateau |
| Describe pacemaker pre-potential: prt 1 | Me + cat (K+) hanging out in the house with lights out wanting to watch Netflix (@-70 unlike cardiac myocyte @-90) You're sitting there about to hit play and puppy comes in through dog door; you walk up to the golden retriever(Na+) and more come in. |
| Describe pacemaker pre-potential: prt 2 | you and the cat get up to check it out and cat (K+) leaves. As soon as you reach out to pet Golden R. the labs start coming in (TONs- Ca+) |
| Describe pacemaker pre-potential: prt 3 | You go and open the window (gap junct) and yell to the neighbors that the labs are out and they experience what you experience- dogs leave your house and disturb them. Cycle begins again- |
| What is the sinoatrial node's nickname? | the pacemaker |
| Cardiac output= | heart rate times stroke volume (amount of blood the heart pumps in one minute) |
| What is stroke volume? | Amount of blood ejected by the heart with each beat |
| Only two ways to affect cardiac output: | 1-change heart rate (faster=less time for ventricles to fill) 2-stroke volume (less time to fill means less volume) |
| Avg. heart rate for young adult female: | 72-80 bpm |
| Avg. heart rate for young adult male: | 64-72 bpm |
| bradycardia | persistent heart rate below 60 bpm |
| tachycardia | persistent heart rate above 100 bpm |
| two ways to change cardiac output: | Hormones Ionotropic/chronotropic agents |
| two neurotransmitters that affect cardiac output: | Norepinephrine-speeds Acetylcholine-slows |
| How to change C.O. with receptors: | proprioceptors baroreceptors chemoreceptors |
| What do proprioceptors measure? | balance |
| What do baroreceptors measure? | pressure |
| What do chemoreceptors measure? | chemical concentration (CO2, O2, and ph) |
| What receptor type detects change in BP? | baroreceptors |
| What kind of receptors are in your aorta, carotid arteries, and medulla oblongata? | chemoreceptors |
| What does ejection fraction mean? | heart only pushes out around 60-80% of blood from the left ventricle |
| Factors affecting stroke volume: | Preload Contractility Afterload |
| What is Preload? | tension/stretch due to filling of blood in ventricles (STRETCH) |
| What is contractility? | force of ventricular contraction |
| What is afterload? | obstacles like pressure that the ventricles have to overcome (PUSH) |
| What happens with fibrillation? | heart isn't contracting properly- depends on area for type |
| What do Ionotropic agents do? | affect contractility (force) of the heart (how strong) |
| What do chronotropic agents do? | Factors which influence heart rate (pulse) (how fast) EX: ACH +Nori |
| Describe Right sided heart failure: | blood is allowed to go back to the body (flooding); patient has Systemic edema (esp legs and feet), enlarged liver + spleen, ascites, jugular venous distension (JVD) |
| Describe Left sided heart failure: | Left ventricular failure; blood allowed to go back into the lungs/pulmonary circuit; patient has shortness of breath, pulmonary edema and coughing(pneumonia all the time) |
| What vein does the blood travel up from superior vena cava to the brain during Right Side heart failure? | Jugular vein |
| What is JDV? | Jugular Vein Distension; When blood travels up through Jugular vein through Superior vena cava to the brain |
| What does EKG/ECG stand for? | Electrocardiogram |
| What is an EKG? | record of electrical events in the heart |
| What does EKG measure? | wave of depolarization as it spreads |
| EKG tracks the.... | changes in polarity |
| What records the voltage difference between inside and outside the cell? | electrodes |
| What is the voltage difference between inside and outside the cell called? | transmembrane potential |
| depolarization wave traveling towards the lead will show a what? | a positive deflection above the baseline |
| depolarization wave traveling away from the lead will show a what? | a negative deflection below the baseline |
| Describe the P-R Interval: | Time from onset of P wave to beginning of QRS complex From beginning of atrial depolarization to beginning of ventricular depolarization |
| Describe the Q-T interval: | Time for both ventricular depolarization and repolarization to occur Rough estimate of the average ventricular action potential |
| Describe the S-T Interval: | Time that both ventricles are completely depolarized (plateau phase of action potential) |
| If the SA node fails what happens? | the AV node takes over and beats at 40/60 bpm |
| What is the AV node's nickname? | "the gatekeeper" |
| Elevated P wave indicates what? | Atrial enlargement |
| Elevated QRS indicates what? | ventricular enlargement |
| Tall and elevated P wave indicates what? | Myocardial ischemia |
| Long P-Q interval indicates what? | blockage of normal conduction pathway |
| Long Q-T segment indicates what? | Unidentifiable myocardial damage. Many tests ensue to locate source. |
Created by:
smhoffman
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