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The Heart

The Heart Part 2

QuestionAnswer
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