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Heart Test 4
A&P
| Question | Answer |
|---|---|
| How many chambers does the heart have | 4 |
| where is the heart found | mid sternum line, mid thorax, hand over heart is wrong |
| how many times does the heart beat per day? | 100,000 |
| How many liters does the heart pump a day? | 3,800 liters |
| Pericardium layers | Parietal and visceral layers, and myocardium |
| Parietal Layer, two layers | fibrous pericardium and parietal layer of serous pericardium |
| area between the pericardial layers with pericardial fluid | pericardial cavity |
| 3 heart wall layers | epicardium, (visceral layer of serous pericardium) myocardium, endocardium, (inner lining of the heart) |
| serous membrane dry? | No, always moist |
| Ventricles | ascending chambers |
| receiving chambers of heart | atria |
| Pulmonary artery | artery that carries O2 poor blood to lung from heart |
| Pulmonary Vein | Vein that carries O2 rich blood from lungs to heart |
| What do heart valves do? | Keep blood from flowing backwards |
| atrioventricular valves | atria to ventricle |
| systole | contract |
| diastole | relax |
| where is the lowest blood pressure in the body? | After semilunar valves when body relaxes in isovolumetric ventricular phase |
| How does metabolism compare from humans to trees? | The heart feeds the metabolism fast enough to keep it warm, trees don't have the metabolism to stay warm like mammals do |
| What is the myocardium made of primarily? | cardiomyocytes |
| What two kinds of cardiomyocytes are there? | Conducting and contracting cardiomyocytes |
| What is the shared job of intercalated discs and desmosomes? | Keep the heart cells attached to each other in spite of massive strain |
| What is the job of gap junctions? | Communicate via flow of ions between cells |
| Which is the right side semilunar valve? | Pulmonary semilunar valve |
| What is the left side semilunar valve? | Aortic semilunar valve |
| Conducting, or pacemaker cardiomyocytes, what are they? | Modified muscle cells, instead of contracting they generate action potentials |
| Explain how the heart has an intrinsic conduction system | The pacemaker cardiomyocytes form the SA and AV nodes, so on and so forth. The SA node creates action potentials the fastest, so it tells the other cells what to do, at 100 bpm if left on its own. |
| What kind of fibers are towards the end of the hearts conduction system? | Purkinje fibers |
| What slows down the SA node from beating 100 bpm? | Vagal tone, through the vagus nerve. |
| Pacemaker/SA node activity for action potentials | autorhythmic, (doesn't need to be told) with no resting potential. |
| Pacemaker/SA node activity for action potentials, explain how it works | Extra leaky "funny" sodium channels always leaking, so the cell rises to -40, which then leaves threshold as Ca++ channels open into cell, up to +5-10, then potassium leaves the cell, bringing repolarization, and restarting again with the funny NAchannel |
| What does the SA node have instead of a resting potential? | Pacemaker potential, those funny sodium channels leaking like crazy into the cell. |
| What two ions are outside the cell? What one is on the inside? When does this flip flop? | Na+ and Ca++ outside the cell. K+ inside the cell. This flip flops at zero. |
| What junctions are between pacemaker and contractile cardiomyocytes? | Gap junctions, they need to talk |
| Electrical activity in contractile cells. Explain it | The cells start at -90. Na+ channels open, slowly rising to threshold, -70, and shooting up. Voltage gated K+ channels open at around +30, rapid repolarizing, quickly followed by slow Ca++ channels opening, this maintains a slow descent plateau until slow |
| Electrical activity in contractile cells. Explain it Part 2, you stopped at the Ca++ channels closing at the end of the plateau | Once Ca++ channels close, a rapid repolarization follows again, until K+ channels close, leading to -90 again. |
| Why is the absolute refractory period necessary in contractile cardiomyocytes. What about relative? | Absolute refractory periods are necessary as to not let the heart muscle involuntarily contract. Relative refractory periods are able to start another action, but need great stimulus to do so. |
| What two things affect cardiac output? | Stroke volume and heart rate |
| Tachycardia | fast heartrate |
| Internodal pathway | sinoatrial node Internodal pathway atrioventricular node atrioventricular bundle, bundle branches, then the Purkinje fibers |
| What is extrinsic control/regulation when regarding the heart? | Anything controlling the heart that isn't the heart |
| What are some examples of extrinsic control of the heart? (For the parasympathetic nervous system) | autonomic nervous system, parasympathetic. Decreases heart rate. Medulla oblongata (dorsal motor nucleus of vagus) cardioinhibitory center, vagus nerve, then SA and AV nodes through muscarinic cholinergic receptors |
| What receptors are responsible for slowing the heart rate? | muscarinic cholinergic receptors |
| Where does vagal tone like to stay for heart beats? | 70-75 bpm |
| Sympathetic cardiac nerves increase what two things? | Heart rate and force of contraction. |
| What is the sympathetic pathway to the heart? | Medulla oblongata, cardio acceleratory center, spinal cord (thoracic) sympathetic trunk ganglion, SA and AV nodes. |
| What receptors respond for the sympathetic pathway of the heart? | Adrenergic, beta adrenergic receptors on heart for norepinephrine. |
| Chemical regulation of the heart | Hormonal, and ionic |
| Hormonal regulation of the heart, epinephrine, what way does this reach the heart? | sympathomimetic, through the blood |
| Hormonal regulation of the heart, thyroxine, what does this do to the heart? | Stimulant |
| What ions are effective in regulating the heart? | Ca++, K+, Na+ (electrolytes) |
| Thinking of stroke volume, what is EDV, End diastolic volume? | Highest amount of blood found in ventricles |
| What is ESV, End Systolic Volume? | Least amount of blood found in the ventricles |
| How do you find stroke volume from knowing EDV and ESV? | Subtract end systolic volume from end diastolic volume, this is stroke volume. What was there minus what is left. |
| Stroke volume is what? | The amount of blood that leaves the heart. |
| Arteries go in what direction? | Away from the heart |
| Veins go in what direction? | To the heart |
| What is postural hypotension? | Getting up too fast without enough stroke volume to keep blood to the head. |
| What is preload? | The amount of stretch in the heart, corresponds up or down with stroke volume. The more it stretches, the more potential it has of blood to push out. |
| Arteries hold their shape, veins collapse. So, with this in mind, what effect would standing up have on End diastolic volume? | More blood would be pumped up to the heart, leading to higher EDV. Inaction drops it down. |
| What is contractility? | strength of squeeze, an increase of contractile strength due to sympathetic stimulation |
| What effect would norepinephrine have on b1 adrenergic receptors to the heart? | cardiac muscle force and velocity would increase. |
| What squeezes the heart harder to get a higher stroke volume | Anxiety/sympathetic nervous system |
| What is afterload? | The backpressure of the arterial blood pushing back |
| If the afterload pressure is 80 mm Hg, what pressure does the heart need to open the valve? | 81 mm Hg, gotta be higher than the afterload to open the door. |
| What is hypertrophy? | Thickening of the heart walls. Very bad, leads to lower age heart failure. |
| How does preload affect EDV and stroke volume? | They go up or down at the same time. One influences the other |
| How does contractibility affect ESV and stroke volume? | If one goes up, the other goes down. Getting more blood out. Decrease ESV creates increased stroke volume. Decreased EDV creates decreased stroke volume. |
| How does afterload affect ESV and stroke volume? | The opposite of contractability, increase of ESV creates a decrease in stroke volume. Decrease ESV creates an increase in stroke volume. |
| What is cardiac output? | The amount of blood pumped by each ventricle in 1 minute |
| What is the equation for cardiac output? | Heart rate x stroke volume = cardiac output |
| Cardiac cycle | all events associated with the flow of blood through the heart during one heartbeat |
| What is happening in the heart during ventricular filling? | semilunar valves closed, atrioventricular valves open, atrial contraction. |
| What is happening in isovolumetric contraction phase? | atrioventricular valves close, semilunar valves closed too. No fluid transfer. |
| What is happening at ventricular ejection phase? | atrioventricular valves closed, semilunar valves open. |
| What happens in isovolumetric relaxation? early diastole | All valves closed again, back to ventricular filling. |
| The lubb sound is the turbulence at the end of? | diastole |
| The dubb sound is the turbulence at the end of ? | systole |
| Murmurs | Abnormal, additional heart sounds. Turbulence where it shouldn't be. |
Created by:
JoshuaB5