Cardio Flashcards
<p>T/F Oxygenated blood from the upper body is returned to the heart via the superior vena cava</p>
<p>F-oxygen poor blood is returned</p>
<p>What vessel is blood returned to the heart from the upper body?</p>
<p>The superior vena cava</p>
<p>What is the normal resting heart rate for a human?</p>
<p>70 bpm</p>
<p>What is the normal arterial pressure for a human?</p>
<p>120/80 mmHg</p>
<p>What are the normal hemocrit values for a human male and female?</p>
<p>F = 38-46% M = 40-54%</p>
<p>What is the top number in BP readings?</p>
<p>Systolic</p>
<p>What is the bottom number in BP readings?</p>
<p>Diastolic</p>
<p>What is hemacrit?</p>
<p>The total number of blood cells in the total blood volume</p>
<p>A normal heart shape and size = what?</p>
<p>A normal cardiac cycle</p>
<p>What does dialated cardiomyopathy cause?</p>
<p>Congestive heart failure (backflow of blood)</p>
<p>What are the three CV system components?</p>
<p>1. Heart2. Blood Vessels3. Blood</p>
<p>What does persistant high blood pressure cause?</p>
<p>High blood pressure damages the endothelium in the artery causing inflammation. The inflammation causes a plaque formation in the artery. The plaque causes a turbulant blood flow</p>
<p>What is atheroscleric plaque consist of?</p>
<p>Lipids, Calcium, Cellular Debris</p>
<p>What is a myocardial infarcation caused by?</p>
<p>The fibrous cap in the artery when there is plaque formation breaks and blood flow is hindered causing a heart attack.</p>
<p>What does the plasma contain?</p>
<p>WBCs and Platelets</p>
<p>What does coagulation of the blood lead to?</p>
<p>Thrombus formation leading to myocardial ischemia or infarcation (zero blood flow)</p>
<p>What is ischemia?</p>
<p>Decrease in Blood Flow</p>
<p>Define Hemorrhage</p>
<p>You lose the entire RBC including its membrane from the body</p>
<p>Hemolysis</p>
<p>RBC membrane ruptures</p>
<p>What can cause Hemorrhage or hemolysis?</p>
<p>Trauma, Major Surgery, Hemolytic Anemia or Hemophilia</p>
<p>How is cardiac muscle different than skeletal muscle in a histological sample?</p>
<p>Branching of fibers and intercalcated discs (At the tissue level)</p>
<p>What does it mean when we say cardiac muscle is a syncytium?</p>
<p>Many cells joined together allowing for fast conduction of action potentials from cell to cell</p>
<p>What does the distinct features of cardiac muscle allow for?</p>
<p>Resist fatigue and contract in a corrdinated fashion</p>
<p>What feature of cardiac muscle is important for pumping blood throughout the entire CV system?</p>
<p>Rapid, involuntary contraction and relaxion</p>
<p>What is responsible for providing low electrical resistance in cardiac muscle?</p>
<p>Intercalcated discs</p>
<p>Describe the pathway of blood to and from the heart</p>
<p>1.Low oxygenated blood -superior vena cava from upper limbs -inferior vena cava from lower limbs into the right atrium 2. right atrium 3. tricuspid valve 4. right ventricle. 5. pulmonary valve 6. pulmonary artery 7. Lungs Blood Picks up Oxygen</p>
<p>Where does the blood go after gaining oxygen in the lungs?</p>
<p>The pulmonary veins into the left atrium of the heart</p>
<p>Describe blood flow through the heart from the left atrium</p>
<p>1. Left atrium2. Mitral Valve (Bicuspid)3. Left Ventricle4. Aortic Valve5. Aorta6. Circulation</p>
<p>Define cardiac cycle</p>
<p>The sequence of events that occur during systole and diastole</p>
<p>Define Systole</p>
<p>Cardiac muscle contracts and pumps blood from the ventricles into the arteries (Blood leaves the heart)1st phase</p>
<p>Define Diastole</p>
<p>(Ventricle)Muscle relaxes and chambers fillBlood returns to the heart
2nd phase</p>
<p>Where is the heart located?</p>
<p>Slightly left and center</p>
<p>what do the coronary arteries supply?</p>
<p>Oxygenated blood</p>
<p>Where do electrical impulse begin in the heart?</p>
<p>At the Sinus Node</p>
<p>What does the conduction system of the heart do?</p>
<p>Keeps your heart pumping in a normal rhythum</p>
<p>On the posterior side of the heart what does low oxygenated blood enter?</p>
<p>The coronary sinus</p>
<p>How is the heart able to contract without any extrinic stimulation?</p>
<p>Through the intrinsic conduction system</p>
<p>Define the hearts intrinsic conduction system</p>
<p>It can be described as a group of specialized cardiac muscle cells in the walls of the heart that sends signals to the heart muscle causing it to contract.</p>
<p>Describe the path of the hearts internal conduction system</p>
<p>1. SA node2. Internodal pathways3. AV node4. AV bundle 5. Left and Right bundle branches6. Purkinje fibers to ventricle</p>
<p>What happens at the AV node</p>
<p>1. Impulse is delayed2. The delay allows atria to contract before ventricles</p>
<p>Where does the AV bundle take the electrical impulse?</p>
<p>Into the Ventricles</p>
<p>Where are the left and right bundle branches located?</p>
<p>Interventricular Septum</p>
<p>What is the other name for the sinus node</p>
<p>pacemaker node</p>
<p>What is the function of the SA node?</p>
<p>Signals the atria to contract</p>
<p>What is the primary function of the AV node?</p>
<p>To cause the ventricles to contract</p>
<p>What is the pacemaker potential?</p>
<p>Rhythmic discharge of Sinus Atrial nodal fiber</p>
<p>How many discharges are there in a minute at the SA node?</p>
<p>70-80</p>
<p>Which has a higher action potential in millivolts, the Sinus nodal fiber or ventricular muscle fiber?</p>
<p>Ventricular</p>
<p>What does the AV node do to the impulse conduction?</p>
<p>Slows it considerably to allow sufficient time for the atrial depolarization and contraction (systole) before the ventricle</p>
<p>Why don't the purkinje fibers need to discharge as frequently as the AV node?</p>
<p>They are located very close to the muscle</p>
<p>What is depolarization?</p>
<p>Membrane potential increases Phase 0 -->Fast Na+ channels open, then slow Ca++ open</p>
<p>Describe phase zero of ventricular muscle action potential</p>
<p>It is the phase where depolarization occurs and the fast sodium ion channels open and then the slow Calcium ion channels open. There is a sharp increase in membrane potential from negative to positive</p>
<p>Descibe what happens at phase 1 of ventricular muscle action potential</p>
<p>Slight repolarization-apex of the graph-K+ channels open</p>
<p>What happens in phase 2 of Ventricular AP?</p>
<p>There is a plateau-slower Ca++ channels open, -decreased permeability to K+-Membrane potential decreases but it is still postive</p>
<p>What happens in phase 3 of ventricular AP?</p>
<p>Repolarization-more K+ channels open-Membrane potential decreases to about -50</p>
<p>What happens in phase 4 of ventricular ap?</p>
<p>Resting membrane potential is acheived-85-95 mV</p>
<p>How long does an action potential take in the ventrcle?</p>
<p>about 1.75 second</p>
<p>What does calcium flowing into the cell cause?</p>
<p>Coordinated contraction</p>
<p>What does a S-T Segment elevation mean?</p>
<p>possible myocardial infarcation</p>
<p>What does the P wave of the ECG coorospond to?</p>
<p>Atrial depolarization</p>
<p>What does the QRS complex of the ECG corrospond to?</p>
<p>Ventricles depolarizing</p>
<p>What segments of the ECG does an R-R interval include?</p>
<p>RSTPQR -a full cycle</p>
<p>What is the Q-T interval on the ECG?</p>
<p>QRST</p>
<p>How long is a P-R interval</p>
<p>0.16 seconds</p>
<p>What does a T wave on an ECG indicate?</p>
<p>When the heart is being primed to relax</p>
<p>How does the heart speed up?</p>
<p>The sympathetic nervous system....1. Norepinephrine is released at the synapse2. Sinus node discharge increases3. Impulse conduction rate increases4. Force of contraction into atria and ventricles increases</p>
<p>What system is responsible for the heart rate to slow down?</p>
<p>Parasympathetic (Vagus cranial nerve X)</p>
<p>What is released to slow the heart rate?</p>
<p>Acetylcholine</p>
<p>What is the SA node and AV junctional fibers innervated by to slow the heart rate?</p>
<p>The vagus nerve (X)</p>
<p>When Ach is relased at the SA and AV junctional fibers what occurs?</p>
<p>Increased permeability of K+ causing hyperpolarization-rate of conduction impulse decreases-Decrease in force of contraction in atria and ventricles</p>
<p>What do we measure on the Y axis of the cardiac cycle?</p>
<p>Volume and pressure (Ventricular and Atrial volume and pressure)</p>
<p>What is the lub sound corrospond to?</p>
<p>Systole</p>
<p>What does the Dub sound corrospond to?</p>
<p>Diastole</p>
<p>Contraction \_\_\_\_\_\_ the pressure within a chamber</p>
<p>Increases</p>
<p>Blood Flows from \_\_\_\_ to \_\_\_\_\_\_ pressure.</p>
<p>Higher to Lower</p>
<p>Semilunar valves open when \_\_\_\_\_\_</p>
<p>Ventricular pressures are higher than aortic pressure</p>
<p>AV valves \_\_\_\_\_ when atrial pressures are \_\_\_\_\_\_ than ventricular pressure.</p>
<p>Open, higher</p>
<p>What is the first heart sound?</p>
<p>S1</p>
<p>What is each cardiac cycle initiated in?</p>
<p>The SA Node</p>
<p>How do you find the duration of the cardiac cycle?</p>
<p>Take the reciprocal of heart rate</p>
<p>What phase is ventricular systole?</p>
<p>Phase 1</p>
<p>How long does ventricular systole last?</p>
<p>0.3 seconds</p>
<p>What happens during phase 1: Ventricular Systole?</p>
<p>1. Isovolumic contraction2. Ventricular ejection</p>
<p>Define ventricular systole</p>
<p>Contraction in the ventricular myocardium</p>
<p>What happens during phase 2 of the cardiac cycle?</p>
<p>Diastole</p>
<p>What is diastole?</p>
<p>Relaxtion of the ventricular myocardium</p>
<p>How long is diastole?</p>
<p>0.4 sec</p>
<p>What are the steps in diastole?</p>
<p>3. Isovolumeric relaxation4. Rapid inflow5. Diastasis6. Atrial Systole</p>
<p>What is atrial systole?</p>
<p>Contraction of the myocardium (rt. and left atria)</p>
<p>How long does atrial systole last?</p>
<p>0.1 sec</p>
<p>Why does atrial systole occur during diastole?</p>
<p>Some blood volume is being deposited into the ventricles prior to ventricular systole</p>
<p>What happens during isovolumic contraction?</p>
<p>First step of Sytole- 1.The ventricular pressure rises rapidly without a change in volume2. All valves are closed</p>
<p>What do you hear during isovolumeric contraction?</p>
<p>The AV valves snap shut and you hear the lubb sound (S1)</p>
<p>Which statement about hypovolemia is accurate?AIt is defined as high ECF volumeBIt is caused by low ECF Na+ concentrationCIn response, sympathetic flow to the kidneys is increasedDTo correct it, the Renin-Angiotensin system will be inhibitedSubmit</p>
<p>In response, sympathetic flow to the kidneys is increased</p>
<p>An increase in afterload causes stroke volume to</p>
<p>Decrease</p>
<p>What does the cardiac cycle refer to?</p>
<p>The sequence of events that occur with every heartbeat</p>
<p>What are the two major phases of the cardiac cycle?</p>
<p>Systole and Diastole</p>
<p>What does Systole refer to?</p>
<p>Ventricular contraction</p>
<p>What does diastole refer to?</p>
<p>Ventricular relaxation</p>
<p>Valves open and close according to \_\_\_\_\_\_\_</p>
<p>pressure gradients</p>
<p>Contraction \_\_\_\_\_\_\_\_the pressure</p>
<p>Increases</p>
<p>Blood flows from \_\_\_\_ to \_\_\_\_\_\_ pressure</p>
<p>Higher to lower</p>
<p>Semilunar valves open when Ventricular pressures are \_\_\_\_\_ than aortic pulmonary pressures</p>
<p>Higher</p>
<p>AV valves \_\_\_\_\_\_when atrial pressures are \_\_\_\_ than ventricular pressure.</p>
<p>Open, higher</p>
<p>How is the cardiac cycle initiated?</p>
<p>When the SA node fires(p wave)</p>
<p>What happens to the pressure when contraction begins?</p>
<p>Pressure increases in the atrium and blood flows through the AV valve to the ventricle</p>
<p>T/F atrial contraction is responsible for filling the entire ventricle</p>
<p>False-it only accounts for a fraction of the filling as the ventricles already have some blood in them.</p>
<p>What causes the AV valves to close?</p>
<p>A decrease in atrial pressure</p>
<p>What marks the beginning of systole?</p>
<p>Closing of the AV valves (S1 heart sound)</p>
<p>At the beginning of ventricular contraction, are the semilunar valves open?</p>
<p>No they are closed and the ventricle contracts in a closed space</p>
<p>What is isovolumetric contraction?</p>
<p>Semilunar valves are closed while ventricle contracts, no blood is ejected and pressure in the ventricle is unchanged</p>
<p>When does ventricular ejection start?</p>
<p>When ventricular pressures exceed the pressures within the aorta and pulmonary artery</p>
<p>what valves open to allow ejection from the ventricles?</p>
<p>pulmonary and aortic</p>
<p>What produces the second heart sound?</p>
<p>Closing of the semilunar valves</p>
<p>Where is each cardiac cycle initiated?</p>
<p>SA Node</p>
<p>What is phase 1 of the cardiac cycle called?</p>
<p>Ventricular Systole</p>
<p>What steps occur during ventricular systole?</p>
<p>1. Isovolumic contraction2. Ventricular ejection</p>
<p>What is phase 2 of the cardiac cycle called?</p>
<p>Diastole</p>
<p>What steps occur during diastole?</p>
<p>3. Isovolumic relaxation4. Rapid inflow5. Diastasis6. Atrial Systole</p>
<p>What happens during atrial systole?</p>
<p>More blood is being deposited into the ventricles</p>
<p>What happens to ventricular pressure during step 1 of the cardiac cycle isovolumeric contraction?</p>
<p>It rises rapidly without a change in volume</p>
<p>Are the valves open or closed during isovolumic contraction?</p>
<p>All 4 are closed</p>
<p>Which heart sound is the loudest?</p>
<p>S1 because the pressure is going to be the highest</p>
<p>When the bicuspid valve is closed what is the chordae tendiae and papillary muscles doing?</p>
<p>Paillary muscle is contracted and chordae tendinae are taut</p>
<p>What happens to ventricular pressure in step 2 of phase 1 (Ventricular Ejection)?</p>
<p>Left ventricular pressure is greater than aortic pressure and the right ventricular pressure is greater than the pulmonary trunk pressure</p>
<p>What valves open during step 2 of phase 1 ,Ventricular Ejection?</p>
<p>Semilunar</p>
<p>On the ECG What is happening during the T wave?</p>
<p>Ventricular ejection</p>
<p>What is end systolic volume (ESV)</p>
<p>The amount of blood remaining in the ventricle after systole (50 ml)</p>
<p>How do you calculate stroke volume?</p>
<p>SV = EDV-ESV</p>
<p>What is the stroke volume output into the aorta and pulmonary trunk?</p>
<p>70 mL</p>
<p>What happens to aortic pressure during ventricular ejection?</p>
<p>It starts increasing during systole after the aortic valve opens</p>
<p>When does aortic pressure decrease during ventricular ejection?</p>
<p>Toward the end of the ejection phase</p>
<p>What happens to atrial pressure during ventricular ejection?</p>
<p>C wave- there is a slight backflow of blood into the atria</p>
<p>What happens to ventricular volume during isovolumic relaxion?</p>
<p>Stays the same</p>
<p>What do the valves do during isovolumic relaxation ?</p>
<p>They close (all 4)</p>
<p>What sound do you hear when isovolumic relaxation occurs?</p>
<p>S2-the Dupp sound</p>
<p>What is happening when you hear the Dupp sound?</p>
<p>Semilunar valves are closing (pressure in the ventricle decreases and blood flows back to the ventricles which closes the semilunar valves</p>
<p>What happens to ventricular volume during the rapid inflow phase of diastole?</p>
<p>Increases</p>
<p>What happens to ventricular pressure during the rapid inflow phase of diastole?</p>
<p>it is low due to the AV valves being open and rapid ventricular filling and blood flowing continually from the great veins in the atria</p>
<p>How much blood flows directly through the atria into ventricles before atrial systole?</p>
<p>80%</p>
<p>What happens to atrial pressure during the rapid inflow phase of Diastole?</p>
<p>There is a slow venous return of blood into atria from veins while AV valves are closed</p>
<p>What is a V wave?</p>
<p>It is the end of ventricular contraction</p>
<p>What happens to aortic pressure during the rapid inflow phase of diastole?</p>
<p>Decreases slowly due to elasticity of the aorta and blood flow to the periphery.</p>
<p>What will you see on the graph during rapid inflow during diastole?</p>
<p>An incisura on the aortic pressure due to the sudden cessation of back flow toward the left ventricle</p>
<p>What happens during the diastasis stage of diastole?</p>
<p>A small amount of blood passively flows into the ventricles</p>
<p>On an ECG what occurs during diastasis?</p>
<p>A P wave</p>
<p>What do you see on an ECG during atrial systole?</p>
<p>QRS complex</p>
<p>What happens to ventricular volume during atrial s during atrial systole?</p>
<p>Increases by 20% and the end diastolic volume of each ventricle is 120 ml</p>
<p>What is the end diastolic volume of each ventricle?</p>
<p>120 ml</p>
<p>What happens to ventricular pressure during atrial systole?</p>
<p>It increases slightly</p>
<p>What do you see on the atrial pressure graph during atrial systole?</p>
<p>A small wave occurs on the graph due to atrial contraction</p>
<p>During atrial systole that occurs during diastole what is happening?</p>
<p>Atria contract and this accounts for 20% of ventricle filling during the cardiac cycle.</p>
<p>What do atria function as during atrial systole?</p>
<p>A primer pump or kick that increases ventricular pumping effectiveness by 20%</p>
<p>What happens to aortic pressure during atrial systole?</p>
<p>It decreases slightly</p>
<p>During the Ventricular Systole in the isovolumic contraction step, What do the valves do?</p>
<p>AV valves close and semilunar valves close</p>
<p>During the Ventricular Systole in the isovolumic contraction step, What do you hear?</p>
<p>S1 heart sound (Lubb)Closure of AV valves</p>
<p>During the Ventricular Systole in the isovolumic contraction step, What is the ventricular volume?</p>
<p>120ml</p>
<p>During the Ventricular Systole in the isovolumic contraction step, What is ventricular pressure?</p>
<p>Rapid increase from 0-90 mmhg</p>
<p>During the Ventricular Systole in the isovolumic contraction step, What is the aortic pressure?</p>
<p>80 mmhg</p>
<p>During the Ventricular Systole during Ventricular ejection What do the valves do?</p>
<p>AV valves close and semilunar valves open</p>
<p>During the Ventricular Systole during Ventricular ejection What do you see on a ECG?</p>
<p>A T wave</p>
<p>During the Ventricular Systole during Ventricular ejection, what is the ventricular volume?</p>
<p>ESV=50 mLSV=70 ml</p>
<p>During the Ventricular Systole during Ventricular ejection What is the ventricular pressure?</p>
<p>Increases from 90-120 mmhg</p>
<p>During the Ventricular Systole during Ventricular ejection What do the valves do?</p>
<p>120 mmhg</p>
<p>During Diastole, During isovolumeric relaxation (Phase 3) What do the valves do?</p>
<p>AV valves close and semilunar valves close.</p>
<p>During Diastole, During isovolumeric relaxation (Phase 3) What heart sound do you hear?</p>
<p>S2-(Dupp)-semilunar valves closing</p>
<p>During Diastole, During isovolumeric relaxation (Phase 3) What is the ventricular volume?</p>
<p>Decreased from previous stage to 50 ml</p>
<p>During Diastole, During isovolumeric relaxation (Phase 3) What is the ventricular pressure?</p>
<p>Rapid decrease from 90-0mmhg</p>
<p>During Diastole, During isovolumeric relaxation (Phase 3) What is the aortic pressure?</p>
<p>You will see an incisura on the graph and it is 100 mmhg</p>
<p>During Diastole, During Rapid inflow (Phase 4) What do the valves do?</p>
<p>AV valves openSemilunar valves close</p>
<p>During Diastole, During Rapid inflow (Phase 4) What is the ventricular volume?</p>
<p>50-90 ml</p>
<p>During Diastole, During Rapid inflow (Phase 4) What is the aortic pressure?</p>
<p>Decreases from 100-90 mmhg</p>
<p>During Diastole, During Diastasis (Phase 5) What do the valves do?</p>
<p>AV Valves open and Semilunar valves close</p>
<p>During Diastole, During Diastasis (Phase 5) What do you see on a ECG?</p>
<p>A p wave</p>
<p>During Diastole, During Diastatis(Phase 5) What is the ventricular volume?</p>
<p>90-96 ml</p>
<p>During Diastole, During Diastasis(Phase 5) What is the aortic pressure?</p>
<p>Decreases 90-85 mmhg</p>
<p>During Diastole, During Atrial systole(Phase 6) What do the valves do?</p>
<p>AV valves open and semilunar valves close</p>
<p>During Diastole, During Atrial systole (Phase 6) What do you see on an ECG?</p>
<p>QRS complex</p>
<p>During Diastole, During Atrial systole(Phase 6) What is the ventricular volume?</p>
<p>Adds 24 ml so EDV = 120 ml</p>
<p>During Diastole, During Atrial systole(Phase 6) What is the ventricular pressure?</p>
<p>0 mmhg</p>
<p>During Diastole, During Atrial systole(Phase 6) What is the aortic pressure?</p>
<p>Decreases 85 to 80mmhg</p>
<p>What is stroke volume?</p>
<p>The amount of blood pumped from each ventricle</p>
<p>What is cardiac output?</p>
<p>The amount of blood pumped from each ventricle per minute</p>
<p>What is ejection fraction?</p>
<p>How well the heart is pumping, what is the percentage of blood ejected by the ventricles each contraction.</p>
<p>What number does the American heart association use for staging heart failure?</p>
<p>Ejection fraction(Normal is 55-60%)</p>
<p>What are three factors that regulate stroke volume?</p>
<p>1. Preload2. Afterload3. Contractility</p>
<p>What volume do we want to regulate so there are equal amounts?</p>
<p>Ventricular volume</p>
<p>What is the external work of the heart?</p>
<p>The work required for normal stroke volume</p>
<p>What is preload?</p>
<p>the degree of tension (amt. of stretch) on the myocardium when it begins to contract</p>
<p>What does the frank starling mechanism refer to?</p>
<p>Greater stretch on cardiac muscle fibers prior to contraction increases force of contraction (stretching and releasing a rubber band)</p>
<p>What is preload measured as?</p>
<p>Measured as End diastolic pressure when ventricle is filled with blood = (EDV)</p>
<p>What is the cause of increased pre-load?</p>
<p>Increased stroke volume caused by hypervolemia, Aortic valve stenosis and regurgitation or pulmonary valve stenosis</p>
<p>What are some causes of decreased pre-load (decreased sV)?</p>
<p>Atrial FibHemorrhage</p>
<p>What is afterload?</p>
<p>The pressure that must be overcome before a semilunar valve can open</p>
<p>During Afterload pressure in the ventricle needs to be \_\_\_\_\_\_pressure in the aorta</p>
<p>greater</p>
<p>What causes increased afterload?</p>
<p>Decreased stroke volume such as atherosclerosis, hypertension, aortic stenosis</p>
<p>What causes decreased afterload?</p>
<p>increased stroke volume such as mitral valve regurgitation (endocarditis)</p>
<p>What does an increased afterload do to the frank starling curve?</p>
<p>shifts it down and to the right, which decreases SV (y axis) but increases left ventricular end diastolic pressure (x axis) (LVEDP)</p>
<p>An increase in afterload \_\_\_\_the velocity of fiber shortening</p>
<p>decreases</p>
<p>What does the decrease in fiber velocity shortening do to the rate of volume ejection in the ventricle?</p>
<p>reduces it so that more blood is left within the ventricle at the end of systole</p>
<p>What are positive inotropic agents?</p>
<p>Substances that increase contraction by enhancing Ca2+ inflow during cardiac action potential</p>
<p>What do positive inotropic agents stimulate?</p>
<p>The sympathetic nervous system (epinephrine and norepinephrine)</p>
<p>What does digitalis do?</p>
<p>Enhances Ca2+ inflow during cardiac action potential for dilated cardiomyopathy</p>
<p>What are negative inotropic agents?</p>
<p>substances that decrease contraction by blocking Ca2+ inflow during cardiac action potential</p>
<p>What do inotropic agents inhibit?</p>
<p>Sympathetic nervous system (anoxia, acidosis, increased K+ in intersticial fluid)</p>
<p>What does diltiazem do?</p>
<p>It is an enhanced Ca2+ blocker for hypertrophic cardiomyopathy</p>
<p>What is dilated cardiomyopathy?</p>
<p>Heart cannot contract as well</p>
<p>What is ventricular myopathy?</p>
<p>Increase in the size and mass of the right or left ventricle</p>
<p>Is ventricular myopathy always bad?</p>
<p>No, in athletes it enables the heart to pump more effectively. It is physiological and not abnormal. It is reversible</p>
<p>What are causes of pathogenic ventricular hypertrophy?</p>
<p>Ventricle adapting to increased stress either increased volume load (preload) or increased pressure load (afterload)-valve disease-cardiomyopathies-genetic abnormalitiescoronary heart disease</p>
<p>What is concentric hypertrophy?</p>
<p>Increase in afterload = chronic pressure overload due to chronic hypertension or aortic valve stenosis</p>
<p>Does the ventricular radius always change in concentric hypertrophy?</p>
<p>it may not</p>
<p>What happens to the heart wall in the ventricle in concentric hypertrophy?</p>
<p>wall thickness increases and the ventricle is capable of generating greater forces and higher pressures</p>
<p>why is ventricle filling compromised in ventricular hypertrophy?</p>
<p>compliance is reduced because ventricle is stiffer</p>
<p>what is eccentric hypertrophy?</p>
<p>there is an increase in preload (a volume increase) and afterload (increase in pressure) which leads to a volume and pressure overload</p>
<p>What happens to the ventricular chamber in eccentric hypertrophy?</p>
<p>Ventricular chamber radius is increased and wall thickness may increase</p>
<p>What is right sided heart failure?</p>
<p>A small amount of blood transfers from the pulmonary circulation to the systemic circulation</p>
<p>what increases as a result of right sided heart failure.</p>
<p>small increase in atrial pressure and a small increase in cardiac output.</p>
<p>What happens to systemic circulation in right heart failure?</p>
<p>large volume and capitance</p>
<p>What are some symptoms of right sided heart failure?</p>
<p>Congested liver leading to ascitesJugular vein distensionperipheral distension (sweilling in feet and ankles)</p>
<p>What is pulmonary circulation?</p>
<p>Only in the lungs-it cannot store a lot of blood. it only has small volume and capitance</p>
<p>Why is there jugular distention in right heart failure</p>
<p>Blood backs up in the superior and inferior vena cava due to the increased volume and pressure but due to gravity it will be mostly towards the inferior vena cava</p>
<p>What happens when there is left sided heart failure</p>
<p>A large amount of blood transfers from the systemic circulation into the pulmonary circulation and causes a big increase in left atrial pressure</p>
<p>Why is there pulmonary edema in left heart failure?</p>
<p>due to the pressure increase in the left atria there will be a backup of blood into the bicuspid valve and then into lungs</p>
<p>How could we evaluate for heart failure?</p>
<p>Could hear it in the lungs, more shallowradiographyincrease in radioopacity will see fluid (cloudy)</p>
<p>What would we see in a echocardiogram in left heart failure?</p>
<p>Encarditis-inflammation of the endocardium(lines the valve)</p>
<p>What causes inflammation of the endocardium?</p>
<p>Bacteria enter the bloodstream during dental procedures, sx, iv drug useBacteria attach to heart valve and there are growths holes and scarringvalves get leakyleaky valves can become fibrotic and calcified causing stiffnessif they are stiff papillary muscles can stretch or tear</p>
<p>How are we able to measure the electrical activity in the heart through electrodes?</p>
<p>when heart depolarizes and repolarizes electrical currents spread through the body</p>
<p>How many leads in bipolar leads?</p>
<p>3</p>
<p>What is an ECG?</p>
<p>A recording of the electrical difference between 2 leads</p>
<p>In lead 1 the right arm is</p>
<p>positive</p>
<p>How are we able to generate an electrical cardiogram?</p>
<p>As the heart undergoes depolarization and repolarization the electrical currents that are generated spread both within the heart but also throughout the body.</p>
<p>What are the first 3 leads of the 12 lead ecg?</p>
<p>1. 1st 3 leads are called the bipolar leads
| 2. The ecg is recording the difference between these 2 leads (rt arm - and left arm +)</p>
<p>What are the second type of leads in a 12 lead</p>
<p>1. Augmented unipolar leads (a)</p>
<p>What does the aVR lead tell us about the heart?</p>
<p>hooked up to the right arm and corresponds to the right upper side of the heart. It provides information about the right ventricle outflow tract and basal part of the septum</p>
<p>What does the aVL lead correspond to?</p>
<p>Left arm and health of lateral wall of the left ventricle</p>
<p>What does the aVF lead correspond to?</p>
<p>left leg or foot, inferior wall of the left ventricle</p>
what leads detect minor electrical abnormailities in the ventricles?
Chest or precordial leads
What are Chest leads (Precordial leads) very sensitive to?
Electrical potential changes underneath the electrode
How are the chest leads named?
V1, V2, V3, V4, V5,V6
What is on the x axis of an ecg?
Time
What is on the Y axis of an ecg?
Voltage
What is happening during the p wave?
Atrial Depolarization
When does the p wave occur?
Immediatly before the atrial contraction (they need the electrical signal)
What is going on in the heart during the QRS complex?
Ventricular depolarization
When does the QRS complex occur?
Right before ventricle contracts
what does the T wave represent?
Ventricular repolarization and the ventricles remain contracted until a few milliseconds after T wave ends
Also the atria remain contracted until repolarized
what are the waves with negative voltage
Q and S
What type of voltage do repolarization waves produce?
Positive voltage (move away from a positive recording electrode)
how long is the P-R interval?
0.16 seconds
What is the p-r interval?
Duration of time between the beginning of the p wave and beginning of QRS wave.
what does the P-R interval represent?
Time between the beginning of atrial contraction and beginning of ventricular contraction
How long is the Q-T interval?
0.35 seconds
What is the Q-T interval?
the duration of time from the beginning of the Q wave to the end of the T wave
What does the Q-T interval approximate?
Time of ventricular contraction
when does the T wave occur?
During systole
what are the bipolar leads?
Lead 1, Lead 2, Lead 3
Can you get faulty readings if electrodes are in the wrong spot?
yes
When does the S-T Segment Begin and End and what does it represent?
End of the S wave to the beginning of the T wave
Represents the time when the ventriclar contractile fibers are depolarized during the plateau phase of the action potential
What is the R-R interval and what does it represent?
R to R heart rate
How do you calculate heart Rate?
determined with the reciprocal of tthe time interval between each.
What is a normal S-T segment?
0 millivolts
What will you see on the ECG with a myocardial infarcation?
ST elevation, myocardial injury due to prolonged ischemia
What will you see on the ECG with myocardial ischemia?
ST depression-mild ischemia in the apex of the heart which prevents the apex from repolarizing first and T wave inverts
What is ischemia?
Low blood Flow
what is realeased when someone is having a heart attack?
troponin
What can cause cardiac arrhythemias?
- Abnormal rhythumicity of the pacemaker
- Shift of pacemaker from the sinus node
- Blocks at different points in the transmission of the cardiac impulse (Fibrotic tissue)
- Abnormal pathways of transmission in the heart
- spontaneous generation of abnormal pulses from any part of the heart
Describe a normal sinus rhythum on a ecg.
The QRS complexes are normal, evenly spaced and the rate is 60-100
What does bracdycardia look like on a ECG and what part of the autonomic nervous system causes this?
QRS complexes are normal and evenly space but beat is under 60 bpm
What does Tachycardia look like on an ECG?
Complexes normal,evenly spaced but rate is over 100 bpm (sympathetic)
What happens in an AV block?
Impulses through the AV node and Bundle of His are slowed down or blocked
What causes a AV block?
- Ischemia of AV nodal or AV bundle fibers(coronary ischemia)
- Compression of AV bundle (scar of calcified tissue)
- AV nodal or AV bundle inflammation
- excessive vagal stimulation
What is a First Degree AV block?
impulses from the AV node are delayed but not blocked
-no missed beats
What does a first degree AV block look like on an ECG?
Prolonged P-R interval
What is a Premature Ventricular Contraction?
QRS is prolonged (impulse is conducted through muscle)
QRS voltage is high(one side depolarizes ahead of the other)
What is the most frequent cause of a-Fib?
Atrial enlargement
what does A-Fib look like on a ECG?
No p wave and no P-R interval
What is the treatment for A-Fib?
Beta Blockers (Propranlol), Diltiazem, Blood Thinners (Wayfarin, Pradaxa)
How does the circulatory system service the needs of the tissues?
Transporting
Nutrients
waste products away
hormones
What are the components of a large vein? ex) superior vena cava
Tunica externa
Tunica intima
Tunica Media
endothelium
What makes up the aorta?
Elastic artery
Tunica externa
tunica media
Tunica intima made of enternal elastic membrane and endothelium
What is a medium size vein made up of?
Same as a large vein
What is a muscular artery made of?
Tunica externa
Tunica media
Tunica interna
Endothelium
What is a venule made of?
Tunica externa
Endothelium
What is an arteriole made of?
Smooth muscle (tunica media) Basement membrane Endothelium
How is a fenestrated capillary different from a continous capillary?
It has pores
which side of the heart is the peripheral circulation?
Right
Function of arteries?
transport blood under high pressure to the tissues
Describe special features of arteries
strong vascular walls
high velocity flow
Arteriole function
Control site for blood flow(resistance site of circulation)
Special features of arterioles
strong muscular walls for dilation
Capillary Function
Major site of water and solute exchange between blood and tissues
Describe a capillary
Thin walls with
Where does most of the blood circulate?
Veins, Venous sinuses, venules
What do the pulmonary capillaries do?
Site of oxygen and CO2 exchange
Veins and Venule function
Return the blood to the heart under low pressure,
Reservoir for blood
What type of blood vessel has the greatest crossectional area?
Capillaries need to get more stuff through their walls in the same amount of time
Velocity
The speed at which blood flows in the circulation
V=Blood Flow/Crossectional area
Velocity of blood flow is the greatest in _____
Aorta
Velocity of blood flow is _____to vascular crosssectional area
inversley proportional
Equation for velocity of blood flow
v=F/A
velocity = volume of blood flow/crosectional area
What vessel has the lowest velocity?
capillaries
Define Blood Pressure
Force exerted by blood against any unit area of vessel wall
Where do you find high blood pressure?
Arterial Tree
What blood vessels have low pressure?
Venous Side
Where do you find a very large BP drop?
Across arteriolar capillary junction
What is the basic theory of circulatory function?
- Blood flow to tissues is controlled in relation to tissue needs
- Cardiac Output is controlled by local tissue blood flow
- Arterial pressure is controlled independly
How is blood flow in the tissues controlled?
- microvessels monitor need
- act on local BP (dilation or constriction)
- Also, CNS and hormones help
What is Blood Flow?
Q
Quantity of blood that passes a given point in the circulation in a given period of time
What do the variables mean in the blood flow equation?
Q = change in pressure/ Resistance of vessel
Change in pressure = Pressure difference between 2 ends of the vessel
R =
What is cardiac output?
Overall flow in the circulation of an adult = 5l/min.
What is Laminar flow?
Blood Flows in streamlines with each layer of blood remaining same distance from the wall
Where is the velocity the greatest in laminar blood flow?
Center of the vessel Creating a parabolic profile
Can you hear laminar flow?
No
What is turbulant blood flow?
It does not flow in a streamline and applies greater force to endothelium causing damage/inflammation
What causes turbulant Blood Flow?
High velocity
Sharp turns
rough surfaces
rapid narrowing
What are bruits?
Murmurs and are important for diagnosing vessel stenosis in the carotid artery, vessel shunts, cardiac valvular lesions
Decreased blood vessel radius _____vascular resistance and ______blood flow
increases
decreases
(poiseuilles)
If there is more hemocit then……
Blood viscosity goes up and so does vascular resistance
Resisance is_____
an impediment to blood flow
A serial arrangement has______resistance and is found among_____,_____,______,____and _______
increased Arteries Arterioles capillaries venules veins
What type of arrangement has decreased resistance?
parallel
Where do you find decreased resistance?
Brain
Kidney
Muscle
GI tract
What is conductance?
Measure of the ease at which blood flows
What happens if you remove a kidney?
You remove a parallel circuit and decrease vascular conductance and blood flow but increases total peripheral resistance
What is vascular distensibility?
Fractional increasein volume for each mmHG rise in pressure
What is more distensible arteries or veins?
Veins (8 times more)
What is Capacitance?
Vascular compliance-total quantity of blood stored in a given portion of circulation for each mmHG
Equation for Distensibility
Increase of Volume/(increase in pressure x original volume)
What has more compliance (capacitance)?
Veins 24 time
In the arterial tree changes in volume results in larger ______in pressure than in veins.
increases
What factors affect pulse pressure?
Stroke volume
Arterial compliance
when there is an increase in stroke volume there is a _____in pulse pressure
increase
______in compliance _____pulse pressure
Decreases, increases
What is a patent ductus arteriosus associated with?
Low diastolic pressure and high systolic pressure so an increase in pulse pressure
What happens in arteriosclerosis?
Decreases compliance of arterial tree which increases pulse pressure
If the BP cuff pressure is greater than 120 mmHG what happens?
no flow and no sound
What cuff pressure do you need for free flow and no sound?
80
What happens when cuff pressure reaches systolic pressure?
tapping sounds called korotcoff in the antecubital artery
When should you record diastolic pressure?
No sound
What are three functions of veins?
- Blood reservoir (60%)
- Central and peripheral venous pressure affects on right atrial pressure
- Venous Valves and skeletal muscle pump
How is right atrial pressure regulated?
a balance between the ability of the heart to pump blood out of the atrium and the rate of blood flowing into the atrium from peripheral veins
What factors increase Right Atrial Pressure?
Decreased cardiac function (increased blood volume and increased venous tone)
When there is an increase inright atrial pressure what happens?
Causes blood to back up into the venous system increasing venous pressure and resistance.
Why is the venous pressure higher in the feet than the right atrium?
Gravitational weight of blood
What maintains low venous pressure in the legs?
Venous valves and skeletal muscle pump
What are varicose veins?
increase in venous and capillary pressure causing edema when standing
What enhances capillary diffusion?
Concentration differences
What can diffuse accross a capillary?
Lipid soluable substances
How do lipid insolable substances cross capillary walls?
intercellular clefts
What is bulk flow?
Move a large amt. of water containing small lipid insolable solutes in the same direction based on net filktration pressure.
Faster than diffusion or osmosis
What is bulk flow most important for?
Regulation of relative volumes of blood and intersticial fluid
Define filteration
Bulk flow from arterial end of the capillary into interstitual fluid
Define reabsorption
Bulk flow from interstitial fluid to venous end of capillary
What is a balance of filteration and reabsorption pressure called?
net filtration pressure
Starlings law of capillaries
Volume of fluid and solutes reabsorbed is almost as large as amt. filtered
When capillary hydrostatic pressure is greater than blood colloidal osmotic pressure what occurs?
Filteration-fluid exits capillary
When Capillary hydrostatic pressure is less than blood colloidal osmotic pressure what happens?
Reabsorption-fluid reenters capillary
what is cardiac Output controlled by?
Local Tissue Blood Flow
Each tissue Autoregulates its own blood flow in proportion to its ______
Metabolic rate or needs
What is arterial pressure controlled by?
Autonomic nervous system, independent of cardiac output or local blood flow control
What factors does blood flow increase or decrease and what is this an example of?
Acute control of tissue blood flow
- Tissue Metabolic rate
- Arterial O2 saturation
- Amt. of oxygen and Nutrients present
- Accumulation of vasodilator metabolites (Co2, H+, lactic acid)
- LAck of other nutrients (glucose, amino acids or fatty acids)
Blood flow _____ as tissue metabolism increases.
Increases
what happens to blood flow when arterial oxygen saturation moves from 100 to 50 %?
It increases gradually
What happens to blood flow when arterial saturation is 50 % and below?
It increases from 1.5 to 3 times the normal rate.
When there is an increased demand for oxygen and nutrients what happens to local (tissue) blood flow?
It increases
-through local vasodilation and vasoconstriction of arterioles, metarteriole, and pre capillary sphinctors
What is a metariole?
A metarteriole is a short microvessel in the microcirculation that links arterioles and capillaries. Instead of a continuous tunica media, they have individual smooth muscle cells placed a short distance apart, each forming a precapillary sphincter that encircles the entrance to that capillary bed.
what is the term used for precapillary and metarteriole sphincters for controlling capillary blood flow?
Vasomotion
Does the accumulation of vasodilator metabolites increase or decrease tissue blood flow?
increase
What are the vasodilator metabolites?
Histamine Adenosine and Adenosine Phosphate compounds CO2 H+ ions K+ ions
Define Reactive Hyperemia
Occurs after blood supply to a tissue is blocked for a short time
What happens during Reactive Hyperemia?
- Blood flow rate increases 4-7X normal after blockage
- Tissue vasodilator metabolites accumulate and hypoxia
Define Active Hyperemia-
Exercise
What happens to blood flow in active hyperemia?
- Blood flow needs to increase to compensate for increased metabolic demand
- Local tissue metabolism causes accumulation of vasodilator substances
What is the result of active hyperemia after the blood flow change?
-Local tissue metabolism causes accumulation of vasodilator substances
Define Autoregulation
Within < 1 minute tissue blood flow returns to normal if arterial pressure is increased or decreased
What are the two theories for how blood flow is regulated during changes in arterial pressure
!. Metabolic Theory of Autoregulation
2. Myogenic Theory of Autoregulation
what happens to arterial pressure in the metabolic theory of autoregulation?
-Arterial pressure increases a lot
What happens to local blood flow in the metabolic theory of autoregulation and what is the effect?
-Blood Flow increases too much as a result of increased arterial pressure
-As a result there is too much O2 and nutrients
This washes out the vasodialtors metalbolites
-Washing out metalbolites causes vasoconstriction and allows normal blood flow despite increased arterial pressure
In the myogenic theory of autoregulation what does decreased arterial pressure do to local blood flow?
- They dilate in response to decreased wall tension
- decreased wall tension decreases vascular resistance
- this allows blood flow to be maintained at a constant rate
What is the formula for Wall tension in the Myogenic Mechanism?
Wall Tension (T) = Internal Pressure (P) x Radius (R)
How does acute metabolic control of local blood flow work in the kidney?
Tubuloglomerular Feedback
How does Tubuloglomerular feedback regulate local blood flow in the kidney?
-The macula densa detects the composition of fluid in the distal convoluted tubule
-This tells it that GFR has increased as a result of increased blood flow
Since the GFR is increased the macula densa cause the contraction of the afferent arteriole and less blood enters the glomerulas, Pc decreases, and the GFR decreases
How does acute metabolic control of local blood flow occur in brain?
When there is an increase of CO2 or H+
- Cerebral Blood Vessels Dilate
- blood flow increases
How does acute metabolic control of local blood flow occur in the skin?
When there is an Increase in body temperature
- blood flow increases to 7 to 8 L/min
Body senses this and decreases body temperature
What part of the ANS controls skin blood flow when there is an increase in body temp?
sympathetic
What does blood do to retain heat?
Avoid surface of the skin
How Does Control of Tissue Blood Flow by Endothelial Derived Relaxing or Constricting Factors work?
- A vasoconstrictor called endothelian is released from a damaged endothelium
- A vasodilator called nitric oxide is released from healthy endothelial cells
What is long term control of blood flow?
Slow controlled changes (days to weeks to months) in blood flow
How is Long-term control of blood flow achieved?
Changes in tissue vascularity
How do changes in tissue vascularity control blood flow long term?
- Increasing the vascularity of tissue- size and number of blood vessels.
- Angiogenesis = Development of new blood vessels
What is Angiogenesis?
Development of new blood vessels
when does Angiogenesis occur?
Occurs in response to angiogenic (small peptides) factors called vascular endothelial cell growth factors
What are angiogenic factors called and what kind of molecule are they?
Small peptides called Vascular endothelial growth factors
Where are angiogenic growth factors released from?
- Tissues with High Metabolic Rates
- Ischemic Tissues
- Rapidly growing tissues or neoplasia
what stimulates the regulation of tissue vascularity?
Oxygen
Describe Acute Blood Flow in terms of increasing mean arterial pressure
When mean arterial blood pressure changes from 10 to 50, acute blood flow into the tissues rises from 0 blood flow to 1 x normal, then it rises slowly at mean arterial pressure increases to 200 mmhg. At 200 mmhg, mean arterial pressure blood flow is 1 times the normal flow but when arterial pressure increases from 200 to 250 mmhg, blood flow increases rapidly to 2.5 times normal.
What is Humoral Regulation of Blood Flow?
Control of blood flow by substances secreted or absorbed into the body fluids
What are the vasoconstrictor players in humoral blood flow?
Norepinephrine and epinephrine
Angiotensin II
Vasopressin (ADH)
Increase Ca2+
What are the vasodilators hormones in humoral blood flow?
Bradykinin
Histamine
Increase H+ vasodilation
Increase CO2
Describe three functions of nervous system regulation of the circulation
- Resdistribution of blood flow
- Pumping Activity of the Heart
- Rapid Control of arterial pressure
Where does the sympathetic system increase blood flow?
- Lungs-pulmonary circulation
2. Heart-Coronary system
where does the parasympathetic system increase blood flow?
- Digestive system
2. Urinary System
Does the sympathetic nervous system increase or decrease pumping activity of the heart?
Increase
Does the parasympathetic nervous system increase or decrease pumping activity of the heart?
Decrease
How does the sympathetic system control arterial blood pressure?
Increases it
How does the parasympathetic system control arterial blood pressure?
Decreases
what does the sympathetic nervous system do to regulate blood flow, heart pumping and arterial pressure?
It causes vasoconstriction, cardiac output and heart contractability in times of need
what does the parasympathetic nervous system do to regulate blood flow, heart pumping and arterial pressure?
Decreases cardiac output and contractability in times of need
Where is the vasomotor center located?
Medulla Oblongota and lower 3rd of the pons
What are the Vasomotor Center components?
Vasoconstrictor
Vasodilator
Cardioinhibitor nucleui
What does the vasomotor center receive inputs from?
Neural inputs directly from the :
baroreceptors
hypothalamus
higher order neural centers throughout the cerebrum
Where does the vasomotor center transmits impulses to?
the spinal cord
sympathetic nervous system to the blood vessels and heart
Where is the distribution of vasoconstrictor fibers the greatest?
Kidneys Gut Spleen Skin (Distributed throughout all segments of circulation) They are important for autoregulation
Why is the vasoconstrictor fiber system less potent or dangerous in the coronary circulation and brain?
Heart and Brain are suceptible to not receiving enough blood flow because when the fibers are activated you are going to have ischemia or decreased blood flow and you wouldn’t want this in the brain
What do the sympathetic nerve fibers NOT innervate?
capillaries, precapillary sphincters, and metarterioles
How is vasomotor tone and an increase in vascular resistance acheived?
through Innervation of small arteries, arterioles, and large veins by sympathetic nerves. They saw this when injecting patients with neurotransmitter norepinephrine
What is the neurotransmitter for the vasoconstrictor nerves and what does it do?
Norepinephrine-it constricts the blood vessels through alpha adrenergic receptors
How can EPI dilate blood vessels?
through a potent Beta2 receptor (decreasing vascular resistance)
What is the parasympathetic nervous system important for in terms of regulation of the circulation?
Controls heart rate via the Vagus nerve
How does vasovagal syncope occur?
Syncope = faint
1. Emotional Stress interpretated by cerebral cortex
2. signal sent to medulla
3. sympathetic output is decreased and vagal output is increased.
-Decrease of
sympathetic output
leads to a
decrease in total
peripheral
resistance
- Increased vagal
output leads to a
decrease in venous
return and
decrease in cardiac
output
4. Decrease in arterial pressure
5. Decrease in cerebral blood flow
6. loss of consciousnessHow is rapid control of arterial pressure acheived?
Through the vasomotor control system:
- Constricting large vessels of the circulation thereby increasing venous return and cardiac output
- Directly increasing CO by increasing heart rate, stroke volume and contractility
- Constricting almost all arterioles of the body increasing total peripheral resistance (TPR)
What is a barorecptor?
Baroreceptors are spray type nerve endings
Where are barorecptors located?
- Carotid sinus- found at carotid bifurcation
2. Aortic arch
What is the significance of the carotid sinus reflex?
maintaining normal blood pressure in the brain
Where are the signals transmitted in the carotid sinus reflex?
Signals from the carotid sinus are transmitted by Hering’s nerve to the Glossopharyngeal nerve and then to the VMC
Significance of the Aortic Reflex?
maintaining normal general systemic blood pressure
Where are the signals transmitted in the aortic reflex?
Signals from the arch of the aorta are transmitted through the vagus to the VMC
Arterial Baroreceptor reflex significance
Important in short term regulation of arterial pressure
What is the arterial baroreceptor reflex initiated by?
Stretch receptors (baroreceptors)
How does the arterial baroreceptor reflex work?
- Increase in pressure stretches the baroreceptors
- signals to VMC
- ANS
- circulation 5. decrease arterial pressure back to normal
What pressure changes do carotid sinus receptors respond to?
changes between 60 and 180 mmHg
Baroreceptors reflex is most sensitive at a pressure of ______.
100 mmhg
As pressure increases the number of impulses from carotid sinus increases-Why?
1) Inhibition of vasoconstriction
2) Activation of the vagal center
When there is an increase in arterial pressure what will happen?
Opposes either increases or decreases in arterial pressure thereby reducing daily variations in arterial pressure
When common carotid arteries are constricted what happens to the baroreceptors at the carotid sinus?
Pressure decreases resulting in an increase in arterial pressure
What is a chemoreceptor?
Chemoreceptors are chemosensitive cells sensitive to decreased O2, increased CO2 and H+
Where are Chemoreceptors located?
located in carotid bodies near the carotid bifurcation and arch of the aorta
How are chemoreceptors activated?
Decreased O2
Increased CO2
Increased H+
What is the result of activated chemosensitive receptors?
- excitation of the vasomotor center
- Increased sympathetic activity
- Increased BP
Describe the CNS ischemic response
- Cerebral ischemia occurs
- Increase in CO2
- VMC activated
- increased sympathetic activity
- Arterial pressure increases
What is one of the most powerful activators of the sympathetic vasoconstrictor system?
CNS ischemic response
When is the CNS ischemic response activated?
when pressure falls below 60 mmhg
-15-20 mmhg greatest activation
What happens when CNS ischemia is prolonged?
a depressant effect on the vasomotor center
What do low pressure receptors do?
Low pressure receptors in atria and pulmonary arteries minimize arterial pressure changes in response to changes in blood volume
How are low pressure receptors activated?
By Increases in blood volume
When low pressure receptors are activated what happens?
arterial pressure drops
How does the activation of low pressure receptors enhance water and Na excretion?
Decreasing rate of antidiuretic hormone
Increasing glomerular filtration rate
Decreasing Na+ reabsorption
Describe the atrial and pulmonary artery reflexes
- Blood Volume Increases
- Atrial Stretch increases
- Renal sympathetic activity drops and atrial natruuretic peptide increases
- Sodium and Water excretion increases
- Increase in blood volume
What does the Bainbridge reflex prevent?
damming of blood in veins, atria and pulmonary circulation
Describe the bainbridge reflex
Stretch of atria sends signals to VMC via vagal afferents to increase heart rate and contractility
What does an increase of atrial pressure do to heartrate?
Increases it
Define Shock
Decreased Blood Volume and Decreased Blood Pressure =
Hypovolemic Shock
What are the causes of hypovolemic shock?
- Hemorrhage
- GI
a. Vomiting
b. Diarrhea - Renal fluid loss
a. Diabetes mellitus
b. Diabetes insipidus
c. Excessive use of diuretics - Cutaneous fluid loss
a. Burns- direct plasma loss
b. Perspiration - Intestinal obstruction
What is circlatory shock?
Decreased cardiac function and decreased venous return
What cause decreased cardiac function?
- Myocardial infarction
- Valvular disease
- Arrhythmias
- Metabolic problems
- Myocarditis
What causes decreased venous return?
- Blood volume
2. Vascular tone
How does the body respond to shock
Disrupts homeostasis:
By decreasing Blood Volume and Pressure
What happens to the baroreceptors when Blood Volume decreases along with blood pressure in shock?
the baroreceptors in the kidney (juxtaglomerular cells) secrete renin resulting cleaving of angotensenogen to angiotensin II in the blood
2.The baroreceptor in the carotid sinus and aortic arch decrease the rate of nerve impulses causing the hypothalamus and posterior pituitary to release ADH into the blood and cardiovascular center in medulla signals to increase sympathetic stimulation and hormones from the adrenal medulla
What happens as a result of more angiotensen II in the blood during shock?
Aldosterone is released from the adrenal cortex and blood vessels constrict
What happens when there is ADH in the blood?
Kidneys conserve salt and water and blood vessels constrict
What happens when there is increased sympathetic stimulation and hormone release from the adrenal medulla?
Heart rate and contractability increase
What does aldosterone release and kidney conservation of salt and water lead to?
Increased Blood Volume
What does the constriction of blood vessel lead to during shock?
Increased systemic vascular resistance
What does the increase in heart rate and contratability lead to during shock?
increased blood pressure
What two things lead to increased blood pressure during shock?
Increased blood volume and increased vascular resistance
What needs to happen for the body to return to homeostasis during shock?
When responses bring blood pressure and volume back to normal
What does a patient experience during shock?
Clammy, cool, pale skin (drop in BP) Tachycardia (Increased sympathetic stim and hormones from adrenal medulla) Weak and rapid pulse Sweating Hypotension Systolic pressure < 90 mm hg Altered mental status Decreased urinary output Thirst Metabolic acidosis- Acidosis in shock prevents glycolysis
What are the shock characteristics at a cellular level?
Cellular membrane dysfunction
Cellular metabolism is abnormal
Cellular death may eventually occur without proper treatment.
Inadequate perfusion
Cells forced to switch to anaerobic respiration lactic acid increases
What are the physical characteristics of blood?
Increased viscosity (thicker) when compared with water Slower flow rate for blood pH 7.4 (7.35-7.45) 8 % of total body weight Blood volume 5 to 6 liters in average male 4 to 5 liters in average female
What are the three components and approximate percentages of blood when it is spun down in a centrifuge?
55% plasma
45% hematocrit (packed red cell)
<1% Buffy Coat
Which blood cells are found in the buffy coat
White cells and platelets
List the formed elements in blood
Platelets
WBCs(Neutrophils,Lymphocytes, Monocytes, Esinophiles, Basophils)
RBCs
What are the components of plasma?
> 90% Water
7% Plasma Proteins- Produced in the liver, confined to bloodstream
1. Albumin- Maintains blood oncotic pressure
Oncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins in a blood vessel’s plasma that pulls water into the circulatory system.
2. Globulins (immunoglobulins)- Form antigen-antibody complexes
3. Fibrinogen (soluble)- During the coagulation cascade, there is eventual conversion to insoluble fibrin via thrombin to stabilize the platelet plug.
2% other substances
Electrolytes, nutrients, hormones, gases, waste products
Where are plasma proteins made?
Liver
Where are plasma proteins Confined to?
Blood Stream
What are the functions of the three plasma proteins?
- Albumin- Maintains blood oncotic pressure
Oncotic pressure, or colloid osmotic pressure, is a form of osmotic pressure exerted by proteins in a blood vessel’s plasma that pulls water into the circulatory system. - Globulins (immunoglobulins)- Form antigen-antibody complexes
- Fibrinogen (soluble)- During the coagulation cascade, there is eventual conversion to insoluble fibrin via thrombin to stabilize the platelet plug.
what is the definition of hematocrit?
Percentage of total blood occupied by erythrocytes
Why do males have higher hematocrits (hct) than females?
Female normal range 38 - 46% (average of 42%)
Male normal range 40 - 54% (average of 46%)
What is the definition of anemia?
decreased HCT or decreased Hb or both
How is anemia classified?
Classified based on cell size (micro, macro, normocytic) and amount of hb present (hypo, hyper, normochromasia)
What is the definition of polycythemia?
Increased HCT (>65%) or increased Hb or both Dehydration, tissue hypoxia, blood doping in athletes
What is the most common cause of polycythemia?
Dehydration, tissue hypoxia, blood doping in athletes
Hemoglobin is a globin protein consisting of ___ polypeptide chains with one heme pigment attached to each chain.
Hemoglobin is a globin protein consisting of 4 polypeptide chains with one heme pigment attached to each chain.
What does each heme contain?
Each heme contains Fe2+ that can combine reversibly with one oxygen molecule
what does this bind to?
oxygen
Each hb molecule can carry ___ O2 molecules from lungs to tissue cells.
Hemoglobin also transports 23% of total CO2 waste from tissue cells to lungs for exhalation
What is HbA1C used to monitor?
Used to monitor long-term blood glucose control (3 months) in diabetes type I and II
Measures amount of glycosylated hemoglobin in blood
Why is HbA1C more reliable than analyzing trends in daily or weekly blood glucose measurments?
- Measures amount of glycosylated hemoglobin in blood
- Hemoglobin, like all proteins, link up with sugars- glucose excess glucose enters the erythrocyte binds to Hb Glycosylated hemoglobin. *Excess glucose in the blood = increased glycosylation of hemoglobin
How is iron transported in the blood plasma?
Transferrin
Transports iron in plasma
Two iron binding sites
Responsible for pink color of plasma
How is iron stored in the tissues?
Ferritin
What is hemosiderin?
Water insoluble
Yellowish-brown granular intracellular pigment that is formed in some phagocytic cells (as macrophages) by the breakdown of hemoglobin
If hemosiderin is not removed from the tissues by the macrophages, what happens?
Liver affected by hemosiderosis-excessive dispositon of iron in the liver in kuppfer cells and hepatocytes causing liver cell death and cirrosis
Erythrocytes live for 120 days. Why?
- Globin can be reused
Heme is used
Describe how hemoglobin is recycled.
- RBC dies and phagocytosis occurs
- Globin is broken into amino acids reused for protein synthesis
- Iron is released from Heme
- Iron binds to transferrin and goes to the liver and bind to ferritin. Ferretin releases iron from the liver and it binds again to a transferretin to go to bone marrow. Iron with globin, vitamin B12 and Erythropoiden undergoes erythropoiesis in bone marrow
- Heme relesaes
What is the definition of hematopoiesis
Blood Cell Maturation and Production
Myeloid progenitor cells give rise to?
- Mast Cells
- Reticulocytes
- Megakaryocytes
- Myeleblasts
What do Reticulocytes mature into?
Erythrocytes
What do Megakaryocytes mature into?
Thrombocytes
What do Myeloblasts mature into?
- Basophils
- Esinophils
- Neutrophils
- Monocytes
Where does hematopoiesis occur in the embryo?
Hematopoietic tissue in bone
Where does hematopoiesis occur in the child?
Yellow marrow
Where does hematopoiesis occur in the and adult- healthy vs. illness?
Healthy- yellow and red marrow
ill-Liver, spleen, more red and some yellow
What happens to the amount of red vs. yellow bone marrow- healthy vs. illness?
more yellow in healthy adult
What hormone stimulates erythropoiesis?
Erythropoietin (EPO)
Where is EPO produced?
peritubular interstitial cells of the kidney
Explain the negative feedback mechanism of erythropoiesis.
There is an increase in the production of RBCs when tissue oxygenation increases
- Tissue oxygen decreases
- EPO is produced
- Hematopoietic stem cells are produced giving rise to proerythroblasts and RBCs
- Oxygen is broght to tissues
Which factors will decrease tissue oxygenation and thus stimulate erythropoiesis?
- Low Blood Volume
- Anemia
- Low Hemoglobin
- Poor Blood Flow
- Pulmonary Disease
What is a reticulocyte?
Immature RBC
What would a red bone marrow response indicate?
Increased reticulocytes
Indicates recent blood loss or successful iron therapy
What would a lack of red bone marrow response indicate?
Decreased reticulocytes
Perform bone marrow aspirate (Primary bone marrow problem?)
Perform renal function tests (Problem with kidneys (CRF) not producing EPO)
What is TPO?
Thrombopoietin (TPO)
- Hormone from liver and kidney
- Stimulates thrombocyte production
What are cytokines?
local hormones of bone marrow-Interleukins stimulate WBC production
EPO stimulates production of ____
Reticulocytes
TPO stimulates the production of _____
Megakaryocytes
GM-CSF stimulates production of
Basophils, esinophils, neutrophils and monocytes from myleoblasts
EPO stimulates production of ____in chemotherapy
Reticulocytes
TPO stimulates the production of _____in chemotherapy
Megakaryocytes
GM-CSF stimulates production of ___in chemotherapy
Basophils, esinophils, neutrophils and monocytes from myleoblasts
How is EPO used in medical?
- Available through recombinant DNA technology
- Recombinant erythropoietin (EPO) -Very effective in treating CRF
How is EPO, TPO, and GM-CSF used in chemotherapy?
Stimulate cell production
