Midterm 1

What does the P wave of the EKG show? 1. Atrial repolarization 2. Atrial depolarization 3. Ventricular repolarization 4. Ventricular depolarization

2. Atrial depolarization

Which of the following would you expect to have the thickest tunica media relative to their overall diameter? 1. Elastic arteries 2. Muscular arteries 3. Arterioles

2. Muscular arteries have large amounts of smooth muscle in their tunica media. Sympathetic nerves innervate this muscle and when active determine the vessel diameter and thus blood pressure and blood flow. They are important in maintaining vascular tone.

Which of the following do NOT activate cells of the healthy heart? 1. Ions from adjacent cells entering contractile cells 2. Neurotransmitter arriving at contractile cells 3. Spontaneous depolarization of non-contractile cells 4. Ions from adjacent cells entering non-contractile cells

2. Neurotransmitter arriving at contractile cells

Systole is contraction of heart muscle. The atria contract independently of the ventricles. When is ventricular systole with respect to the QRS wave/complex of the ECG? 1.Part way through the P wave until about the QRS complex 2.Part way through the QRS wave until about the T wave 3. Part way through the T wave until the next P wave

2. Part way through the QRS wave until about the T wave.

Using the Blood O2 image above, what organ releases erythropoietin? 1.bone 2.kidney 3.spleen 4.heart

2. kidney

The ____ return blood from the systemic circulation into the ____. 1.pulmonary arteries; left atrium 2. superior and inferior vena cavae; right atrium 3.pulmonary veins; right atrium 4. aorta; left ventricle

2. superior and inferior vena cava; right atrium

True or False? Sympathetic stimulation increases heart rate but decreases stroke volume due to less time for ventricular filling.

False

True or False? To increase blood flow to a working muscle, sympathetic activation would constrict the arteriole serving that skeletal muscle.

False

True or False? The left side of the heart pumps more blood than the right side of the heart (in volume).

False, Right! Because the CV system is a closed system, whatever volume leaves the heart ultimately returns. Therefore, both sides of the heart must pump the same volume at the same time to keep flow the same through either side of the heart. If both sides do not pump the same volume whichever ventricle pumps less will have excess blood remaining in the chamber. Then excess blood will back up into the atrium and eventually into the circuit (pulmonary or systemic). If too much blood stays in pulmonary capillaries, the lungs fill with fluid and you cannot load oxygen into your blood - you would feel like you were suffocating. If too much blood remains in the systemic capillaries, the tissues fill with fluid and your limbs become swollen. This condition of unmatched ventricular pumping is called congestive heart failure.

True or False? The right ventricle has a thicker myocardium than the left ventricle and it contracts and relaxes before the left ventricle.

False, No part of this sentence is true. The left ventricle has a thicker myocardium because it pumps to the entire systemic circuit and must overcome more resistance than the pulmonary circuit. Also, both ventricles contract and relax at the same time so that the same amount of blood is ejected into both circuits at the same time.

True or False? The myocardium receives its oxygen supply from the endocardium via diffusion through gap junctions.

False, the myocardium receives it's oxygen supply from the left side of the heart at the root of the aorta, just after the aorta exits the left ventricle branching into the right and left coronary arteries.

in which location would you expect to find blood richest in oxygen? a.pulmonary trunk b.left atrium c. superior vena cava d. right ventricle

b. left atrium because pulmonary veins bring in oxygen rich blood form the lung to the left atrium the pulmonary trunk forms into the pulmonary arteries to deliver oxygen poor blood to lungs

Which WBC can become a macrophage? a.basophil b.monocyte c.eosinophil d.neutrophil

b. monocyte: macrophages (wondering and fixed), actively phagocytotic, crucial in self defense against viruses and chronic infections basophil: promote inflammation, similar to mast cells eosinophil: attack objects coated with antibodies , attack parasitic worms, lessen severity of allergies (inactivates inflammatory chemicals neutrophil: bacteria slayers, lysosomal enzymes, defensins, highly mobile, active phagocytes, partial to bacteria and some fungi lymphocytes: non specific defense

Which of the following is not a formed element: a. erythrocyte b. platelet c. fibrinogen d. basophil

c. fibrinogen is a plasma protein. Formed elements include RBC, WBC and platelets

What vessels feed the heart tissue? What are the metabolic processes that the heart performs for energy?

coronary arteries, the heart undergoes aerobic metabolism using its high mitochondrial density.

Which of the following could occur in a heart with a non-functioning SA node? a. missing P wave on EKG b. abnormally slow rhythm c. AV-node determines the heart's pace d. all of the above

d. all of the above

True or false; Blood pressure in veins is greater than that of capillaries

false, blood pressure goes: arteries, capillaries, veins.

What happens to stroke volume when there's increased resistance/pressure in major arteries?

high ESV, not as much blood can be pumped out to the body

What is the most common way to increase CO?

increased venous return

Where are sinusoidal capillaries found?

liver and bone marrow to allow passage of large molecules

Components of whole blood

plasma and formed elements (platelets, WBC, RBC)

What intracellular blood protein transports oxygen and carbon dioxide? 1.Globulin 2.Albumin 3. Hemoglobin 4.Fibrinogen

3.Hemoglobin: Oxygen binds to hemoglobin as the red blood cells move through the pulmonary (lung) capillaries; it unbinds from hemoglobin when the red blood cell enters the systemic (peripheral) capillaries allowing the oxygen to move to the tissue cell mitochondria. Carbon dioxide is produced in the mitochondria of the peripheral tissues. It binds to hemoglobin (on a different part than where the oxygen binds) and is carried away from the tissues; it detaches from hemoglobin in the pulmonary capillaries where it can move into the air of the lungs and be breathed out. Hemoglobin is made in the red bone marrow where red blood cells are also made. Albumin, globulin and fibrinogen are plasma proteins which function not to carry respiratory gases. Albumins are important to maintaining blood osmotic pressure and transporting substances in the blood. Globulins are important for immunity (and some transport of hormones). Fibrinogen is important for blood clotting. Most plasma proteins are made in the liver.

Using the Blood O2 image above, and using what you know about hematopoiesis, what cells in the red bone marrow do you think are targeted by erythropoietin? Hint: you will likely need to review the Lecture 2 slides for this one! 1.Erythrocytes 2.Lymphoid stem cell 3.Myeloid stem cell 4.Leukocytes

3.myeloid stem cell

In which timepoint do the ventricles repolarize on the EKG?

4

What is vagal tone?

Constant parasympathetic stimulation (by vagus nerve) that slows the pacemaker rate

During which time points is the volume in the left ventricle changing?

1, 2 and 4 (atrial diastole, atrial systole, ventricular ejection).

What vessel would have the lowest flow? 1. A small diameter (internal diameter = 1 mm) vessel with a proximal-distal change in pressure of 25 mmHg 2. A large diameter (internal diameter = 2 mm) vessel with a proximal-distal change in pressure of 25 mmHg 3. A small diameter (internal diameter = 1 mm) vessel with a proximal-distal change in pressure of 50 mmHg 4. A large diameter (internal diameter = 2 mm) vessel with a proximal-distal change in pressure of 50 mmHg

1. A small diameter (internal diameter= 1mm) vessel with a proximal-distal change in pressure of 25mmHg

Why is resting heart rate lower than the automatic depolarization rate of the SA node? 1. At rest, the vagus nerve causes SA node cells to hyperpolarize 2. At rest, sympathetic cardiac nerves release neurotransmitter 3. Venous return is high 4. The Bainbridge reflex dominates the heart at rest

1. At rest, the vagus nerve causes SA node cells to hyperpolarize The Vagus nerves synapse on the SA node and AV node. They release acetylcholine (Ach) that binds to chemically gated channels on these cells. The Ach triggers potassium release from the SA & AV node cells, causing the SA node to reach threshold less often and fire action potentials less often (a slower heart rate). Sympathetic activation increases heart rate by allowing calcium entry into the SA node cells (increases contractility too through the same mechanism). Venous return is low at rest. The Bainbridge reflex is triggered when increased venous return activates stretch receptors in the right atrium. These receptors communicate with the cardioacceleratory center in the brainstem which then activates sympathetic nerves to increase heart rate. Although this reflex is activated during inhalation when thoracic pressure increases blood flow into the right atrium, it would not lower the heart rate and it is not dominant.

Which of the following is the most accurate description of whole blood with a hematocrit of 60%? 1. By volume, it is composed mostly of red blood cells. 2.By volume, it is composed mostly of plasma. 3.By volume, it is composed mostly of platelets. 4. By volume, it is composed mostly of white blood cells.

1. By volume, is is composed mostly of RBC, A hematocrit of 60% means that by volume, a sample of whole blood is 60% red blood cells and ~40% plamsa. White blood cells (leukocytes) and platelets should also never be so abundant that they make up 60% of the whole blood volume. This condition of having too high RBCs (erythrocytes) is called polycythemia. This can result from many causes, including blood doping

Which of the following is NOT a function of the three most abundant plasma proteins? 1. Carry oxygen 2.Maintain the osmotic pressure of blood 3. Act in blood clotting 4.Transport fat soluble substances 5.Immunity

1. Carry oxygen The three most abundant plasma proteins are: albumins-Albumins are important for carrying fat soluble substances & maintaining osmotic pressure of the blood. globulins-can be clotting factors, transport proteins or function during immunity (as antibodies). fibrinogen- dissolved protein which, when precipitated, forms a fibrin mesh to stop blood loss.

What factors determine blood flow through a vessel? (Assume no factor is 0) 1. Change in pressure from the proximal to the distal end of the vessel and resistance to blood flow in the vessel 2. The amount of pressure at the proximal end of the blood vessel and the velocity of blood moving through the vessel 3. The amount of pressure at the distal end of the blood vessel and the cross sectional area of the blood vessel

1. Change in pressure from the proximal to the distal end of the vessel and resistance to blood flow in the vessel

When is pressure in both ventricles high enough to close the AV valves, but too low to open the semilunar valves? 1.During the earliest phases of ventricular systole and diastole 2.During ventricular ejection 3.During early ventricular filling 4.During late ventricular filling

1. During the earliest phases of ventricular systole and diastole When both valves (AV and semi-lunar) are closed, the ventricles can neither fill nor empty. This occurs at two times during the cardiac cycle. The first is when the ventricles begin contracting; the pressure in the ventricles exceeds that in the atria, causing the AV valves to close (with the AV valves closed, the ventricles cannot fill). But, the pressure in the ventricles is still lower than that in the pulmonary trunk and aorta and so the blood cannot flow out of the heart into these arteries. This phase is called isovolumetric contraction - because the volume is the same in the ventricles during this time period, nothing in, nothing out. All valves are closed again during the initial phase of ventricular diastole called isovolumetric relaxation. Again, this terminology refers to the volume in the ventricles, nothing in, nothing out. Isovolumetric relaxation occurs after ventricular ejection, but before ventricular filling. The pressure in the ventricles is lower than the great vessels, and backward flowing blood causes the SL valves to close (preventing complete backward flow into the ventricles). But pressure in the ventricles is still higher than pressure in the atria, and as such, the AV valves are still closed.

Large arteries near the heart passively expand and recoil as blood is pumped into them from the ventricles. Which of the following is the classification of these large arteries? 1.Elastic arteries 2.Muscular arteries 3.Arterioles

1. Elastic arteries

Gap junctions allow for rapid transmission of which of the following? a. oxygen b.AP/electrical signals c.erythrocytes d all of the above

b. AP/electrical signals

The coronary sinus is..

where deoxygenated blood, used o oxygenate the heart, returns to the heart.

A patients blood agglutinates when exposed to anti-Rh antibodies, what do we know about this patients blood type? a. this patient is type O- b. this patient's blood has Rh antigens c. this patients blood has anti-Rh antibodies d. this patient is blood type- AB+

b

Which of the following is essential to the proper coordination of a single heart beat? 1. Gap junctions between adjacent cardiac muscle cells 2. Neurons of intrinsic conduction system 3. Hormone binding to neurons of SA node 4. Neurotransmitter passing through intercalated discs

1. Gap junctions between adjacent cardiac muscle cells Right! The cells of the intrinsic conduction system are cardiac muscle cells that do not contract. Instead, they are responsible for automatically depolarizing to fire action potentials that control the contraction cycle of the heart. Action potentials spread through the heart via the gap junctions in the intercalated discs. An action potential is initiated in the SA node. Ions spread from the SA node cells to the atrial muscle via gap junctions - these arriving ions initiate action potentials in the contractile cells. The signal travels to the AV node, AV bundle, bundle branches, Purkinje fibers and finally reaches the ventricular muscle cells. It is gap junctions between all these cells that spreads the signal - and it is ions (sodium, calcium) that actually move through the gap junctions to trigger the next action potential. Even the intrinsic conduction system cells (which are non-contractile cardiac muscle cells) are connected to one another and the contractile cells by gap junctions.

How do you feel about this statement? Blood returns from lungs via pulmonary arteries to the left atrium. 1. I think it should say: Blood returns from lungs via pulmonary veins to the left atrium. 2. I think it should say: Blood returns from lungs via systemic arteries to the left atrium. 3. I think it should say: Blood returns from lungs via pulmonary arteries to the right atrium. 4. I feel good about this sentence.

1. I think it should say: Blood returns from lungs via pulmonary veins to the left atrium.

Systole is contraction of heart muscle. The atria contract independently of the ventricles. When is atrial systole with respect to the P wave of the ECG?1. Part way through the P wave until about the QRS complex 2. Part way through the QRS wave until about the T wave 3. Part way through the T wave until the next P wave

1. Part way through the P wave until about the QRS complex.

How are the left and right sides of the heart similar or different? 1.The left ventricle consumes more oxygen than the right ventricle. 2.The left atrium receives more blood than the right atrium during diastole (fills with more blood). 3.The right ventricle generates the same amount of pressure as the left ventricle during systole. 4.The right side of the heart has a higher cardiac output than the left side of the heart. 5.The left side of the heart has a higher cardiac output than the right side of the heart.

1. The left ventricle consumes more oxygen than the right ventricle. Right! The left ventricle has more muscle mass and therefore requires more blood to be delivered to it by the coronary circulation. The left side generates much greater pressures than the right side because it must pump to the entire systemic circuit which has a very large resistance. Therefore, the left side must generate more pressure to overcome the resistance and keep blood moving to the tissues. All of the other options are incorrect because they either state or imply that the amount of blood returning to or leaving the heart is unequal on both sides. This is of course incorrect because the left and right sides must move the same amount of blood per unit time (same cardiac output) to prevent blood backing up in a circuit. When the left and right sides are not matched, this is called congestive heart failure.

Which of the following best explains why the systemic circuit pressure gradient is so much greater than the pulmonary circuit pressure gradient? 1. The pulmonary circuit has lower total resistance than the systemic circuit 2. The right ventricle pumps less blood into the pulmonary circuit per minute than the left ventricle does into the systemic circuit 3.The pulmonary circuit has lower flow than the systemic circuit 4. The pulmonary circuit has smaller diameter vessels than the systemic circuit

1. The pulmonary circuit has lower total resistance than the systemic circuit

Red blood cells do not have mitochondria although they do have glycolytic enzymes. What is an advantage of this in these cells? 1.They do not use the oxygen they carry for ATP production 2.They do not require ATP for cellular processes 3.They cannot produce proteins needed for self-repair

1. They do not use the oxygen they carry for ATP production. RBCs lack nuclei and mitochondria as well as most other organelles. This allows more room for hemoglobin content in the cell - which then enables more oxygen carrying capacity. However, RBCs do use ATP for some processes and when they need ATP, they make it anaerobically using glycolytic enzymes. The advantage of not using oxygen is that they can deliver it to hungry tissues without reducing the blood's oxygen content before it reaches the tissues.

Which of the following prevent backflow in the large veins of the lower extremity? 1. Venous valves 2. Thick tunica media 3. Porous tunica interna 4. Vasa vasorum

1. Venous valves Just like in the heart, valves in the veins prevent backflow of blood (backflow back down to the feet in the case of the veins). Skeletal muscle contractions also help venous blood move upward toward the heart, as does negative intrathoracic pressure generated during ventilation of the lungs. The vasa vasorum is the blood supply of the vessels - the vessels are tissue too and need their own source of nutrients to live. The blood moving though vessels cannot supply all the vessel tissue with nutrients, just like the blood inside the heart chambers does not supply nutrients to the heart muscle.

The liver is responsible for the production of most clotting factors. Which of the following best describes the role of these clotting factors when a blood vessel is broken? 1.When a vessel ruptures, clotting factors become activated to permit the conversion of soluble fibrinogen to insoluble fibrin. 2.When a vessel ruptures, clotting factors are immediately released from the liver, find the site of injury and then bind to prevent further blood loss. 3.Platelets are made in the liver and store clotting factors. When a vessel ruptures, platelets release these clotting factors which stop blood loss. 4.When a vessel ruptures, clotting factors from the liver stimulate vascular spasms which decrease blood loss from the site of injury.

1. When a vessel ruptures, clotting factors become activated to permit the conversion of soluble fibrinogen to insoluble fibrin. -Clotting factors are chemicals or proteins used in the multi-step process that ultimately converts soluble plasma fibrinogen into insoluble fibrin. Fibrinogen floats around in the blood dissolved in the plasma. When vessel injury occurs, platelets stick to the site of injury and release their contents. This causes a temporary platelet plug to form. Next, clotting is initiated. This process causes fibrin strings to form which then span the injury and trap blood cells, thus sealing the break in the vessel. For fibrin to precipitate out of the plasma, the protein (enzyme) thrombin must be formed. Thrombin is found in the blood in its inactivated form, prothrombin (made by liver). To convert prothrombin to thrombin, other clotting factors found in the blood are converted from their inactive forms to active forms. The initial stimulus causing activation of all clotting factors can be either the exposed collagen from a broken vessel or a chemical released from damaged tissue. The chain reaction that occurs ultimately results in clotting.

Under normal resting conditions or light exercise, the primary factor altering cardiac output is: 1. venous return 2. sympathetic stimulation of the heart 3. parasympathetic stimulation of the heart 4. hormonal stimulation of the heart

1. venous return, Venous return is the volume of blood returning to the heart from systemic veins. It is the primary mechanism for changing cardiac output as explained by the Frank-Starling law of the heart. The more blood that flows into the heart, the more blood that will be pumped out thus altering cardiac output. Changes in hormones or neural stimuli do alter cardiac output, but the primary mechanism that acts to alter cardiac output to match tissue demands at rest and during routine activity is venous return. Parasympathetic activation keeps cardiac output low at rest, but it does not affect changes to match needs during shifts in venous return.

During the time of early ventricular filling, which has the lowest pressure in the cardiovascular system? 1.Right ventricle 2. Pulmonary trunk 3.aorta 4.right atrium 5. inferior vena cava

1.Right ventricle Right! During early ventricular filling, blood is flowing into the ventricle from the atrium. Therefore blood pressure must be lower in the ventricle than the atrium because blood flows from high pressure to low pressure. Pressure in the aorta and pulmonary trunk is definitely higher than either the atrium or the ventricle at this time as well. Pressure in the inferior vena cava is higher than the pressure in the atrium because blood is flowing into the atrium from the vena cavae.

Using the Blood O2 image above, what would be the effect on hematocrit of injecting oneself with synthetic erythropoietin? 1.Increased hematocrit 2.Decreased hematocrit 3.No change to hematocrit

1.increased hematocrit

Which of the following will directly increase cardiac output? 1. decreased SV with no change in HR 2. increased ESV with no change in HR 3. increased EDV with no change in HR 4. decreased SA node firing rate with increased ESV

3. Increased EDV with no change in HR Increasing EDV leads to a higher SV because of the Frank-Starling law of the heart. The more blood that returns to the heart, the stronger the heart contraction to empty more blood. Any increase in ESV will decrease CO because of a lower SV. A decreased SA node firing rate is the same as slowing the heart rate, and a lower HR with the same or lower SV means a lower CO.

Regarding cardiac output: 1. Increased heart rate will always lower cardiac output because the ventricles fill less 2. People with slow heart rates always have low cardiac outputs 3. Increased venous return increases stroke volume and cardiac output 4. Increasing heart rate will always increase cardiac output

3. Increased venous return increases SV and cardiac output. Increased heart rate will always lower cardiac output because the ventricles fill less. - Not true. Although EDV may decrease, if you increase contractility, the ventricle will squeeze harder and eject more, lowering the amount left behind (ESV). This may keep SV normal or even increased, thus maintaining or increasing CO. Furthermore, increased exercise may increase venous return, so that even though filling time is less, more volume may come back, maintaining EDV. People with slow heart rates always have low cardiac outputs. - Not true. Slower heart rate allows more filling time and a higher EDV. If EDV is higher, SV will be higher due to the Starling law of the heart. Increased venous return increases stroke volume and cardiac output. True. This is the Starling law of the heart. When more volume comes into the ventricle, that volume stretches the muscle into better interaction between actin and myosin. This better interaction means a more forceful contraction. This more forceful contraction leads to more volume being ejected (a higher SV) which means a higher CO. Increasing heart rate will always increase cardiac output. - Not true. If HR is high, but SV is low, CO will not increase. CO = HR x SV. This type of thing may happen when someone loses a lot of blood (hemorrhage). The heart rate increases, but with a low stroke volume (due to low blood volume) they may not be able to maintain CO needed to maintain life.

Using the graph, S: 1.is the result of K+ ions crossing the membrane. 2.allows the heart to generate its own action potentials. 3. ensures that the heart does not achieve tetanus. 4. occurs due to decreased membrane permeability to Ca2+.

3. ensures that the heart does not achieve tetanus.

Ian visits the doctor because he is feeling weak and tired. His hematocrit is 50% and his hemoglobin concentration is 10 g/dL of blood. Which of the following most likely explain his symptoms? 1.High platelet numbers are clogging his capillaries 2.He likely has a very low RBC count per microliter of blood 3.His bone marrow cannot make formed elements 4.He has a low ability to transport oxygen throughout his body

4. He has a low ability to transport oxygen throughout his body. He hemoglobin concentration should be around 16-17g/dL given his hematocrit level. With the values given, the hematocrit is high, but still within normal ranges but his hemoglobin is low. Hemoglobin within the RBCs binds oxygen, allowing the blood to be 70X more able to carry oxygen than when hemoglobin is not present. To make hemoglobin, the body needs iron and certain amino acids. Without enough iron, red blood cells cannot make hemoglobin. When the body senses that oxygen delivery is low (anemia), it signals more red blood cells to be produced to increase oxygen delivery. However, if the new red blood cells still cannot make hemoglobin, the cycle continues causing high RBC counts, but low hemoglobin counts. Typically, hemoglobin levels (by number) should be 1/3rd the hematocrit. So, for a hematocrit of 50, you would expect hemoglobin levels of about 16-17 g/dL. The place in the body that senses oxygen carrying capacity of the blood is the kidney (mostly). When low oxygen levels are detected, cells of the kidney release a hormone called erythropoietin (EPO). EPO travels to the bone marrow and stimulates RBC and hemoglobin productions. In the bone marrow, stem cells called hemocytoblasts produce all formed elements are derived (formed elements are the RBCs, WBCs and platelets). If formed elements were not present, the hematocrit would not be within normal ranges. Beyond other things needed for cell production, vitamin B12 is required for production of RBCs. Without vitamin B12, hematocrit would be very low. The condition pernicious anemia develops when vitamin B12 is not able to absorbed by the body (usually due to gastric ulcers/disease). There is no mention of platelet counts. However, capillaries can clog with RBCs when the hematocrit is very high (polycythemia). This condition is not likely to be observed here. Given that the hematocrit is within normal limits, it is unlikely that the RBC number is low.

For a single cardiac cycle, why does sympathetic activation increase stroke volume? 1. It increases EDV 2. It increases ESV 3. It decreases EDV 4. It decreases ESV

4. It decreases ESV Right!Sympathetic activation increases contractility of the heart, making ventricular systole more effective. This lowers the volume left in the ventricle at the end of a contraction (ESV). Since stroke volume is the difference between how full the ventricle is before it contracts and how empty it is at the end of a contraction, sympathetic input increases stroke volume.

Using the Erythropoiesis image one more time, why does the early erythroblast need to synthesize ribosomes? 1. The cell needs ribosomes to make plasma proteins 2. The cell needs ribosomes to make ATP 3. The cell needs ribosomes to prepare to make platelets 4. The cell needs ribosomes to make hemoglobin

4. the cell needs ribosomes to make hemoglobin

Valves ensure unidirectional flow through the cardiovascular system. Which of the following structures prevents inappropriate blood flow backward from the left ventricle into the left atrium?

Bicuspid left AV valve, Blood should flow from the atria into the ventricles and not in the reverse. Pressure is the driving force for blood flow. When ventricular pressure (during ventricular contraction, also called ventricular systole) exceeds atrial pressure, the blood would try to flow from high pressure in the ventricles into the lower pressure atria. The AV valves prevent this action. The same mechanisms apply to prevent backward blood flow from the great vessels (pulmonary trunk and aorta) into the ventricles. After blood ejection from the ventricles, the ventricles begin to relax (relaxation = diastole). As they relax, their pressure drops below that of the great vessels. The aortic and pulmonary semi-lunar valves close as ventricular pressure drops below arterial pressure so that blood cannot flow backward into the ventricles. If a valve does not close properly to prevent backflow, the valve is said to be incompetent. Physicians can hear some improperly closing valves using a stethoscope - when they hear inappropriate heart sounds, it is called a heart murmur. Murmurs are distinguishable from normal heart sounds because they sound like a "whoosh" instead of the "Lubb" or "Dupp" of normal heart function during a heart beat.

Does the ejection phase (ventricles emptying into aorta) occur during all of ventricular systole?

No, Ventricular systole occurs during 3 4. But, during 3, both the AV SL valves are closed - this means no blood can flow in and no blood can flow out. The reason the valves are closed is because the LV pressure is greater than the LA pressure (AV closed) but the LV pressure is less than the aorta (so aortic SL valve closed). The LV pressure is rising above LA values but has not met aortic pressure to cause SL valve to open.

Does the left ventricle fill with new blood during all of ventricular diastole?

No, During ventricular diastole, the left ventricle is relaxing. But, at the beginning (time 5), the pressure is too great in the LV (much greater than LA), to allow the AV node to open, so the ventricle cannot fill until time 1.

During the time of early ventricular filling, where is the lowest pressure in the cardiovascular system?1.Right ventricle 2.Pulmonary trunk 3.Aorta 4.Right atrium 5.Inferior vena cava

Right ventricle During early ventricular filling, blood is flowing into the ventricle from the atrium. Therefore blood pressure must be lower in the ventricle than the atrium because blood flows from high pressure to low pressure. Pressure in the aorta and pulmonary trunk is definitely higher than either the atrium or the ventricle at this time as well. Pressure in the inferior vena cava is higher than the pressure in the atrium because blood is flowing into the atrium from the vena cavae.

When does ventricular systole begin?

Shortly after the QRS complex, in the ST segment (aka when the mitral valve closes). You can see a sudden increase in ventricular pressure during time 3 - this is also when all valves are closed. The pressure increase is due to ventricular contraction (not to blood volume increase because all valves are closed and blood can neither enter nor leave the ventricles). The pressure rises and rises throughout time 4 as the ventricle squeezes, only to begin to fall during time 4. The fall during 4 is because blood is leaving the ventricle into the aorta (you can see a concomitant increase in pressure in the aorta as it accepts blood during time 4.) However, the blood moves through the aorta downstream, causing pressure to fall in both the aorta and ventricle. As the ventricle begins to relax (time 5), pressure falls in the ventricle and the aortic SL valve closes.

What would most likely happen if the AV bundle were damaged? 1. The ventricles would not be activated appropriately after the atria 2. The atria would not contract 3. The ventricles would not contract

The ventricles would not be activated appropriately after the atria. The heart relies on coordination between the atria and ventricles to an effective pump. The AV bundle is the only electrical connection between the atria and ventricles that ensures the activation of the ventricles only after the atria contract. The SA node activates the atria and the signal spreads through the atria to the AV node. From the AV node, the signal passes through the AV bundle, down the bundle branches to the Purkinje fibers and ultimately, the ventricular muscle mass. If the bundle is damaged, the ventricles will receive signals from other intrinsic conduction cells in the ventricular muscle mass. The bundle branch cells or the Purkinje fibers can fire spontaneously and trigger ventricular contraction. Usually when this happens, normally timed QRS complexes are not seen on the ECG and they seem to occur at their own rate regardless of the appearance of the p wave. This question does not state that the SA node is damaged, so there is no reason to assume atrial non-function.

True or False? Following clotting, actin and myosin fibers in platelets help draw the edges of the wound together.

True

True or False? The right ventricle is the pump for the pulmonary circuit.

True Right! The right ventricle pumps blood to the pulmonary trunk and then the blood goes to the lungs. The left ventricle pumps blood to the aorta and then the blood goes to the systemic circulation.

True or False? The systemic circuit contains more blood volume than the pulmonary circuit.

True The systemic circuit delivers oxygen rich blood to the tissues and carries away oxygen poor blood. It is much longer and has more capacity than the pulmonary circuit because it has more tissues to serve. Interestingly, blood volume distribution between the arteries, veins and capillaries in the systemic circuit is not equal. At rest 64% of your blood volume is found in the flabby, thin walled systemic circulation veins. These veins are called the volume reserve of the cardiovascular system. During exercise, skeletal muscle contractions squeeze the veins that lie between them and move more of the pooled venous blood toward the heart. Sympathetic activation during intense exercise also increases the pressure in these vessels, encouraging further blood flow back to the heart - this increased flow towards the right side of the heart is termed increased venous return. Blood flow is volume per unit time. Meaning, 2 ml/sec. Even though capacities and total volumes of the systemic and pulmonary circuits are different, blood flow (the amount entering and the amount leaving each circuit) are always equal. Additionally, blood velocity and blood flow are also not equal. Velocity refers to the distance traveled in a length of time, flow is a volume in a length of time. The same volume (say 5L) may enter and leave the heart every minute, but if the pulmonary circuit is short and the systemic circuit is long, the same volume can travel through the short distance very slowly, while it must travel the long distance very quickly.

True or False? The right ventricle is the pump for the pulmonary circuit.

True, The right ventricle pumps blood to the pulmonary trunk and then the blood goes to the lungs. The left ventricle pumps blood to the aorta and then the blood goes to the systemic circulation.

What is happening during isovolumetric contraction/relaxation?

Ventricular volume is not changing

At what point does the ventricles eject blood out into the aorta?

When the pressure in the aorta is less than the ventricles (ventricles are filled up with blood and thus at a high pressure).

Can stroke volume increase if EDV does not change?

Yes, EDV is end diastolic volume (it is how full the ventricle is before it contracts). ESV is end systolic volume - it is how full the ventricle is at the end of a ventricular contraction (not all blood is actually pumped out of the ventricle with each beat - there is always some residual volume). The amount that is ejected is called SV (stroke volume) and it is calculated by this formula: SV = EDV-ESV. So, stroke volume can increase by increasing EDV or decreasing ESV. ESV will go down if the heart squeezes harder and ejects more. The higher the stroke volume, the greater the cardiac output (for a given heart rate).

A patient's cardiac output (CO) is increased after exposure to the hormone epinephrine. What is the most likely way this hormone altered CO? a. hormone increased HR b. hormone increased SV c. hormone increased HR and SV d. hormone decreased EDV and ESV

a.

Thinking about capillaries, what do we call the osmotic force pushing into the capillary? a. colloid osmotic pressure b. hydrostatic pressure c.net filtration pressure d.blood pressure

a. colloid osmotic pressure

Which of the following cells did not originate from a myeloid stem cell? a.lymphocyte b.reticulocyte c.basophil d.erythrocyte

a. lymphocyte

Formation of a platelet plug (platelet phase) includes: a. positive feedback to recruit additional platelets b.contraction of smooth muscle to reduce blood flow c. conversion of soluble fibrinogen to insoluble fibrin

a. positive feedback to recruit additional platelets

Which of the following is present in blood plasma but not in the blood serum? a. fribrinogen b.platelets c.water d.leukocytes

a.fibrinogen

What is the difference between serum and plasma?

plasma is the fluid component of blood including all dissolved proteins (no formed elements) serum is the fluid component of blood after clot has formed (no dissolved clotting protein, less calcium, no formed elements). certain clinical test require plasma, not serum

What structure in the heart is responsible for electrical insulation and where is it located in the chamber?

the fibrous skeleton of the heart separates the atria from the ventricles in the bicuspid, tricuspid and aortic and pulmonary semilunar valve.