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Chp 17, 18 & 20 pt 1
Chapter 17
| Question | Answer |
|---|---|
| The heart is situated in the middle of the thoracic cavity in a region known as the | mediastinum |
| The right side of the heart receives: | deoxygenated blood from the systemic circuit |
| The visceral pericardium is the same as the: | epicardium |
| The right and left coronary arteries receive blood from the: | aorta |
| What is the function of the valves in the heart? | prevent backflow of blood through the heart. |
| What muscles, present in the ventricles, anchor the atrioventricular valves by tendon-like chords called chordae tendineae? | papillary muscles |
| Autorhythmicity in the heart is the responsibility of: | cardiac pacemaker cells |
| What characteristic differentiates cardiac muscle cells from skeletal muscle cells? | intercalated discs |
| The rapid influx of calcium ions into pacemaker cells creates a positive membrane potential inside the cell and is responsible for the | full depolarization phase |
| The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the: | atria |
| Which of these structures is NOT found in the mediastinum? | the lungs |
| Which of these descriptions of the heart's location is correct? | The heart lies obliquely in the mediastinum. |
| The epicardium | is the visceral pericardium |
| The heart valves have a double layer of _____ with a layer of _____ in between. | Endocardium, connective tissue. |
| Musculi pectinati are found in the _______; trabeculae carneae are found in the ____________. | auricles, ventricles. |
| Which of these structures deliver(s) blood to the left atrium? | Pulmonary veins |
| the anterior interventricular artery is a branch of the | left coronary artery |
| The valve located between the left atrium and left ventricle is the | bicuspid (mitral) valve |
| strong connective tissue strings that are attached to papillary muscles and to the cusps of the atrioventricular valves are | chordae tendinae |
| Arrange these valves in order in which an erythrocyte would pass through them after returning to the heart from the left arm. | tricuspid valve, pulmonary semilunar valve, biscuspid valve, aortic semilunar valve. |
| The skeleton of the heart | electrically insulated the atria from the ventricles. |
| Which of these structures is NOT present in cardiac muscle cells? | terminal cisternae |
| The group of modified cardiac muscle cells that delays action potentials between the atria and the atrioventricular bundle is called | AV node |
| If the SA node becomes damaged and nonfunctional, which of these is the most likely to occur? | Another part of the heart, possibly the AV node, will become the pacemaker. |
| Which of these statements concerning cardiac muscle is correct? | Cardiac muscle has prolonged period of slow repolarization called the plateau phase |
| Action potentials pass rapidly from one cardiac muscle cell to another because of | intercalated disks and numerous gap junctions |
| The depolarization phase of the cardiac muscle action potential occurs when? | voltage - gated Na+ ion channels open. |
| Early repolarization of cardiac muscle cells occur when | voltage gated K+ ion channels open and voltage gated Na+ ion channels close. |
| Which of these conditions occur in the cardiac muscle cell during the plateau phase? | voltage-gated Ca+ ion channels are open, voltage gated K+ ion channels are open, and voltage-gated Na+ ion channels are closed. |
| Which of these conditions occurs in the cardiac muscle cell during the final repolarization phase? | voltage-gated K+ ion channels are open |
| Unlike other cardiac muscle cells, the movement of ______ into the pacemaker cells is primarily responsible for the depolarization phase of the action potential | CA 2+ ions |
| Which of these conditions results in a prepotential in pacemaker cells? | Na + ions move into the cell through specialized Na+ ion channels. |
| In an EKG, the P wave represents | depolarization of the atria |
| During the QT interval of an EKG | ventricles contract and begin to relax |
| Which of these conditions is most likely to cause bradycardia | excessive parasympathetic stimulation |
| During the period of ejection in the cardiac cycle, the atrioventricular valves are _____and the semilunar valves are _____. | Closed, open. |
| Blood flows neither into nor out of the ventricles during | the period of isovolumic contraction and the period of isovolumic relaxation. |
| At the end of ________ the ventricles are 70% filled | passive ventricular filling |
| The average end-diastolic volume of the ventricles is about _______, whereas the end-systolic volume is about __________ | 125mL, 55mL |
| During the period of ejection, the left ventricular pressure reaches a high point of approximately | 120mm Hg. |
| The second heart sound, described as "dupp" is actually the sound of the | S2 sound is produced when the semilunar valves close. |
| If the heart rate for a patient is 80 bpm, and her stroke volume is 70 mL/beat, then her cardiac output is | CO would be 5600mL/min |
| Preload | is the extent to which the ventricular walls are stretched. |
| Increased venous return to the heart causes increased | stroke volume, preload, cardiac output, force of contraction. |
| Parasympathetic nerve fibers | if stimulated, result in an increased heart rate. |
| When normal arterial blood pressure decreases, baroreceptors cause a response that | returns blood pressure to normal. |
| If blood pH decreases and blood carbon dioxide increases, | the change is detected by chemoreceptors in the internal carotids and aorta. |
| Increased sympathetic stimulation of the heart | increases the force of ventricular contraction, opens larger numbers of calcium slow channels, and increases heart rate and cardiac output. |
| Generally, an increase in extracellular Ca2+ ions causes __________ force of contraction, and __________ heart rate. | increased force of contraction, decreased heart rate. |
| Excess K+ ions in cardiac tissue cause heart rate and stroke volume to __________ and decreased extracellular K+ ions result in a __________ in heart rate. | excess K+ ions cause HR and SV to decrease, extracellular K+ ions result in decrease in HR. |
| Sodium ion influx results in what stage of a contractile cell action potential? | rapid depolarization phase |
| Potassium ion efflux results in what stage of contractile cell action potential? | breif initial repolarization phase |
| Calcium ion influx and simultaneous potassium ion influx results in what stage of contractile cell action potential? | Plateau phase |
| What happens during the repolarization phase? | Continued potassium ion efflux |
| What determines cardiac output? | how much blood is pumped into the pulmonary and systemic circuits in 1 minute, or stroke volume. |
| What is the resting stroke volume in the average heart? | 70mL |
| What is the cardiac ouput equation? | heart rate times stroke volume equals cardiac output |
| What factors affect stroke volume? | preload (degree of cardiac muscle stretch) contractility (hearts ability to generate tension) and afterload ( |
| what is end diastolic volume? | highest volume of blood after ventricular diastyole |
| what is end systolic volume? | lowest volume of blood at the end of ventricular contraction. |
| What are the five cardiac phases? | Atrial systole (active filling) isovolumetric contraction, ejection phase, isovolumetric relaxation, passive filling |
| Friction between the blood and the vessel wall. | the skeletal muscle pump, increasing sympathetic activity to the veins, and increasing respiratory movements. |
Created by:
babynugnug