Unit Vb - Ch 19 - Heart
Sinoatrial node
In the heart, an action potential originates in the ____
1. the plasma membrane at the end of the cell, folded somewhat like the bottom of an egg carton 2. the folds of adjoining cells interlock with each other and increase the surface area of intercellular contact
Interdigitating Folds
Responsible for: 1. pumps blood to the left ventricle 2. preloads the left ventricle 3. passively fills the blood returning from the lungs
Left Atrium
Responsible for: 1. pumps blood to the aorta 2. the strongest chamber 3. dysfunction of this chamber leads to pulmonary edema 4. greatest contributor to systemic blood pressure
Left Ventricle
1. the fascia adherens is the most extensive type, a broad band in which the actin is anchored to the plasma membrane 2. desmosomes between cells prevent the cardiocytes from pulling apart when they contract
Mechanical Junctions
Coronary arteries Descending aorta Carotid artery Left ventricle
Oxygenated Blood
1. Beginning with the return from the systemic circulation, blood enters the RIGHT ATRIUM 2. Blood enters the right ventricle from the right atrium through the right AV valve, which is also known as the TRICUSPID valve 3. The right ventricle contracts next, which forces blood up through the RIGHT SEMILUNAR valve, which is also known as the pulmonary valve 4. After circulating through the PULMONARY capillaries, blood returns to the left atrium 5. From the left atrium, blood moves through the left AV valve, which is also known as the MITRAL valve 6. From the left ventricle, the blood is pumped up to the AORTA via the LEFT SEMILUNAR valve, which is also known as the aortic valve
Place sentences in logical order beginning with blood entering the right side of the heart
1. Right Atrium 2. Tricuspid Valve 3. Right Ventricle 4. Pulmonary Valve 5. Pulmonary Trunk 6. Pulmonary Artery 7. Lungs 8. Pulmonary Vein 9. Left Atrium 10. Left AV valve
Place the labels in order denoting the flow of blood through the pulmonary circuit beginning with the right atrium
Responsible for: 1. pumps blood to the right ventricle 2. preloads the right ventricle
Right Atrium
Responsible for: 1. pumps blood to the pulmonary trunk
Right Ventricle
Epicardium
Serous membrane; membrane simply squamous epithelium over areolar connective tissue with an adipose covering
AV bundle
Signals leave the AV node and descend along this structure toward the apex
Pulmonary Arteries Pulmonary Trunk Pulmonary Veins Lungs Right Ventricle Respiratory Capillaries
Structures of Pulmonary Circuit
Aorta Carotid Arteries Vena Cavae Left Atrium
Structures of Systemic Circuit
True
T OR F Action potentials are carried by the purkinje fibers from the bundle branches to the ventricular walls
True
T OR F In the ventricles, the action potential travels along the interventricular septum to the apex of the heart, where it then spreads superiorly along the ventricle walls
true
T OR F blood pressure is expressed in mm of mercury bc mercury is so dense it enables pressure to be measured with short columns
true
T OR F blood pressure is usually measured with a sphygmomanometer which is a calibrated mercury manometer
false
T OR F the atria never contract due to passive ventricular filling
false
T OR F the audible heart sounds are caused by the contraction of the atria and ventricles
False
T OR F the beginning of ventricular systole is when blood flowing back toward the relaxed ventricles causes the semilunar valves to close
DEPOLARIZES
The P wave is produced when a signal from the SA node spreads through the atria and ____ them
VENTRICULAR
The QRS complex is produced when the signal from the AV node spreads through the ____ myocardium and depolarizes the muscle
DIASTOLE
The T wave is generated by ventricular repolarization immediately before ____
T
The chart includes 3 principle deflections above and below the baseline, the P wave, QRS complex and the ____ wave
Myocardium
Thickest layer; made of muscle and performs the work of the heart
the AV valves close, and then the semilunar valves open
Which of the following is caused by ventricular contraction
Sinoatrial node AV valve AV bundle Bundle branches Purkinje fibers
Which of the following is the correct sequential path of an action potential in the heart?
action potentials pass slowly through the AV node
Which of the following is true concerning the heart's conduction system?
AMPLIFIES
An instrument called the EKC ____ these signals and produces a record on moving paper chart
cardiac reserve
the difference between the maximum and resting cardiac output is called ____
contraction force
the frank-starling law of the heart states that an additional stretch of the myocardium produces a significant increase in ____ on the next beat
the AV valves open
when the pressure in the ventricles becomes lower than the pressure in the atria, ____
Isovolumic contraction, ejection, isvolumic relaxation, passive ventricular filling, active ventricular filling
which of the following is the correct sequence of events regarding the cardiac cycle
Purkinje fibers
Distributes the electrical excitation to the ventricle
1. gap junctions, forming channels that allow ions to flow from one cardiocyte directly into the next 2. allows the entire myocardium of the two atria to behave almost like a single cell
Electrical Junctions
CURRENTS
Electrical ____ in the heart can be detected by means of electrodes applied to the skin
all of the above
Exercise has which of the following effects on cardiac output
1. firing of the SA node excites atrial cardiocytes and stimulates the two atria to contract almost simultaneously 2. in the AV node, the signal slows down to about 0.05 m/sec bc the cardiocytes have fewer gap junctions over which the signal can be transmitted 3. the entire ventricular myocardium depolarizes within 200 m/sec after the SA node fires, causing the ventricles to contract one after another 4. Signals travel through the AV bundle and purkinje fibers at a speed of 4 m/sec the fastest in conduction system 5. the delay at the AV node is essential bc it gives the atria time to fill with blood before it contracts (all of the above)
Choose the correct statements that accurately explain the impulse conduction to the myocardium
Endocardium
Covers the valve surfaces and is continuous with the endothelium of the blood vessels
Jugular vein Pulmonary trunk Pulmonary arteries Right atrium Superior vena cava Great cardiac vein
Deoxygenated Blood
AV node
The electrical gateway to the ventricles
SA node
The pacemaker that determines the heart rate
ventricular filling
during which complete phase of the cardiac cycle do the atria both relax and contract
isvolumetric - ventricles relax
during which phase of the cardiac cycle do both the atria and ventricles relax
ventricular ejection
during which phase of the cardiac cycle does aortic pressure its maximum
???
if a person's heart is pumping 5000 mL of blood in one minute and the heart rate is 50 bpm, what is the cardiac output
