Cardiac Muscle Physiology
Which of the following describes the effect of addition of catecholamines, such as norepinephrine and epinephrine, to cardiac muscle cells?
- Increases contractility by increasing Ca2+ influx into the cell
- Increases contractility by decreasing activity of the Na+/K+ ATPase pump
- Decreases contractility by increasing Ca2+ exchange out of the cell
- Decreases contractility by increasing activity of the Na+/K+ ATPase pump
- Catecholamines have no effect on contractility; they only increase transmission of electrical impulses between adjacent cardiac muscle cells
A patient with a history of myocardial infarction has _________ preload due to scar tissue in the heart. It requires _________ energy to overcome this.
- Normal, the same
- Decreased, more
- Increased, less
- Increased, more
- Decreased, less
Which step is involved in correcting hypoxia in cardiac muscle?
- Decrease blood flow to lower extremities by vasoconstriction
- Increase production of norepinephrine
- Dephosphorylation of AMP to create adenosine
- Decrease ATP utilization to minimize oxygen consumption in the electron transport chain
- Increase the influx of acetylcholine to stimulate release of sarcoplasmic Ca2+
Organophosphates are inhibitors of acetylcholinesterase, which leads to an accumulation of acetylcholine. Which effect would we expect to see in a patient that has been exposed to an organophosphate?
- Decreased Ca2+ concentration, tachycardia
- Decreased Ca2+ concentration, bradycardia
- Decreased Ca2+ concentration, normal heart rate
- Increased Ca2+ concentration, tachycardia
- Increased Ca2+ concentration, bradycardia
Which of the following is primarily responsible for maintaining cardiac membrane potential?
- Na+/Ca2+ pump
- Na+/K+ ATPase pump
- ATP exchanger in the sarcoplasmic reticulum
- A & B
- All of the above
Cardiovascular Histology
A pathologist is analyzing the sample of muscle shown below. Unfortunately, it has been mislabeled as “skeletal muscle.” But the pathologist knows from experience that this must be cardiac muscle. Which of the following structures is a clear indicator that this micropictograph specimen is indeed cardiac muscle?
- A
- B
- C
- D
- E
You are on rotations in the Emergency Department with a student from NYIT-Jonesboro. The physician mistakenly asks that student to assist with a pericardiocentesis which is an invasive procedure that involves using a needle and catheter to remove fluid from the pericardium. Unfortunately, the student became distracted and pierces the needle through the heart itself and into the chamber of the left ventricle. In what order (from superficial to deep) would the needle encounter the various layers of the heart?
- Endocardium → Myocardium → Epicardium
- Epicardium → Tunica Media → Endocardium
- Tunica Externa → Tunica Media → Tunica Interna
- Epicardium → Myocardium → Endocardium
- Tunica Interna → Tunica Media → Tunica Externa
Which of the following is true regarding the differences between atrial myocardium and ventricular myocardium?
- The atrial muscle cells are generally smaller in diameter with less gap junctions
- The ventricular muscle cells are generally smaller in diameter with less gap junctions
- The atrial muscle cells are generally larger in diameter with more gap junctions
- The ventricular muscle cells are generally larger in diameter with less gap junctions
- The ventricular muscle cells conduct impulses at a higher rate
The DES gene is responsible for encoding Desmin, a protein intermediate filament used in the intercalated discs of the cardiomyocytes. Which of the following would be the most likely clinical presentation of a person with a mutation in this gene?
- The terminal sarcomeres would be unable to connect to Zonula adherens
- The cardiomyocytes would be unable to bind to one another
- Action potentials would be unable to spread between the cardiomyocyte gap junctions
- The cardiomyocytes would be fused together
- Zonula adherens would be non-existent
You are on rotations in the Emergency Department when a patient presents with all the cardinal signs of a myocardial infarction. Which of the following is NOT a potential medication you would consider administering immediately?
- Nitroglycerin
- Morphine
- Lidocaine
- Atropine
- Lisinopril
You are on rotations in a family med clinic when a 65 year old male patient presents with a pulsatile mass that can be palpated in the upper left quadrant of the abdomen. The patient has been an avid smoker for the last 30 years and has a history of atherosclerosis. Which of the following is the most appropriate differential diagnosis?
- Myocardial Infarction
- Pulmonary Embolism
- Congestive Heart Failure
- Abdominal Aortic Aneurysm
- Pericardial Effusion
You are practicing venipuncture on your good friend, Lucas. Upon puncturing his ante-cubital fossa, you notice his blood is bright red and is entering the collection tube in a pulsatile fashion leaving you to believe you accidentally punctured an artery. Through which of the following layers (from superficial to deep) would the needle have had to go through in order for this to occur?
- Tunica intima → Tunica Media → Tunica Adventitia
- Tunica Media → Tunica Intima → Tunica Adventitia
- Tunica Adventitia → Tunica Media → Tunica Intima
- Tunica Adventitia → Tunica Intima → Tunica Media
- Tunica Media → Tunica Adventitia → Tunica Intima
The carotid body is a small cluster of chemoreceptors and supporting cells located near the bifurcation of the carotid artery. These chemoreceptors are sensitive to which of the following?
- Low oxygen content
- High carbon dioxide concentration
- High arterial blood pH
- A & B
- A, B & C
Cardiac Electrophysiology
Zatebradine is an experimental drug designed to inhibit the If current. Which of the following would be consistent with administration of this drug?
- Flatter phase 4 in modal cells; decrease in HR
- Hyper-polarization of nodal cells; increase in HR
- Steeper phase 4 in nodal cells; increase in HR
- Flatter phase 0 in nodal cells; decrease in HR
- Slower phase 3 repolarization in nodal cells; decrease in HR
Cardiac Cycle
Which one of the following statements about the jugular venous pulse (JVP) is true?
- The height reflects left atrial pressure
- The JVP falls with abdominal compression
- It is best examined with the patient supine
- Large systolic waves are associated with tricuspid regurgitation
- Prominent a waves suggest atrial fibrillation
Administration of a muscarinic agonist, such as Pilocarpine, would cause which physiologic response?
- Increased conduction velocity in the SA node
- Increased contractility of the ventricles
- Vasoconstriction
- Increased frequency of depolarization of the SA node
- Slowed conduction through the AV node
A 24 year old female patient presents to your ER with chest discomfort and you perform a physical exam. Upon auscultation of the heart, you suspect S2 splitting during exhalation and order an ECG. The ECG shows a prolonged QRS wave. Which of the following would be your diagnosis?
- Left Bundle Branch Block
- Aortic Regurgitation
- Normal physiologic splitting
- Coronary Artery Disease
- Raynaud’s syndrome
The closure of the A-V valves as a result of the change in A-V pressure gradient that follows atrial contraction and that accompanies ventricular contraction occurs
- Immediately following repolarization
- At the onset of diastasis
- Immediately prior to rapid ejection
- At the onset of isovolumic contraction
- Immediately following isovolumic relaxation
An increase in systemic blood pressure (or an increase in afterload) would result in
- Increased blood ejection from the right ventricle into the pulmonary artery
- Decreased blood ejection from the left ventricle into the aorta
- Increased blood ejection from the left ventricle into the aorta
- Decreased blood ejection from the right ventricle into the pulmonary artery
- Uneven filling of the right and left atria after rapid ejection
Blood Pressure Regulation
The picture below shows a diagram of the aortic pulse pressure in a healthy 23 yo female patient. Which of the following is closest to the mean arterial pressure of this patient?
- 76 mm Hg
- 110 mm Hg
- 60 mm Hg
- 85 mmHg
- 126 mm Hg
Which of the following is true regarding the arterial pulse waveform shown below?
- The red line is associated with arteriolar dilation, increased sympathetic tone and decreased compliance
- The red line is associated with arteriolar constriction, decreased sympathetic tone and decreased compliance
- The red line is associated with arteriolar constriction, increased sympathetic tone and decreased compliance
- The blue line is associated with arteriolar dilation, decreased sympathetic tone and increased compliance
- The blue line is associated with arteriolar constriction, decreased sympathetic tone and decreased compliance
Lucas is a 76 yo obese, male patient. He has a hx of HTN that is being controlled with a variety of medications. Currently, Lucas’s BP reads 160/80 mm Hg. Which of the following is true regarding Lucas?
- His blood pressure is not unusual for a man his age as arterial stiffening occurs as patients grow older
- His HTN is associated with an increase in pulse pressure which tends to increase cardiac stress
- His blood pressure is associated with a decrease in compliance
- A & B
- A, B & C
A 25 yo male patient presents to the Emergency Department following a motorcycle accident. The patient had his spinal cord transected at the level of T9, causing paralysis in both legs. The most imminent danger, however, is the patient’s plummeting blood pressure. Which of the following is the most likely reason for his falling blood pressure?
- The patient is likely in an immense amount of pain which stimulates vasodilation to allow for increased blood flow to the area of injury
- The patient is undergoing an increase in parasympathetic stimulation below the level of the transection, causing generalized vasodilation and spinal shock
- The patient is most likely bleeding internally, causing the systemic lowering in blood pressure
- The patient has lost sympathetic stimulation below the level of the transection, causing generalized vasodilation and spinal shock
- The lowering in blood pressure is a response to systemic vasoconstriction which often occurs following acute injury
Carotid sinus hypersensitivity is an exaggerated response to carotid sinus baroreceptor stimulation. It results in dizziness or syncope from transient diminished cerebral perfusion. Which of the following is true regarding the autonomic response to the hypersensitivity of the carotid sinus?
- It would increase the impulses traveling from the vagus nerve to the nucleus solitarius
- It would result in an increased activation of the CVLM, which acts as an inhibitory impulse to the RVLM
- It would result in an increased activation of the CVLM, which directly acts on the heart to cause vasodilation
- It would result in an increased activation of the RVLM, which directly acts on the heart to cause vasodilation
- It would result in an increased activation of the RVLM, which directly acts on the heart to cause vasoconstriction
Capillary Circulation
Cirrhosis is a late stage of scarring of the liver caused by many forms of liver diseases and conditions, such as hepatitis and chronic alcoholism. A common symptom of hepatic cirrhosis is hypoalbuminemia. Which of the following is a likely outcome of hypoalbuminemia caused by hepatic cirrhosis?
- Net hydrostatic pressure will fall on the venous side of the capillary bed, resulting in systemic edema.
- Net oncotic (colloid) pressure will fall on the venous side of the capillary bed, resulting in systemic edema.
- Net hydrostatic pressure will rise on the venous side of the capillary bed, resulting in dehydration.
- Net oncotic (colloid) pressure will rise on the venous side of the capillary bed, resulting in dehydration.
- Net osmotic pressure will be too low for filtration to occur on the arteriole side of the capillary bed.
Coronary Circulation
Which of the following best explains the reasoning for why aortic regurgitation leads to coronary insufficiency?
- Aortic regurgitation can result in an extremely high systolic blood pressure, which attenuates the pressure gradient between the aorta and coronary arteries during systole and decreases exchange of nutrients
- Aortic regurgitation can result in an extremely low systolic blood pressure, which attenuates the pressure gradient between the aorta and coronary arteries during systole and decreases exchange of nutrients
- Aortic regurgitation can result in an extremely low diastolic blood pressure, which attenuates the pressure gradient between the aorta and coronary arteries during diastole and decreases exchange of nutrients
- Aortic regurgitation can result in an high low diastolic blood pressure, which attenuates the pressure gradient between the aorta and coronary arteries during diastole and decreases exchange of nutrients
- Aortic regurgitation results in decreased cardiac output, which causes a less blood flow to the coronary arteries
You are on rotations in the Emergency Department when a 35 yo female patient presents with severe tachycardia (260 bpm) following an overdose of Epinephrine. The nurse accidentally administered 5 mL Epi instead of the 0.5 mL that the physician ordered (whoops). One of the first things that you are concerned about (besides your rising malpractice insurance) is imminent myocardial infarction. Which of the following best explains why this patient is at a high risk for an MI?
- Severe sympathetic stimulation and tachycardia decrease the time in which diastolic filling occurs, thus decreases the time in which the coronary arteries can fill and feed the heart during diastole.
- Severe sympathetic stimulation and tachycardia increase the time in which diastolic filling occurs, thus decreases the time in which the left coronary arteries can fill and feed the heart during diastole.
- Severe sympathetic stimulation and tachycardia increase the time in which systole occurs, thus increases the coronary pressure leading to cardiac tamponade.
- Severe sympathetic stimulation and tachycardia decrease the time in which systole occurs, thus decreases the ability to of the coronary arteries to fill and feed the heart during systole.
- Severe sympathetic stimulation and tachycardia decrease the time in which systole occurs, thus increases the ability to of the coronary arteries to fill and feed the heart during systole.
Increased myocardial oxygen demand can be met by:
- An increase in coronary blood flow
- An increase in parasympathetic stimulation
- An increase in oxygen extraction from the cardiac capillaries
- A & B
- A, B, & C
Coronary artery disease develops when the the coronary arteries become damaged or diseased. Cholesterol-containing deposits (plaque) in your arteries and inflammation are usually to blame for this condition. When plaque builds up, it narrows your coronary arteries, decreasing blood flow to your heart. If a patient were to develop a partial obstruction over time due to this condition, which of the following biological mechanisms might occur in order to compensate?
- No compensation could occur quickly enough; this would result in an infarction
- Collateral anastomoses would develop upstream from the occlusion
- Ventricular hypertrophy would occur due to the increase in coronary pressure
- Adenosine would decrease, causing vasodilation in the coronary arteries
- Left ventricular volume would increase overtime allowing for a higher cardiac output and compensation for the obstruction in the coronary artery
Which of the following is true regarding coronary artery circulation under normal conditions?
- The greatest flow through the right and left coronary arteries is during diastole
- During systole there is very little to no blood flow through the left coronary artery
- During systole there is a significant amount of blood flow through the right coronary artery
- A & B
- A, B & C