Sample Questions

Unit B - Cardiac Anatomy and Physiology

Taken directly from Todd's CV Review books, 7th Edition

Unit B, Chapter 1 - Fetal Circulation
Question #269

Which normal cardiovascular fetal shunt normally closes off immediately after the infant’s first breath?
a. Patent foramen ovale
b. Sinus venosus
c. Ductus venosus
d. Patent ductus arteriosus

Check Your Answer

ANSWER: a. The patent foramen ovale normally closes at the first breath.
When the lungs inflate and decrease the PVR and PA pressures, then the RA-LA pressure gradient reverses. Since the LA pressure exceeds RA pressure the LA flap (septum primum) closes and covers the foramen ovale. It normally seals itself to the atrial septum and eventually grows into it.

The umbilical arteries and veins close when the umbilical cord is tied. The ductus venosus remains as a potential channel to shunt blood but eventually closes. The patent ductus arteriosus is dependent on O2, PH and vasoconstrictor levels. It may not close for weeks after birth. Sinus venous is a type of ASD.
See: Braunwald, chapter on "Congenital Heart Disease"

Unit B, Chapter 2 - Blood
Question #288

Which one of the following blood lipoproteins is the major carrier of cholesterol?
a. Triglycerides
b. Cholymicrons
c. LDLs
d. HDLs

Check Your Answer

ANSWER: c. LDLs
Low density lipo-proteins are the bad ones and are the major carrier of cholesterol (being low in density, they float like cream). High density lipo-proteins (HDL's) are beneficial by removing and excreting excess cholesterol from the body. Triglycerides are composed mainly of the very low density lipo-proteins (VLDL) which are of unknown importance in heart disease. The Framingham study has shown that the ratio of total cholesterol to HDL is one of the best predictors of CAD in asymptomatic persons.
See: Underhill, chapter on "Laboratory Tests Using Blood and Urine"

Unit B, Chapter 3 - Cardiac Anatomy
Question #355

In this lateral chest X-ray projection of the heart identify the most anterior structure labeled #1.
a. Interventricular septum
b. LV apex
c. RV
d. PA
e. LA

Check Your Answer

ANSWER: c. RV.
The RV is the most anterior structure. Here it is clearly seen anterior to the LV. This X-ray view is good for identifying RV dilation/hypertrophy since it shows the RV and RV outflow track in silhouette.
CORRECTLY MATCHED ANSWERS ARE:
1. RV
2. Anterior IV Groove (LAD area)
3. LV apex
4. LA
5. PV
6. AO
7. PA
8. Pulmonic Valve
9. Tricuspid Valve
10. Aortic Valve
11. Mitral Valve
See: Netter's collection of medical illustrations, "The Heart"

Unit B, Chapter 4 – Coronary Anatomy and Physiology
Question #411

Identify the three major coronary arteries of the heart. (Select 3 below.)
a. RCA
b. LAD
c. Circumflex
d. PDA
e. Diagonal
f. Left Main

Check Your Answer

ANSWERS: a, b, & c.
Because the LAD is usually the largest coronary artery, it is called "the artery of life." It runs down the front of the heart between the two ventricles. The RCA and circumflex are the other two major arteries. These two run around each side of the heart in the right and left AV grooves.
BE ABLE TO MATCH ALL ANSWERS.
1. RCA
2. LAD
3. Circumflex
The PDA is NOT normally called a separate coronary artery, but a branch of the RCA. Even so, it is vital since it runs on the inferior and posterior wall of the heart from base to apex, in the inferior interventricular groove.
See: Grossman, chapter on "Coronary Arteriography"

Unit B, Chapter 5 – Autonomic CNS and ECG Basics
Question #470

What area of the brain regulates heart rate and peripheral vascular resistance?
a. Pneumotaxic center in the hypothalamus
b. Reticular system in the cerebral cortex
c. Nucleus tractus solitarius area in the medulla
d. Vasomotor center in the cerebellum

Check Your Answer

ANSWER: c. Nucleus tractus solitarius area in the medulla.
The Nucleus Tractus Solitarius (NTS) area is a primitive regulatory center in the medulla oblongata at the base of the brain. The medullary regulatory center receives input from the pressor-receptors, chemoreceptors and other afferent nerves. After processing this information, the medulla sends efferent impulses out the sympathetic and parasympathetic nerves to regulate the heart rate, contractility, and vasomotor tone, etc.
See: Berne & Levy, chapter on "Regulation of the Heartbeat"

Unit B, Chapter 6 – Hemodynamics and Pressure Basics
Question #537

This diagram shows the relative values of 4 hemodynamic measurements as the systemic blood moves from the aorta, arterioles, through the capillaries and venules, and into the vena cavae.
The principal level at which the vascular RESISTANCE (vasoconstriction) develops is in the:
a. Venules
b. Arterioles
c. Large veins
d. Large arteries

Check Your Answer

ANSWER: b. Arterioles.
Arterioles contain precapillary sphincters which pinch off the pressure. Constricted arterioles are the chief resistance to blood flow. Thus, vasoactivity dramatically affects vascular resistance, blood pressure and flow. BP is directly proportional to the cardiac output and the resistance (BP = CO x SVR.)
See: Berne & Levy, chapter on "The Circuit”

Unit B, Chapter 7 – Contractility and Frank-Starling Law
Question #611

What ION enters the sarcomere in systole and combines with the troponin-C molecule? This then allows actin and myosin cross-bridges to form. The sarcomere then contracts.
a. Na+
b. K+
c. Mg++
d. Ca++

Check Your Answer

Sarcomere: Actin/Myosin ANSWER: d. Ca++.
Ca++ enters the cell through calcium channels (of calcium blocker fame). This triggers release of large amounts of calcium stored in the sarcoplasmic reticulum. This Ca++ combines with troponin-C to uncover these troponin activation sites (beads shown on the actin molecule). The troponin then couples with myosin molecules to form cross-bridges. This causes systolic contraction. The heads of the myosin molecules are like little oars that pull against the actin beads and slide the sarcomere filaments together.
See: Berne and Levy, chapter on "Cardiac Pump"
See: Underhill, chapter on "Physiology of Heart"

Unit B, Chapter 8 – Vascular Anatomy
Question #635

Match the anatomic positions listed below with their definitions in the box.
a. Superior or cranial
b. Inferior
c. Anterior
d. Posterior
e. Farther from the midline
f. Nearer to the point of origin
g. Farther from the point of origin

Check Your Answer

ANSWERS: 1g, 2d, 3e, 4f, 5c, 6a, 7b.
BE ABLE TO MATCH ALL BELOW.
1. Distal = g. farther from the point of origin
2. Dorsal = d. posterior = near the back of the body
3. Lateral = e. farther from the medial plane or midline
4. Proximal = f. nearer to the point of origin
5. Ventral = c. anterior = near the front of the body
6. Cephalic = a. superior = cranial = toward the head
7. Caudal = b. inferior = away from the head.
See: Tortora, chapter on "Organization of the Human Body"

Unit B, Chapter 9 – Vascular Physiology
Question #699

The elastic arteries filter and smooth out the pulsatile pressure within the aorta. This effect is termed the:
a. Pulse pressure
b. Stiffness effect
c. Peripheral resistance
d. Windkessel effect
e. Impedance

Check Your Answer

Hand operated fire hose pump ANSWER: d. Windkessel effect.
A windkessel is an air ballast chamber used by the old hand pumped fire trucks. Similar air chambers are still attached to wells to smooth out pump strokes. The aorta stores and dampens the pulsatile pump flow by expanding the aorta in systole. This stores systolic energy and then returns that potential energy to the blood during diastole. Without this "windkessel effect" the aortic pressure would resemble the LV pressure.
See: Berne & Levy, chapter on "Microcirculation