Cardio #75
Fri, 01/24/03, 1pm
Exam Review
Jennifer Uxer for David Jenkins
Page 1 of 5
Exam 4 Review
I.
Exams
A. Written
 10am – 11am
 25 questions
 Anatomy – 9
 Physiology – 9
 Histology – 4
 Embryology – 3
B. Practical—Dr. Sheedlo
 We’re divided into 4 groups. Check the lists on the boards outside of
the lab. You can trade with someone if you’d like.
 23 questions
 Histology – 3
There is histology in the dissector. Scroll down to the bottom to find it.
Exam images are similar to the histology in the dissector.
Know the structure and characteristics of:
a vein – flat, adventitia with endothelium; a large vein is flat
an artery – has smooth muscle; a large artery is packed
Know the distinguishing layers: tunica intima, media, and adventitia
 Heart-pericardium – 11
 Mediastinum – 9
 7—2nd order questions
 An artery is tagged: What’s its origin?
 A vein is tagged: Where does it drain?
 Know the diaphragm
 Gross Anatomy breakdown
 Heart – 11
 Arteries – 1 (+1—because there are arteries inside the heart; go over
these)
 Nerves – 3 Questions can be 2nd order, identify the tagged structure
 Veins – 3 Remember that there are veins in the heart
 Structures – 1 Includes things like the thoracic duct (which comes from
a vein).
 Cross Section – 1
You can find this at the end of the dissector. Study cross sections 30 &
31. Each has 2 different labelings, so there are 4 drawings to study.
Know what’s labeled on the cross sections—there is an exam
question directly from this.
C. Heart Development—embryology
 Go to the heart section in the clinical human embryology and print it.
 Septal formation (interventricular and interarterial)
Cardio #75
Fri, 01/24/03, 1pm
Exam Review
Jennifer Uxer for David Jenkins
Page 2 of 5
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II.
Fetal circulation, especially with regards to the heart (umbilical vein and
artery, ductus arterioss, ductus venoss, foramen ovale)
Early development of heart (regions—follow movie)
Congenital anomalies of cardiovascular system, septa defes, patent foramen
ovale, ductus arteriosus
Individual Professors for Written
A. Dr. Cammarata—Histology
 About 96% of the class got the histo questions right last year
 Go through the notes; don’t worry much about it if he didn’t talk about it in
class. The book provides more details than he covered. Highlights were
covered in the lecture—study the scribe.
 Know the morphology, structures of a blood vessel, the walls, sizes of blood
vessels
 Note that a descriptive written question can be asked or shown as a picture
in the practical to tell what type of vessel it is.
 He looked at the 3 practical questions and feels that they are fair.
B. Dr. Leppi
 Writes questions as clinically oriented as possible
 This was said twice: Know the heart sounds and where they’re best
heard (auscultation) on the chest
 2 sounds—Know how they’re associated with the 4 heart valves
 S1 – lub
 S2 – dub
 Pericarditis—When the heart fills with inflammatory fluid, it forms a
cardiac tamponade and the ventricles have a hard time contracting. Know
how to perform the pericardiocentesis without hurting something.
 Mediastinum
 Know the relationships of structures in the superior mediastinum and
how they relate to each other: aorta, pulmonary trunk, trachea,
esophagus
 Some structures then continue to the posterior mediastinum and know
their relationships to each other.
 Trachea stops at T4
 Esophagus and aorta cross each other on the way to the diaphragm.
 Diaphragm—know the 3 openings. Inferior vena cava – T8, esophagus
– T10, aorta – T12
 Know the thoracic duct (whose contents flow up the body), azygous vein
 Refer to a normal PA (Posterior anterior) radiograph of the chest: know
what’s along the left margin and right margin, know the normal space
occupied by the heart
 Focus on the study questions that apply to what is in this review.
C. Dr. Smith
Cardio #75
Fri, 01/24/03, 1pm
Exam Review
Jennifer Uxer for David Jenkins
Page 3 of 5
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2 questions (integrate with Dr. Downey’s lectures)
Sent an e-mail with comments of what to study and practice questions. The
answers have now been e-mailed. Work on the practice questions
 Wigger’s diagram will be covered next week, so we’re not responsible for
specifics
 Likes to ask questions like “If this happens, what will happen next, what
will increase or decrease?” Dr. Downey asks questions like this, too.
 Know concepts:
 Electrical event precedes mechanical event
 Ohm’s Law
 CO = HR * SV
D. Dr. Downey
 Sent out revised practice questions and their answers. He said that none are
exactly like the exam questions, but they are representative. If you can work
them with confidence, you’re pretty comfortable with the material.
 7 questions from Dr. Downey
 He will be around Monday morning to answer last minute questions. He
will also try to answer questions e-mailed to him.
 Note that his questions and Dr. Smith’s require us to think and demonstrate
an understanding of the material in addition to memorizing information
Rectification
 Resistance to current flow changes as a function of voltage.
 A resistor conducts current directly in proportion to the voltage. A rectifier
changes resistance depending on the applied voltage.
 For K+, there’s an increasing driving force for K+ efflux during the plateau
stage (Phase 2).
 Know this is true because the driving force = Em – EK+ = -95mV. (Em is
calculated using the Nernst equation)
 During the plateau, the driving force is 20mV, yet efflux does not increase.
 Therefore, channels show rectification because they do not let as much K+
escape as you’d expect for such a large driving force.
 This is important because it keeps the K+ from repolarizing the membrane.
 During the plateau, need Ca influx and K+ efflux to equal. At the end, the
Ca2+ influx decreases while K+ efflux decreases causing a repolarization of
the membrane.
 Book calls it inward rectification because the efflux is slow since the
channels are not open much. If the driving force is reversed experimentally,
the channels happily conduct K+ inward quickly. So, they are called inward
rectifiers.
 Know that the rectifiers prevent efflux of K+ in the plateau preventing
repolarization of the membrane—allow it to remain depolarized for a
sustained time.
Cardio #75
Fri, 01/24/03, 1pm
Exam Review
Jennifer Uxer for David Jenkins
Page 4 of 5
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Need to know and appreciate that the K+ conductance decreases below its
resting value allowing sustained depolarization. It then rises to its basal
level to allow repolarization.
Won’t ask us to ID specific K+ currents, I1 etc.
Know that there are voltage- and ligand gated K+ channels. Ligand gated
channels are sensitive to ATP and Acetylcholine.
Ischemia
 Na+/ K+ pump is essential for maintaining transmembrane gradients. Pumps
Na+ out, and brings K+ in.
 If it is compromised by a lack of energy (ATP), K+ is lost and not replaced,
while Na+ enters and is not extruded.
 Consider the Nernst equation for K+, plug in values lower than normal. It
won’t be as negative as usual. As this happens, membrane gets closer to the
threshold for the Na+ channels, causing premature contractions. Na
channels remain inactive because the membrane is not negative enough to
move the inactivation gates. Thus, the Na channels are out of the picture.
 If transmembrane is more negative than Ca2+ threshold and rises to its level,
the Ca2+ channels open and create a slow rising ventricular contraction.
 Na+/ K+ pump maintains normal transmembrane gradients.
 Efflux of K+ and waning Ca2+ current cause repolarization.
Timing in the Heart
 There are questions on this in the practice questions.
 Example: How many msec are required for an electrical excitation from the
pacemaker to the Bundle of His?
 If there aren’t any on the exam, they’ll help next week for ECGs.
Heart Block
 Action potential conduction stopped in the AV nod due to intense
parasympathetic stimulation.
Factors responsible for diastolic repolarization in the pacemaker
 Decreasing K+ outward current allows inward Na+ current through the
“funny channels” and transient Ca2+ current. These inward currents
depolarize the membrane.
 Parasympathetic stimulation: Increases the probability for the K channels to
open. The do, so more charge leaves the cell and competes with the positive
inflow of ions. Threshold of the Ca channels may not be reached or may be
reached at a later time. This causes the heart to beat at a slower rate.
 Sympathetic stimulation: Increases the influx of Ca2+ and Na+ in diastole
causing a faster rise to threshold and a rapid heart rate.
Cardio #75
Fri, 01/24/03, 1pm
Exam Review
Jennifer Uxer for David Jenkins
Page 5 of 5
Practice questions on X, Y, Z #6 & #7
#6. Net negativity inside the cell. Ion X has equal concentrations inside and
outside, so there’s no concentration gradient. There is an electrical gradient
because the inside of the cell is negative and this is a positive ion, so X will
enter the cell passively. Y & Z are in high concentrations outside and are
attracted by the electronegativity inside the cell, so they will also enter.
#7. Read questions carefully!!
Inside concentration of Y & Z is higher than the outside. There’s a
concentration gradient favoring their efflux, yet there’s an electrical gradient
favoring their influx. Calculate the equilibrium potentials for Y & Z. These
will be negative because there’s more inside than outside. This equilibrium
potential won’t be as negative as the membrane potential, so Y & Z enter the
cell. K equilibrium potential is greater than the membrane potential, so it
passively leaves the cell. If this answer was -89mV, the driving force would
be less, but the direction of movement would be the same.