AP2 Exam 1 Flashcards
Chemical gradient
concentration based
requires no energy
Electrical gradient
equalize the charge
requires energy due to active transport
think Na+/K+ pump and Ca2+ channels in regards to APs
Of the fluids in the body, ______/3 is intracellular fluid and ______/3 is extracellular. Most (80%) of ECF is ______ fluid.
2/3
1/3
interstitial
Base of the heart
Formed, mostly, by the LA and a small portion of RA
Consists of 4 pulm. veins and 2 pulm. arteries
Apex of the heart
formed by the inferolateral portion of the LV
*rests on diaphragm
Situs inversus totalis
most serious form of dextrocardia
general transposition of the thoracic and abdominal viscera including the heart vs. isolated dextrocardia
The pericardium consists of which layers?
Fibrous pericardial layer: attached to central tendon of diaphragm
Serous pericardial layer: consists of the parietal and visceral layers
The epicardium is synonymous with the ______ ______.
visceral pericardium
______ tissue protects the major coronary vessels.
Adipose
Blood vessels and lymphatics that supply the epicardium, myocardium and endocardium rest/start on the ______ and dive inward through the other layers.
Epicardium
Muscle fiber cells of the ______ are wrapped and bundled with sheaths. They are organized in bundles that swirl diagonally around the heart. This is what gives the heart a ______ like appearance as it contracts
Myocardium
Torque
*although striated, cardiac muscle is involuntary
Endocardium
smooth lining for chambers of the heart
covers the valves of the heart
continuous with the endothelial lining of the vessels
Endocarditis will often produces these two signs amongst the other typical signs of an illness.
Heart murmur: bacteria literally growing on heart valves creating turbulent noise
Irregular heart beat
Auricles of the heart
atrial appendages
pouch like structure that can increase the collecting and pumping capacity of the atria
can be diff. sizes in diff. indiv.: some indiv. can have floppy auricles where blood can collect and clot
has some muscle that allows for contraction at the same time as atrial contraction
have pectinate muscles within both atria
Coronary sulcus
“crown” aka atrioventricular sulcus
externally separates the atria from ventricles
can be seen on anterior and posterior surfaces, however:
it is not complete on the anterior surface because of the great vessels
the coronary sinus sits in the posterior portion of the coronary sulcus
Pectinate muscles
special feature of the ATRIA
special ridges of muscle found in the anterior portion of RA
also found in both auricles
Crista terminalis
dividing line in RA: smooth surface transition to pectinate muscles
The ______ receives blood from the coronary sinus.
RA
Right atrium (RA) posterior and anterior walls
smooth posterior wall
anterior wall is rough>pectinate muscles
Moderator band of the RV
particular bridge that carries a portion of the RBB (conduction system)
The ______ forms most of the base of the heart. It receives blood from the lungs via ______ pulmonary veins. Its posterior and anterior walls are both ______.
LA
4
smooth (pectinate muscles are only found in RA and both auricles)
The inferolateral portion of the ______ forms the apex of the heart.
LV
The ______ septum contains the electrical tract that sends a signal from the RA to the LA.
interatrial septum
Bachmann’s bundle
Interventricular septum
mostly left ventricular myocardium
only normal pathway for electricity to get from the atria into the ventricles
The ______ ______ acts as an electrical insulator between the atria and ventricles.
Fibrous skeleton
Remnant of the ductus arteriosus
Ligamentum arteriosum
*helps stabilize between the aortic arch and pulmonary trunk
Incomplete closure of heart valves is:
insufficiency
As ______ contract, a small amount of blood does flow back into great veins. As the ______ contract, they compress, and nearly collapses the venous entry points.
atria
atria
LCA (left main coronary artery) divides into:
LAD aka anterior interventricular branch
LCA aka circumflex
RCA (right main coronary artery) divides into:
Marginal aka acute marginal branch
posterior descending artery aka posterior interventricular artery
LCA (left main coronary artery) supplies:
most of anterior LA
LAD supplies:
anterior 2/3 septum
bundle branches
bulk of LV
small portion of RV
aka anterior interventricular branch
Left circumflex artery supplies:
high lateral wall of LV
posterior wall of LV
rest of LA
SA node (25% of people)
RCA to include its branches supplies:
RA
RV (marginal mostly supplies)
posterior 1/3 septum (posterior descending supplies)
SA node (75% people)
AV
apex portion of LV
Marginal branch of RCA supplies:
most of RV
Coronary circulation picture
*Most heart anatomy receives blood from more than one artery; collateral circulation via anastomoses
Posterior descending artery of RCA supplies:
posterior inferior wall of LV
part of posterior interventricular septum
aka posterior interventricular artery
Great cardiac vein drains:
portion of both ventricles and LA
Middle cardiac vein drains:
posterior aspect of both ventricles
Small cardiac vein drains:
portion of RV and RA
Posterior cardiac vein drains:
posterior LV
Anterior cardiac veins drain:
superior portion of RV
opens directly into RA
does NOT drain into the coronary sinus vs. all other cardiac veins drain into coronary sinus
Coronary circulation picture
*all veins drain into the coronary sinus EXCEPT for the anterior cardiac veins
Aortic arch gives rise to these three arteries (in order from R to L)
Brachiocephalic artery
Left common carotid artery
Left subclavian artery
Brachiocephalic artery divides into:
Right subclavian artery
Right common carotid artery
How many pulmonary veins do we have?
Four
two from R and two from L
Electrical vs. Chemical potential
charge vs. concentration
*these are in constant battle
*results in CONSTANT state of electrolytes moving across cell membrane
Voltage
the measure of potential energy generated by separated charges
in a cell this is known as MEMBRANE POTENTIAL (measured in mV)
Influx
movement of ions into a cell
Efflux
movement of ions out of a cell
Because cardiac conductive cells are autorhythmic, there is no ______ period.
rest
Bachmann’s bundle
comes off the anterior internodal pathway through interatrial septum to depolarize the LA
The change in ______ at various locations through the conduction system allows for synchronous contractions throughout the heart.
velocity
*SA 0.01-0.02 m/s
*AV 1m/s
*Purkinje fibers 2 m/s
Phase 0
Depolarization
rapid influx of Na+ and Ca2+
+10mV
Phase 1
Cell is a peak positive charge
Rapid Ca2+ and Na+ influx slows then shuts off completely
K+ channels open allowing outflow of K+ leading to slight/brief repolarization
Brief repolarization
Voltage gated slow Ca2+ channels open>>>leads into phase 2 (plateau)
Phase 2
Plateau
Slow influx of Ca2+ balanced with efflux of K+
Ca2+ reaches saturation level need to initiate contraction>>muscle contraction occurs in this phase
Phase 3
Repolarization
Completion of contraction occurs at the beginning of this stage
Voltage gated K+ channels open allowing rapid mass efflux of K+ (not leakage channels)
Phase 4
Resting membrane potential
-90mV
reached once the rapid efflux of K+ is complete
the cells is ready to accept another AP
Types of ion channels in cell membrane
Leakage
Voltage gated
Mechanically gated (change in temp. or pressure)
Ligand gated
Cardiac cell picture
shorter and less circular than skeletal muscle
usually 1 central nucleus but may have 2
gap junctions allow entire myocardium of atria or ventricles to contract as a single unit
Intercalated disc
ends of cardiac myocytes>>connected to another myocyte
contains:
desmosome
gap junction
Mitochondria in cardiac tissue are much ______ and more ______.
larger
numerous
*25% cardiac vs. 2% in skeletal muscles
Action potential graph of conductive cells
Conductive cells contain a series of sodium ion channels that allow a normal and slow influx of sodium ions that causes the membrane potential to rise slowly from an initial value of −60 mV up to about –40 mV. The resulting movement of sodium ions creates spontaneous depolarization (or prepotential depolarization).
At this point, calcium ion channels open and Ca2+ enters the cell, further depolarizing it at a more rapid rate until it reaches a value of approximately +15 mV.
At this point, the calcium ion channels close and K+ channels open, allowing outflux of K+ and resulting in repolarization.
When the membrane potential reaches approximately −60 mV, the K+ channels close and Na+ channels open, and the prepotential phase begins again.
What are the 2 types of cardiac cells?
Conductive:
specialized cardiac muscle cells
relatively non-contractile
initiates APs>>no rest period because they are autorhythmic
self-excitable
Contractile:
requires an AP from conductive cells
resting period
The AP from SA node propagates through which 3 internodal pathways in RA?
anterior internodal: bachmann’s bundle comes off this pathway>>sends signal to LA through interatrial septum
middle internodal
posterior internodal
Only site where APs propagate from the atria to the ventricles
atrioventricular bundle (aka bundle of His)
Q wave on EKG
true beginning of ventricular depolarization
if present, represents rapid, early septal depolarization
not seen in every lead
permanent Q wave can be indicative of previous MI
Flat portions of EKG represent:
muscle contractions
*there is some overlap such as when the superior aspect of the septum and ventricles start to contract while electricity is still making its way throughout the rest of the ventricles
Contraction of the ventricles begins during the QRS and finishes during the:
ST segment
*ventricles start to relax as the T wave begins
Heart sounds come from:
Blood rebounding off of valve leaflets (causes them to close)
NOT a “door shutting sound”
smooth flowing blood is silent
S1 indicates the start of:
ventricular systole
*closure of the AV valves
S2 indicates the start of:
ventricular diastole
*closure of semilunar valves
*split S2: sometimes the aortic closes before the pulmonic valve causing split S2 sounds; can usually hear this when a person inhales
S3 sound:
occurs during early diastole
ventricular gallop: blood rapidly filling of the ventricles (sounds louder with decreased ventricular distensibility)
under 40y/o can be normal
S4
occurs late ventricular diastole (atrial contraction)
hitting non-compliant ventricular walls>>stiffness
S4
coincides with atrial contraction (late ventricular diastole)
aka atrial gallop
hitting non-compliant ventricular walls as atrial contract>>ventricular stiffness
Although the L and R sides of the heart have different pressures, they still expel the same ______ of ______ with each beat.
volume
blood
End of atrial systole equals:
end of ventricular diastole
*130mL
End Diastolic Volume
end of atrial systole=end of ventricular diastole
130mL of blood in ventricle
affected by two factors: lengths of ventricular diastole (shorter=less preload) and venous return (less return=less preload)
Isovolumetric contractions
0.05 second when both the AV and SL valves are closed
ventricles are beginning to contract and ventricular pressure is rising to the point that the SL valves can open
no blood movement
Aortic valve opens at ______ mm Hg
80
left side/systemic afterload
Pulmonic valve opens at ______ mm Hg
20
right side/pulmonary afterload
End systolic volume
volume of blood remaining in the ventricle at end of systole
SV equals:
EDV-ESV
Resting stroke volume is 50-60% of EDV
Ejection Fraction (EF): anything greater than 50% is considered normal (estimated via US/echocardiogram)
Isovolumetric relaxation
period of time where all 4 valves are closed
Typical resting adult male averages a SV of ______mL/beat.
70mL
*typical blood volume of adult male is 5L
The entire ______ volume flows through the pulmonary and systemic circulation each minute.
blood volume
*~5L in adult male
Cardiac reserve
max CO - resting CO
*average person has a cardiac reserve of 4-5x the resting CO
3 factors that affect SV:
Preload
Contractility
Afterload
Frank starling law (principle)
the more the heart fills with blood during diastole, the greater the force of the contraction
Calcium: positive vs. negative inotropy
Increase in Ca2+ influx during APs, increases HR and strengthens contractions (catecholamines, digitalis)>> positive inotropy
Reduced Ca2+ influx during APs, reduces strength of contractions (CCBs, anesthetics)>> negative inotropy
High extracellular K+, ______ HR and contractility.
decreases
*prevents complete repolarization
Blood vessel walls separate the ______ ______ from blood plasma.
interstitial fluid
The open end of the fibrous pericardium is attached to what?
The great vessels
The epicardium is synonymous with:
Visceral layer of the serous pericardium
Fibrous skeleton
Electrical insulator between the atria and the ventricles
Structural support
Anchors the myocardium
Prevents valves from being overly distended
The weight/volume of ______ in the atria is what forces the AV valves open
blood
Autonomic regulation of the heart
cardiovascular center is located in the medulla oblongata
receives input from: sensory receptors, limbic system, cerebral cortex, and afferent nerve fibers from ventricles
proprioceptors (body position and movement), chemoreceptors (pH, blood chemistry), and baroreceptors (blood pressure) [aortic arch and carotid arteries]
Sympathetic vs. parasympathetic innervation of heart
SNS: efferent cardiac accelerator nerves from thoracic spinal cord to SA and AV node (increases Ca2+ entry)
PNS: L/R efferent vagal nerve to SA and AV node; afferent fibers send feedback to CV center in medulla
Adult females have slightly ______ resting HR.
higher
Fever and HR
Exercise and CO
fever can increase HR
after exercise training, maximum CO increases
