CARDIAC1 A AND P

Question 0

HOW MUCH BLOOD IS LEFT ATRIUM RESPONSIBLE FOR CONTRIBUTING TO LVEDV VIA ATRIAL KICK?

Answer 0

20-30%

Question 1

FLUID IN WHAT AREA OF THE HEART CAUSES CARDIAC TAMPONADE?

Answer 1

A THIN POTENTIAL SPACE BETWEEN THE VISCERAL AND PARIETAL PERICARDIUM. IT NORMALLY CONTAINS 10-25 ML OF SEROUS FLUID.

Question 2

WHAT PART OF THE MYOCARDIUM IS AT GREATEST RISK FOR MI AND WHY?

Answer 2

SUBENDOCARDIUM BECAUSE IT IS SUPPLIED DURING DIASTOLE.

Question 3

WHAT DOES THE A, C, AND V WAVE REPRESENT?

Answer 3

A= CONTRACTION OF THE RIGHT ATRIUM
C = CLOSURE OF THE TRICUSPID VALVE
V= PASSIVE FILLING OF THE RIGHT ATRIUM.

Question 4

WHAT IS THE ONLY WAY TO INCREASE O2 DELIVERY TO THE MYOCARDIUM?

Answer 4

INCREASE BLOOD FLOW TO THE MYOCARDIUM

Question 5

IF THE HEART RATE IS INCREASED WHAT IS HAPPENING TO THE DIASTOLIC FILLING TIME?

Answer 5

ITS DECREASED.

Question 6

WHEN IS THE LEFT VENTRICLE PERFUSED?…HOW ABOUT THE RIGHT VENT?

Answer 6

LEFT V =75% PERFUSION DURING DIASTOLE

RV=PERFUSED BOTH SYSTOLE AND DIASTOLE.

Question 7

WHAT IS THE BLOOD FLOW (CO) TO VARIOUS PARTS OF THE BODY?

Answer 7

BRAIN 12
LIVER 24
KIDNEY 20
MUSCLE 23 
INTESTINES 8
SKIN 6
HEART 5

Question 8

CORONARY BLOOD FLOW IS ? CC/MIN TO HEART?

Answer 8

225-250

Question 9

CPP=?

Answer 9

DP-LVEDP

Question 10

WHAT ARE THE EFFECTS OF VA ON CBF?

Answer 10

DIRECT VASODILATION, REDUCE MYOCARDIAL METABOLIC DEMANDS, REDUCE BLOOD PRESSURE (PRELOAD AND AFTERLOAD),

NO EVIDENCE VA CAUSE CORONARY STEAL

Question 11

ARE SARCOMERES INVOLVED IN BOTH SKELETAL AND MYOCARDIAL MUSCLE?

Answer 11

YES

Question 12

WHAT IS THE CHEMICAL AND MECHANICAL PROCESS FOR SARCOMERE INTERDIGITATION….THUS CONTRACTION?

Answer 12

CALCIUM IS RELEASED FROM SARCOPLASMIC RET. WHICH BINDS TO TROPONIN/TROPOMYOCIN, SITES ON MYOCIN HEADS ARE UNCOVERED AND ALLOWS ACTIN AND MYOCIN TO BIND. ATP IS NEEDED FOR THIS. TROPONIN C’S AFFINITY FOR CALCIUM DETERMINES FORCE OF CONTRACTION. AND CONSEQUENTLY CARDIAC OUTPUT.

Question 13

WHAT IS OPTIMAL SARCOMERE LEGTH FOR GOOD CARDIAC OUTPUT?

Answer 13

2-2.4 UM.

Question 14

ARE CARDIAC CELLS AEROBIC OR ANAROBIC?

Answer 14

AEROBIC. THEY DONT STORE OXYGEN.

Question 15

WHAT ARE THE PHASES OF THE ACTION POTENTIAL AND WHAT HAPPENS AT EACH PHASE?

Answer 15

PHASE0=DEPOLARIZATION NA INFLUX, GATES OPEN AT -70
PHASE 1=INITIAL REPOLARIZATION. OVERSHOOT 2-30
P 2=PLATEAU. SLOW CA CHANNELS OPEN . ALLOWS VENTRICULAR FILLING. GET A QRS. LASTS .2-.3 SEC.
P3= REPOLARIZATION. RAPID. K LEAVES, CALCIUM CHANNEL INACTIVATED. CELLS ARE REFRACTORY TO SUBSEQUENT DEPOLARIZATION UNTIL PHASE 4.
P4= COMPLETION OF REPOLARIZATION. RETURN TO RESTING POT AND READY FOR NEXT AP. NA/K PUMP REESTABLISHED. RELAXATION OCCURS AS CALCIUM IS ACTIVELY PUMPED BACK INTO THE SR BY CA MG ATPASE.

Question 16

WHY IS THE SA NODE CAPABLE OF SPONTANEOUSLY DEPOLARIZING?

Answer 16

LEAKEY CALCIUM CHANNELS.

Question 17

WHY DO THE ATRIA AND AV NODE CONTRACT?

Answer 17

DUE TO THE CA ENTERING THE CELLS DURING PHASE 2

Question 18

WHAT IS THE FORCE OF CONTRACTION DIRECTLY RELATED TO?

Answer 18

THE AMOUNT OF INITIAL CALCIUM INFLUX.

Question 19

HOW DOES CA LEAVE THE CELL AFTER CONTRACTION?

Answer 19

BY EXCHANGE WITH MAGNESIUM VIA ATP-ASE IN THE CELL MEMBRANE.

Question 20

THE PRESSURE VOLUME LOOPS ARE REFERRING TO WHAT/

Answer 20

LEFT VENTRICLE.

Question 21

WHAT RELATIONSHIP DOES VENTRICULAR COMPLIANCE EXAMINE?

Answer 21

REL BTW VOL AND PRESSURE IN VENT

Question 22

WHAT IS STROKE VOL?

Answer 22

AREA WITHIN V/P CURVE. VOL EJECTED WITH CONTRACTION. SV=EDV-ESV

Question 23

WHAT IS EF?

Answer 23

EF=EDV-ESV/EDV. SO…..THE % OF TOTAL VOL IN HEART THAT WAS EJECTED. NORM IS 60% ITS NEVER 100% SICK PEOPLE IS AROUND 40%.

Question 24

WHATS THE MOST IMPORTANT DETERMINANT OF PRELOAD?

Answer 24

VENOUS RETURN

Question 25

WHAT PARTS OF THE SMP/PARASYMP NS INNERVATE THE HEART?

Answer 25

SNS: T1-T4 TO SA NODE. INCR IN HR SV. SNS HAS GREATER EFFECT ON CONTRACTILITY. PNS: VAGUS. DECR HR AND CONTRACTILITY. THIS PNS TONE PREDOMINATES...NORMAL RESTING HR IS 72BPM R VAGUS INNERVATES SA L VAGUS INNERVATES AV

Question 26

WHAT ARE THE 3 FACTORS THAT AFFECT HR AND CONTRACTILITY?

Answer 26

CARDIAC INNERVATION (ANS), HUMORAL CONTROL, CARDIAC REFLEXES.

Question 27

WHAT IS THE BARORECEPTOR REFLEX?

Answer 27

THESE MECHANORECEPTORS IN CAROTID SINUSES AND AORTIC ARCH SENSE STRETCH FROM INCREASED PRESSURE AND RESPOND BY MODIFYING (DECREASE) HR. THESE ARE NOT AS SENSITIVE AS PEOPLE AGE.

Question 28

WHAT IS THE BAINBRIDGE REFLEX?

Answer 28

RECEPTORS IN ATRIA. INCREASED STRETCH IN SA NODE CAUSES SA TO INCREASE RATE. INCREASE HR. (IF HR IS LOW) IF THERE ALREADY IS A HIGH HR, THEN ADDITION STRETCH ON TOP THE HR DECREASES. A TRUE REFLEX IE: VALSAVA.

Question 29

WHAT IS THE RESPIRATORY REFLEX?

Answer 29

A NORMAL ARRYTHMIA SOMEWHAT COMMON IN YOUNG HEALTHY MEN....RECEPTORS IN MEDULLA......UPON INSPIRATION GET AND INCREASED HR AND VICE VERSA.

Question 30

WHAT IS A CHEMORECEPTOR REFLEX?

Answer 30

RECEPTOR IN AORTIC ARCH AND CAROTID SINUS....ACTIVATED BY HYPOXIA AND HYPERCAPNEA STIMULATED DURING ASPHYXIA AND SEVERE HYPOTENSION....CAUSING A STIMULATION IN BREATHING AND CV EFFECTS INCLUDING SYMP CONSTRICTION OF SKEL MUSC ARTERIOLES, SPLANCHINIC VENOCONSTRICTION, AND INCR HR. THIS HELPS MAINTIAN BLOODFLOW TO THE BRAIN AT ART PRESSURE TOO LOW TO ACTIVATE THE BARORECEPTORS. BUT EVENTUALLY THIS WILL CRAP OUT AND A DECR O2 SAT =DECR. HR/ASYSTOLE.

Question 31

WHAT IS THE FRANK STARLING CURVE AND WHAT DOES IT SHOW?

Answer 31

PLOTS LVEDP AGAINST STROKE VOLUME. IT LOOKS AT THE ABILITY OF THE HEART TO CHANGES ITS FORCE OF CONTRACTION (STROKE VOL) IN RESPONSE TO CHANGES IN VENOUS RETURN (LVEDP). THEY DO NOT SHOW HOW CHANES IN VENOUS RETURN AFFECT DIASTOLIC VOL.

Question 32

WHAT DOES EF EVALUATE?

Answer 32

THE INOTROPIC STATE OF THE HEART. (HOW HARD THE HEART CAN CONTRACT) NORM IS 60% INCR. INOTROPY INCREASES THE EF.

Question 33

WHAT ARE THE DETERMINANTS OF MYOCARDIAL O2 SUPPLY?

Answer 33

CORONARY ARTERY ANATOMY DIASTOLIC PRESSURE DIASTOLIC TIME ART O2 CONTENT/ O2 EXTRACTION (HGB SAO2)

Question 34

WHAT ARE DETERMINANTS OF O2 DEMAND (CONSUMPTION) ? AKA CO

Answer 34

``` HR MYOCARDIAL CONTRACTILITY MYOCARDIAL WALL TENSION (PRELOAD-MYOCARDIAL WALL TENSION, AFTERLOAD-MAP) VENTRICULAR COMPLIANCE NORMAL CO IS 4-8L/MIN CO=SV X HR ```

Question 35

HOW DO YOU CALC. MAP?

Answer 35

MAP= [SBP + (DBP X 2)] / 3

Question 36

WHAT IS THE FORM FOR SVR?

Answer 36

SVR= [(MAP-RAP) X 80] / CO

Question 37

FORMULA FOR CPP?

Answer 37

CPP=DIASTOLIC BP - PAWP

Question 38

FORMULA FOR EF?

Answer 38

EF= SV/EDV