CP LEC 1 Flashcards
Where is the right portion of the heart located in relation to the ribs?
3rd costal cartilage to 6th intercostal space
Where is the left portion of the heart located in relation to the ribs?
From the 2nd to the 5th intercostal cartilage
The viseral pericardium is also known as the….
Epicardium
4 Layers of the heart
which one makes the pericardial fluid?
Parietal Pericardium
Visceral Pericardium (epicardium - pericardial fluid)
Myocardium
Endocardium
Which layer of the heart contains the coronary blood vessels?
visceral pericardium (epicardium)
What are the 2 parts of an intercalated disc and their functions?
Desmosomes- attach cells together
Connexins- spread electrical impulse
The right coronary artery supplies
most of right ventricle, SA node, AV node in 55%
(and right posterior descending and right marginal branches)
The left coronary artery supplies
left ventricle muscles, left atrium, ventricular septum, left anterior descending (widow maker), left circumflex artery, SA in 45% of people
Why is it a problem if you have a blockage in your left anterior descending artery? (widow maker)
left ventricle wont get blood/oxygen, and wont be able to contract and pump oxygenated blood to the body!
What are the consequences of having a history of MI in the right atrium?
Previous MI may have resulted in scarring of the myocardium, which doesn’t conduct like normal myocardial cells. the SA node/pacemaker is in this atria, so we need conduction to set good HR!
Primary cause of coronary artery disease (CAD)
atherosclerosis
due to high BP, high cholesterol, diabetes, smoking
The SA node automatically paces the heart to beat ___bpm
100
The parasympathetic NS (via the vagus nerve) slows it down to 60-90
The SA node must set a pace of depolarization that is _____ than any other cell
Faster
The AV node can spontaneous discharge at a rate of…
40-60bpm
Why is the SA node suspectible to disease?
Proximity to epicardium (Pericarditis)
Coronary artery occulsion
What does the PR interval represent on an EKG
The conduction time between the atria and the ventricles
time it takes for electrical signal to go from SA node to AV node and into ventricles
INCLUDES DELAY AT AV NODE before ventricular depolarization
What does the QT interval represent
The time between the onset of ventricular depolarization and the end of ventricular repolarization
What is a bundle block and what is the consequence?
electrical signal delay or blocked at the L or R bundle branch, causing delay in ventricular contraction = decreased CO
SA - AV - bundle of his - R and L bundles - pujunkee fibers
What does the red portion of the chart represent?
Rapid influx of ___ ions during depolarization
Calcium (Ca2+)
The green part of the chart represents what ion?
K+ Ions
Normal K+ levels are __ to __
hypokalemia would cause
hyperkalemia would cause
3.5-5.0
hypokalemia - *arrhythmias, cramps (increased with diuretic)
hyperkalemia - nausea, vomiting
normal levels of Ca are __ to ___
hypocalcemia would cause
hypercalcemia would cause
9-11
hypo - decreased myocardial contractility
hyper - erratic cardiac contraction
Ca, think contractility
what are 3 main properties of the myocardium
automaticity - conduct without external stimuli (different than skeletal mm)
rhythmicity
conductivity - nerve impulses transmitted from one myocardial cell to another because intercalated discs
Normal stroke volume is ____L and may increase ____ times during exercise
5-6L of blood
x4-7 or 40-60%
A HR that is too fast leads to insufficient ____ and increased or decreased CO?
ventricular filling
decreased
How do you calculate mean arterial pressure?
Diastolic + 1/3(Systolic - Diastolic)
Diastolic + 1/3(pulse pressure)
systolic - diastolic = pulse pressure
Normal MAP is about __. At what MAP should we be cautious with getting a patient out of bed?
What does MAP measure?
93
60 or below
MAP measures perfusion of the body tissues and organs
What are the three factors that effect blood pressure?
Heart rate
Stroke volume
Periphreal Resistance
How would renal insufficiency affect MAP
renal insufficiency = cant filter excess water and salts = fluid retention = increased blood volume = increased MAP
At what resting BP should you avoid doing vigorous activity with your pt?
what BP does the ACSM say stop exercising?
180/120 at rest - no vigorous
ACSM - 260/120 (pretty high, above 200/__ brewer says CAUTION)
An increase of 1 MET would cause an increase in HR and BP of
10bpm
10mmHg
if its more or it drops significantly, thats NOT good.
Resistance of a system to blood flow is determined by the diameter of _____
Arterioles
Where are baroreceptors located?
Carotid Sinus and Aortic arch
What is the primary determinant for increased cardiac output and blood pressure during exercise
Heart rate
Cardiac preload AKA End Diastolic volume is….
amount of left ventricular blood volume prior to contraction
explain the frank sterling law and how it affects cardiac preload
the more the chamber is stretched, the harder the contraction
however during heart failure (decreased iontropy) the hearts ability to respond to increased filling is weakened
What is cardiac afterload?
Amount of resistance (pressure) encountered by the left ventricle (aortic pressure)
Increased afterload leads to ______ stroke volume and ______End systolic volume (ESV)
Decreased SV
Increased End Systolic Volume (ESV)
tricuspid and mitral valves close when ____ pressure is greater than ____
ventricle pressure is greater than atrium
pulmonary and aortic valves close when ____ pressure is greater than ____
aortic and pulmonary artery is greater than ventricle (after ejection)
What is ejection fraction and how do you calculate it?
Amount of ventricular blood volume pumped per heart beat
Stroke volume/ end diastolic volume
What is the normal ejection fraction at the left ventrical?
55-70%
The S1 Sound _____ the carotid pulse, whereas the S2 sound _____ the carotid pulse
S1 precedes whereas S2 follows
most of the blood in the body (64%) is found in the….
Veins
What is the percentage breakdown of blood composition? Plasma? WBC? RBC?
55% plasma
> 1% WBC/Platelet
45% RBC
True or false: Thrombocytes are a bloodcell
False
hematopoiesis is what and where does it happen
production of RBC, regulated by erythropoietin from the kidney
Bone Marrow
At what level of hemoglobin should you NOT get your patient up?
< 7
Low levels of hematocrit lead to…
Anemia, vitamin deficienies, nutrition deficienies
High levels of hematocrit may indicate…
dehydration (relative high % of RBC bc low fluid), polycythemia vera, lung/heart disease
can lead to increased blood viscosity and increased risk for clotting
What does the hematocrit mean
the concentration of RBC in blood
What is hemogloblin
Specialized protein in RBCs that binds to O2 for delivery to all bodily tissues
One HgB molecules can bind up to four O2 molecules
Each gram of HgB can combine with _____ ml of O2
1.34 ml
__% of oyxgen in blood is bound to Hgb
97%
whereas 2% is dissolved plasma
Amount of O2 that is bound to HgB is called __________
O2 saturation (SaO2):
Normal is 95-97%
What is PaO2?
Partial pressure of oxygen in blood
this measuring the pressure of the “2%” of oxygen that is free floating in the plasma, not bound to hemoglobin. depending on its level, the body may desaturate or not to provide more oxygen in the blood
If PaO2 is over or equal to 50mmHg, what happens to SaO2 (amount of oxygen bound to hemagloblin)
SaO2 does not need to decrease to release the oxygen into the blood to increase the pressure (NO CHANGE IN SaO2)
If PaO2 drops below 50mmHg what happens to SaO2?
SaO2 decreases because oxygen is released back into the blood from the hemaglobulin
what happens when SaO2 drops below 80%?
desaturation becomes more rapid
what causes the saturation curve to shift to the right?
(desaturate at higher levels of PaO2)
increased temp (think tissues need more oxygen so desaturate), increased H+/increasedCO2/low pH, EXERCISE (but normally doesn’t affect much)
what causes the saturation curve to shift to the left?
takes much lower PaO2 levels to desaturate
low temp, high pH
What is Capillary hydrostatic pressure?
Pressure originates from the blood pressure in the arterial system
Moves blood from capillary to interstitium
What is Capillary oncotic pressure?
osmotic pressure induced by the albumin in a blood vessel’s plasma that causes a pull on fluid back into the capillary.
Albumin causes fluid to re-enter the capillary from the interstitial fluid
What does Interstitial hydrostatic pressure do?
Moves fluid from interstitium into the capillaries
what is Interstitial oncotic pressure:
Draws fluid out of the microcirculation (capillaries) into the interstitium
What is the fick equation?
Determines VO2
VO2 = cardiac output x (arterial oxygen content - venous oxygen content)
What is the net fluid exchange from a capillary?
2mmHg outward from capillary
Muscles normally receive ____% of cardiac output
but under intense exercise they can receive ____ % of cardiac output
10-15%
80-85%
Exercising muscle will require increased blood flow while tissue beds of other organs (GI, Splenic, Kidneys) are reduced
Increased blood flow directed to the skin to promote cooling
Mesenteric, splenic and portal tissues receive _______% of cardiac output
Brain and myocardium receive ~ __% of cardiac output
20-30%
5%
What is the oxygen extraction ratio at rest?
23%
4 effects of VO2 falling below critical levels
Anaerobic metabolism will ensue
Serum lactate levels will increase
Multi-organ system failure may be present
Sedation may be necessary to reduce tissue metabolism
(think glycolysis (no O2 used), which = lactate byproduct = acidosis, fatigue)
What happens to VO2 levels in the blood if DO2 decreases (DO2= global oxygen delivery)
The tissues will utilize the same relative amount of O2 that is present in the blood
Tissue metabolism will decrease to survive on a lesser absolute amount of O2
Therefore VO2 does not decrease
Diffusion of O2 and CO2 across the alveoli to the pulmonary arterial circulation dependent on four factors:
Area of capillary membrane
Diffusion capacity of alveolar capillary membrane (emphysema/COPD can stretch out the aveoli and make the diffusion capacity less)
Pulmonary capillary volume (increases during exercises!)
Ventilation to perfusion ratio (V/Q) - Blood flow to avleoli must match the amount of oxygen
What happens if the V/Q Ratio is too low?
If ventilation volume is too small for relative blood flow:
vasoconstriction occurs at the arterioles to reduce blood flow through the capillaries
What is the normal V/Q ratio?
0.8
Where is the physiological dead space of the lungs? Why does this occur?
apices = more ventilated but don’t get as much blood
(bases of lungs are most perfused and shunt blood to other areas of lungs)
Decreased O2 or increased ___ , ____ , _____ can lead to vasodilation
H+ ion
CO2
Metabolites
how does the autonomic system control peripheral gas exchage
sympathetic = vasoconstriction
lack of sympathetic = relaxation, vasodilation
How does the endocrine system control peripheral gas exchange?
epinephrine binds to
alpha receptors = vasconstriction
beta 1 = increased HR and contraction
beta 2 = vasodialtion
What controls the endocrine system?
Hypothalamus
Which nervous system decreases heart rate,
which nervous system increases it?
Sympathetic or parasympathetic
Sympathetic- Increases HR and contractility using norepi
Parasympathetic- decreases HR (via the vagus nerve) and contractility using acetyllcholine
Systolic heart failure results in a low ejection fraction whereas diastolic heart failure results in…
No change to ejection fraction
What does the S1 sound represent?
Closure of the mitral and tricuspid valves
What does the S2 sound represent
Closure of the Aortic and pulmonary valves
What part of the stethoscope do you use to hear heart sounds?
Diaphram (not the drum)
Blood makes up what percent of bodyweight on average?
7-8%
Orthostatic hypotension
when you go from lying to standing, the blood is pulled down to LE
insufficiency of HR increase and/or vasoconstriction to pump blood back up to head causes a delay in return of blood and = dizziness
