Lecture 13 Flashcards
what are the three steps of oxygen delivery and consumption
1.oxygenation
2. oxygen delivery
3. oxygen consumption
what is the amount of oxygen bound to the hemoglobin plus the amount of oxygen dissolved in arterial blood?
what is the normal amount?
Arterial oxygen content (CaO2)
20 mL O2/dL
____ mL in a Liter
____ mL in a deciliter
1000
100
what is the amount of oxygen bound to hemoglobin plus the amount of oxygen dissolved in mixed venous blood?
normal amount is about ?
Mixed venous blood oxygen content (CvO2)
15 mL O2/dL
The change in oxygen levels from the arteries to the veins is ____________ minus ____________
Arterial Oxygen Content – Mixed Venous Blood Oxygen Content
CaO2 - CvO2= 4-5 mL/dL
rate at which oxygen is transported from the lungs to the microcirculation is ______. The equation is _______.
DO2
COxCaO2=1000 mL/min
rate at which oxygen is removed from the blood for use by the tissues is _______.
Equation is ___________.
Target number?
VO2
CO x (CaO2 - CvO2)
200-250 mL O2/min
what is the Fick Principal
Pulmonary blood flow (right ventricular output) equals systemic blood flow (left ventricular output)
Rate of oxygen utilization by the body is equal to the difference between the amount of oxygen leaving the lungs in the pulmonary venous blood and the amount of oxygen returning to the lungs in pulmonary artery blood
In the setting of diminished oxygen delivery, maintenance of a normal oxygen consumption (VO2) can be accomplished by ___________
increasing oxygen extraction.
When increased oxygen extraction is insufficient to maintain normal oxygen consumption, _________ will increase to improve delivery.
cardiac output
At rest the heart’s oxygen consumption is ____________
8mL/min/100 g (heart tissue mass)
Coronary vessels extract ___% (maximum) of available oxygen
Brain, muscle ___%
Portal system ___%
Kidney ___%
70%
34%
18%
8%
With maximal exertion, oxygen demand increases ___ times, so
_________ flow must increase to accommodate this need
How does this happen?
5x
Coronary blood
Chemical byproducts of metabolism: carbon dioxide, potassium, hydrogen ions, adenosine** (all act as vasodilators)
the arteries lie on _____ of the heart, and smaller arteries can _____ the cardiac muscle.
small fraction of endocardium receives supply from the __________
surface
penetrate into
blood inside the heart chambers
Branches of the _________ and ____________ (pericardium) supply some of the blood flow
bronchial
esophageal vessels
Refers to which coronary vessel gives rise to the __________ artery that perfuses the posterior interventricular septum and a portion of the LV is ________?
Usually the ________
posterior interventricular artery
Coronary dominance
- Usually right coronary
the period of time during which contraction occurs
systole
The period of time during which the heart refills with blood.
diastole
Ventricles in systole
________ mm Hg in the myocardium, ______ phase
Ventricles in diastole
_______ mm Hg, numerous large caliber subendocardial capillaries perfuse the muscle during this phase. _____ phase.
90-140 mm Hg
contraction
2-7 mm Hg
relaxation
coronary perfusion is ___% of total cardiac output
___ cc/min in systole
___cc/min in diastole
5%
80
300
the Left coronary artery branches off the _______.
It is ______ than the right
ascending aorta
shorter
what does left coronary artery supply?
left ventricle
left atrium
bundle of HIS
anterior aspect of interventricular septum (IVS)
what are the branches of the left coronary ?
LAD
Left circumflex
What does the LAD of left coronary supply?
anterior LV
anterolateral myocardium
apex
anterior IVS
anterolateral papillary muscle
widow maker
LAD (bc it commonly cause myocardial infarction)
what does the left circumflex of the left coronary supply?
left marginal branches-posterolateral LV
occasionally PDA
- SA nodal branches come off this
what are the branches of the aorta?
posterior descending
right marginal
SA nodal artery
what does the aorta supply?
RA
RV
SA node
AV node
what does the posterior descending aorta supply?
inferior wall
posterior IVS
posterior medial papillary muscle
what is the largest cardiac vein? Where does it lie?
coronary sinus
coronary sulcus
smaller run offs of the coronary sinus ?
great cardiac vein
middle cardiac vein
small cardiac vein
anterior cardiac veins include?
drain anterior portion of RV
empty directly into RA
What is primary control of coronary Blood Flow?
effect of?
local muscle metabolism
- oxygen demand
what is secondary coronary blood flow?
effect of?
nervous control
- direct effects of stimuli on coronary vessels
ANS control of coronary blood flow can be ____ or ______
direct
indirect
Direct ANS control of coronary blood flow effects ________
Ach results in ________ of vessels
Epi/norepi
- Alpha receptors have _________ properties of ______ vessels
- Beta receptors have ______ properties of ______ vessels
vessels themselves
dilation
vasoconstrictive
intramuscular
vasodilator
epicardial
indirect ANS control of coronary blood flow comes from the ________
indirect has ____ of an impact
norepinephrine/epi release results in increased ____, ____, and _____
Ach _____
activity of the heart
more
HR, contractility, muscle metabolism
does opposite effects
Metabolic Control of Blood Flow can override nervous control
Hypoxia (______) triggers _______, which works as an _____ and ____
This response can be of benefit if area is of recent duration and minimal area involved
ischemia
adenosine
antiarrhythmic (slows rate) & potent vasodilator
what is perfusion scan
injected with radioactive substance into blood supply and ECG taken to show low perfusion
