Exam 2 - Cardiac Loose Ends Flashcards
Where are the bodies baroreceptors?
Aortic arc and both carotid bifurcations
The carotid baroreceptors are innervated by the ____ .
The aortic baroreceptors are innerated by the ____ .
- Hering’s Nerve, branched from the Glossopharyngeal nerve
- Vagus nerve
What are the protected vascular beds?
CNS and coronaries
What system can shunt blood and be uderperfused for a longer time?
GI system
What modulates vasopressin release?
Changes in osmolarity
What drugs prevent epi/norepi from having there full effect?
Beta blockers
How does atrial stretch effect the kidneys via the nervous system?
Atrial and large venous stretch acts directly via a neural pathway to decrease SNS output to the kidneys causing increased urine output
How can an increased blood volume be a problem?
Decreases circulation rate from a decreased velocity leading to an increased risk of clots
What is ANP?
What are its effects?
Atrial Naturetic Peptide released primarily from the right atria in response to atrial stretch
Causes decreased Na+ reabsorption leading to increased water loss
What is BNP?
What are its effects?
Brain Naturetic Peptide released from the ventricles under increased stretch
Also causes Na+ and water loss.
Used as a lab marker for degree of ventricular stress during heart failure
How long do the effects of ANP/BNP last?
Only about a week and then they lose their effect
How much of a normal blood volume is plasma and hematocrit?
Plasma: 3 L
Hct: 2 L
What are the ratios for plasma and ISF in the ECF?
ECF = 14 L
Plasma = 1/4 - 1/5
ISF = 3/4 - 4/5
What is a normal plasma oncotic pressure?
What contributes most to it?
28 mmHg
Fibrinogen, Albumin, Immunglobulins
With a 1 L volume loss, how much would be plasma and RBC?
Plasma = 600 mL (3/5)
RBC = 400 mL (2/5)
How do ECF ratios stay the same during blood loss?
Fluid shifts from if ISF to the vascular system (plasma)
What other ways are there to treat blood loss if whole blood is unavailable?
- Plasma - has blood proteins to increase oncotic pressure
- Dextran/Hetastarch - synthetic large sugar moleucles that increase oncotic pressure
- NS - only 1/4-1/5 will stay in the vascular system
What is the problem with giving NS to someone who has hemorrhaged?
NS has no proteins/low oncotic pressure, causing 3/4 - 4/5 to move into the ISF.
This includes the ISF in the lungs leading to pulmonary edema
What are 2 reasons why there is only a transient increase in BP with rapid fluid administration?
- Most of the fluid moves out of the CV system into the interstitum
- Stretch- Relaxation: a property of large veins - when they become distended, the smooth muscles will relax decreasing venous pressure
What is reverse stretch relaxation?
The ANS overrides the stretch relaxtion reflex during SNS stimulation
What is the strongest SNS CV system reflex?
CNS ischemic response
Maximazation of all SNS reflexes in an attempt to keep a person alive
What negative effect happens to cells during shock?
They are underperfused, die, and release there contents.
Causes hyperkalemia
What organ is affected by underperfusion very quickly?
The liver
How can we determine CO based on blood oxygen?
The Fick equation
CO = O2 absorbed per min by the lungs (mL/min) ➗ Arteriovenous O2 difference (mL/L blood)
What are the normal oxygen contents for arteries and veins?
What does this mean for tissue O2 requirements?
Arterial: 20 mL O2/ dL blood
Veins: 15 mL O2/ dL blood
Tissues: Taking up 5 mL O2 / dL blood
What is the normal oxygen consumption?
250 mL O2 / min
What is the normal cardiac reserve?
25 L or 400 %
What is an athletes cardiac reserve?
600 % or more
What decreases cardiac reserve?
Age, coronary disease, and severe valve disease
What causes decreased coronoary flow during aortic stenosis and regurg?
Stenosis: plaque on the valves block coronary arteries
Regurg: Blood falls back into ventricle decreasing flow
How many people have a congenital bicuspid aortic valve?
1-2% of the population
