End of cardiac lecture - exam 2 Flashcards
What are the 2 SNS reflexes for the CV system? Where are they located and which nerves are they attached to?
- Carotid baroreceptors located at carotid bifurcation/sinus (glossopharyngeal nerve)
- Aortic baroreceptors - aortic arch (vagus nerve)
What is the main endogenous pressor in the CV system?
norepi - released around blood vessels, regulate SVR, contractility, HR
How can epi/norepi be released into the CV system?
Locally via nerves or adrenal glands
What are the protected vascular beds?
Coronaries, CNS, kidneys (kind of)
What area of the body can undergo decreased blood flow under stress?
GI system
What modulated vasopressin release?
Changes in osmolarity or emergent hypotension
Where are stretch receptors located in low-pressure areas?
Large veins leading up to atria and R atria itself
What happens when stretch receptors are activated in the large veins and atria?
- stretch receptors activated, direct neural pathway tells kidneys that there is inc blood volume, sympathetic tone to kidneys is reduced, inc urine output from kidneys to prevent slowing of blood flow
- ANF/ANP - proteins released from atria when stretch reflex activated - inc water and sodium excretion
How can BNP indicate the efficacy of HF therapy?
BNP is released from ventricles when stretched and tell kidneys to get rid of sodium and water
- inc BNP = more stretch, bad
- dec BNP = good, less stretch
How long are BNP and ANP effective for?
~ 1-2 weeks, will need diuretics after
What does BNP stand for? ANP?
Brain and atrial natriuretic peptide
How much of the blood is plasma vs hematocrit?
plasma - 3L
hematocrit - 2L
What is the normal amount of ECF?
14 L
What portion of the ECF is plasma?
1/4-1/5
What makes up ECF?
plasma and interstitium
How much of the ECF is interstitial fluid?
3/4-4/5
What is the normal oncotic pressure of blood?
28 mmHg
What substances account for the oncotic pressure of blood?
fibrinogen, albumin, immunoglobulins, antibodies, coagulation factors
What would you ideally administer to a patient after blood loss?
plasma, synthetic colloids (dextran or hetastarch)
Why is normal saline not ideal for blood loss?
no colloids - fluid will mostly stay in the interstitium, resulting in pulmonary edema
Why doesn’t BP stay high after administering a fluid bolus?
fluid relocation to the interstitium
stretch relaxation in SM of large veins, dec venous pressure
What is reverse stretch relaxation?
Occurs in response to fluid volume loss, autonomic NS overriding what the SM in veins want to do on their own - tightens the walls of veins
arterial oxygenation concentration:
20 mL of O2/dL blood
venous oxygenation concentration:
15 mL of O2/dL blood
arteriovenous O2 difference =
5 mL O2/dL blood
normal oxygen consumption for average adult =
250 mL O2 / minute
What is the CNS ischemic response?
as a result of low brainstem perfusion for a few minutes - strongest SNS response of all the reflexes to inc BP and BF to brain
What happens to the tissues after inadequate perfusion?
cell death and necrosis - inside of cells leak out → hyperkalemia and acidotic
What organ has quick cell death after ischemia?
the liver
What is the Fick equation?
- uses blood gas measurements to est CO
oxygen absorbed per mun by lungs (mL/min)/ arteriovenous oxygen difference (mL/L of blood)
