Exam 1: 6 Feb 25 CV Phys And Thyroid Flashcards
What is the primary focus of Dr. Schmidt’s discussion?
The regulation of cardiac output and blood pressure during stress
Emphasizes the role of baroreceptors and the autonomic nervous system.
What role do baroreceptors play in the body?
They help maintain blood pressure and cardiac output by responding to positional changes
Located in the carotid sinus and aortic arch.
What neurotransmitters are involved in regulating blood pressure?
Norepinephrine and epinephrine
Norepinephrine is the main presser in the cardiovascular system.
What is the significance of the renin-angiotensin-aldosterone axis?
It is crucial for blood pressure regulation
Involves compounds like vasopressin and aldosterone.
Which circulatory beds are prioritized during stress?
- Coronary circulation
- Central nervous system
- Kidneys
The GI system is less prioritized during stress.
What happens to blood flow in the GI system during stress?
Blood flow is diverted away from the GI system
The GI system can tolerate reduced perfusion for a while.
What is the role of Atrial Natriuretic Peptide (ANP) and B-type Natriuretic Peptide (BNP)?
They help regulate blood volume by increasing urine output and reducing sodium retention
BNP levels can monitor heart failure treatment effectiveness.
How does hemorrhage affect blood volume?
It decreases blood volume and plasma proteins
The body redistributes fluid to maintain plasma volume.
What is the effect of intravenous fluid administration on cardiac output?
It can initially increase cardiac output and blood pressure
Stretch relaxation in large veins reduces venous pressure over time.
What is the CNS ischemic response?
The strongest sympathetic nervous system response to low blood pressure
It can lead to tissue dysfunction and cell necrosis.
What is cardiac reserve?
The maximum increase in cardiac output above normal levels
Factors affecting it include age, health, and valvular disease.
What are common valve diseases affecting cardiac output?
- Aortic stenosis
- Aortic regurgitation
Congenital bicuspid aortic valves are more prone to stenosis.
What is the function of digoxin in heart failure treatment?
It affects sodium-potassium ATPase pumps
Used as a last-resort drug, it can cause various side effects.
Fill in the blank: The body has built-in systems to prevent _______ retention.
volume
True or False: The kidneys increase urine output when there is increased atrial stretch.
True
What is the impact of anesthesia on compensatory mechanisms?
Deeper anesthesia reduces compensatory capacity
Most compensatory mechanisms become less effective.
What happens during reverse stretch relaxation?
Vein walls tighten during sympathetic nervous system engagement
The benefits of this response are not fully understood.
How does increased blood volume affect circulation rate?
It typically lowers the circulation rate
Slower blood flow can lead to coagulation problems.
What happens to blood flow when blood volume increases?
Blood flow tends to move at a slower velocity.
Slower blood flow can lead to coagulation problems and an increased risk of blood clots.
What is the role of atrial natriuretic peptide (ANP)?
ANP is released from the right atrium when it becomes stretched, promoting sodium and water excretion.
ANP increases urine output and helps prevent volume overload.
Where is brain natriuretic peptide (BNP) produced?
BNP is produced in the ventricles of the heart.
BNP is released when the ventricles are stretched and serves a similar function to ANP.
What does an increase in BNP levels indicate?
An increase in BNP levels typically indicates worsening ventricular stretch and potential heart failure.
Monitoring BNP levels can help evaluate heart failure treatment progress.
True or False: ANP and BNP have long-lasting effects on urine output.
False.
ANP and BNP effects are temporary, lasting about a week.
What is oncotic pressure primarily determined by?
Oncotic pressure is primarily determined by plasma proteins, such as albumin.
Oncotic pressure helps retain fluid in the cardiovascular system.
What happens to fluid distribution after significant blood loss?
Fluid redistributes between compartments to maintain blood volume.
This includes movement from interstitial fluid to the cardiovascular system.
Fill in the blank: Normal saline has no _____ in it.
colloids.
This means that only a fraction of normal saline stays in the cardiovascular system after administration.
What are synthetic colloids used for?
Synthetic colloids like dextran and hydroxyethyl starch are used to maintain oncotic pressure in the cardiovascular system.
They provide volume expansion without using blood products.
What is stretch relaxation in large veins?
Stretch relaxation is the response of smooth muscle in large veins to distention, causing the muscle to relax.
This can lead to decreased blood pressure following rapid fluid administration.
What is the effect of rapid intravenous fluid administration on blood pressure?
Blood pressure initially increases but often decreases shortly after due to fluid redistribution and stretch relaxation.
This phenomenon is commonly observed after administering crystalloid fluids.
What is the consequence of losing plasma proteins during blood loss?
Loss of plasma proteins reduces oncotic pressure, affecting the ability to retain fluid in the cardiovascular system.
This can lead to further complications in maintaining blood volume.
What happens if excessive normal saline is given during hemorrhage?
Excessive normal saline can lead to pulmonary edema.
This occurs when too much fluid enters the interstitial space of the lungs.
What is stretch relaxation in large veins?
A response of smooth muscle in large veins that relaxes when the veins become distended, reducing venous pressure over a period of minutes.
Stretch relaxation helps accommodate increased blood volume without immediate pressure spikes.
What is reverse stretch relaxation?
A response where the sympathetic nervous system overrides the natural relaxation of smooth muscle in veins, causing them to tighten in response to hemorrhage.
This is part of the body’s compensatory mechanisms during severe blood loss.
What triggers the CNS ischemic response?
It occurs when there is low perfusion of the brain or brain stem for a few minutes, usually during severe hypotension.
This response involves maximal sympathetic nervous system engagement to restore blood pressure.
What happens to tissues during shock?
They experience dysfunction due to inadequate perfusion, leading to cell necrosis and release of intracellular contents that can worsen the condition.
Common complications include hyperkalemia and acidosis.
Which organ is particularly sensitive to underperfusion during shock?
The liver is one of the first organs to deteriorate under conditions of low perfusion.
Renal failure typically takes longer to develop compared to liver dysfunction.
How is cardiac output estimated using oxygen consumption?
By calculating the amount of oxygen delivered and unloaded in the systemic circulation based on arterial and venous oxygen content.
The thick equation can be used to relate oxygen consumption to cardiac output.
What is the normal oxygen consumption for an average healthy adult?
250 mL of O2 per minute.
This value may vary based on individual characteristics like size and fitness level.
How do you calculate the required cardiac output to meet oxygen demands?
Divide total oxygen consumption by the amount of oxygen delivered per deciliter of blood.
For example, if 5 mL O2 is delivered per deciliter and consumption is 250 mL, the required output is 50 deciliters.
What is cardiac reserve?
The maximum amount of cardiac output that can be achieved above baseline levels.
A healthy adult may have a cardiac output upper limit around 25 liters per minute.
What factors can reduce cardiac reserve?
- Age
- Sedentary lifestyle
- Heart diseases (e.g., valvular disease)
- Coronary artery disease
Cardiac reserve typically decreases with age and health status.
What is the role of digoxin in heart failure?
It is a sodium-potassium ATPase pump inhibitor used as a last-resort treatment to improve heart function.
While it can help, digoxin affects multiple systems and can have serious side effects.
What happens when the heart fails to sustain adequate cardiac output?
The patient may require temporary support to survive while the heart recovers.
This could involve pharmacological interventions or mechanical support.
What are the components of the thick equation used for cardiac output?
It relates arterial oxygen content, venous oxygen content, and oxygen consumption to determine cardiac output.
The equation helps in calculating how much blood must circulate to meet the body’s oxygen needs.
What is the significance of calcium and cholesterol deposits in valve diseases?
They lead to inflammation and structural changes in heart valves, contributing to dysfunction.
These deposits can affect the normal functioning of the heart valves.
What is cardiac reserve?
The ability of the heart to increase its output during increased activity or stress.
Cardiac reserve can decrease with age and health conditions.
What typically initiates valve diseases?
Inflammation leading to calcium and cholesterol deposits.
This process can eventually lead to stenosis or regurgitation.
What does a healthy valve look like?
Clean with a clear opening for coronary arteries.
Healthy cusps fit tightly together.
What is aortic stenosis?
A condition where the aortic valve becomes narrowed, making it difficult for blood to flow out of the heart.
It is characterized by calcified buildup on the valve.
How does calcified buildup affect valve function?
It makes it difficult for the valve to open and can lead to stenosis.
The more calcification, the more stenotic the valve becomes.
What happens when the valve does not close completely?
Blood is funneled back into the ventricle instead of into the coronary arteries.
This condition is known as regurgitation.
What is the most common heart valve problem?
Aortic stenosis.
It affects approximately 1-2% of the population.
What is a congenital bicuspid valve?
A valve with only two cusps instead of the normal three.
This abnormality can lead to complications later in life.
What is a common misconception about congenital bicuspid valves?
That everyone with this condition must have their valve replaced.
Some individuals may not need replacement, especially if they are asymptomatic.
What can happen if a congenital bicuspid valve develops complications?
It may lead to aortic stenosis or even an aortic aneurysm.
Notable cases like Bono from U2 illustrate serious outcomes.
What is the relationship between aortic stenosis and coronary arterial perfusion?
Aortic stenosis can impair coronary arterial perfusion due to obstruction.
The heart has to work harder, exacerbating the issue.
True or False: All patients with congenital bicuspid valves require surgery.
False.
Many individuals may remain asymptomatic and not need surgery.
