[Exam 2] Lecture 1 Flashcards
What typically happens to blood when there is a significant blood loss?
blood can pool in the legs if not regulated
blood pressure may drop
The body has mechanisms to prevent blood pooling and maintain arterial pressure.
What are the two main baroreceptors involved in maintaining blood pressure?
- Carotid baroreceptors
- Aortic arch baroreceptors
Carotid baroreceptors are connected to the brainstem via the glossopharyngeal nerve, while aortic arch baroreceptors are connected via the vagus nerve.
What is the primary neurotransmitter involved in regulating systemic vascular resistance (SVR)?
Norepinephrine
Norepinephrine is released locally by nerves or dumped into circulation by adrenal glands.
True or False: The kidneys are protected circulatory beds during systemic stress.
False
The coronary circulation and central nervous system are the most protected, while the kidneys are less so.
What happens to the kidneys during increased stretch in the atria?
Urine output increases
This is due to reduced sympathetic tone to the kidneys, helping to decrease blood volume.
Fill in the blank: The Renin-Angiotensin-Aldosterone System (RAAS) helps regulate _______.
Blood pressure
RAAS is crucial for maintaining blood pressure during systemic changes.
What is the role of vasopressin in the cardiovascular reflex system?
It can increase systemic vascular resistance (SVR) during emergencies
Vasopressin release is typically modulated by changes in osmolarity.
What is Atrial Natriuretic Peptide (ANP) primarily responsible for?
Increasing urine output and reducing blood volume
ANP is released when the right atrium is overstretched.
What does Brain Natriuretic Peptide (BNP) indicate in heart failure treatment?
BNP Increase: Ventricles are stretched, treatment is not working
BNP Decrease: Ventricles are less stressed, treatment is working
What is a consequence of increased blood volume on circulation rate?
Slower circulation rate
This can lead to coagulation problems and increased risk of blood clots.
What happens when compensatory mechanisms like Angiotensin II are removed?
The overall ability to maintain cardiac output and blood pressure decreases
This highlights the importance of these mechanisms in cardiovascular stability.
What is the primary function of the autonomic nervous system in low-pressure areas?
To regulate kidney output based on blood volume and pressure
Stretch receptors in veins and atria signal the kidneys to adjust urine output.
True or False: ANP and BNP are effective natriuretic agents for long periods.
False
They are effective for only a couple of weeks, necessitating the use of diuretics for long-term management.
What is the effect of beta-blockers on the cardiovascular system?
They reduce the effectiveness of epinephrine and norepinephrine at the heart
This can impair compensatory mechanisms during stress.
What is the purpose of ANF/ANP in the cardiovascular system?
To prevent problems caused by excess blood volume expansion
ANF (Atrial Natriuretic Factor) and ANP (Atrial Natriuretic Peptide) are hormones that help regulate blood pressure and fluid balance.
What is the average blood volume in the human body?
Approximately 5 liters
What is the plasma portion of blood volume?
About 3 liters
What is hematocrit?
The proportion of blood volume that is made up of red blood cells, typically around 0.4
What is oncotic pressure and what is its normal value?
The pressure exerted by proteins in the blood plasma, typically 28 mmHg
What happens if 20% of blood volume is lost?
Not typically fatal, but can lead to significant physiological changes
How much plasma is lost when 1 liter of blood is lost?
About 600 cc’s
What happens to fluid distribution after blood loss?
Fluid from the interstitial compartment shifts into the cardiovascular system
What is the effect of losing plasma proteins on oncotic pressure?
It decreases oncotic pressure, making it harder to maintain blood volume
Why can normal saline be problematic for volume replacement?
Only 1/4 to 1/5 remains in the cardiovascular system; the rest goes to the interstitium
systemic circulation can handle this, the pulmonary circulation can not = pulmonary edema
What are synthetic colloids used for?
To maintain oncotic pressure and blood volume after fluid loss
What is stretch relaxation?
The relaxation of smooth muscle in large veins in response to distension
What is reverse stretch relaxation?
The tightening of vein walls due to sympathetic nervous system activation
What triggers the CNS ischemic response?
Severely low brain perfusion
What are potential outcomes of prolonged shock?
Tissue dysfunction, cell necrosis, and release of intracellular substances
What is the Fick Equation used for?
To estimate cardiac output based on oxygen levels in blood and tissue demands
What happens to oxygen in the tissues?
Oxygen is consumed, producing CO2, which is returned to the lungs for exhalation
What is arterial blood oxygen content in mLs O2/deciliter?
20 mLs O2/deciliter
What is venous blood oxygen content in mLs O2/deciliter?
15 mLs O2/deciliter
How much O2 is dropped off by each deciliter of blood in systemic circulation?
5 mLs of O2
What is the normal oxygen consumption for an average healthy adult per minute?
250 mLs O2/minute
Fill in the blank: The Fick Equation is used to calculate _______.
cardiac output
What is the cardiac reserve?
The maximum amount of cardiac output that can be achieved above normal levels.
If normal cardiac output is 5 liters per minute, what would a cardiac output of 25 liters per minute represent in terms of cardiac reserve?
400%
What is the effect of age on cardiac reserve?
Cardiac reserve typically decreases with age.
What is a common heart valve problem that affects coronary artery perfusion?
Aortic stenosis
What is the impact of calcified buildup on heart valves?
It makes it more difficult for the valve to open, leading to aortic stenosis.
What is the main issue caused by aortic regurgitation?
Blood is funneled back into the ventricle instead of into the coronary arteries.
decreased coronary perfusion
What is the estimated prevalence of congenital bicuspid aortic valves in the population?
1-2%
What is a consequence of severe valvular disease on cardiac reserve?
It may result in a complete loss of cardiac reserve.
What is digoxin used for?
It is a cardiac glycoside used as a last resort to improve cardiac output.
Fill in the blank: Digoxin inhibits the _______ pump.
sodium potassium ATPase
What structural change occurs in heart valves due to inflammation?
Calcium and cholesterol deposits accumulate.
What happens to the coronary arteries when valve problems occur?
Coronary arterial perfusion is compromised.
What is the normal cardiac output limit for a healthy adult?
25 liters per minute
non athletes
What is the primary factor affecting the need for a congenital bicuspid aortic valve replacement?
The development of stenosis or other complications over time.
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Glossopharyngeal Nerve
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Carotid Sinus
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Glossopharyngeal nerve
2
Carotid Sinus
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Aortic Baroceptors
