EXAM 2: Lecture 8 Flashcards
What type of nervous system reflexes respond to short-term stress in the cardiovascular system?
Neurological reflexes from the sympathetic nervous system
These reflexes respond almost instantaneously to changes in position or stress.
What happens to blood when a person goes from sitting to standing without reflexes?
Blood would pool down at the legs
This pooling occurs due to the increased height of the blood column when standing.
What are the primary baroreceptors involved in blood pressure regulation?
- Carotid baroreceptors
- Aortic baroreceptors
Carotid baroreceptors are located at the carotid sinus, while aortic baroreceptors are located at the aortic arch.
What cranial nerves are associated with carotid and aortic baroreceptors?
- Glossopharyngeal nerve (carotid)
- Vagus nerve (aortic)
These nerves connect the baroreceptors to the brain stem.
What neurotransmitters are involved in regulating systemic vascular resistance (SVR) and contractility?
- Epinephrine (epi)
- Norepinephrine (norepi)
Norepi is the main catecholamine in the system.
What is the effect of increasing contractility and SVR on cardiac output?
It increases cardiac output
Increased SVR helps maintain blood pressure necessary for perfusion of vital organs.
Which circulatory beds are prioritized for blood flow during stress?
- Coronary circulation
- Central nervous system
- Kidneys
Blood flow to the heart and brain is prioritized over less critical areas.
What is the role of vasopressin in the cardiovascular reflex system?
It helps increase systemic vascular resistance (SVR)
Vasopressin release is modulated by changes in osmolarity.
What does the RAAS system do?
It regulates blood pressure and fluid balance
The RAAS system activates the release of ADH and aldosterone to retain fluid.
What happens when an ACE inhibitor is administered?
It lowers the system’s ability to compensate for blood pressure drops
ACE inhibitors block the RAAS system’s function.
What is the function of stretch receptors in the cardiovascular system?
They trigger reflexes to regulate blood volume
Located in low-pressure areas such as the superior and inferior vena cava and right atrium.
What hormone is released by overstretched right atria?
Atrial Natriuretic Peptide (ANP)
ANP acts as a natural diuretic to increase urinary output.
What is the role of B-type Natriuretic Peptide (BNP)?
It signals the kidneys to increase sodium and water output
BNP is released from the ventricles when they are overstretched.
What happens to BNP levels with successful heart failure treatment?
BNP levels will decrease
Lowered BNP indicates improved ventricular function.
What is the CNS ischemic response?
A maximal sympathetic nervous system response to low brain perfusion
It is the strongest response aimed at stabilizing blood pressure during severe hypotension.
What occurs to oncotic pressure after losing blood volume?
It decreases
Loss of plasma proteins reduces the oncotic pressure that keeps fluid in the cardiovascular system.
What type of fluid is preferred for replacing blood loss?
Whole blood, then plasma
Plasma contains colloids that help maintain volume in the cardiovascular system.
What is stretch-relaxation in large veins?
Relaxation of smooth muscle in response to distension
This property reduces venous pressure over a period of minutes.
What is reverse stretch-relaxation?
Tightening of vein walls due to sympathetic nervous system activation
This occurs during hemorrhage when the body attempts to maintain blood pressure.
What occurs to tissues during shock?
Tissue dysfunction and cell necrosis
Inadequate perfusion leads to cell death and the release of metabolic waste.
What is unique about septic shock compared to other types?
It has an initial increase in cardiac output
This is due to the body’s response to infection and systemic inflammation.
What does the Fick equation measure?
Arterial and venous oxygen levels
It assesses how much oxygen is delivered or unloaded as blood circulates.
What are the normal oxygen levels in arteries and veins?
- Arteries: 20 mL O2/dL of blood
- Veins: 15 mL O2/dL of blood
These values reflect the total oxygen content in blood.
What does the Fick equation analyze?
Arterial oxygenation and venous oxygenation
The Fick equation is used to calculate oxygen consumption based on the difference between arterial and venous oxygen levels.
What is the oxygen content in arteries?
20 mL O2/dL of blood
What is the oxygen content in veins?
15 mL O2/dL of blood
Calculate the amount of O2 delivered per deciliter of blood.
5 mL O2/dL of blood
This is calculated as 20 mL - 15 mL = 5 mL O2 delivered.
What is the average O2 consumption for a healthy adult?
250 mL O2/min
What does the Fick equation formula include?
O2 absorbed per minute by the lungs (mL/min) / arteriovenous O2 difference (mL/L of blood)
What technique does a PA catheter use to determine cardiac output?
Thermodilution
True or False: Digitalis is a sodium potassium ATPase pump inhibitor.
True
What is a primary use of Digitalis in heart failure?
To improve cardiac output temporarily
What is the normal cardiac output for a healthy adult?
5 L/min
What cardiac output represents a 400% cardiac reserve?
25 L/min
What cardiac output indicates a 500% cardiac reserve?
30 L/min
How can athletes exceed a 600% cardiac reserve?
Through conditioning and training
What happens to cardiac reserve as people age?
It generally decreases
What is the effect of severe valvular disease on cardiac reserve?
It likely reduces or eliminates cardiac reserve.
Which nerve innervates the diaphragm?
Phrenic nerve
Which spinal segments correspond to the pudendal nerve?
S2, S3, and S4
Fill in the blank: The sodium potassium pump pumps ______ out of the cell.
3 Na
Fill in the blank: The sodium potassium pump pumps ______ into the cell.
2 K
What is the formula for Mean Arterial Pressure (MAP)?
Diastolic pressure + 1/3(systolic - diastolic)
What does compliance refer to in a cardiovascular context?
Delta volume / delta pressure
What is the formula for resistance in blood flow?
Delta pressure / blood flow (cardiac output)
