[Exam 1] Lecture 1: Review, CV Function [1/16/26] Flashcards
What units do you use for Clearance?
mL/min
What does renal clearance measure?
Volume of plasma cleared of a compound per unit of time
Renal clearance is a function of how the kidney handles that compound, whether it’s easily filtered or secreted.
What is the definition of free water clearance?
Volume of water removed from the body per unit time
Free water clearance does not take into account any electrolytes or solutes dissolved in the water.
How does ADH affect free water clearance?
High ADH levels result in low free water clearance
Conversely, absence of ADH leads to high free water clearance.
What are normal blood pressure values for systolic and diastolic pressure?
Systolic: 120 mmHg, Diastolic: 80 mmHg
Normal blood pressure is often simplified to around 100 mmHg.
What is the formula for calculating Mean Arterial Pressure (MAP)?
MAP = DBP + 1/3 (SBP – DBP)
DBP = Diastolic Blood Pressure, SBP = Systolic Blood Pressure.
What is the expected blood pressure at the right atrium in a healthy individual?
Zero mmHg
In critically ill patients, right atrial pressure may be significantly higher.
What is the normal pressure profile in the pulmonary circuit?
Normal pulmonary arterial pressure is about 16 mmHg
This is sometimes referred to as mean pulmonary arterial pressure (mPAP).
What is pulse pressure?
Difference between systolic and diastolic pressures
Normal pulse pressure in the aorta is around 40 mmHg.
How does arterial stiffness affect pulse pressure?
How/Why?
Increased stiffness leads to higher pulse pressure
Stiff arteries do not accommodate blood volume well, resulting in higher pressure spikes.
What happens to blood pressure as it moves through high resistance areas?
Blood pressure decreases downstream of high resistance areas
Arterioles are considered the highest resistance blood vessels.
What is compliance in the context of the cardiovascular system?
Change in volume over change in pressure (delta V / delta P)
Compliance applies to both blood vessels and airways.
What is the relationship between stroke volume and pulse pressure?
Increased stroke volume leads to increased pulse pressure
Conversely, decreased stroke volume results in reduced pulse pressure.
What is the expected pressure at the venular end of capillaries?
Approximately 10 mmHg
The arterial end of capillaries has a pressure of around 30 mmHg.
What is the delta P of the systemic circulation?
100 mmHg
This is calculated as the difference between pressure at the aorta and the right atrium.
What is the expected pressure at the left atrium in a healthy person?
2 mmHg
This is the pressure at the end of the pulmonary circuit.
True or False: Veins have high compliance.
True
This allows them to accommodate large volumes of blood without significantly increasing pressure.
What happens to pulse pressure in the pulmonary circulation compared to systemic circulation?
Pulse pressure is lower in the pulmonary circulation
This is due to the lower vascular resistance in the pulmonary circuit.
What does low compliance in a rigid container indicate?
It requires lots of pressure to put a little bit of volume into the container.
Low compliance indicates that a small change in volume requires a large change in pressure.
What is the relationship between pressure and volume in determining compliance?
Higher pressure with low volume results in low compliance.
Compliance can be calculated using the formula Delta V / Delta P.
What indicates high compliance in a container?
A large volume can be accommodated easily with low pressure.
High compliance is represented by a high ratio of Delta V over a low Delta P.
What are the units typically used for measuring pressure in the cardiovascular system?
Millimeters of mercury (mmHg)
lung pressure units are centimeters of water (cmH2O).
What is the pressure in the left atrium typically measured at?
About 2 mmHg.
This value is important for understanding the pressure dynamics in the heart.
What occurs to left ventricular pressure during diastole?
It should be fairly low to permit filling.
Diastole is the phase of the heartbeat when the heart muscle relaxes.