Biophysics

Question 1

Flow Q

Answer 1

Volume of fluid passing through a vessel or airway per unit of time. L/min

Question 2

Resistance (R)

Answer 2

opposition to flow through a vessel or airway. dyn-s-cm

Question 3

COPD and Hypertension

Answer 3

examples of high resistance in vessels

Question 4

Pressure

Answer 4

Force exerted by fluid per unit area w/I C&R systems. mmHG or cmH20

Question 5

Ohm’s Law for Fluid Flow

Answer 5

Q (flow)=P (pressure)/ R (resistance)

Question 6

Laminar Flow

Answer 6

Smooth orderly flow pattern in which fluid moves in parallel layers w/o mixing. Re <2000

Question 7

Where is Laminar Flow seen

Answer 7

Smaller airways and blood vessels.

Question 8

Turbulent Flow

Answer 8

Chaotic disordered flow pattern that moves irregularly. Seen in vortices and eddies. Re >2000

Question 9

Reynolds Number (Re)

Answer 9

predicts flow patterns in different fluid flow
situations. R𝑒 =𝜌𝑣𝑑/𝜂

Question 10

Compliance

Answer 10

Ability of a hollow organ to stretch and expand in response to pressure
C=𝛥𝑃/𝛥𝑉

Question 11

Poiseuille’s Law

Answer 11

resistance to the flow of a fluid through a cylindrical vessel. R=(8 𝜂 𝐿)/𝜋𝑟4

Question 12

Caveat of Poiseuille’s Law

Answer 12

It was originally used to calculate flow.
F=𝝅 𝒓𝟒∆𝑷
𝟖𝜼 L

Question 13

Bernoulli’s Principle

Answer 13

An increase in the speed of a fluid occurs simultaneously with a decrease in pressure or potential energy of the fluid.

Question 14

Drop in blood pressure across stenotic heart valves or airflow patterns in obstructive lung diseases.

Answer 14

Clinical Relevance of Bernoulli’s Principle

Question 15

the significant impact of vessel or airway radius on resistance to the blood flow, which is crucial for understanding and treating conditions like asthma or vascular occlusions

Answer 15

Clinical Relevance of Poiseuille’s Law

Question 16

indicates flexible vessels or lungs, while low
compliance can signify stiffness, as seen in conditions like pulmonary fibrosis or
arteriosclerosis.

Answer 16

Clinical Relevance of Compliance

Question 17

Helps determine whether the flow is laminar or turbulent, which is crucial for diagnosing and managing cardiovascular and respiratory conditions.

Answer 17

Clinical Relevance of Reynolds Number

Question 18

occur in large airways or major blood vessels and is often associated with pathological conditions like atherosclerosis or valvular heart disease.

Answer 18

Clinical Relevance of Turbulent Flow

Question 19

Predominant in smaller airways and blood vessels. Disruptions to laminar flow can indicate pathology, such as turbulent flow in stenotic arteries.

Answer 19

Clinical Relevance of Laminar Flow

Question 20

helps clinicians understand how changes in
resistance and pressure affect blood flow and can guide treatment strategies in
conditions like shock or heart failure.

Answer 20

Clinical Relevance of Ohm’s Law

Question 21

can lead to hypertension and
strain on the heart. Increased airway resistance, as seen in asthma or COPD, makes
breathing difficult.

Answer 21

Clinical Relevance of Resistance

Question 22

Starlings Law of the Heart

Answer 22

heart’s stroke volume increases in response to an increase in the
volume of blood filling the heart (the end-diastolic volume)

Question 23

Essential for understanding heart function and managing conditions like heart failure, where preload and afterload must be carefully balanced.

Answer 23

Clinical Relevance of Starling’s Law

Question 24

Mean Arterial Pressure

Answer 24

average pressure in a patient’s arteries during one cardiac cycle
MAP =1/3 SBP +2/3 DBP

Question 25

indicator of overall cardiovascular health and tissue perfusion. Abnormal MAP can signal conditions like shock or hypertension.

Answer 25

Clinical Relevance of Mean Arterial Pressure