Week 3 Quiz

• Hemodynamics is the study of ___ moving through the circulatory system.

  blood
• Flow (Volume flow rate) is:

  the volume of blood flowing during a particular time
• Velocity is:

  speed of a fluid moving from on location to another
• Hydrostatic Pressure:

  Pressure related to weight of blood pressing on a vessel measured at a height above or below heart level
• Capacitance:

  measure of the ability to hold a change in volume per change in time; amount of blood a vessel can hold at a particular time
• Resistance:

  Force opposing blood flow; impedance
• Compliance:

  Measure of the ability to hold a change in volume per change in pressure; ability to stretch
• Viscosity:

  Measure of the internal resistance of a fluid to flow; blood thickness
• What are the 3 types of energy ?

  Kinetic, potential, and gravitational
• Kinetic energy:

  Associated with a moving object; motion energy
• Potential energy:

  the ability to perform work; stored energy
• Gravitational energy:

  Form of stored energy, associated with an elevated object
• There must be a ___ pressure at one end of a vessel and a ___ pressure at the other end for flow to occur.

  higher , lower
• Blood moves from regions of higher to lower energy due to an:

  Energy gradient or Pressure Gradient
• The greater the difference in pressures the __ the flow.

  more
• What are the three ways blood loses energy as it flows through circulation ?

  Frictional, viscous, inertial
• What determines viscous energy loss ?

  Hematocrit
• Frictional loss is energy converted to __ as blood slides across vessel walls.

  heat
• Small vessel radius = __ friction and __ flow

  more, less
• Friction causes ____ flow.

  laminar
• Inertial loss:

  objects at rest tend to stay at rest and objects in motion tend to stay in motion
• In inertial loss, energy is lost when there is a change in ___.

  speed
• Inertial loss occurs during:

  Pulsatile, phasic, at stenosis
• What are the factors that influence blood flow ?

  Cardiac function, compliance / capacitance, wall stiffness, vessel diameter change
• Formula for hydrostatic pressure:

  p (density) x g (gravity) x h (height of column)
• In hydrostatic pressure, pressure ___ with depth.

  increases
• What is transmural pressure ?

  The difference in pressure within a vessel compared to outside the vessel
• Venous valves:

  keeps the blood flowing in the right direction - towards the heart
• What is Ohm's law ?

  Pressure = flow x resistance
• What is the law of hemodynamics ?

  ΔP (pressure gradient) = Q (flow) x R (resistance)
• In blood flow, the resistance is the _____.

  arterioles
• What determines resistance ?

  Length of a vessel (l), viscosity of a fluid of blood (h), radius of a vessel (r)
• The longer the vessel, the ___ the resistance.

  higher
• When the viscosity increases, resistance ____.

  increases
• The smaller the radius, the ___ the resistance.

  higher
• What is the resistance equation ?

  R=8 l η /π r 4
• What is the principal factor affecting resistance ?

  Radius
• What is Poiseuille's equation ?


   Q= ∆P π r 4 / 8 l η
• In Poiseuille's equation, Q (volumetric blood flow) is ___ related with pressure gradient and vessel radius

  directly
• In Poiseuille's equation, Q (volumetric blood flow) is ___ related with the vessel length and blood viscosity.

  inversely