BIO 132 – Anatomy and Physiology II

LECTURE 17:  VASCULAR PHYSIOLOGY I:

HEMODYNAMIC PRINCIPLES & CAPILLARY EXCHANGE

Study Outline

 

 

17.1.  Profile of Blood Pressure and Velocity in the Systemic Circulation:

a.       ________________________ is the study of how blood moves and involves the relationships between blood pressure, flow, and hydraulic resistance.

b.      The main factor that drives blood along blood vessels is a gradient of ______________________________.

c.       Arterial pressure is ___________________________ in elastic and muscular arteries, but becomes increasingly damped in the arterioles.

d.      The greatest pressure drop occurs in the ___________________________ and ____________________________.

e.       The velocity of blood flow refers to the linear displacement of blood with time and has units of _____________________ per unit _____________________.  Velocity is defined as flow divided by _______________________________.

f.        As blood travels from the aorta down to the capillary level, the mean velocity __________________________________.  This is because although flow is essentially constant (in this case equal to ____________________________), the ______________________________ is increasing.

g.       As blood flows from capillaries back to the heart in veins, the velocity ________________________________.

 

17.2.  Principles Governing Blood Flow:

a.       Blood flow is proportional to the _________________________ and inversely proportional to the _________________________________.

b.      When the basic flow equation is applied to the systemic circulation, the flow is equal to ________________________________; the inlet pressure is ___________________________________; the outlet pressure is equal to _________________________________; and the resistance is equivalent to _______________________________________.

c.       Be rearrangement we obtain the basic relationship that mean arterial pressure is equal to the product of ______________ and ______________________.

 

17.3.  Vascular Resistance:

a.       Vascular resistance arises from ______________________ between adjacent _______________________________ within the moving fluid.

b.      In the smallest arteries and arterioles where we find the greatest pressure drop, the large pressure drop is associated with a high _______________________.

c.       According to Poiseuille’s Law, vascular resistance is proportional to ________________________ and ____________________________; and inversely proportional to ___________________ raised to the fourth power.

d.      Any condition that increases blood viscosity will _____________________ resistance.  As an example, when the number of RBCs is elevated, viscosity will ___________________, a condition known as ___________________.

e.       A decrease in the number of RBCs (a condition known as _____________________________) will result in ______________________ in resistance.

f.        Owing to the fourth power term, changes in ___________________________ have profound influences on vascular resistance.  Thus __________________ will increase vascular resistance and ___________________ will decrease it.  Changes in vessel dimensions can control ______________________ through an organ or can be used to affect ______________________________.

 

17.4.  The Arterial Pressure Pulse:

a.       The radial pulse can give you an indication of _________________________ and the magnitude of the ___________________________.  A strong pulse is usually an indication of a large ________________________ whereas a weak pulse indicates a ____________________________________ stroke volume.

b.      The pulse pressure is equal to ______________________________ minus the ______________________________________.

c.       The magnitude of the pulse pressure depends on the ____________________ and the _______________________.

d.      The degree of distensibility of an artery can be quantified by determining the arterial __________________________________, defined as the change in _________________________________ divided by the change in _____________________________________.

e.       Arterial compliance ________________________________ with age.  As a result, pulse pressure will ____________________________________.  An unfortunate consequence of decreased arterial compliance is that the ________________________________________ of the heart is increased.

f.        Pulse pressure is proportional to the difference of _____________________ and _______________________.

g.       In the aortic pressure wave form, the ___________________ is an indication of aortic valve closure.

 

17.5.  Measurement of Arterial Pressure:

a.       Mean arterial pressure is determined by adding diastolic pressure to the quantity: (_____________________ minus _________________________) divided by 3.

b.      The ordinary method for determining blood pressure is called _____________________________________.  In this method when the cuff pressure is lowered to a point just below _____________________________, there is a brief spurt of blood into the artery causing a ______________________________ sound.  When cuff pressure is lowered to the point where sounds cease, this pressure is considered to be _____________________________.

 

17.6.  Determinants of Arterial Blood Pressure:

a.       Arterial pressure will increase when either _______________________ or ______________________ increase.

b.      Heart rate is controlled by the _____________________________ (positive chronotropic) and ___________________________ (negative chronotropic) systems.

c.       Stroke volume will increase with an increase in ________________________ (positive inotropic) and ___________________________.  Venous return will increase with ___________________________, _______________________, _________________________, and venoconstriction.

d.      Mean blood pressure will ______________________ with an increase in total peripheral resistance (a.k.a systemic vascular resistance).  Total peripheral resistance will increase with an increase in ___________________________, ________________________ and a decrease in _______________________.

 

17.7.  Capillary Exchange:

a.       Substances enter and leave capillaries via one or more of three different mechanisms called  ________________________, _________________________, and __________________________.

b.      The factors that govern bulk flow are summarized by ______________________________.  In this process the movement of water and solutes from blood to interstitial fluid is called _____________________ whereas the movement from interstitial fluids to blood is called ______________________________.

c.       Starling’s Law states that relative fluid and solute movement is dependent on the balance of two sets of forces: ________________________________ and ______________________________.

d.      Hydrostatic forces are due to pressures found within blood vessels (called _____________________________) and those in interstitial fluids (called ________________________________).  The CHP varies from about __________________________ to about __________________________ as blood flows through the capillary.  By contrast the IHP is essentially zero.

e.       Oncotic forces are due to osmotic pressure created by solutes that are restricted to plasma (called __________________________) or interstitial fluid (called ___________________________).  The COP is usually about ____________________ whereas the IOP is about ____________________.

f.        Starling’s Law states that the net filtration pressure is equal to _______________________ minus ____________________________.  The two forces that promote filtration are ________________________________ and _________________________; whereas the two forces that promote reabsorption are _________________________________________ and _____________________________________.

g.       At the arterial end of a capillary the net filtration pressure is ____________________, favoring net ____________________________.

h.       At the venous end of a capillary, the net filtration pressure is _______________________, favoring net __________________________.

 

17.8.  Causes of Edema:

a.       Excess fluid that is not reabsorbed back into capillaries passes to __________________________.  When fluid accumulates in the interstitial space, this condition is called _________________________.

b.      The four basic conditions that will favor edema are ____________________ (which will increase CHP); ________________________ (which will increase IOP), ___________________________ (which will decrease COP), and _____________________________.