+
Related Flashcards
Related Topics
Cards In This Set
| Front | Back |
|
Capillaries
|
Smallest of vessels across which all exchanges between blood and tissues takes placeThin wall, small radius, extensively branchedMaximize surface area and minimize diffusion distanceUnder resting conditions, many are not open
|
|
Capillaries are surrounded by _____________
|
Precapillary sphincters at their entrance
|
|
Contraction of sphincters
|
Reduces blood flowing into capillaries in an organ
|
|
Relaxation of sphincters
|
Increases blood flowing into capillaries in an organ
|
|
Forces influencing bulk flow
|
A result of hydrostatic pressure and osmotic pressure1. Capillary blood pressure- pushing out2. Plasma colloid osmotic pressure- pulling in3. Interstitial fluid hydrostatic pressure- pushing in4. Interstitial fluid colloid osmotic pressure- pulling out
|
|
Venules
|
Formed when capillaries rejoin
|
|
Veins
|
Formed when venules mergeReturn blood to heartServe as a blood reservoir- highly distendible and large radius
|
|
Factors that enhance venous return
|
1. One way valves2. Venoconstriction3. Skeletal muscle activity4. Respiratory activity
|
|
Blood pressure
|
Force exerted by blood against a vessel wall
|
|
Blood pressure depends on:
|
1. Volume of blood contained within vessel2. Compliance of vessel walls
|
|
Systolic pressure
|
Maximum pressure exerted by ejected blood against vessel walls during ventricular systoleAverages 120mm Hg
|
|
Diastolic pressure
|
Minimum pressure in arteries when blood is draining off into vessels downstream and ventricular diastoleAverages 80mm Hg
|
|
Blood pressure can be measured indirectly using a ________________
|
Sphygmomanometer
|
|
Pulse pressure
|
Pressure difference between systolic and diastolic pressure
|
|
MAP- Mean arterial pressure
|
Average pressure driving blood forward into tissues throughout cardiac cycleMAP = [(2 x diastolic)+systolic] / 3
|
