Chapter 21 Blood Vessels Part 2 Flashcards
measure of force blood exerts against BV walls via ausculataton
BP
what is used as instrument to measure BP in mmHg, Measure via Auscultation
mercury manometer
bp cuff
sphygmomanometer
where does the sthescope go during BP
over brachial artery
you inflate BP cuff until
brachial artery is compressed
you lower the cuff until below
systolic pressure - tuberlent and vibrates in blood and sounds heard through sthetoscope
what are these sounds called during BP
korotkoff sounds
1st sound is
systolic
when sound disappears it is
diastolic
Tendency for Blood vessel volume to increase concurrent with
BP increases
compliance
if vessel= greater comliance -
stretches more easily
vessels with large compliance have large increase in volume when
pressure increases a small amount
venous compliance is about
24x greater than arterial due to thinness of walls
veins are storage reservoirs for
blood
veins hold large amound of volume which is
64% of blood volume
Pressure wave as blood ejected from LV into Aorta travels quickly along the
arteries, 15 x greater in Aorta
pulse
pulse determines
HR, if in rhythm
common carotid artery, superficial temporal artery, facial
H&N
axillary artery, brachial, radial
arm
femoral artery, popiteal, posterior tibial, dorslis pedis
leg
pulse is generated by
pulse pressure
pulse pressure is influenced by 2 factors which are
stroke volume and vascular compliance
pulse pressuer has a inverse relationship w
vascular compliance
as compliance increases what decreases
pulse pressure decreases
arterial BP depends on
how much the elastic arteries can stretch and volume of blood forced into elastic arteries at any time
not constant arterial bp=
pulsatile
BP drop to ~35mmHg at beginning of Capillaries
& 17mmHg at ends of Capillary Beds
Low pressure needed as fragile & risk of rupture
capillary BP
steady pressure with little change. Pressure in veins ~15mmHg, low due to
Resistance (Too low for adequate venous return)
venous bp
3 functional adaptations
muscular pump
respiratory pump
sympathetic venoconstriction
increase in venous return causes increase in what which causes increase in what
increase in SV and increase in CO
pressure in vessels are affected by
gravity
when u stand there is an increase
pressure in vessels- edema when stand for prolonged period of time
If there is NO skeletal muscle movement, pressure at the venous end of the capillaries increase or decrease
increases up to 20% of total blood volume passing through capillary walls into interstitial spaces of lower limbs when standing still
As change position Lying down to Stand
BP in lower limb veins increases
Increased BP causes Compliant veins to
expand
as veins expand and fill with blood
venous return decreases because there is less blood returning to the heart
as venous return decreases
CO and BP decreases
if neg feedback not kick in and compensate, delivery of blood to brain is
inadequate to maintain homeostasis and dizzy
