Venous circulation Flashcards
بسم الله الرحمن الرحيم
اللهم عليك توكلنا فانصرنا وأنت نعم المولي ونعم النصـير
Arterirs contains more elastic than collagen circular shape steep p/v
veins contains more collagen than elastic varible shape flat p/v relationship
II- Past medical history
for asthma
-Patients with asthma may have past history of: • Recurrent upper and lower respiratory-tract infections (particularly children). • Allergy, such as eczema and hay fever. • Sinusitis • GERD • Co-morbidity: -HTN: B-blockers, ACE
describe forward function of the veins ?
they are the capacitance vessels wide have 2/3 blood of circulation
and they control the EDV so the the preload of the heart and the Cardiac output
so they are determinants of the COP
Describe backward function of the veins ?
they recive the capilary blood without a marked loss in the pressure
becasue they are low resistance vessels
veins are compliant structure as it fills with little increase in pressure
they have reserve in theri shape
ربنا نعوذ بك من الهم والحزن والعجز والكسل والجبن والبخل وغلبة الدين وقهر الرجال وشماتة الأعداء والمرض والحسد والسحر والحياء و إلف النعمة
Why veins are imp blood resevoir ?
because they can accommodat a large amount of blood without a marked increase in the pressure and as you know the gradient of flow of blood from high to low
the veins are still low pressure with high amount of blood because of theri complicance
Mention The role of vasomotor tone on the vein .
It decrases its capacitance making them reach the point of stiffness and stretching earlier than usaul and smaller amount of blood increases the pressure in them as this is the function os sympaththic> increase venous return ? ok?
Veins has high radius/wall tension ratio high raidus and low walltension
Show the variable confugration of the veins during differnt encapacitated states,
First it is flat and collapsed 0-6 mm Hg
incrasing the amount of blood becomes ellipitical
incrasing … becomes oval
incrasing beomes cirular now the smooth muscles are stretched and any incrase in the volume will lead to increase the pressure inside the vein due to increase wall tension and decrease in capacitance
Mention the effects of the sympathtic on the venous capactiance .
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it contracts the smoooth muscles of the vessel casuing its stifness and loss of capacitance and this will lead to increase of venous pressure at any given amount of blood in it
tip change in the voulme of blood from ellipitical to cirular shape of veins has no stretch or incrase in wall tension but when it becomes circular the wall tension increases with any added volume leading to incrase the pressure
Mention the effects of the sympathtic on the venous capactiance .
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it contracts the smoooth muscles of the vessel casuing its stifness and loss of capacitance and this will lead to increase of venous pressure at any given amount of blood in it
tip change in the voulme of blood from ellipitical to cirular shape of veins has no stretch or incrase in wall tension but when it becomes circular the wall tension increases with any added volume leading to incrase the pressure
لما تيجي تاخذ دم من عيان ويخاف الوريد بيختفي ليه ؟ عشان تاثير السمبثاوي عليه ونقص الاتساعية بتاعته بسبب انقباض العضلات الملساء ده هيسبب انه ينكمش في الحجم و الدم يعدي منه
Mention the direction of the venous blood ? and factor preserving it ?>
It is always unidirectiontal towards the heart due to
1- venous valves
2-skeletal muscle pumping
describe change in the venous blood flow velocity? and why ?
As we approximate to heart i mean when the venules are collecting together finally forming the big veins the TOTAL cross sectional area decrease so the velocit increases dt the inverse relationship to reach (25cm/s ) in vena cava
blood is faster in which of them the vena cava or aorta ?
definitely aorta as it has less total cross sectional area ^_^
GR/The rapid ejection phase casue increasing in VR?
This is due to pulling down of the AV rings during venricular contraction casuing strtch of the artium and decreasing their pressure also the deep veins connectin to it so the flow of VR increased as the gradient between the peripheral and central veins increase
GR/ the rapid filling phase increase the VR?
AV Valves are open allowing blood to move from the atria to the ventrciles decrasing the pressure in the atria and so the central veins increaing the flow gradient and the VR
