complete venous circulation

Question 1

بسم الله وكفي به وكيلا

Where is the refence point ?

Answer 1

In midpoint of the Right atrium and is located at the level of the costosternal junction
which pressure equals Zero

Question 2

What happens in case of increased vr to the refence point ?

Answer 2

the pressue increases above the 0 so heart increase its contraction and pumping to eject the added amount to retain the 0 pressure at mid point of the right atrium

Question 3

what happens in case of decreased VRto the Refernce point ?

Answer 3

the pressure is below the 0 and this decrased the blood to the left ventricle decreasing its activity and contractility and pumping and this leads to retain the 0 pressure at mid point of right atrium

Question 4

Mechanism of action
• Diuresis →↓ plasma volume → ↓ venous return (VR) → ↓ preload → ↓pulmonary congestion & peripheral edema
• ↓ signs & symptoms of venous congestion such as orthopnea & nocturnal dyspnea

Answer 4

لما يرمي الحجم الزائد في الشارع ايه هيحصل؟
هيقلل اعراض الاحتقان كمان هيقلل الحمل علي القلب فهيقلل الحمل علي الرئة
لان القلب الان شايف شغله علي الكمية الباقية

Question 5

Hydrostatic indifferent point explain /

Answer 5

it is a subdiapharagamtic point lies 2-3 inches below the opening of the inderior vena cava opeining in the diapharagm and the pressue at this point is not changed according to the position either supine or erect
all the point below it show increase in pressure in erect than supine
all the points above it show decrease in pressure #####
all humans have antigravity mechanisms to reduce effect of gravity on our circuation>

this point repersnts balance between gravit and anti gravity mechanisms

if anti gravit mechanisms are strong they cause its upward shift
if anti gravity are weaker it causes it downward shift

Question 6

Mention antigravity mechanisms and theri role .

Answer 6

They are  trying to decrease capcatiance to increasr VR
1- venomotor tone 
2- incrasing blood vloume 
3-skeletal muscle contraction
4-water immersion
VISWA
they cause upward shift of HIP

Question 7

The Factors causing downward shift of the HIP .

Answer 7

AlHOr
1-alpa blockers DERESING VR
2-hypovlemia due to hemorrhage DECRASING VR
3-orthostatic hypotension postural hypotension DECRASING VR
Decrasing the activity of anitgravity m mechanisms

ليا دعوة باللي ظاهر ! ! ! ! ! !
اعمل اسكيمات براحتك طالما هتراجعها كتير

Question 8

What is VR ?

Answer 8

It is the amount of venous blood entering the right atrium per minute and it is always equal to cardiac output and it is
VR=Change of pressure / resistance of veins
resistance of veins is ngelected
so (VR= Change of pressure )
VR = PVP-CVP

Question 9

Factors affecting venous return mention .

Answer 9

Forces from the front visa foronto and forces fron the behind visa tergo

1- forces from the front
affect by decreasing the CVP to increase the gardient
a-thoracic pump
b-cardiac suction

2-forces from behind
affect by increaing the pvp
PMA VB

pressure gradient
muscles pump
arterial pulsaiton
venomotor tone
blood volume
V MAP

Question 10

Describe cardiac suction as vis A fornto .

Answer 10

During rapid ejection phase the ventricle contract casuing dilation of the right atria by the pulled cusps rings and the connecting CVENIS causing their VD and decrasing the CVP so the gradient increase and the VR increase !

Question 11

in case of heart failure what happen to cardiac suction

Answer 11

the ventricle cannot contract cannot dilate the ra and the veins and the vr decreasses

Question 12

لا حل مع الآلام والعقبات إلا بمواصلة العمل التشكي والتأوه لا يصنعان شيئا بل يزيدان الآلام والعقبات

Answer 12

ومن للأمة الغرقي إن كنا نحن الغريقينا ؟!

ان تدرس تعمل
تدرس تتعلم 
تدرس ترضي ربك
تدرس تزاد علما وفقها
تدرس ترتقي منازل الصالحين 
تدرس تعلم الناس 
تدرس تنشر العلم

Question 13

the effect of inspiration on the VR?

Answer 13

it increases negativity of the intrathoracic pressure thus decreases compression on the veins and casuing its dilatitation and decrasing pressure the veins central so the CVP decreases increaing the pressure graident and the Venous Return >.

Question 14

expiration and VR ?

Answer 14

This incrasing the intrathoracic pressure and the central veins so the Central venous pressure increases decresing the pressure gradient so the VR is decreased

Question 15

Factor incrasing the pressure graident by increasing the peripheral pressure :?

Answer 15

1-Arteriolar dilatation !

2-precapillay sphincters constrictions !

Question 16

arteriolar dilatation increases the pvp ?

Answer 16

this is due to more blood flowing to the capillary and to venous side

Question 17

describe the muscle pump ?

Answer 17

the skeletal muscles contract causing decraing capactance of veins and MCP increasing casues increased VR HELEPED BY VENOUS valve allowing unidierctional flow of blood towards the heart

Venous valves cannot be considered a counter
gravity force, but they are essential for the counter
gravity force of skeletal muscle contraction. Also,
venous valves divide the blood column in the vein
into short columns , thus minimizing venous
pressure increase in the dependent part of the
body

Question 18

mention mecahnsisms of minimization of the venous pressure .

Answer 18

1-The valves in the veins divinding the blood clumns into small separate columns
2- the skeleteal muscle contraction casuing constircton of the artery decraseing flow of blood into the capillary and the vein

Question 19

ربنا أصلح لنا ديننا الذي هو عصمة أمرنا وأصلح لنا دنيانا التي فيها معاشنا وأصلح لنا لآخرتنا التي فيها معادنا وأجعل الحياة زيادة لنا في كل خير و اجعل الموت راحة لنا من كل شر

What is the role of the arterial pulsation in the vr?>

Answer 19

it is Vis A tergo mechanism

Causing a milking effect on the vein like the skeletal muscles causing increased pressure and gradient and VR

Question 20

Blood volume increases the VR why?

Answer 20

it is Vis A tergo mechanism causing increased MCP thus the PVP and then the Pressuure gradient thus the VR

Question 21

Venoconstriction affects the VR? GR?

Answer 21

This is becacuse it is a Vis A tergo mechanism causing increased MCP and PVP and pressure gradient so the VR

Question 22

Increasing pressure imaprted from cardiac contraction to blood ?

إن الله لا يضيع أجر ( المحسنيــــــــــــــــــن)

Answer 22

increasue pvp and pressure gradient and vr

tergo!

arteriolar vasodilation and capillary constriction ?!

Question 23

What happens on standing?

Answer 23

The gravit affect blood making it flow down increasing the blood to lower part of body in the arterirs
arteries is tight system cannot accommodate large amount of blood casuing flowing of blood from the aretres to veins of high capacitance
congestion of the capillaries will lead capillaty shift fluid into ISF

The displacement of the blood causes increased capacitance of the veins decreasing the MCP ………………………..
And the increased Venous pressure increases shift of fluid from capillaries to the tissue

Question 24

Counter gravity mechanisms and capacitance of veins

Answer 24

they attempt to decrease the capacitance causing the siffness of wall and increased MCP and VR by muscles contraction and sympathatic alpha receptor mediated contraction

Question 25

atretiolar VD and capillary shift fluid?

Answer 25

the blood go to the veins but they are of high comliance and this make less effect on the blood pressure and make blood stasis in the capillary increasing its pressue and capillary shift into tissues

Question 26

STANDING Withouts touching the ground this leads to ?

Answer 26

No anti gravity mechanisms 
Standing without  touching the  ground the 
HIP is shifted downward
 and this leads to
 reduced cardiac filling
VR قليل بسبب الجائبية

Question 27

the cardiac activity of the heart and the VR RELATIONSHIP?

Answer 27

• increased cardiac activity decreases the pressure on the refernce pressue and the big veins and the pressure gradient increases and the VR increases
• decreased cardiac activity increases the pressre on the refencce point of the right atrium and big veins decreasing the pressure gradient and thus the VR

Question 28

STOP OF CARDIAC ACTIVITY AND VR?

Answer 28

stop of cardiac activity abolishes the Pressure gradient and leading to no VR

Question 29

تم بحمد الله له الشكر والفضل والمنة له الحمد في الأولي والاخرة وهو الحكيم الخبير

Answer 29

ا