Venous return is the volume of blood flowing back to the heart through the veins. Blood from the systemic veins flows into the right atrium, where the pressure is called central venous pressure. Venous return is regulated by the balance between the heart's ability to pump blood out of the right atrium and ventricle into the lungs, and the tendency of blood to flow from the peripheral veins into the right atrium. There are five main factors that enable blood to flow back to the heart: one-way valves in the veins, muscle pumps that push blood during contraction, the respiratory pump during exercise, sympathetic activation of veins, and gravity draining blood from the upper body.

1. Venous ReturnVenous Return
Muhammad Anwaar Ahmad (MBBS 1st year 2016)
Sahara medical college Narowal, Lahore

2. Venous ReturnVenous Return
define Venous Returndefine Venous Return
Venous return is the volume of blood flowingVenous return is the volume of blood flowing
back to the heart through the veins.back to the heart through the veins.

3. Venous ReturnVenous Return
Right Atrial pressureRight Atrial pressure
(Central Venous Pressure)(Central Venous Pressure)
Blood from all the systemic veins flows into theBlood from all the systemic veins flows into the
right atrium of heartright atrium of heart
pressure in the right atrium is called Centralpressure in the right atrium is called Central
Venous Pressure.Venous Pressure.

4. Venous ReturnVenous Return
Right Atrial pressure is regulated byRight Atrial pressure is regulated by
balance between:balance between:
(1).Ability of heart to pump blood out of the(1).Ability of heart to pump blood out of the
right atrium and ventricle into the lungs.right atrium and ventricle into the lungs.
(2).Tendency of blood to flow from peripheral(2).Tendency of blood to flow from peripheral
veins into the right atrium.veins into the right atrium.

5. Venous ReturnVenous Return
Factor effecting venous returnFactor effecting venous return
There are 5 main factors that enable blood toThere are 5 main factors that enable blood to
flow back to our heart.flow back to our heart.

6. Venous ReturnVenous Return
1. Pocket Valves1. Pocket Valves
One-way valves, called pocket valves, in theOne-way valves, called pocket valves, in the
veins prevent backflow of blood and directedveins prevent backflow of blood and directed
blood to flow back towards the heart.blood to flow back towards the heart.

7. Venous ReturnVenous Return
2.Muscle Pump2.Muscle Pump
Veins are situated between skeletal muscleVeins are situated between skeletal muscle
which when contracting and relaxing helpswhich when contracting and relaxing helps
push blood through the veins back towardspush blood through the veins back towards
the heart.the heart.

8. Venous ReturnVenous Return
3.Respiratory Pump3.Respiratory Pump
During exercise, breathing becomes faster. ThisDuring exercise, breathing becomes faster. This
causes pressure changes to occur in thecauses pressure changes to occur in the
thorax and abdomen. This increases thethorax and abdomen. This increases the
pressure in the abdomen causing the largepressure in the abdomen causing the large
veins in that area to be squeezed/sucked. Thisveins in that area to be squeezed/sucked. This
forces the blood back to the heart.forces the blood back to the heart.

9. Venous ReturnVenous Return
4.Venous compliance4.Venous compliance
Due to Sympathetic activation of VeinsDue to Sympathetic activation of Veins
Decrease venous complianceDecrease venous compliance
Increase central venous pressureIncrease central venous pressure
Increase Venous returnIncrease Venous return

10. Venous ReturnVenous Return
5.Gravity5.Gravity
Blood from the upper body, above the heart, isBlood from the upper body, above the heart, is
drains by gravity, which helps blood flow backdrains by gravity, which helps blood flow back
to the heart.to the heart.

11. Venous ReturnVenous Return
Varicose VeinsVaricose Veins
the Valves of the venous system frequently becomethe Valves of the venous system frequently become
incompetent or destroyed.incompetent or destroyed.
Veins have been overstretched by excess venous pressureVeins have been overstretched by excess venous pressure
lasting.lasting.
Causes:Causes:
PregnancyPregnancy
One stands most of timeOne stands most of time
Treatment:Treatment:
Compression ctockings on legsCompression ctockings on legs
Continual elevation of the legsContinual elevation of the legs

12. Venous ReturnVenous Return
Edema:Edema:
(Accumulation of excess fluid in tissue)(Accumulation of excess fluid in tissue)
veins expand, their blood capacity is increaseveins expand, their blood capacity is increase
Blood Pressure in Capillary increaseBlood Pressure in Capillary increase
Excessive fluid filter out of capillary in lower extremitiesExcessive fluid filter out of capillary in lower extremities
Edema (Swollen Feet & Ankles)Edema (Swollen Feet & Ankles)

13. ..
Thank YouThank You