0
Give an outline of the circulation of blood to the head and neck venous return.?
Wiki User
∙ 15y ago
The carotid artery supplies the head with blood and the jugular vein returns it to the heart.
Wiki User
∙ 15y ago
Add your answer:
Earn +20 pts
Why does walking prevent stagnation of blood in the legs?
The venous circulation of the legs requires muscle contractions to assist with blood return. Walking helps provide this muscle contraction.
Why the circulation in man is double circulation where as in fish is single circulation?
blood circulation was first reported by william harveyin man there is a comlpete separation of venous blood and arterial blood
What is return blood?
Return blood, most likely, refers to the venous blood that is returned to the heart.
Why are vein important in blood circultion?
Veins are the vessels that carry de-oxygenated blood back the heart. Without the venous system, there would be no way for blood to return to the heart, and circulation would not be complete.
How does venous circulation help to maintain blood pressure when hemorrhaging causes blood loss?
carefully
What is the function of venous valves?
Valves aid in venous return by preventing the back flow of blood.
What happens when there is a reduction to the blood returning to the heart does it increase?
Venous return (VR) is the flow of blood back to the heart. Under steady-state conditions, venous return must equal cardiac output (CO) when averaged over time because the cardiovascular system is essentially a closed loop.if systemic venous return is suddenly decreased, right ventricular preload decreases leading to an decrease in stroke volume and pulmonary blood flow.Decreased pulmonary venous return to the left atrium leads to decreased filling (preload) of the left ventricle, which in turn decreases left ventricular stroke volume by the Frank-Starling mechanism.In this way, a decrease in venous return to the heart leads to an equivalent decrease in cardiac output to the systemic circulation.
How is blood in arteries different from blood in veins?
Arterial blood in the systemic circulation is higher in oxygen and lower in carbon dioxide than venous blood. In the pulmonary circulation, arterial blood is lower in oxygen and higher in carbon dioxide than venous blood.
Where do venous valves channel blood?
They prevent back flow and help to return blood to the heart.
What is the medical term meaning abnormal circulatory condition characterized by decreased return of venous blood from the legs to the trunk of the body?
venous insufficiency
Who discovered that venous valves help aid in the return of blood to the heart?
William Harvey
What does the venous return depend on?
The veins act as a blood reservoir, because of the ease of distending them. 55-60% of blood is in systemic veins which is important for blood pressure. The volume of blood returned to the right atrium of the heart per minute is called the venous return. Generally venous return is equal to cardiac output, due to the closed system of the circulation, except for minor transient periods. A number of factors affecting the venous return are: Smooth muscle: Due to presence of smooth muscle, the diameter of the veins can be altered by sympathetic discharge(normally vasoconstrictive), adrenaline and angiotensin II (cause venoconstriction). But because the diameters of veins are large, venoconstriction has little effect on peripheral resistance. Elasticity of the heart: If the elasticity decreases, then the ability to fill the heart is reduced. valves: one way valves in the veins (not in large veins) ease blood flow to heart. Muscle pump: When muscles, particularly leg muscles contract, the thin walled veins are squeezed and the blood is forced towards heart, when muscles relax, blood enters the veins, but only from the arterial side. This is an important mechanism for facilitating venous return. Respiratory pump: Breathing in causes negative pressure in thorax causing a suction effect, i.e. the pressure gradient pushing blood towards the right atrium is increased, thus more blood returns to the heart, which means that inspiration leads to an increase in venous return. The opposite occurs with expiration, and venous return is decreased. Gravity: Opposes return of blood from the periphery during sitting or standing. The effect is lost when we lie down. Blood pressure at venous end of capillary: An increased pressure at the venule end of the capillary reduces venous return, because the pressure difference between the right atrium and the peripheral veins is reduced. Similarly a decrease in pressure at the venule end would increase venous return. Right atrial pressure: Is the inflow pressure for the heart. It is a function of the amount of blood returned to the heart and the pumping ability of the heart. Its value at rest is normally close to zero but can also become negative (between -4 to 5 mmHg). Its value is increased by blood volume, a weak heart, rapid increase in venous return. Its value is decreased by lower blood volume and a strong heart. The lower the pressure the greater the venous return (due to suction effect), but there is a limit to the increase in venous return because veins are collapsible.
