Terms in this set (5)
- pressure gradient. 7-13 mm hg pressure towards heart. lower neard vena cava. …
- gravity. drains head and neck. …
- skeletal muscle pump limbs. valves push blood towards heart when squeezed by skeletal muscle.
- thoracic pump. abdominal to thoracic cavity. …
- exercise. increased venous return.
What are the three factors that are responsible for venous return?
Venous return is facilitated by a number of factors, including inspiration, increased total blood volume, increased venomotor tone, the cardiac suction effect, the presence of venous valves and the skeletal muscle pump.
Which of the following is the mechanism in which skeletal muscles assist venous return of the blood to the heart quizlet?
skeletal muscle pump: The mechanism whereby skeletal muscles aid the return of blood to the heart by compressing embedded veins.
Which of the following is the mechanism in which skeletal muscles assist venous return of blood to the heart group of answer choices?
Skeletal Muscle Pump
A major mechanism promoting venous return during normal locomotory activity (e.g., walking, running) is the muscle pump system. Peripheral veins, particularly in the legs and arms, have one-way valves that direct flow away from the limb and toward the heart.
Which two factors promote the return of venous blood to the heart group of answer choices?
Chapter 21
- Extensive vasodilation as oxygen consumption increases.
- Increased venous return through the action of muscle contraction and respiratory pump.
- A rise in cardiac output in response to increased venous return and atrial pressure.
How does the respiratory system enhance venous return?
Respiration – During inspiration, venous return increases as the thoracic cavity’s pressure becomes more negative. This reduced intrathoracic pressure draws more blood into the right atrium. This results in greater venous return. Venous Compliance – Increased sympathetic activity will reduce venous compliance.
How does exercise influence venous return?
5), and as a result, 95% of venous return comes from muscle tissue where venous oxygen content is very low. Thus, with increasing exercise intensity, the relative amount of venous blood returning to the heart from active striated muscle increases so that mixed venous oxygen content decreases as shown in Fig. 4.
What is venous compliance?
The ability of a blood vessel wall to expand and contract passively with changes in pressure is an important function of large arteries and veins. At higher pressures and volumes, venous compliance (slope of compliance curve) is similar to arterial compliance. …
What does the Frank-Starling law state?
The Frank-Starling Law states that the stroke volume of the left ventricle will increase as the left ventricular volume increases due to the myocyte stretch causing a more forceful systolic contraction. This assumes that other factors remain constant.
Why does squatting increase venous return?
Upon squatting, the compression of the veins in the lower extremities augments venous return to the right atrium. In contrast to the Valsalva maneuver, which leads to a smaller preload, squatting increases end-diastolic volume due to increased venous return.
What is difference between Elastance and compliance?
Compliance: reflects ability to change the shape of the structure when mechanical load applied. Elastance: reflects resistance to change the shape when mechanical load applied. When compliance is less than elastance – rigidity predominates.
What is the difference between compliance and distensibility?
Distensibility is related to elastic properties of the arterial wall, and compliance reflects the buffering function of the artery. Distensibility is a determinant of stress on the vessel wall.
What is the difference between compliance and capacitance?
Thus, compliance and capacitance are related; capacitance describes how much volume is added before an elastic recoil pressure is generated while compliance describes change in pressure per volume as the recoil pressure starts to rise.
How do you increase venous return?
Lifestyle changes can also help prevent symptoms from returning after you have had minimally invasive procedures or surgery.
- Wear Compression Garments. …
- Maintain a Healthy Weight. …
- Increase Activity Levels. …
- Elevate the Legs. …
- Avoid Tight Clothing and High Heels. …
- Avoid Salt. …
- Moisturize the Skin.
Why does exercise increase venous return quizlet?
Exercise increases venous return because: … muscle contractions decrease venous return by means of the skeletal muscle pump. blood vessels of the skeletal muscles, lungs, and coronary circulation dilate, increasing flow.
How is venous return to your heart affected when you go for a jog?
During intense exercise, it is known that the increased blood pressure may drive plasma into the interstitial space, reducing blood volume. A reduction in blood volume would, in turn, cause decreased venous return to the heart. This would translate into a decreased stroke volume and therefore cardiac output.
What are the three mechanisms that assist venous return to the heart?
Mechanisms to Return Blood
The return of blood to the heart is assisted by the action of the skeletal-muscle pump and by the thoracic pump action of breathing during respiration. As muscles move, they squeeze the veins that run through them. Veins contain a series of one-way valves.
How does Valsalva maneuver affect venous return?
The increase in intrathoracic pressure that occurs during the Valsalva maneuver incites a sequence of rapid changes in preload and afterload stress. During the strain, venous return to the heart is decreased and peripheral venous pressures become increased.
What factors contribute to venous return to the heart quizlet?
– Venous return: the movement of blood from the capillaries back to the heart via the veins. Two factors that assist venous return to the heart are the skeletal muscle pump and the respiratory pump. The respiratory pump uses the diaphragm, which contrats as we inhale, increasing pressure in the thoracic cavity.
Does vasoconstriction increase venous return?
Peripheral vasoconstriction, particularly in the smaller arterioles, limits muscle perfusion during exercise thereby contributing to a decrease in exercise capacity. Contraction of venous vessels enhance venous return and preload, which helps to maintain stroke volume through the Frank-Starling mechanism.
Which of the following tasks must the circulation control mechanism accomplish?
Which of the following tasks must the circulation control mechanism accomplish? … Maintain circulation. Vary the volume and distribution of the blood circulated.
What is meant by distensibility?
: capable of being distended.
What is arterial distensibility?
Arterial distensibility is a measure of the arterial ability to expand and contract with cardiac pulsation and relaxation.
Why are veins more Distensible?
Anatomically, the walls of the arteries are far stronger than those of the veins. Consequently, the veins, on average, are about eight times more distensible than the arteries. That is, a given increase in pressure causes about eight times as much increase in blood in a vein as in an artery of comparable size.