Venous valves of the veins of the lower extremities, venous valves venous valves .

There are many valves in deep and superficial veins and communicating veins, and the valves are generally located on the distal side of the main branches of the veins, and their function is to ensure the unidirectional return of venous blood.

The number and location of deep vein valves in the lower extremities vary from person to person. The general rule is that there are valves at the distal end of the confluence of the venous branches. The most constant valves are located in the deep femoral and superficial femoral veins before meeting, each with a pair of valves; The second pair of valves in the superficial femoral vein are mostly located about 10 cm below the first pair of valves; The common femoral vein is mostly a pair, located at the proximal end of the common femoral vein; There are more than 2 pairs of valves in the popliteal vein.

The number of valves in other veins is large and inconstant.

Venous valves are formed by endovenous folds, and most of them have two corresponding and symmetrical leaflets, i.e., a bivalve. Each leaflet has a free margin and an attachment margin, and in the bivalve type, the junction of the free and attachment margins is the intersection point of the two petal leaflets. The venous distention proximal to the valve attachment margin is mostly venous sinus.

Through in vitro mechanical testing, the highest pair of valves in the superficial femoral vein were the strongest, which could withstand 350 420 mmHg reverse pressure. In the superficial venous system, the saphenofemoral vein valve (saphenous vein.

The pair of valves before it joins the common femoral vein are the strongest, but only 180 250 mmHg, and the valve below it is weakened. Under normal circumstances, when blood flows back to the center, the valve attaches to the wall of the vein and the vein is unobstructed. When the venous pressure increases due to standing or other reasons, the two lobes open and the free margin is brought closer together under the impact of reverse blood flow, preventing the blood from flowing backwards.

At this point, the venous sinuses are distended and resemble bamboo joints.

The venous valves of the lower extremities are different from heart valves, and their activity is affected by a variety of factors. The concentric return of venous blood in the lower limbs, in addition to the effects of chest inspiratory exercise and negative pressure suction generated by diastolic, mainly relies on the squeezing effect of the calf muscle pump and the unidirectional opening function of the venous valve, so that the blood flows from the distal end to the proximal end and from the superficial vein to the deep vein. The unidirectional opening function of the valve is of great significance, as it effectively prevents the backflow of blood when the calf muscles are relaxed.

It ensures blood return in the upright position.

Venous valve refers to the valve above the vein, and there are three types of blood vessels in the human body, namely: veins, arteries, and capillaries. Of these, only the veins have valves.

Because the veins are responsible for bringing blood from all parts of the body back to the heart, there are valves in the veins to prevent blood from flowing backwards.

Only veins in the human body have valves. When blood flows to the heart, the valve opens, allowing blood to flow to the heart, and when the blood is gone, the valve closes. Damage to the vein valve can cause the venous pressure to become too high, resulting in varicose veins.

If it is simple superficial varicose veins of the lower limbs, the general clinical symptoms are mild, the progression is slow, and most of them are manifested as simple varicose veins, and in a few cases, there may be thrombophlebitis, venous ulcers, etc.; If it is a deep vein valve insufficiency, or even a deep venous return obstruction, the condition is relatively serious, the calf has a feeling of heaviness when standing, easy fatigue, and even swelling and bursting pain of the lower limbs, and the later stage will occur ** nutritional changes, desquamation, atrophy, pigmentation, eczema ulcer formation.

Hello, now I am here to answer the above questions for you. Vein valves, vein valves, I believe that many friends still don't know, now let's take a look! 1. The venous valve is very thin, soft, and. <>

1. The venous valve is very thin, soft, and transparent.

2. In the case of blood flowing to the heart, the valve is attached to the vein wall, and the vein is unobstructed.

3. When the venous pressure increases due to standing or other reasons, it causes the reverse flow of venous blood.

4. Under the impact of reverse blood flow, the two valve leaflets open and move closer together to prevent blood from flowing backwards.

5. Therefore, the only function of the venous valve is to make the venous blood return in one direction to the heart, that is, to play the role of a one-way valve.

6. If for some reason, the valve loses the function of the one-way valve, the blood will flow backwards, so that the venous blood can not flow smoothly in the direction of the heart, which will lead to venous reflux disease.

7. Poor venous valve function is also a common cause of varicose veins of the lower limbs.

Except for the veins of most organs in the internal organs, brain, head and neck, there are no venous valves, and the veins of the rest of the body have valves with veins with a diameter of more than 2 mm. There are more valves in the veins of the limbs, especially in the lower limbs.

Rectal veins and their branches lack venous valves, and blood is prone to backflow and stasis. This is the cause of hemorrhoids, hemorrhoids patients are extremely painful, and hemorrhoids are extremely susceptible. One of the manifestations of the imperfection of human evolution.

The aortic valve is only present in the aorta and pulmonary artery, and only opens towards the artery, and their function is also to prevent blood from flowing backwards, and the aorta is the large artery that supplies blood rich in nutrients and oxygen to the whole body, and the pulmonary artery is the blood that flows back from the body to the lungs, where the blood and the lungs exchange blood gases, absorb oxygen, exchange carbon dioxide, and then pass through the pumping pressure of the heart, and finally pass through the aorta** The whole body, is the valve between the artery and the ventricle.

The capillaries throughout the body merge into veins, and finally into the superior and inferior vena cava and coronary veins into the right atrium. Except for the veins of most organs in the internal organs, brain, and head and neck, which do not have venous valves, the veins in all parts of the body have valves that prevent blood from flowing backwards, called venous valves.

Vein imitation book is the blood vessel that transports blood back to the heart from all over the body, some veins are accompanied by arteries, the position is deeper, and some veins are shallow, which can be seen on the surface of the body, such as the green tendons on the arm of the hand ruler, which is the vein; Compared with the accompanying arteries, the walls of the veins are thin, the elasticity is small, the official lumen is large, the blood flow in the tube is slow, and the inner sedan surface of the veins of the limbs has venous valves that prevent blood from flowing backwards

a. There is a venous valve in the vein, which can prevent blood from flowing backwards, and there is no avalve, and a does not conform to the topic;

b. The blood flow velocity in the capillaries is very slow, which is conducive to the exchange of substances, and b does not conform to the topic;

c. The wall of the artery is thick, elastic, and the blood flow speed in the tube is fast, and C is in line with the topic;

d. Venous vessels are generally located in superficial parts, and the pressure is small, and it is easy to stop bleeding, so when donating blood for free or patients taking "intravenous drips", the needle is pierced into the vein, and D does not meet the topic

Therefore, c

There are more venous valves in the lower limbs than venous valves in the lower limbs, the venous valves in the lower limbs are more and fragile, the valves in the upper limbs are few and tough, and the varicose veins of the lower limbs will occur in the following situations

1. Extended venous thrombosis: For example, calf venous thrombosis may develop upward to the femoral, iliac and inferior vena cava.

2. Thromboembolism: such as pulmonary embolism, which can occur within a few hours or days after thrombosis.

3. Chronic venous insufficiency after phlebitis: such as in the lower leg, when the venous valve is seriously damaged, the collateral circulation is not fully established, that is, it is prone to serious conditions, first of all, edema in the lower part of the calf, gradually varicose veins, **pigmentation, and finally stasis dermatitis, stasis subcutaneous sclerosis and stasis ulcers.

There are more in the lower limbs than in the upper limbs.

There are many venous valves in the lower limbs, and the main reason for the formation of varicose veins is due to the congenital vascular wall membrane is relatively weak or the same posture is rarely changed for a long time, blood accumulates in the lower limbs, and the venous valves are damaged in the case of accumulation over time, resulting in high venous pressure, which makes the blood vessels protrude on the surface of the ** surface.

Varicose veins are an irreversible phenomenon, but they can still be prevented from expanding and reducing their symptoms by conservative** (e.g. use of elastic stockings, exercise, diet and lifestyle changes). Gentle exercises, such as walking, swimming, and cycling, can improve circulation and reduce the rate at which new varicose veins occur. In terms of diet, you should eat more high-fibre and low-fat diets and fortify vitamin C and E supplements.

In daily life, you should control your weight, avoid taking contraceptive pills, avoid wearing tight clothing and high heels, stilt your legs, and avoid sitting or standing for long periods of time. Elevate your legs for a period of time before bedtime each day, and sleep on your side to reduce pressure on your pelvic veins. Smoking can increase blood pressure and damage the arteries and veins, so patients with varicose veins should quit smoking immediately.

"Upper ring metal allergy", did you take out the ring?

In addition, your condition may seem to be a little different from the clinical manifestations of phlebitis.

1. Thrombotic deep lower extremity phlebitis is manifested in the early stage of swelling of the affected limb, local redness, swelling, heat and pain, aggravation after exertion, and relief after rest.

2. In the early stage of migratory superficial lower extremity phlebitis, it presents with local redness, swelling, heat and pain, and palpable subcutaneous induration or cord-like objects and tenderness. After the inflammation subsides**, the pigmentation is black. It can be repeated multiple times, the location is uncertain, and it is migratory.

Yours is just "bleeding spots in both lower limbs".

Can you describe your situation in more detail?

The atrioventricular valve is present between the atria and ventricles and is not in the veins of the extremities; The aerial valve is present between the ventricles and arteries, not in the veins of the extremities; Venous valves are present in the veins of the extremities The characteristics of arterial vessels and venous vessels are shown in the figure: on the inner surface of the veins of the extremities, it usually has the effect of preventing blood from backflowing

Therefore, c