yes bcz O2-bound heamoglobin (called oxyheamoglobin) is bright red in colour.
Your venous system certainly falls in the category along with your arterial system.
Yes, the capillaries are the smallest kind of blood vessel, that facilitate the movement of substances (like oxygen and glucose) in and out of the blood through their very thin walls.
Yes. Sort of. In a healthy person at rest - the average venous saturation is approximately 75%. This is the result of mixing blood from muscles (or the brain) which is usually down to 25% with blood from places like the kidneys and the skin where venous blood is often greater than 90% saturated.
A capillary is a small blood vessel in the body that branches off from the larger veins. The capillaries help get blood to the other parts of the body like the fingers and toes.
lymphatic capillaries are very permeable Lymphatic capillaries have valves that keep fluid from flowing backward. The blood capillaries are regulated by smooth muscle. Lymphatic capillaries are also a but larger than blood capillaries.
Blood flow through the arterial system is pressure driven. The heart pushes the blood outward to the peripheral parts of the body. By contrast, the venous system is a low pressure system and the return of the blood to the heart is the result of contractions of surrounding muscle tissue. When you walk you are also helping return blood from the venous system. Since the movement is mostly passive the valves in the veins serve to keep the flow of blood in one direction. Another point is that valves would increase resistance which would be detrimental to the function of the arterial system. Farther along within the arterioles the vessels are contractile (an artery is more like a passive hose). While much of the contractility is controlled by the sympathetic nervous system local factors like internal pressure can also cause the arterioles to contract. In situations of blood loss this redirects blood flow to the more critical tissues.
arachnoid villi
A very narrow organic flexible tube
An individual's blood pressure is dependent on several factors including genetics, weight and stress levels. While there is nothing we can do to change our genetics one can eat a healthy diet and manage stress in an attempt to control blood pressure.
collateral hyperemic venous blood flow in abdominal wall due to portal cirrhosis of liver for example
If you're not getting enough protein in your diet the body turns on itself and starts to consume it's own proteins. These are the structural proteins in cells and tissues and the soluble proteins (including blood proteins, enzymes, antibodies and the like). This leads to loss of tissue and a reduction in the concentration of blood proteins. These soluble blood proteins - found in the plasma - are responsible for creating the osmotic pressure which draws tissue fluid into the capillaries. The reduction in the osmotic pressure gradient between blood and tissue fluid means that more fluid leaves the capillaries at the arterial end and less is re-absorbed at the venous end of the capillary network. The fluid then builds up in the tissues, a condition known as oedema.
It's simply a trick question health teachers like to put in their tests. The only vein that carries oxygenated blood (in an adult) is the pulmonary vein which leaves the lungs and enters the left atrium of the heart. In a fetus, however, things can change. There is oxygenated blood delivered by the mothers placenta which travels to the fetal heart (via the venous system) and bypasses the lungs through the foramen ovale and the arteriosus ductus to return partially oxygenated blood to the arterial system.