These "doors" are the following valves:Tricuspid Valve - arterioventricular valve of the right sidePulmonary Semilunar Valve - right side of the heartMitral or Bicuspid Valve - AV valve of the left sideAortic Semilunar Valve - left side of the heart
Blood is pumped around the body by the heart (that's what gives us our blood pressure readings). Every vein, artery, blood vessel and capillary in our body, has tiny valves in it which stops the blood flowing backwards between heartbeats. Think of the valves like tiny doors that only opens one way. If the blood tries to flow backwards, the force of the blood pushes the valve shut.
the un-oxygenated blood is pumped into the lungs where the oxygen is transfused out of the tiny air sacks or avioli before being pumped back to the heart and around the body
The lungs are the organs responsible for filling blood with oxygen. In the lungs, oxygen from the air we breathe diffuses into the blood in the capillaries surrounding the alveoli, which are tiny air sacs in the lungs. This oxygenated blood is then pumped by the heart to the rest of the body.
The blood passes through tiny capillaries that lie in close proximity to the alveoli in the lungs. This is where the gas exchange takes place.
The blood gets oxygen from the lungs during the process of respiration. Oxygen is inhaled into the lungs, where it diffuses into the bloodstream via tiny air sacs called alveoli. This oxygenated blood is then pumped by the heart to the rest of the body.
Why are nephrons surrounded by many tiny blood vessels
From what I remember of secondary eduation i think the nutrients and oxygen from the food turn into enzymes in the intestines and them they are absorbed through the wall of the intestines and into the bloodstream. Hope I helpd! =)
The tiny sacs insure that the maximum area of tissue can be in close contact with the blood vessels to facilitate gas transfer
Tiny valves in your veins keep blood from backing up. The pumping force of your heart keeps the blood flowing forward. If a valve in your leg stops working properly, the blood seeping back causes varicose veins mainly in your legs, though can occur anywhere.
There are three types of blood vessels; arteries, veins, and capillaries. Capillaries are tiny blood vessels.
the air enters the bronchioles, and into the aveoli, which are small, one cell-thick sacks of air. These sacks are surrounded by tiny capillaries, which is how your blood retrieves its oxygen. From here, the oxygenated blood is carried back to the heart through the pulmonary vein and pumped into your body.