The exchange of gases (O2 & CO2) between the alveoli & the blood occurs by simple diffusion: O2 diffusing from the alveoli into the blood & CO2 from the blood into the alveoli. Diffusion requires a concentration gradient. in the alveoli must be kept at a lower lever than in the blood. We do this, of course, by breathing - continuously bringing fresh air (with lots of O2& little CO2) into the lungs & the alveoli. Breathing is an active process - requiring the contraction of skeletal muscles.
Quick Answer. During a rooster injection on a knee, the doctor cleans an injection site near the kneecap, inserts a needle and withdraws any extra fluid from the knee area, and then through the same needle injects a solution containing hyaluronic acid, a substance obtained from rooster combs, into the knee joint, according to WebMD.
This video depicts the XP total Knee Replacement performed in Houston in motion demonstrating the anterior and posterior cruciate ligaments being preserved and functioning normally in the knee. These ligaments together stabilize the human knee through a full range of motion. XP stands for cruciate preserving knee replacement. The XP knee replacement procedure retains both of the major ligaments of the knee, the posterior cruciate and the anterior cruciate. Posterior cruciate retaining knee replacement has been available for many years, but the procedure requires removing the anterior cruciate ligament.