(When reading through these steps, keep the information provided above in mind). A contraction begins when a bound ATP is hydrolyzed into ADP and inorganic phosphate, causing the myosin head to extend, helping it attach to a binding site on the actin filament, forming a cross bridge. 

An action called the power stroke is triggered allowing myosin to pull the actin filament toward the M-line, shortening the sarcomere. During this, ADP and the inorganic phosphate are released, the myosin stays attached to the actin until a molecule of ATP bonds. This frees the myosin to do two things. 

Either go through another cycle of contracting, or do nothing allowing the muscle to relax. Muscle contractions are controlled by the actions of calcium. The thin actin filaments are associated with regulatory proteins called troponin and tropomyosin. 

When a muscle is relaxed, tropomyosin blocks the cross bridge binding sites on the actin. When the calcium ion levels are high enough and ATP is present, calcium ions bind to the troponin. This displaces tropomyosin, exposing the binding sites on the actin filament. Allowing the myosin to attach to a binding site on actin, forming a cross bridge. 

Before anything is said, I would like to include that the nephrons work in what is called a two step process. Even though this amazing process is broken down to only two categories, there is so much work that goes on behind the scenes. Each kidney is said to contain millions of nephrons!  

But how does the blood get to the kidney anyway? Blood flows into your kidney through the renal artery. This artery continuously branches into smaller blood vessels until the blood reaches the nephrons. Here, your blood is filtered by the tiny blood vessels in the glomeruli and then flows out of your kidney through the renal vein.

Firstly, the blood flows into each nephron, it enters a cluster of tiny blood vessels: the glomerulus. The thin walls of the glomerulus allow smaller molecules, wastes, and fluid (mostly water) to pass into the tubule. Larger molecules, such as proteins and blood cells, stay in the blood vessel.

A blood vessel runs alongside the tubule. As the filtered fluid moves along the tubule, the blood vessel reabsorbs almost all of the water, along with minerals and nutrients your body needs. The tubule helps remove excess acid from the blood. The remaining fluid and wastes in the tubule become urine.

One thing that I learned about CPR is that you can sing Stayin' Alive by Bee Gees in your head to guarantee you an accurate pace for compression. For adults, it is important that you are going about 2 inches into the chest, while allowing  for FULL recoil before pumping again. Additionally, when doing one person CPR do 30 compression to two breaths. But when doing team CPR, do five sets of fifteen compression to two breaths. 

It is important to remember the differences between how you would approach CPR on an infant and an adult. Anyone under the age of 18 months is considered an infant. Instead of reaching a depth of 2 inches during compressions, for an infant only go down to about 1.5 inches. You would do the same amount of compressions on an infant as you would an adult, but the way you do it is different. Instead of using the traditional heel of your fist, you would use two fingers in place of the heel. 

The ambu bag is used to pump air into the lungs. The best way to describe its job is mouth to mouth but without the mouth. When in use, it is very important to tilt the person's chin up to allow the airway to open up. If there are air leaks from the mask, this device will not be effective. The AED is a lot easier to use. Upon activation, the machine will give you verbalized instructions on what to do next. When the shock is being administered, make sure you say "CLEAR!" 

The best way to tell if someone is choking, or not receiving enough oxygen, is if the areas around their mouth or finger tips start turning blue (cyanosis). If the person chocking is an adult or adolecent, encourage them to cough. If they are still choking, resort to abdominal thrusts. If an infant is choking, give them five solid back blows, turn them over and give them five compression. Switch between these movements until the infant stops chocking. 

To measure blood pressure, we used a stethoscope. First we put the sphygmomanometer on the person whose blood pressure we were measuring. After that, you put the stethoscope on (make sure that the ear pieces are pointed towards the front of your face. Put the diaphram of the stethoscope on the fold of the person's hand, right above from where the sphygmomanometer is placed. 

(Make sure the arrow on the sphygmomanometer is pointed towards where you are placing the diaphram).Then, with everything in place, grab the ball of the sphygmomanometer and pump until the line on the cuff reaches at least 180 and pact 160. Use the nob attached to the ball to let the red arrow come back down again. While you watch the arrow come down, look for which number the arrow is on when you hear the first and last heart beat.

To measure respiratory rates, we counted each other's breaths. For about thirty seconds, I watched for chest rise and counted. After thirty seconds, I multiplied the number I got by two to approximate how much the respiratory rate would be for a minute. 

The most popular way to measure your pulse is the radial artery, which is located at the wrist (which is what I practiced in class). Other places may include: nthe carotid artery (neck), the popliteal artery (behind the knee), the femoral artery (the groin), the brachial artery (inside the elbow), the dorsalis pedis and posterior tibial artery (foot), and the abdominal aorta (the abdomen).