The Urinary System

The urinary system has many functions including the following: regulation of glucose levels, blood volume, blood pressure and pH. Also produces hormones and excretion of waste and foreign substances. The kidneys do a major part of the work in the urinary system. The blood flow of the kidneys starts at the renal arteries. From there the renal artery divides into several segmental arteries. Then the segmental arteries goes into the interlobar arteries and then to the arcualte arteries. These arteries divide and make interlobular arteries. These arteries enter the renal cortex and branch into afferent arterioles.

The kidneys are important and we have are lucky to have two of them. We can live with one if we have to. A kidney transplant is one of the few organs that can be taken from a live donner. This is incredible to be able to help someone else and still live to do it.

The Digestive System

The digestive system starts with the gastrointestinal tract, also called the alimentary canal. This canal starts at the mouth and ends at the anus. The functions of the digestive system are: ingestion, secretion, mixing, digestion, absorption, and defecation. There are four layers of the alimentary canal. The first later is the mucosa layer that is made of simple c. epithelium. This layer is avascular and the cells in this area are constantly being replaced. The second layer is the submucosa layer. This layer is highly vascular and is made of dense irregular connective tissue. The third layer is the muscularis. This layer consist of the circular and longitual layers. This is made of smooth muscle. The last layer is serosa which is made of areolar connective tissue and is also highly vascular.

Most of us eat on a daily basis and the digestive system is working all the time. Could you imagine having Achalasia? Your probably thinking what in the world is that. Achalasia is a muscular disorder in the esophagus. This disorder makes it very difficult to swallow and sometimes your food does not even reach your stomach. I am thankful that I do not have this. It would make it very difficult to eat.

Blood And The Heart

Last time we talked about the importance of blood and the process of blood clotting. Now we are going to take a look at blood flow through the heart. This includes two pathways: the pulmonary circuit and the systemic circuit. The pulmonary circuit circulates blood through the heart and into the lungs. The systemic circuit circulates blood through the heart only. The pulmonary circuit starts at eh right atrium, goes through the tricuspid valve, and into the right ventricle. From here the blood goes through the pulmonary semilunar valve and through the pulmonary trunk into the right and left pulmonary arteries. Then the blood reaches the lungs. They systemic circuit starts in the left atrium, goes through the bicuspid valve, and into the left ventricle. From there the blood goes through the aortic semilunar valve and into the aorta.

The blood flow to the heart is an important subject for me to understand because of my mother. Just recently she was in the hospital because the blood was pumping faster in the atrium then in the ventricle. This gave her a "flutter" in her chest, also known as atrial fibrillation.

Blood

Blood is one of the easiest parts of the body to donate. Blood transports oxygen, carbon dioxide, nutrients, and waste through the body. Blood also regulates your body temperature and is important in blood clotting. The process of blood clotting is also called hemostasis. This starts with vasocontriction of the damaged blood vessels. Then the platelets form a "plug" over the wound. This is activated by fibrin prothrombinase. This changes into thronbin which forms the blood clot.

This blood clotting process is important to all of us. If anyone loses too much blood, they can eventually die. If you have ever had a large cut, you know the blood will clot and dry up. This is what is supposed to happen. Without this process we would lose to much blood.