We started this week by talking about the urinary system. The urinary system consists of at least one kidney, two ureters, the urinary bladder, and the urethra. The kidneys filter the blood plasma then they return most of the water and solutes into the blood stream. The rest of the water and solutes make the urine. The urine is passed through the ureters and is then help in the urinary bladder until it is passed through the urethra and out of the body.
When you eat food, your body takes nutrients and uses them to maintain all of the bodies functions. After the body takes what it needs from the food. The rest of the waste products are left in the blood stream. The urinary system works with the lungs, skin and also the intestines. All of these excrete waste. On average, adults eliminate about one to two quarts of urine every day. This number can change depending on the amount of food and fluid that adult takes in. It also depends on how much fluid is lost during sweating and breathing. The urinary system releases a waste called urea. This comes form the blood. Urea comes from foods that contains proteins. When this food is broken down, urea is carried in the bloodstream to the kidneys.
Kidneys are about the size of your fist and they are in the shape of a bean. They are located just below the rib cage. Kidneys are responsible for removing urea from the blood using small filtering units called nephrons. A nephron has a ball formed of small blood capillaries. This ball is called a glomerulus. They also have a small tube called a renal tube.
After the kidneys, the urine travels down the ureters. These are small tubes, about 8 to 10 inches long, leading to the bladder. The muscles of the ureter constrict and relax which forces the urine down away from the kidneys. Urine is moved through the ureters to the bladder about every 10 to 15 seconds.
Your bladder is balloon shaped organ that sits in your pelvis and is held in that place by ligaments. The bladder is the organ that holds urine until you are ready to go pee and empty it. In a healthy urinary system, a bladder can hole about 2 cups of urine for about 2 to 5 hours. Sphincters are circular muscles that help keep the urine from leaking. They close tightly around the opening of the bladder into the urethra. When you urinate, the brain sends a signal to the bladder muscles which says to tighten. When tightened the urine is squeezed out of the bladder. While the brain is telling the bladder muscles to tighten, it is also telling the sphincter muscles to relax. This allows the urine to exit from the urethra.
Tuesday, May 5, 2009
Saturday, May 2, 2009
Fetal Circulation
This post is a little out of order but I thought I would talk about fetal circulation due to the fact that it was on our last test.
The fetal circulatory system works differently during pregnancy than it does after birth. During pregnancy, the fetus it attached to the placenta by the umbilical cord. The placenta is the organ that develops and implants in the uterus during pregnancy. Using the blood vessels of the umbilical cord the fetus is provided the necessary nutrition, oxygen and life support from the mother from the placenta. While these things are being moved in, there are other things making their way out of the fetus. Waste products and carbon dioxide are sent back through the umbilical cord and the placenta and moved into the mothers circulation to be released.
The blood from the mother enters the placenta and comes close to the fetal blood that has returned from the fetus to the placenta through the umbilical arteries. When the two circulations get closer in the placenta, the oxygen and nutrients such as sugar, proteins and fat molecules are able to move from maternal blood to fetal blood. While this is happening...carbon dioxide and waste products can move from the fetal blood to the maternal blood. After the fetal blood is nourished, it can return to the baby through the umbilical vein.
This vein goes to the liver and splits into three branches. One of these branches connects directly to the inferior vena cava. This branch allows the blood to reach the fetal heart and is then sent to the rest of the body.
After birth, and the umbilical cord is clamped from the placenta, the circulation changes after the baby is detached from the placenta. When the baby is removed from the placenta, the reservoir to the fetus, the baby's venous/resistance blood pressure rises. When the lungs are filled with air, the blood pressure in the lung arteries goes down.
Since the fetal lungs do not function to exchange gases and oxygenated blood is obtained from the mother, there are some important differences in the circulatory systems from adults and fetuses.
The fetal circulatory system works differently during pregnancy than it does after birth. During pregnancy, the fetus it attached to the placenta by the umbilical cord. The placenta is the organ that develops and implants in the uterus during pregnancy. Using the blood vessels of the umbilical cord the fetus is provided the necessary nutrition, oxygen and life support from the mother from the placenta. While these things are being moved in, there are other things making their way out of the fetus. Waste products and carbon dioxide are sent back through the umbilical cord and the placenta and moved into the mothers circulation to be released.
The blood from the mother enters the placenta and comes close to the fetal blood that has returned from the fetus to the placenta through the umbilical arteries. When the two circulations get closer in the placenta, the oxygen and nutrients such as sugar, proteins and fat molecules are able to move from maternal blood to fetal blood. While this is happening...carbon dioxide and waste products can move from the fetal blood to the maternal blood. After the fetal blood is nourished, it can return to the baby through the umbilical vein.
This vein goes to the liver and splits into three branches. One of these branches connects directly to the inferior vena cava. This branch allows the blood to reach the fetal heart and is then sent to the rest of the body.
After birth, and the umbilical cord is clamped from the placenta, the circulation changes after the baby is detached from the placenta. When the baby is removed from the placenta, the reservoir to the fetus, the baby's venous/resistance blood pressure rises. When the lungs are filled with air, the blood pressure in the lung arteries goes down.
Since the fetal lungs do not function to exchange gases and oxygenated blood is obtained from the mother, there are some important differences in the circulatory systems from adults and fetuses.
Friday, May 1, 2009
The digestive system!!!!!
This week in class we started talking about the digestive system. We discussed the GI tract. The GI tract goes from the oral cavity to the anal cavity. This GI tract is made up of four different layers of tissues. The four layers are mucosa, submucose, muscularis, and serosa. That is the order of the layers from the deepest to the most superficial.
The mucosa :: This is the inner lining of the GI tract. It is a mucous membrane that is composed of a layer of epithelium. This epithelium in the mouth, pharynx, esophagus, and the anal canal, is a mostly nonkeratinized stratified squamous epithelium. This functions as a protector. In the stomach and intestines is a simple columnar epithelium layer that functions in secretion and absorption. The mucosa also has a layer of areolar connective tissue known as the lamina propria. This layer has many blood and lymphatic vessels. These vessels are the routes in which nutrients that have been absorbed into the GI tract reach the other tissues of the body. This layer is responsible for supporting the epitelium and binding it to the muscularis mucosae. The third layer of the mucosa is the muscularis mucosae. This is a layer of smooth muscle fibers. This layer creats a fold in the mucous membrane of the stomach and small intestine. This helps to boost the surface area for digestion and absorption. This layer is avascular and has no blood supply.
The submucosa :: The submucosa layer has areolar connective tissue that helps bind the mucosa to the muscularis. It has many blood and lymphatic vessels that receive the absorbed food molecules. The submusocsa may have glands and lymphatic tissue. In this layer there is also an extensive network of neurons know as the submucosal plexus. This layer is highly vascular. It has clusters of white blood cells to recognize pathogens.
The muscularis :: The muscularis in the mouth, pharynx, and superior and middle parts of the esophagus has skeletal muscle. This muscle produces voluntary swallowing. This skeletal muscle also makes up the external anal sphincter. This permits voluntary control of defercation. For the rest of the tract, the muscularis has smooth muscle that is found in two sheets. There is a sheet of circular fibers and and outer sheet of longitudinal fibers. The food is broken down by the invouluntary contractions of the smooth muscle. The food is then mixed with digestive secretions. It is propeled along the rest of the tract.
The serosa :: The serosa is a serous membrane containing areolar connective tissues and simple squamous epithelium. This layer secretes a slippery/watery fluid that allows the tract to glide easily against the other organs. The serose inferior to the diaphragm, is known as the visceral peritoneum. This is becuase it forms a portion of the peritoneum.
Some other important words that we talked about are the following. The esophagus is what directs food to the stomach. The pyloric region leads to the small intestine. The true sphincter contains smooth or skeletal muscle cells that control the opening. The stomach is a "mixing bag" that works to mechanically digest food particles.
There are many things you can do to make sure you have and can maintain a healthy digestive system. Some of those things include eating healthy, exercising regularly and reduce or manage stress levels. Everything you eat and even drink needs to be broken down. The molecules are to big to just go trough the body.
The mucosa :: This is the inner lining of the GI tract. It is a mucous membrane that is composed of a layer of epithelium. This epithelium in the mouth, pharynx, esophagus, and the anal canal, is a mostly nonkeratinized stratified squamous epithelium. This functions as a protector. In the stomach and intestines is a simple columnar epithelium layer that functions in secretion and absorption. The mucosa also has a layer of areolar connective tissue known as the lamina propria. This layer has many blood and lymphatic vessels. These vessels are the routes in which nutrients that have been absorbed into the GI tract reach the other tissues of the body. This layer is responsible for supporting the epitelium and binding it to the muscularis mucosae. The third layer of the mucosa is the muscularis mucosae. This is a layer of smooth muscle fibers. This layer creats a fold in the mucous membrane of the stomach and small intestine. This helps to boost the surface area for digestion and absorption. This layer is avascular and has no blood supply.
The submucosa :: The submucosa layer has areolar connective tissue that helps bind the mucosa to the muscularis. It has many blood and lymphatic vessels that receive the absorbed food molecules. The submusocsa may have glands and lymphatic tissue. In this layer there is also an extensive network of neurons know as the submucosal plexus. This layer is highly vascular. It has clusters of white blood cells to recognize pathogens.
The muscularis :: The muscularis in the mouth, pharynx, and superior and middle parts of the esophagus has skeletal muscle. This muscle produces voluntary swallowing. This skeletal muscle also makes up the external anal sphincter. This permits voluntary control of defercation. For the rest of the tract, the muscularis has smooth muscle that is found in two sheets. There is a sheet of circular fibers and and outer sheet of longitudinal fibers. The food is broken down by the invouluntary contractions of the smooth muscle. The food is then mixed with digestive secretions. It is propeled along the rest of the tract.
The serosa :: The serosa is a serous membrane containing areolar connective tissues and simple squamous epithelium. This layer secretes a slippery/watery fluid that allows the tract to glide easily against the other organs. The serose inferior to the diaphragm, is known as the visceral peritoneum. This is becuase it forms a portion of the peritoneum.
Some other important words that we talked about are the following. The esophagus is what directs food to the stomach. The pyloric region leads to the small intestine. The true sphincter contains smooth or skeletal muscle cells that control the opening. The stomach is a "mixing bag" that works to mechanically digest food particles.
There are many things you can do to make sure you have and can maintain a healthy digestive system. Some of those things include eating healthy, exercising regularly and reduce or manage stress levels. Everything you eat and even drink needs to be broken down. The molecules are to big to just go trough the body.
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