Appreciate the microscopic anatomy of the liver.....
Liver
Understanding that the livers overall function in the body is to filter and process the blood supply helps with understanding the microscopic anatomy. The photo that I took in lab helps me in grasping the concept that the liver lobules are a six-sided shape with a central vein running through it. The picture from the Anatomy and Physiology text* shows in depth what occurs at the portal triad on each one of those corners. Reading through the text explained the many facets of the liver including:
Glycogen storage
Decomposition of RBC'S
Plasma protein synthesis
Hormone production and detoxification
Bile production
Nurse's Note: Two common diagnoses that pertain to the liver are Hepatitis, a long-term, chromic and potentially fatal infection of the liver caused by a virus and Cirrhosis, a chronic infection of the liver caused by alcoholism.
Relay structure and function of the endocrine system to digestion...........
These two pictures from the Anatomy and Physiology textbook* along with time in both lab discovery and lecture gave a full understanding of the role that the endocrine system plays in digestion. The pancreas is labeled as both and endocrine and exocrine gland. Its exocrine functions include the release of enzymes that aid in digestion and its endocrine functions include the release of both insulin by the beta cells and glucacon by the alpha cells. These two secretions work antagonistically to one another to maintain the proper amount of glucose in both the blood and the cells.
I had an "AHA" moment while listening to one of the podcasts regarding glucagon and insulin. It was so "AHA" and had me so turned around that I actually had to get Jeremy to explain it to me again! While listening to the podcasts on the endocrine system the question was posed "What would be the result of too much insulin in the blood stream"? I know the answer to this, I thought! High blood sugar! WRONG, so WRONG! The answer was hypoglycemia. What? How can that be? I was so perplexed that I actually had to grab Jeremy in the parking lot at school, make him listen to that section of the podcast and then pretty much force him to repeatedly explain it to me. He laughed as he explained that I apparently had the functions of insulin and glucagon backwards. Insulin actually moves the glucose into the cell while glucagon breaks down glycogen from the liver and puts glucose back into the blood stream.
Thank you, Jeremy for setting me straight!
Nurse's Note: Diabetes Mellitus occurs when there is too little insulin in the blood and glucose can not be effectively moved into the cells. There are three cardinal signs of Diabetes Mellitus. These include polyuria or excessive urine output, polydipsia or excessive thirst, and polyphagia or excessive hunger.
State the chemical forms in which the major food classes are absorbed and describing enzymatic and bicarbonate content of pancreatic juices.
This sheet from the Anatomy and Physiology Laboratory Manual** gave a thorough description of how the major food classes were broken down into chemical forms for absorption. In addition to the chart shown here, lab exercises were done to increase understanding of how the foods were broken down and what organs played a mjor part in making that happen. In addition, the chart also highlights the pancreatic enzymes that play a part in digestion of these food sources such as pancreatic amylase that works to breakdown carbohydrates, Trypsin that works to break down proteins, pancreatic lipase that works on fats, and pancreatic ribonuclease and deoxyribnuclease that breakdown amino acids. All of these enzymes are secreted from the pancreas in an inactive form and are activated in the small intestine.
Nurse's Note: Carbohydrates, proteins, and fats are considered macronutrients because our body requries these food sources in large amounts in order to function properly. Carbohydrates are the body's major source of energy and the only source that the central nervous system can use. Proteins fuel and build muscle while fat offers additional energy and protection of the organs.
Describing the structure and function of the renal corpuscles and tubules and identifying the three basic tasks performed by the nephrons and tubules.....
Picture from Anatomy and Physiology textbook*
I have to say, I've really enjoyed this textbook. Its been really easy to read and follow along with compared to some of the science texts that I've used in other classes. The fact that the text and picture are both color coordinated to show the three processes that the nephrons perform and where it occurs in the renal corpuscle and tubules was a geat starting place in understanding these objectives. Breaking the processes down like this makes them seem less overwhelming.
Detailing the kidneys involvement in blood pressure and volume regulation, stating the importance of the juxtoglomerular cells in secretion of renin, and assessing how water excess and dehydration affect kidney function.....
Understanding how the kidneys work to maintain blood volume and blood pressure is tricky because there are multiple methods (and hormones) that can be involved in doing this. I had a good understanding of the hormones that were involved including aldosterone and ADH, but was a little bit iffy on where renin fit into the process. Watching this video where they gave a step by step explanation of how the release of each hormone causes a cascade effect onto another organ helped me to get a better grasp of the entire process.
In all of the processes listed above there is one additional factor that plays a large part in maintaining body homeostasis and that is WATER! So its important to discuss and understand how water excess or dehydration ties into maintaining blood volume and blood pressure as well. When the body becomes dehydrated due to excessive fluid loss or a decrease in fluid intake the extracellular fluid becomes a hypertonic solution for the cells. This means that the water in the cells will move out into the extracellular fluid (following those salts or solutes like water always does!) causing the cell to crenate. On the other hand, when we have excessive amounts of fluid in the system, the cells are in a hypotonic solution. So the water in the extracellular fluid will move into the cells causing them to overfill and lyse.
Nurse's Note: Diuretics are commonly prescribed along with antihypertensive medications to treat high blood pressure. Just another example of how blood pressure and blood volume tie in together.
Contrast volume and electrolyte content in inter and extracellular fluid compartments....
Major fluid compartments of the body from Anatomy and Physiology textbook p.868*
Electrolyte composition of body fluids from Anatomy and Physiology textbook p. 869*
Looking at the first chart shown gives a very specific breakdown of the total body water and how it is broken down into the body's "fluid compartments". The second chart gave an understanding of where the electrolytes are carried in the body's fluids. The second chart showed results that I actually expected based on previous knowledge regarding depolarization events that take place in the nervous and muscular systems. We were taught that there is a higher volume of potassium inside the cells and a higher volume of sodium on the outside of the cells. The influx of sodium ions is what causes the cell to depolarize so that the signal can be transmitted.
Nurse's Note: Many processes in the body, especially in the brain, nervous system, and muscles, require electrical signals for communication. The movement of sodium is critical in generation of these electrical signals. Too much or too little sodium therefore can cause cells to malfunction, and extremes in the blood sodium levels can be fatal.
Increased sodium (hypernatremia) in the blood occurs whenever there is excess sodium in relation to water. There are numerous causes of hypernatremia; these may include kidney disease, too little water intake, and loss of water due to diarrhea and/or vomiting.
A decreased concentration of sodium (hyponatremia) occurs whenever there is a relative increase in the amount of body water relative to sodium. This happens with some diseases of the liver and kidney, in patients with congestive heart failure, in burn victims, and in numerous other conditions.
A Normal blood sodium level is 135 - 145 milliEquivalents/liter (mEq/L).
Describing kidney function, tracing the path of blood flow through the kidneys and describing internal and external gross renal anatomy.......
So, as you know, we weren't able to do our in-class lecture on the urinary system, and we had to do an online lecture for this portion of the text. Well, I have to say that I'm really glad that I didn't take this class online. I enjoy the online lectures, but they always leave me feeling like I've missed ALOT! (I think I actually told you this when I came into the class a week late and had to do the endocrine lectures online!) Anyway, so I went to YouTube looking for videos to help me get a better grasp on the urinary system and this is what I came across. I think that it really helped! Watching this video from the Greater Pacific Company helped me to get a visual understanding of how the kidneys function including understanding how they receive blood from the arterioles and send it into the Bowmans capsule portion of the nephrons for filtering in the Glomerulus, a mass of intertwined capillaries. In the Glomerulus there's a bit of a slow down that allows substances to be filtered due to the fact that the arteriole ENTERING is larger than the arteriole EXITING (I sort of think of a lymph node here where the fact that there are more afferent vessels than efferent vessels gives the lymph fluid time to be filtered).
Nurse's Note: Diabetes Mellitus and Hypertension are the most common causes of End Stage Renal Disease, where the kidneys stop forming filtrate and metabolic wastes build up in the blood stream. The most common treatment for this is hemodialysis where the patient is hooked up to a machine that actually pulls the blood from their bodies in order to filter the wastes from it before the blood is returned into the body. Fluid and Electrolyte testing is done on the patient prior to dialysis being performed so that any electrolytes that are missing or lacking from the blood can be added into the filtered blood as it is returned to the body. Often in a patient that requires frequent dialysis, a fistula is done. A fistula is the connection of an artery and a vein inside the body to provide a permanent port for dialysis. This port helps to strengthen the blood vessel so that insertion of needles for dialysis treatments are easier. Fistula's are commonly tested for Thrill ,a constant palpable vibration at the fistula site, and Bruit, a soft, low-pitched noise heard through the stethoscope when placed on the fistula to ensure that the blood is still flowing properly through the fistula.
