Unit 11 Urinary System PDF

Unit XII. Urinary System and Fluid Balance https://www.youtube.com/watch?v=1NtPjzm1-74 The Functions of the Urinary Tract 1. Filtration. Kidneys filter gallons of fluid from the bloodstream. About 20% of the plasma volume passing through the glomerulus at any given time is f...

Unit XII. Urinary System and Fluid Balance https://www.youtube.com/watch?v=1NtPjzm1-74 The Functions of the Urinary Tract 1. Filtration. Kidneys filter gallons of fluid from the bloodstream. About 20% of the plasma volume passing through the glomerulus at any given time is filtered. 2. Waste processing Kidneys process about 200 quarts of blood to filter out about 2 quarts of waste products and remove extra water. 3. Elimination Eliminate nitrogenous wastes, (Ammonia, uric acid, urea, creatine, creatinine, toxins, and drugs from the body. and amino acids), excess salts, water an other toxins. 4. Regulation Kineys maintain the acid–base balance by 5. Other regulatory functions https://www.youtube.com/watch?v=bY6IWVgFCrQ How enzyme renin regulates the blood pressure? 6. Conversion Kidney cells also convert vitamin D to its active form. https://www.youtube.com/watch?v=gtwK7wcU5Sk How kidneys convert vitamin D to active form? I. Kidneys (inside are the nephrons) Physical Characteristics Dark red, slightly flattened bean-shaped organ Average weight is 120 to 170 grams  It is 10 - 12 cms long and 5 – 6cms wide with 2 -3 centimeters thick The kidneys extend from the T12 to L3 vertebrae.  It lies against the dorsal body wall in the retroperitoneal position (beneath the parietal peritoneum) in the superior lumbar region. They are slightly asymmetrical, meaning the left is placed a little higher than the right  The outer surface of the kidney is concave while the inner surface is convex. The kidneys are surrounded by a layer of adipose that holds them in place and protects them from physical damage. The other organs or structures Adrenal gland. Atop each kidney is an adrenal gland, and is part of the endocrine system. Renal cortex. Light color of the outer region of the kidneys. Produces cortisol which regulate metabolism and helps body respond to stress and aldosterone, control blood pressure. Renal medulla. darker reddish-brown area Controls hormones that initiate the flight or fight response. Renal pyramids. Triangular part with stripes in the renal medulla. Function of renal cortex, renal medulla and renal pyramids: Urine filtration The renal column (or Bertin column, or column of Bertin) is a medullary extension of the renal cortex in between the renal pyramids. It allows the cortex to be better anchored. Renal pelvis. Medial to the hilum is a flat, basin-like cavity. The point of convergence of two or three major calyces. Act as a funnel for urine flowing to the ureter. Renal calyces. They are extensions and serves as passageway of the urine from the pelvis. It also collects urine, which drains from the pyramids. The hilum is the concave part of the bean-shape where blood vessels and nerves enter and exit the kidney; it is also the point of exit for the ureters. Arcuate arteries and veins are vessels of the renal circulation. They are located at the border of the renal cortex and medulla. 2. Ureters These are two slender tubes each 25 to 30 cm (10 to 12 inches) long and 6 mm (1/4 inch) in diameter. To transport urine from the kidney to the urinary bladder. At the point of entry to the bladder, ureterovesical valves are present to prevent urine from flowing back towards the kidneys. 3. Bladder The urinary bladder is a sac-like hollow organ used for the storage of urine. The walls of the bladder allow it to stretch to hold anywhere from 600 to 800 ml of urine. Parts of the Bladder A. Trigone is a smooth triangular region of the bladder base, where infections tend to persist. The area is very sensitive to expansion and once stretched to a certain degree, the urinary bladder signals the brain of its need to empty. B. Detrusor muscle is smooth muscle found in the wall of the bladder. The primary function of the detrusor muscle is to contract during urination to push the urine out of the bladder and into the urethra. 4. Urethra The urethra is a thin-walled tube that carries urine by peristalsis from the bladder to the outside of the body. Urinary elimination is controlled by the internal and external urethral sphincter muscles. The male urethra is around 8 to 10 inches long and ends at the tip of the penis. It is also an organ of copulation. The male urethra is divided into four sections: * Prostatic urethra (widest) * Membranous urethra (Narrow) * Bulbous urethra (round) * Pendulous urethra (Longest) The female urethra is about 3 to 4 cm (1 1/2 inches) long, and its external orifice, or opening, lies anteriorly to the vaginal opening. Nephron and Urine Formation Kidney (nephron) structures and functions https://www.youtube.com/watch?v=QsSdAXv5BEM Each kidney is made up of about a million filtering units called nephrons. There are two types of nephrons: What is the difference between cortical and juxtamedullary nephrons? Cortical nephron Juxtamedullary nephron Contains a short loop of Henle Juxtamedullary nephron which only extends into the contains a longer loop of Henle outer region of the renal which extends deeper into the medulla inner medulla. Juxtamedullary nephrons have a vital role in concentrating urea Excretory and regulatory Main function is to concentrate functions or dilute urine / urea.  Cortical nephron Juxtamedullary nephron Contains reduced vasa recta Contains a large network of (straight arterioles of the vasa recta kidney) The vasa recta capillaries are long, hairpin-shaped blood vessels that run parallel to the loops of Henle. The hairpin turns slow the rate of blood flow, which helps maintain the osmotic gradient required for water reabsorption.  Cortical nephron Juxtamedullary nephron Most nephrons (85% of the total Only 15% of the nephrons in the nephron) in the human kidney human kidney are are cortical nephrons. juxtamedullary nephrons. Therefore, the excretory and regulatory functions of the body are mainly carried out by cortical nephrons. They have small glomerulus They have large glomerulus resulting to low GFR resulting to high GFR Glomerulus. It is a tuft of small blood vessels called capillaries. Filtration occurs as regulated by the pressure of the blood that forces water plus other small molecules out into the BC. The Parts of the Nephron Bowman’s or glomerular capsule is an enlarged and cup-shaped that surrounds the glomerulus. Podocytes are cells in the BC that wrap around capillaries of the glomerulus. Podocyte cells make up the epithelial lining of BC, the third layer through which filtration of blood takes place.  https://www.youtube.com/watch?v=ZDvWnezLdDU The afferent and efferent arterioles: How it works and how it affects the glomerular filtration rate. Urine formation is a result of three processes: https://www.youtube.com/watch?v=es-t8lO1KpA https://www.youtube.com/watch?v=6HJfr00CIqM Nephrons are the structural and functional units of the kidneys. 1. Glomerular Filtration From the body circulation, blood enters into the glomerulus through the afferent arterioles  100%water, glucose & 100% AA, 65% K and 50% urea are push into the Bowman's capsule while blood cells and protein remain in the blood vessels. The glomerulus is composed of small capillaries, so that blood is under pressure Once the filtered substances are being collected by the Bowman’s capsule The filtrates passed into a twisted tubes called proximal convoluted tubules. This reabsorb about 65% of water, sodium, potassium and chloride, 100% of glucose, 100% amino acids, and 85-90% of bicarbonate. The filtrates now goes down to the Loop of Henle thru the descending limb and into the Distal tubule, where reabsorption takes place To the Distal tubule (ph regulator), where reabsorption takes place Only one % of the liquid filtered is Cells in the lining of actually excreted as the tubules are able urine and 99% is to absorb any water, absorbed glucose, salt, and ions which the body needs 2. Tubular Reabsorption Collection of urine in the tubular area, where it moves urine into the renal pelvis and ureters 3. Tubular Secretion Urine color generally ranges from a pale- yellow color to deep amber. This coloring is primarily caused by the pigment urochrome, also known as urobilin. Other Characteristics of Urine 1. In 24 hours, the kidneys filter 150 to 180 liters of blood plasma through the glomeruli into the tubules 2. Daily volume. In 24 hours, only about 1.0 to 1.8 liters of urine are produced. Why are fluids important to the body? It is vital since fluids maintain a proper balance of levels of salts, proteins, and all other components in the blood. What is the role of fluids in the body? Body fluids help regulate body temperature, helps in blood circulation, helps in digestion and keeping the skin moist. Fluids Found in our Body Other Body fluids Cerebrospinal Fluid Bile Feces Fluids found in the Eye Synovial fluid Lymph Rheum (discharges from the Sebum Urine eyes, nose, or mouth) Phlegm Chyme Functions of Body Fluids 1. Cell life. 2. Chemical and metabolic reactions 3. Transport of nutrients and removal of waste. 4. Body temperature regulation. What is the percentage of water in the human body according to age group?  Composition of fluid in the body fluid compartments Total Body water volume 40 Liters or 60% of body weight Intracellular Fluid Volume Extracellular Fluid Volume 25 Liters or 40% of body weight 15 Liters or 20% of Body Weight Plasma Volume 3 Liters of ECF Interstitial Fluid Volume 12 Liters or 80% of ECF Electrolytes found in the body Electrolytes are present for the balance which is essential for normal function of the cells and organs. The kidneys maintain the homeostasis by controlling the excretion of substances out of the body.  https://www.youtube.com/watch?v=BGtLQSfFQsA The Kidneys The Kidneys Systems Involved in Feedback Sense system deviations and send nerve impulses to appropriate organs. Uses the release and action of hormones Fluid Regulation and Balance https://www.youtube.com/watch?v=ezDJ1GSXl4s Normal Intake and Output An adult human at rest takes appropriately 2,500 ml of fluid daily. Daily output should approximately equal in intake. Fluid and Electrolyte Transport The ability of a membrane to allow molecules to pass through is known as permeability. Fluid and Electrolyte Transport The ability of a membrane to allow molecules to pass through is known as permeability. Freely permeable membranes. These membranes allow almost any food or waste substance to pass through. Selectively permeable. The cell membrane is selectively permeable, meaning that each cell’s membrane allows only certain specific substances to pass through. Filtration is the transport of water and dissolved materials concentration already exists in the cell. Active Transport moves ions from low concentration to high, using metabolic energy in the form of ATP. Passive Transport: Diffusion moves ions from high concentration to low, using no metabolic energy. Passive Transport: Osmosis is the movement of solvent particles from a solution that is diluted to a more concentrated one. ABG Interpretation pH CO2 HCO3 Interpretation Normal Respiratory Acidosis Normal Respiratory Alkalosis Normal Metabolic Acidosis Normal Metabolic Alkalosis  Arterial Blood Gas Is the patient’s pH Normal Range normal, acidotic or alkalotic? Acidotic: pH 7.45 Causes of acid/base disturbances Respiratory acidosis is caused by inadequate alveolar ventilation leading to CO2 retention. Causes of respiratory acidosis 1. Respiratory depression r/t opiates 2. Asthma Respiratory alkalosis is caused by excessive alveolar ventilation (hyperventilation) resulting in more CO2 than normal being exhaled. As a result, PaCO2 is reduced and pH increases causing alkalosis. Causes of respiratory alkalosis 1. Anxiety r/t panic attack 2. Severe pain Metabolic acidosis can occur as a result of either: 1. Increased acid production or acid ingestion 2. Decreased acid excretion / GI or renal HCO3 loss Metabolic alkalosis occurs as a result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations. To Simplify: Respiratory acidosis: low pH, high CO2 Respiratory alkalosis: high pH, low CO2 Metabolic acidosis: low pH, low HCO3- Metabolic alkalosis: high pH, high HCO3-  Compensated respiratory acidosis: normal pH, high CO2 Compensated metabolic acidosis: normal pH, low HCO3- Compensated respiratory alkalosis: normal pH, low CO2 Compensated metabolic alkalosis: normal pH, high HCO3-  Exercises ABG Interpretation Exercise Number 1: A 17-year-old patient complains of a tight feeling in their chest, shortness of breath and some tingling in their fingers and around their mouth. An ABG is performed on the patient who is not currently receiving any oxygen therapy. The ABG result shows the following: PaO2: 14 pH: 7.49 PaCO2: 3.6 HCO3-: 24 Answers! A PaO2 of 14 on air is at the upper limit of normal, so the patient is not hypoxic. A pH of 7.49 is higher than normal and therefore the patient is alkalotic. The next step is to figure out whether the respiratory system is contributing the alkalosis (e.g. ↓ CO2). The CO2 is low, which would be in keeping with an alkalosis, so we now know the respiratory system is definitely contributing to the alkalosis, if not the entire cause of it. The next step is to look at the HCO3– and see if it is also contributing to the alkalosis. HCO3– is normal, ruling out a mixed respiratory and metabolic alkalosis, leaving us with an isolated respiratory alkalosis. Exercise Number 2: An ABG result revealed the following: pH = 7.31 pCO2 = 51 HCO3 = 27 **** Respiratory acidosis Exercise Number 3: An ABG result revealed the following: pH = 7.39 pCO2 = 40 Interpretation: Normal ABG Buffer Mechanism https://www.youtube.com/watch?v=ouhAeCMcTUM Buffer solution is one which resists changes in pH in the body. The most important way of maintaining the pH of the blood is through buffers dissolved in blood