Module 8: The Urinary System

Describe the process of Hemodialysis.

"artificial kidney" to filter blood. 1. blood delivery system, 2. dialyzer, 3. dialysis fluid delivery system. Blood circulates through dialyzer composed of bundles of capillary tubes. Dialysate moves on the outside of the tubes. Molecules (except blood and plasma) can move in both direction. Waste will diffuse into dialysate. Blood flows from patients artery through blood chamber in dialysis machine to be filtered and check into patient

What is the norm value for the GFR? Discuss why maintenance of this value is important.

120-125 mL/min or 180 mL a day. Maintenance is important for adequate reabsorption of water and other nutrients from the filtrate.;

List the 3 regulatory mechanisms of the GFR.

Auto regulation, nervous system, hormonal control

What blood values are closely monitored in renal failure?

BUN and creatinine

Be familiar with hypokalemia pathology, clinical presentation, and treatment.

CP: They include nausea, vomiting, constipation, and abdominal distention. The most serious effects occur when the cardiovascular system is affected. Postural hypotension, bradycardia, and ectopic ventricular arrhythmias may result. Diagnosis and treatment: If possible, treatment of hypokalemia is simply to increase dietary intake of potassium. Potassium may also be given intravenously if rapid replacement is necessary.

Define hypocalcemia using blood values

Ca2+ levels falling below 8.5 mg/dL

Be able to list and describe the 4 types of kidney stones.

Calcium stones: increased conc. of calcium in blood and urine; second to increased bone resorption assoc. with immobility, bone disease, hyperparathyroidism Magnesium ammonium phosphate stones: form in alkaline urine. Incr. in pH result of UTI caused by urease enzyme=breaks urea into ammonia and CO2 Uric acid stone: Acidic urine. not visible on x ray Cystine stone: children, result from cystinuria=when there is a decrease in tubular absorption of cystine.;

What are the 3 mechanisms of control for blood pH.

Chemical buffer systems, brainstem respiratory center, renal system;

Describe the location of the hilus and its significance.

Concave cleft where ureters, blood vessels, and nerves enter the kidney

Explain the difference between cortical nephrons and juxtamedullary nephrons.

Cortical nephrons make up 85% of all nephrons. They originate superficially in the cortex and have shorter loops of Henle that extend only a short distance into the medulla. Juxtamedullary nephrons make up the remaining 15% of all nephrons. They originate deeper in the cortex, and their loops of Henle are thinner and extend into the medulla entirely

Be familiar with various diagnostic tests and treatments for renal Calculi.

Diagnostic test: urinalysis, xray, ct scan(most often), ICP, ultrasound. Treatments: Pain management, antibiotic therapy (if UTI). Treatments: Increased fluid intake, decrease stone forming food. Ureteroscopic removal: probe inserted into ureter; Percutaneous nephrolithotomy: needle inserted into collecting system

Name two specialized structures of the glomerular capillaries that contribute to the filtration of blood.

Fenestrations and podocytes

What are the 3 processes involved in urine formation? Describe where they occur.

Filtration (renal corpuscle), reabsorption, and secretion (renal tubules)

Name the structures of the nephron and describe their individual functions.

Glomerular capsule (renal corpuscle) and renal tubule. They are connected through the tubule to the associated collecting ducts. Glomerular capsule filters blood Renal tubule reabsorbs needed materials, collecting ducts carry remaining material away as urine to be excreted.

Be familiar with hypermagnesemia pathology, clinical presentation, and treatment.

Hypermagnesemia: Mg above 3.0 mg/dL. P: due to renal insufficiency or disease or overconsumption of Mg, CP: Diminish neuromuscular functions; hyporeflexia, muscular weakness, confusion, BP decrease, (sev cases)=respiratory paralysis, heart block, cardiac arrest T: Intravenous admin of Ca to inhibit effects of Mg. Peritoneal or hemodialysis

What are the 2 types of Acute Tubular nephrosis (ATN)?

Ischemic and Nephrotoxic

Describe the functions of the nephron

It could control concentration of water and soluble materials by filtering the blood, reabsorbing needed materials and excreting waste products as urine. It Eliminates wastes from the body, regulates blood volume, pH and pressure, and controls the levels of electrolytes

Define hypomagnesemia using blood values.

Mg2+ concentration levels is less than 1.8 mg/dL

Explain the differences in the two systems providing the blood supply to the nephron. How does their structure determine their role?

Nephrons receive their blood supply from 2 systems known as the glomerulus and peritubular capillary network. The glomerulus is a unique system in that it is located between 2 arterioles, afferent and efferent. Arterioles are high resistance vessels resulting in an extremely high-pressure system which can easily force fluid and solutes out of the blood into the glomerular capillary along its entire length. The peritubular capillaries are low-pressure vessels better suited for reabsorption as opposed to filtration. These capillaries surround the tubules in their entirety allowing rapid movement of solutes and water.

Be familiar hypomagnesemia pathology, clinical presentation, and treatment.

P: Occurs when plasma Mg2+ concentration is less than 1.8 mg/dL. Decreased Mg2+ levels can result from conditions of malnutrition and starvation. Diarrhea can decrease intestinal absorption of Mg2+.Cause=alcoholism CP: personality changes, tremors, tachycardia, hypertension, ventricular dysrhythmias. (happens with hypocalcemia and hypokalemia) T: Replacement therapy

Be familiar with hyponatremia pathology, clinical presentation, and treatment.

Pathology: Hyponatremia can present as hypertonic or hypotonic. Hypertonic hyponatremia occurs when water shifts from the intracellular fluid (ICF) to the extracellular fluid (ECF.) Hypotonic hyponatremia is the most common type of hyponatremia and is caused by water retention. It CP: Hyponatremia causes an increase in intracellular water levels because of abnormal flow. Early signs of hyponatremia include muscle cramps, weakness, and fatigue. Nausea, vomiting, abdominal cramping, and diarrhea may develop Diagnosis and Treatment: Diagnosis of hyponatremia blood work and urinalysis to determine sodium concentration within the body. Treatment will focus on the underlying cause. If the cause is water intoxication, limiting fluids and possibly changing medications that contribute to the condition may be enough. The administration of saline solution (orally or intravenously) may be indicated if the underlying cause is a sodium deficiency.

Be familiar with hypernatremia pathology, clinical presentation, and treatment.

Pathology: It is characterized by a deficit of water in relation to the body's Na+ stores. It can be caused by net water loss or sodium gain. Hypernatremia typically follows a loss of bodily fluids that contain a decreased concentration of Na+, an example being diarrhea CP: water loss with thirst, decrease in urine output, a rise in body temperature, and the skin becoming flushed Diagnosis and Treatment: Diagnosis of hypernatremia is made based upon physical exam findings indicative of dehydration and blood work. Treatment for hypernatremia includes treating the underlying cause and replenishing fluids orally or intravenously.

Be familiar with hyperkalemia pathology, clinical presentation, and treatment.

Pathology: The cause of hyperkalemia is one of the following: (1) decreased renal excretion, (2) excessively rapid administration, and (3) movement of K+ from the ICF to the ECF compartment CP: Generalized muscle weakness and dyspnea (shortness of breath) are among the first symptoms to be reported. Life threatening effects occur when the heart is involved. If plasma K+ levels rise too rapidly, ventricular fibrillation and cardiac arrest may occur.

Be familiar with hypercalcemia pathology, clinical presentation, and treatment.

Pathology: The two most common causes of hypercalcemia are increased bone resorption of Ca2+ due to neoplastic activity and hyperparathyroidism. CP: Cardiac effects include increased contractility and ventricular arrhythmias. GI symptoms include constipation, nausea, and vomiting secondary to a decrease in smooth muscle activity. Treatment: rehydration paired with measure to increase excretion of calcium in the urine. Fluid replacement is utilized in cases of volume depletion. Once the ECF volume has been restored, diuretics and NaCl can be utilized to increase urinary excretion of calcium.

Define hypokalemia using blood values.

Plasma K+ levels fall below 3.5 mEq/L.

What are the 3 categories of acute renal failure?

Prerenal: due to blood loss or decrease blood flow Intrarenal: "acute kidney injury" conditions that damage structures within the kidney. Postrenal: outflow of urine from kidney is blocked (stones, tumor, enlarged prostate)

List the 4 segments of the nephron tubule.

Proximal convoluted tubule (highly coiled) which drains Bowman capsule, Loop of Henle, Distal convoluted tubule, Collecting tubule which joins with other nephron tubules to collect the filtrate

Describe the differences between renal-colic pain and non-colicky pain.

Renal-colic pain: type of pain you get when urinary stones block part of your urinary tract. Your urinary tract includes your kidneys, ureters, bladder, and urethra. It could cause acute sharp pain in upper lateral quadrant. Non-colicky pain: deep, dull ache due to urinary stones blocking the flow of the renal pelvis and renal calyces

List 3 ways that the kidney acts as an endocrine organ.

Renin-Angiotensin-Aldosterone RAA, through regulation of red blood cell production through the formation of erythropoietin, calcium metabolism by the activation of vitamin D

Be familiar with hypocalcemia pathology, clinical presentation, and treatment.

The causes of hypocalcemia can be divided into 4 categories: (1) impaired ability to draw calcium from bone stores, (2) abnormal losses of Ca2+ from the kidneys, (3) increased protein binding leading to greater amounts of Ca2+ in its non-ionized form, and (4) soft tissue sequestration CP: patients may experience paresthesias (tingling around the mouth and in the hands and feet) and tetany (continuous muscle spasms.) Severe cases can lead to seizures and death. Treatment: Acute hypocalcemia is treated as emergent. Calcium is infused intravenously (i.e. calcium gluconate or calcium chloride) when any of the acute symptoms described above are present. Chronic hypocalcemia is treated with oral supplementation.

Compare and contrast the renal cortex and renal medulla. Discuss the structures found in each.

The outer cortex houses the glomeruli and convoluted tubules (proximal and distal) of the nephron as well as blood vessels. The inner medulla is comprised of the Loop of Henle of the nephron and cone-shaped masses also known as the renal pyramids.

Describe the action of ADH.

acts on the collecting tubule to increase water absorption; inhibits urine output by increasing number of water channels in the cell membrane of the collecting ducts.

What are the determinants of transplantation success?

depends on patient overall health, degree of compatibility between donor and patient and management of recipient immunosuppression.

What are the 3 phases of ATN?

initiating phase, maintenance phase, and tubular repair

Discuss risk factors for the formation of renal calculi (kidney stones)

levels of stone components in blood and urine, anatomical changes of urinary tract structures, metabolic and endocrine function, dietary and intestinal absorption, UTI history

Define hypercalcemia using blood values.

plasma Ca2+ levels are greater than 10.5 mg/dL.

Define hyperkalemia using blood values.

plasma K+ levels rise above 5 mEq/L.

Define hyponatremia using blood values

plasma sodium concentration below 135 milliequivalents/L,

Define hypernatremia using blood values.

plasma sodium levels above 145 milliequivalents/L

Describe the action of Aldosterone.

promotes reabsorption of sodium and water into the body, which helps in maintaining blood pressure.

Be familiar with the RAA system and Figure 8.4

responds when the blood pressure drops too low. When bp drops, renin is released by juxtaglomerular cells of the nephron. Renin causes constriction of afferent and efferent arterioles and converts angiotensinogen to angiotensin I. Angiotensin I is converted (in the lungs) to angiotensin II. Angiotensin II increases vasoconstriction which in turn increases peripheral blood pressure. When circulating angiotensin II reaches the adrenal cortex, it causes the release of aldosterone. Aldosterone increases the reabsorption of sodium and water from the filtrate;

Describe the process of peritoneal dialysis.

serious membrane of peritoneal cavity is the dialyzing membrane. Sterile dialyzing solution is run through catheter in subcutaneous tissue for 10min. Fluid remains for certain amt. of time and then drained into bag. Done in clinic or at home. Infection risk at catheter exit site;

What are the common causes of acute postinfectious glomerulonephritis?

strep/staph bacterial infections, hepatitis and parasitic infections.;