Chapter 26 The Urinary System

Nephrology/Urinary System CHAPTER 26: THE URINARY SYSTEM FUNCTIONS OF THE URINARY SYSTEM: 1. Regulate blood volume and blood pressure 2. Regulate plasma concentration of certain ions 3. Conserve valuable nutrients 4. Help stabilize blood pH 5. Eliminate organic waste products 6. Pregulate concentrations of electrolytes ORGANS OF THE URINARY SYSTEM: 1. Kidney 2. Urinary bladder 3. Ureter 4. Urethra AGING: 1. 2. 3. 4. 5. A decline in the number of functional nephrons A reduction in the GFR Problems with the micturition reflex Loss of sphincter muscle tone NOT increased sensitivity to ADH THE URETHRA: 1. Where the function of elimination occurs 2. Carries urine from the bladder to the outside of the body THE URETERS: 1. Carries urine to the urinary bladder 2. The expanded beginning of the ureter connects to the renal pelvis. 3. Lined by transitional epithelium THE URINARY BLADDER: 1. Urine is temporarily stored here 2. When the bladder is full, urine is eliminated through the process of micturition 3. Lined by transitional epithelium 4. The pontine storage center controls micturition by increasing contraction of the external urethral sphincter and reducing detrusor muscle activity. MICTURITION: 1. When you relax the external urethral sphincter, the internal sphincter will relax 2. Urination will be completed despite voluntary opposition 3. Parasympathetic nervous control is involved with the micturition reflex 4. Bladder contraction can force open the internal urethral sphincter 5. NOT stretch receptors in the bladder are stimulated by the warm temp. of the urine TRIGONE: 1. The area of the urinary bladder bounded by the openings of the two ureters and the urethra KIDNEYS: 1. Control of hydrogen ion and pH in the blood 2. Control of wastes in the blood 3. Regulation of blood pressure 4. Maintenance of various blood ion concentrations 5. Perform the excretory functions of the urinary system 6. Located in a position that is retroperitoneal 7. Surrounded by a fibrous capsule 8. Held in place by the renal fascia 9. Covered by the peritoneum 10. Renal blood flow: typically, 1200 ml/min under resting conditions 11. Each kidney has about 1.25 million nephrons 12. Renal threshold for glucose is approx. 180 mg/dl 13. Increased levels aldosterone secretion of urine with lower concentration of sodium ions URINE: 1. Constitutes: a. Hydrogen ions b. Urea c. Amino acids d. Creatinine e. NOT large proteins 2. Urine = substances filtered – substances reabsorbed + substance secreted RENAL THRESHOLD: 1. For glucose: approx. 180 mg/dl 2. The plasma concentration at which a specific compound will begin appearing in the urine. HILUM: 1. The prominent indentation on the medial surface of the kidney GLOMERULUS: 1. A knot of capillaries within the renal corpuscle 2. Glomerular blood flow is unique because it flows from arteriole to capillary bed to arteriole 3. Glomerular filtration rate: the amount of filtrate produced by the kidneys each minute 4. Approximately 180 liters of glomerular filtrate enter the glomerular capsules each day 5. Glomerular pressure depends on (1,2, and 4) a. Glomerular hydrostatic pressure i. The main force that causes filtration in a nephron b. Capsular hydrostatic pressure c. Blood colloid osmotic pressure i. Blood colloid osmotic pressure in the glomerulus is generated by the presence of albumin proteins in blood plasma 6. Filtration pressure of the glomerulus = glomerular hydrostatic pressure – (capsular hydrostatic pressure + colloid osmotic pressure) 7. damage to the glomerular filtration membrane allowing proteins into the capsular space would result in: a. an increase in capsular colloid osmotic pressure b. a decrease in blood colloid osmotic pressure c. an increase in net filtration pressure d. an increase in GFR and fluid loss e. NOT a decrease in capsular hydrostatic pressure 8. The creatinine clearance test is often used to estimate the glomerular filtration rate. 9. Located in the renal cortex RENAL SINUS: 1. An internal cavity lined by the fibrous capsule RENAL PELVIS: 1. The cavity of the kidney that receives urine from the calyces RENAL CORPUSCLE: 1. Consists of the Glomerular (Bowman’s) capsule and the glomerulus 2. Where the filtration of plasma takes place PODOCYTES: 1. In the renal corpuscle, the visceral layer of specialized cells FIBROUS CAPSULE: 1. The outermost layer of the kidneys EFFERENT ARTERIOLE: 1. Blood leaves the glomerulus through a blood this blood vessel 2. The efferent arteriole of a nephron divides to form a network of capillaries within the cortex called the peritubular capillaries. AFFERENT ARTERIOLE: 1. Juxtaglomerular cells: modified smooth muscle cells located here that secrete renin PAPILLARY DUCT: 1. Delivers urine to the minor calyx DISTAL CONVOLUTED TUBULE: 1. Includes the region known as the macula densa 2. The portion of the nephron that empties into the collecting duct PROXIMAL CONVOLUTED TUBULE: 1. Filtrate passes to here from the glomerular capsule 2. The primary function is to reabsorb ions, organic molecules, vitamins, and water. 3. Cells are cuboidal with microvilli 4. Where the majority of water is reabsorbed by osmosis RENAL PAPILLA: 1. The tip of the medullary pyramid DETRUSER MUSCLE: 1. Compresses the urinary bladder and expels urine through the urethra ACE INHIBITORS LEAD TO: 1. less secretion of aldosterone 2. increased urinary loss of sodium 3. reduction of blood pressure 4. decreased sodium reabsorption 5. NOT increased fluid retention DIURETICS: 1. Used for: a. Reducing body weight b. Reducing water retention c. Reducing blood pressure d. Treating congestive heart failure e. NOT to reduce glucose levels ORDER OF BLOOD FLOW THROUGH THE VESSELS THAT CARRY BLOOD TO THE KIDNEY: (4,3,2,6,1,5,7,8) 1. Segmental artery 2. Interlobar artery 3. Arcuateartery 4. Cortical radiate artery 5. Afferent arteriole 6. Glomerulus 7. Efferent arteriole FILTRATION BARRIER IN THE RENAL CORPUSCLE CONSISTS OF: 1. Fenestrated endothelium of glomerulus 2. Basement membrane of glomerulus 3. Podocyte filtration slits ORDER OF FILTRATION THROUGH THE STRUCTURES OF THE RENAL CORPUSCLE: (4312) 1. Fenestrated epithelium 2. Basement membrane 3. Filtration slit (slit pore) 4. Capsular space JUXTUGLOMERULAR COMPLEX CONSISTS OF: 1. The cells of the macula densa 2. The juxtaglomerular cells 3. The extraglomerular mesangial cells JUXTAGLOMERULAR COMPLEX: 1. An important structure for blood pressure regulation 2. An increase in secretion of renin by the juxtaglomerular complex will raise systemic blood pressure PERITUBULAR CAPILLARIES: 1. Capillaries that surround the proximal convoluted tubules RENAL COLUMNS: 1. Bundles of tissue that extend between pyramids from the cortex MAJOR CALYCES: 1. Large branches of the renal pelvis RENAL CORTEX: 1. 80% of nephrons in the human kidney are located here and have short nephron loops. 2. Where the majority of glomeruli are located in the kidney RENAL TUBULES: 1. When filtrate passes through, approx. 99% is reabsorbed and returned to the circulation. JUXTAMEDULLARY NEPHRONS: 1. Nephrons located close to the medulla with long nephron loops NEPHRON LOOP: 1. Structure that connects the proximal convoluted tubule to the distal convoluted tubule VASA RECTA: 1. A capillary bed that parallels the nephron loop (loop of Henle) SUBSTANCES THAT ARE FILTERED BY THE KIDNEYS: 1. Glucose 2. Water 3. Amino acids 4. Fatty acids COLLECTING DUCTS: 1. Component of the nephron that is largely confined to the renal medulla 2. The region of the nephron containing intercalated cells primarily associated with pH balance SYMPATHETIC NERVOUS SYSTEM: 1. A majority of renal innervation 2. Sympathetic stimulation of the kidney can: a. Produce powerful vasoconstriction of the afferent arterioles b. Trigger renin release c. Produce renal ischemia d. Reduce blood flow to kidneys e. CAN NOT increase the glomerular filtration rate NEPHRONS: 1. The functional units where blood is filtered, and urine is produced PERITUBULAR FLUID: 1. Reabsorbed water and solutes enter here UREA: 1. The most abundant organic waste WOULD RESULT IN AN INCREASE IN RENIN RELEASE: 1. Decreased blood pressure at the glomerulus 2. Blockage in the renal artery 3. Stimulation of juxtaglomerular cells 4. Decreased osmotic concentration at the macula densa 5. NOT increased blood volume SECRETION: 1. The process that transports solutes including many drugs, into the tubular fluid 2. One mechanism the kidney uses to raise systemic blood pressure, increase secretion of renin by the juxtaglomerular complex. FILTRATION: 1. Driven mainly by blood hydrostatic pressure 2. Substances larger than albumin are normally not allowed to pass through the filtration membrane TUBULAR REABSORPTION: 1. Involves: a. Active transport b. Facilitated diffusion c. Cotransport d. Countertransport e. NOT stem cell movements FACILIATED DIFFUSION: 1. Involves a carrier protein that can transport a molecule across the cell membrane down its concentration gradient. ACTIVE TRANSPORT: 1. Transport mechanism that can move a substance against a concentration gradient by using cellular energy TUBULAR MAXIMUM: 1. The concentration at which all of the carriers in renal tubules for a given substance are saturated. COTRANSPORT: 1. How reabsorption of filtered glucose from the lumen in the PCT is largely done. 2. Chloride ion is reabsorbed in the thick ascending limb by cotransport with Na and K ions. 3. Two substances are moved across a cell membrane in the same direction without directly using cellular energy. One of the substances can be moved against a concentration gradient by this process COUNTERTRANSPORT: 1. Secretion of hydrogen ion by the PCT is by this process. WHAT OCCURS IN THE COUNTERCURRENT MULTIPLIER PROCESS? 1. A higher sodium concentration is produced in the renal medulla that osmotically draws out water, reducing it within the tubules and the urine 2. The thin limb of the nephron loop is permeable to water 3. The thick limb of the nephron loop is permeable to solutes 4. Tubule fluid arrives at the DCT at about 100 mOsm/L 5. The maximum solute concentration is about 1200 mOsm/L ANTIDIURETIC HORMONE: 1. Increases the permeability of the collecting ducts to water. 2. When it decreases: a. the osmolarity of the urine decreases CONCENTRATED URINE: 1. The ability to form: a. Nephron loop b. Distal convoluted tubule c. Collecting duct 2. Mechanism involves: a. Secretion of antidiuretic hormone (ADH) by the posterior pituitary gland b. Aquaporins being inserted into the membranes of the collecting duct cells c. A high concentration of NaCl in the interstitial fluid that surrounds the collecting ducts. d. An increase in facultative water absorption e. NOT obligatory water reabsorption in the proximal convoluted tubule. AUTOREGULATION: 1. Immediate local responses of the kidney to changes in blood flow to maintain GFR occur through this PYELOGRAM: 1. Test for constant pain and discomfort in the low back area CONDITIONS: 1. Floating kidney: an especially dangerous condition because the ureters or renal blood vessels can become twisted or kinked during movement 2. Glomerulonephritis: an inflammatory disorder of the glomeruli that affects the filtration mechanism of the kidneys. a. May occur as a consequence of an infection with streptococcus. b. Lupus is a condition that makes you susceptible to this c. Polycystic Kidney Disease: is an inherited abnormality that affects the development and structure of kidney tubules. 3. Prolonged aldosterone stimulation of the distal convoluted tubule may result in hypocalcemia 4. a patient excretes a large volume of very dilute urine on a continuing basis. This may be due to absence of ADH. 5. if a urine sample is distinctly yellow in color a. it will contain large amounts of urobilin 6. excess release of natriuretic peptides would cause a large volume of dilute urine 7. the inability of the kidneys to excrete adequately to maintain homeostasis is renal failure 8. insoluble deposits that form within the urinary tract from calcium salts, magnesium salts, or uric acid are called kidney stones or renal canculi. 9. Primary symptom of prostatitis dribbling urination RANDOM UNCATEGORIZED: 1. Majority of cotransporters and countertransporters are linked to the reabsorption of sodium 2. Aldosterone-sensitive portions of the distal convoluted tubule and collecting duct allow for the exchange of reabsorption of sodium ions in exchange for potassium ions 3. ADH creates a (small or large) volume of (dilute or concentrated) urine. a. Small; concentrated