Term
| Parts of the Urinary System |
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Definition
| kidneys, ureters, urinary bladder, urethra |
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Term
| Functions of the Urinary System |
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Definition
| filter the blood, regulation of blood volume, synthesis of vitamin D, gluconeogenesis |
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Term
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Definition
| behind peritoneum on posterior abdominal wall, protected by lumbar vertebrae and rib cage, right kidney lower than left b/c of liver |
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Term
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Definition
| removal of toxins and excess ions from blood, regulation of blood volume, chemical composition, pH, renin (BP) and erythropoitin (RBCs) endocrine functions, activation of vitamin D |
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Term
| External anatomy of kidneys |
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Definition
Renal fascia (CT, anchors kidneys) --> perirenal fat (cushioning) --> renal capsule (fibrous CT)
Hilum (arteries and nerves enter) --> Renal Sinus (cavity) |
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Term
| Internal anatomy of kidneys |
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Definition
| cortex --> medulla --> renal pyramids --> renal papilla (apex) --> minor calyces --> major calyces --> renal pelvis --> ureter |
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Term
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Definition
| structural unit of kidney, includes renal corpuscle and renal tubule |
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Term
| Juxtamedullary vs Cortical Nephrons |
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Definition
| J - loops of henle extend much further into the medulla |
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Term
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Definition
Bowman's Capsule - parietal and visceral layers
Glomerulus - network of capillaries |
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Term
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Definition
| where blood enters the glomerulus |
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Term
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Definition
| where blood exits the glomerulus |
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Term
| Visceral layer of Bowman's capsule |
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Definition
| contains podocytes that wrap around the capillaries |
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Term
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Definition
| window like openings in the endothelium of glomerulus |
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Term
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Definition
| gaps between the processes of podocytes |
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Term
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Definition
| includes capillary endothelium, gel like basement membrane, and podocytes. Where the first stage of urine formation occurs by passing into the lumen |
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Term
| Juxtoaglomerular apparatus |
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Definition
| sight of renin production |
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Term
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Definition
| ring of smooth muscle around the vessels at the bowman's capsule that sense pressure |
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Term
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Definition
| specialized tubule cells of the distal tubule |
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Term
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Definition
Renal Corpuscle - glomerulus, bowman's capsule
Proximal tubule
Loop of Henle - descending and ascending limb
Distal tubule
Collecting Ducts |
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Term
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Definition
| Abdominal aorta --> renal arteries --> segmental arteries --> interlobar --> arcuate --> interlobular --> afferent arterioles |
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Term
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Definition
| form plexus around tubules |
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Term
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Definition
| part of peritubular capillaries that extend into the medulla with the loop of henle |
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Term
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Definition
| Interlobular --> arcuate --> interlobar --> renal |
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Term
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Definition
| blood plasma, water, small molecules, ions pass into the Bowman's capsule because of pressure |
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Term
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Definition
| 1% of total filtrate, 1-1.8L, contains wastes and unneeded substances |
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Term
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Definition
| entire plasma volume filtered 60x day |
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Term
| Mechanisms of Urine Formation |
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Definition
1. Glomerular filtration - movement of filtrate across filtration membrane into Bowman's capsule
2. Tubular reabsorption - returns glucose, amino acids, 99% water, and other components to blood
3. Tubular secretion - selective addition to urine |
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Term
| Glomerular Capillary Pressure |
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Definition
| BP inside capillary, highest type of pressure |
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Term
| Blood Colloid Osmotic Pressure |
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Definition
| osmotic pressure caused by proteins in blood, favors fluid movement into capillary |
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Term
| Capsule Hydrostatic Pressure |
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Definition
| pressure of filtrate already in the lumen |
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Term
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Definition
| causes low resistance to blood flow in afferent arterioles and glomerular capillaries, high resistance to BF in efferent arterioles |
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Term
| Autoregulation of glomerular filtration rate |
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Definition
| increased BP leads to increased BF past cells of macula densa signals the juxtaglomerular apparatus causing the afferent arteriole to constrict |
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Term
| Sympathetic regulation of GFR |
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Definition
| NE --> constriction of afferent arterioles --> decreased renal BF --> decreased filtrate formation (why you dont have to pee when exercising) |
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Term
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Definition
occurs as filtrate flows through the lumens of proximal tubule, loop of henle, distal tubule, and collecting ducts
Through diffusion, facilitated diffusion, active transport, symport, and osmosis |
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Term
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Definition
must pass through apical and basal membrane, active transport of Na into the cell, water moves by osmosis
Number of carrier molecules limits rate, affected by glucose
volume reduced by 65% by the end of PCT |
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Term
| Reabsorption in descending loop of Henle |
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Definition
highly permeable to water, moderately permeable to urea and Na
Reduces volume by 15% |
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Term
| Reabsorption in ascending loops of henle |
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Definition
| permeable to solutes which diffuse out, not permeable to water, Na transported into interstitial space, K and Cl symported, ions pass my facilitated diffusion |
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Term
| Reabsorption in DCT and collecting duct |
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Definition
| NA actively transported out, water moves by osmosis |
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Term
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Definition
| enters filtrate, only 40-60% reabsorbed, high in urine |
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Term
| Toxic substances in urine |
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Definition
| urate, creatine, sulfates, phosphates, nitrates |
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Term
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Definition
| produced by epithelial cells of nephron from deamination of amino acids. Eliminated in urine |
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Term
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Definition
| secreted into filtrate at proximal tubules |
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Term
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Definition
| secreted into filtrate at distal tubules |
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Term
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Definition
Na+ and other substances removed
Water follows passively reducing filtrate volume |
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Term
| Urine production in descending loop of Henle |
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Definition
Water exits passively, solute enters
Filtrate volume reduced 15% |
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Term
| Urine production in ascending loop on Henle |
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Definition
Na+, Cl-, K+ transported out of filtrate
Water remains |
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Term
| Urine production in DCT and collecting ducts |
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Definition
Na actively transported out to interstitial fluid
Water reabsorption regulated by ADH
If absent, water not reabsorbed and dilute urine produced
If ADH present, water moves out, concentrated urine produced |
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Term
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Definition
| Kidneys produce small volume of concentrated urine |
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Term
| When a lot of water is consumed |
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Definition
kidneys produce large volume of dilute urine
Total amounts of electrolytes lost not increased |
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Term
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Definition
Maintenance of high concentration of solutes in medulla
Control of permeability of distal nephron to water
Countercurrent functions of loops of Henle |
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Term
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Definition
Increased ECF osmolality stimulates OsmoRs in supraoptic nucleus ADH from posterior pituitary
Decreased stretch stimulation of baroRs in atria, large veins, carotid sinus, aortic arch sensory afferents to SON ADH from post pit
ADH triggers reabsorption of H2O in the distal tubules and collecting ducts by insertion of aquaporins into tubule cell membrane
99% of H2O in filtrate is reabsorbed. |
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Term
| Renin/Angiotensin/Aldosterone Mechanism |
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Definition
Decreased stretch of afferent arteriole (dt decreased BP)
chemoreceptors in Macula Densa senses decreased [Na]filtrate
Renin secr’n from juxtaglomerular apparatus
Renin converts angiotensinogen to angiotensin I ---> angiotensin II BP + aldosterone secrt’n.
Aldosterone thirst sensation, salt appetite, and ADH secretion
Aldosterone increases transport proteins for Na+ in nephron tubules Na+ and water reabsorption concentrates urine
stretch of afferent arteriole (i.e., increased BP, or [Na] filtrate decreases Renin |
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Term
| Atrial natriuretic hormone |
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Definition
Increased blood volume stimulates stretchRs in Rt atrium release of ANH
Inhibits Na+ reabsorption
Inhibits ADH production
Increases volume of urine produced
Venous return is lowered, volume in right atrium decreases, BP decreased |
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Term
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Definition
Chemicals that increases urinary output
Osmotic diuretics: substances not reabsorbed, (e.g., high glucose in diabetics)
ADH inhibitors such as alcohol
Substances that inhibit Na+ (and therefore H2O) reabsorption such as caffeine |
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Term
| Glomerular Filtration Rate |
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Definition
Volume of plasma filtered per unit time
Estimated using plasma clearance: Volume of plasma cleared of a specific (test) substance each minute |
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Term
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Definition
| volume of blood delivered to kidneys |
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Term
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Definition
| Total amount of substances that passes through filtration membrane into nephrons each minute |
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Term
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Definition
Max rate at which a substance is reabsorbed
Each substance has its own |
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Term
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Definition
| tubular load exceeds tubular maximum and glucose appears in urine. Urine volume increases because glucose in filtrate increases osmolality of filtrate reducing the effectiveness of water reabsorption |
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Term
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Definition
BP at afferent arteriole moves plasma thru glomerulus
Hydrostatic pressure forces urine from bowman’s capsule (10mmHg) through nephron (0mmHg)
Peristaltic contractions of sm muscles around ureters move urine through ureters to urinary bladder
Ureters enter bladder obliquely through trigone. Pressure in bladder compresses ureter and prevents backflow |
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Term
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Definition
| interior of urinary bladder. Triangular area between the entry of the two ureters and the exit of the urethra. Area expands less than rest of bladder during filling |
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Term
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Definition
| muscle part of bladder wall is a thick layer of sm muscle |
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Term
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Definition
| extends from the inferior part of the urinary bladder through the penis and carries semen and urine |
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Term
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Definition
| shorter; opens into vestibule anterior to vaginal opening |
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Term
| Internal Urinary Sphincter |
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Definition
| Sm muscles. in males, keep semen from entering urinary bladder during ejaculation. No fxn’l equiv in females |
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Term
| External Urinary Sphincter |
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Definition
| skeletal muscle surrounds urethra as it extends through pelvic floor. Acts as a valve. Ctrls the flow of urine |
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Term
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Definition
Urination or voiding
Filling of bladder is continuous; elimination is controlled
When bladder is full, stretched
sensory afferents sacral spinal cord
info to pons and cerebrum urge to urinate
reflexive contraction of sm muscles of bladder
reflexive relx’n of skeletal muscles
urinate
Cerebrum and pons can override temporarily
These higher control centers mature between ages 2 and 3 |
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Term
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Definition
Kidney stones
form in renal pelvis:
Crystallized calcium, magnesium, or uric acid salts
Large stones can block ureter; cause pressure and pain in kidneys
May be due to chronic bacterial infection, urine retention, Ca2+ in blood, pH of urine
Treated by surgery or shockwave therapy
Prevention by adding acidic foods and drinks to diet (cranberry juice) |
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Term
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Definition
| excessive intake of sugary foods, diabetes mellitus |
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Term
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Definition
| ketone bodies, as in starvation and untreated DM |
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Term
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Definition
| transfusion reaction, hemolytic anemia |
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Term
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Definition
| high-protein diet, renal disease |
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Term
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Definition
Absence of ADH stimulation
Central or nephrogenic
Symptoms:
Polyuria: excessive production of urine
( 15L /day)
Extreme thirst
Treatment:
Low Na+ diet
Synthetic vasopressin |
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