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167 Cards in this Set
- Front
- Back
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Where do cells continuously export their metabolic wastes? |
Into extracellular fluid. |
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What happens to other byproducts of cellular metabolism? |
They travel in the arterial (oxygenated) blood to the renal artery and into the kidneys. |
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The hormone EPO, which regulates RBC production is produced where? |
In the peritubular capillary endothelial cell in the kidney and liver. |
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What is the renal artery? |
A large branch of the abdominal aorta, brings blood into the kidney for filtering. |
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The urinary tract? |
Is the part of the urinary system from the top of the ureter to the external urethral opening- the route of urine out of the body. |
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The ureters? |
Are tubes that transport the urine from a kidney to the bladder. The ureter emerges from the renal pelvis. |
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The mucosa of the bladder is made up of what kind of epithelial tissue? |
Transitional epithelium in which the cells can change shape from columnar to squamous to accommodate larger volumes of urine. |
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What protects the epithelium of the urethra from corrosive urine? |
Mucus from small glands in the mucosa. |
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The internal urethral sphincter is made up of what? |
Smooth muscle and is under the control of the autonomic nervous system. |
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The renal corpuscle consists of the ________ and ________.
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The glomerulus, and glomerular (Bowman's) capsule. |
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Discharge of urine from the urinary bladder is called ________.
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Micturition |
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What is glomerular filtration rate directly related to? |
The pressures that determine net filtration pressure. |
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What hormones help regulate GFR? |
Glomerular filtration rate is regulated by angiotensin II and atrial natriuretic peptide. |
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How do the mechanisms of the urinary system regulate GFR work? |
By adjusting blood flow into and out of the glomerulus and by altering the glomerular capillary surface area available for filtration. |
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What happens to GFR when systemic blood pressure rises? |
Normally it increases very little. |
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What hormones affect Na+, Cl-, Ca2+, and water reabsorption, and/or K+ secretion by the renal tubules? |
Angiotension II Aldosterone ADH Atrial natriuretic peptide Parathyroid hormone |
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What features of the renal corpuscle enhance its filtering capacity? |
1) Large glomerular 2) High glomerular capillary pressure 3) Mesangial cells regulating the filtering surface area. |
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How does the micturition reflex work? |
1) Relies on parasympathetic impulses from micturition centre in S2 and S3. 2) Results in contraction of the detrusor muscle. 5) Inhibits motor neurons in the external urethral sphincter. |
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What are some of the mechanisms that control GFR? |
1) Renal autoregulation 2) Neural regulation 3) Hormonal regulation |
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The route of blood flow through the kidney? |
Renal artery, segmental arteries, interlobar arteries, arcuate arteries, interlobular arteries, afferent arterioles, glomeruli, efferent arterioles, peritubular capillaries, vasa recta, peritubular venules, interlobular veins, arcuate veins, interlobar veins, renal vein. |
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The route of filtrate flow? |
Proximal convoluted tubule, descending limb of loop of Henle, ascending limb of loop of Henle, distal convoluted tubule, collecting duct, papillary duct, minor calyx, major calyx, renal pelvis. |
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Cells in the last portion of the distal convoluted tubule and in the collecting ducts. Regulated by ADH and aldosterone. |
What are principal cells? |
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A capillary network lying in the glomerular capsule and functioning in filtration. |
What is the glomerulus? |
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The functional unit of the kidney. |
What is the nephron? |
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Drains into a collecting duct. |
What is the distal convoluted tubule? |
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Combined glomerulus and glomerular capsule; where plasma is filtered. |
What is the renal corpuscle? |
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The visceral layer of the glomerular capsule consisting modified simple squamous epithelial cells. |
What is the podocytes? |
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Cells of the final portion of the ascending limb of the loop of Henle that make contact with the afferent arteriole. |
What is the macula densa? |
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Site of obligatory water reabsorption. |
What is the proximal convoluted tubule? |
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Pores in the glomerular endothelial cells that allow filtration of blood solutes but not blood cells and platelets. |
What are fenestration's? |
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Can secrete H+ against a concentration gradient. |
What are intercalated cells? |
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Modified smooth muscle cells in the wall of the afferent arteriole. |
What are juxtaglomerular cells? |
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Measure of blood nitrogen resulting from the catabolism and deamination of amino acids. |
What is the BUN test? |
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Produced from the catabolism of creatine phosphate in skeletal muscle. |
What is plasma creatinine? |
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Volume of blood that is cleared of a substance per unit of time. |
What is renal plasma clearance? |
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Can result from diabetes mellitus. |
What is glucosuria? |
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Insoluble stone of crystallized salts. |
What are renal calculi? |
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Usually indicates a pathological condition. |
What is hematuria? |
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Lack of voluntary control of micturition. |
What is incontinence? |
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Can be caused by damage to the filtration membranes. |
What is albuminuria? |
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Membrane proteins that function as water channels. |
What are aquaporins? |
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A secondary active transport process that achieves Na+ reabsorption, returns filtered HC03 and water to the peritubular capillaries, and secretes H+. |
What are Na+/H+ antiporters? |
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Stimulates principal cells to secrete more K+ into tubular fluid and reabsorb more Na+ and Cl- from tubular fluid. |
What is aldosterone? |
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Enzyme secreted by juxtaglomerular cells. |
What is renin? |
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Reduces glomerular filtration rate; increases blood volume and pressure. |
What is angiotensin II? |
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Inhibits Na+ and H20 reabsorption in the proximal convoluted tubules and collecting ducts. |
What is atrial natriuretic peptide? |
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Regulates facultative water reabsorption by increasing the water permeability of principal cells in the distal convoluted tubules and collecting ducts. |
What is ADH? |
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Reabsorb Na+ together with a variety of other solutes. |
What are Na+ symporters? |
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Stimulates cells in the distal convoluted tubule to reabsorb more calcium into the blood. |
What is parathyroid hormone? |
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Kidneys help control blood pressure by the secretion of? |
Renin |
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One of the functions of the kidneys is to? |
Regulate blood ionic composition. |
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The kidneys secrete the hormone erythropoietin, which functions to? |
Control the rate of RBC production. |
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The renal capsule? |
- Is a sheet of dense irregular connective tissue - Serves a barrier against trauma - Helps maintain the shape of the kidney |
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What are the 2 main parts of the nephron? |
The renal corpuscle and the renal tubule. |
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The juxtaglomerular apparatus consists partially of what? |
The juxtaglomerular cells of an afferent arteriole. |
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What can be found in the renal cortex? |
Distal convoluted tubules. |
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The renal pelvis? |
Drains into the ureter. |
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The outer layer of the three layers of tissue that surround the kidney is? |
The renal fascia. |
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The innermost layer of the three layers of tissue that protect the kidney is? |
The renal capsule |
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The renal papillae contain papillary ducts which empty into the? |
Minor calyces |
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What is the pathway of fluid through a juxatmedullary nephron? |
Proximal convoluted tubule, descending loop of Henle, ascending loop of Henle, distal convoluted tubule. |
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The visceral layer of Bowman's capsule is covered with specialized cells called? |
Podocytes |
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Renal blood pressure remains fairly constant due to the function of? |
The juxtaglomerular apparatus |
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In cortical nephrons, the renal corpuscle lies? |
In the outer portion of the renal cortex |
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The proximal convoluted tubule is made up of? |
Cuboidal cells with many microvilli |
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Function? |
Adipose capsule: Protect kidney from trauma and hold it firmly in place within the abdominal cavity. |
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Cortical nephron |
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Constitute the juxtaglomerular apparatus |
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Juxtamedullary nephron: Enables the kidney to excrete very dilute or very concentrated urine. |
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How are cortical nephrons different? |
Cortical nephrons have glomeruli in the superficial renal cortex, and their short loops of Henle penetrate only into the superficial renal medulla. |
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How are juxtamedullary nephrons different? |
Have glomeruli deep in the renal cortex, and their long loops of Henle extend through the renal medulla nearly to the renal papilla. |
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What does tubular reabsorption do vs tubular secretion? |
Selectively removes material from the tubular fluid and returns to the blood while tubular secretion removes material from the blood. |
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If the urinary excretion rate of a drug such as penicilin is greater than the rate at which it is filtered at the glomerulus, how else is it getting into the urine? |
Through tubular secretion |
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What is the major chemical difference between blood plasma and glomerular filtrate? |
Blood plasma contains protein and glomerular filtrate does not. |
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What is the blood pressure in glomerular capillaries? |
Glomerular blood hydrostatic pressure (GBHP) |
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What is capsular hydrostatic pressure? |
CHP is the hydrostatic pressure exerted against the filtration membrane by fluid already in the capsular space and renal tubule. |
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Is due to proteins in blood plasma. |
What is blood colloid osmotic pressure (BCOP)? |
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Glomerular filtration is regulated by? |
Renal autoregulation, neural regulation and hormonal regulation. |
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Fenestrations are associated with? |
The golermulus |
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Occurs in the glomerulus. |
What is the filtration of blood? |
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Cannot pass the filtration membranes in the kidneys. |
What are large proteins? |
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Glomerular filtrate is produced as a result of? |
Blood hydrostatic pressure |
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In the proximal convoluted tubule, sodium ions are? |
Reabsorbed through the apical membrane by the Na+ -glucose symptoms and the Na+/H+ antiporters. |
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In the loop of Henle, Na+, K+, and -2Cl- symporters reclaim what? |
Sodium, potassium, and chloride from fluid in the tubule lumen. |
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Principle cells help do what? |
Absorb sodium in the collecting duct. |
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What do intercalated cells can do what? |
Reabsorb potassium ions, bicarbonate ions, and secrete hydrogen ions. |
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Sodium is moved out of the cells of the proximal convoluted tubule and into interstitial fluid by the process of? |
Active transport |
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Reabsorption is the movement of molecules from the _____ into the _____ .
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Renal tubules, peritubular capillaries |
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Very little water absorption occurs where? |
In the thick ascending loop of Henle |
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Sodium ions move through the apical membranes of principle cells of the collecting duct? |
Via diffusion |
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Chloride ions are actively reabsorbed from the? |
Thick ascending loop of Henle |
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Potassium ions are actively secreted into the tubular fluid of the? |
Distal convoluted tubule |
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Most reabsorption occurs in the? |
Proximal convoluted tubule |
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The juxtaglomerular apparatus secrets? |
Renin |
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Glucose enters the proximal convoluted tubule cells by _____ and leaves the cell into the interstitial fluid by _____.
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Sodium ion-glucose symporters, facilitated diffusion .
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The thick ascending limb of the loop of Henle is? |
The main region of the kidney tubule that is impermeable to water. |
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ADH is? |
The main regulator of facultative water reabsorption. |
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What action occurs by Na+ symporters in the apical membranes of tubule cells? |
Both reabsorption of glucose by proximal convoluted tubule cells and reabsorption of amino acids by proximal convoluted tubule cells. |
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Ions but not water, are reabsorbed from the tubular fluid in the ascending loop of Henle. Therefore_______. |
The osmolarity of the fluid entering the distal convoluted tubule is less than blood. |
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Remember, the loop of Henle is________. |
Associated with reabsorption! |
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What is the process of forming concentrated urine? |
Symporters in the loop of Henle cause sodium ions and chloride ions to build up in the renal medulla helping to form the osmotic gradient. ADH increases the reabsorption of water by principal cells in the collecting ducts. |
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How does ADH increase the solute concentration of urine? |
By causing less water to be reabsorbed |
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Sodium chloride concentration increases from cortex to medulla. |
What is renal interstitial fluid? |
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Increased sodium and chloride ion concentrations in the interstitial fluid of the renal medulla is the result of_______. |
What is the countercurrent mechanism? |
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The most important solutes that contribute to the high osmolarity of the interstitial fluid in the renal medulla. |
What are sodium ions, chloride ions, and urea? |
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The pH of normal urine? |
Between 2 and 3 |
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Chemical substances normally present in urine. |
What are electrolytes, urea, creatinine, and uric acid? |
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Useful in evaluating kidney function. |
What is blood urea nitrogen, plasma creatine, and renal plasma clearance? |
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Why do plasma clearance rates vary? |
Because substances are reabsorbed and excreted in differing amounts. |
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Is a close estimate of glomerular filtration rate. |
What is creatine clearance? |
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Is normally close to 0. |
What is renal plasma clearance? |
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Creatinine is produced by the breakdown of creatine phosphate in the skeletal muscles. It is useful for determining glomerular filtration rate (GFR) because it is? |
Filtered but not reabsorbed or secreted. |
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The colour of urine is due to the presence of a chemical called________. |
Urochrome |
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The only place in the kidney where filtration occurs. |
What is the renal corpuscle? |
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Urine is moved from the renal pelvis to the urinary bladder by___________. |
Peristalsis |
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Micturition involves: |
1) Voluntary and involuntary muscle contractions. 2) Micturition center in the sacral spinal cord. 3) Relaxation of the internal urethral sphincter. |
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The urethra in females: |
Lies posterior to the pubic symphysis and is 4 cm long. |
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In females where is the external urethral orifice located? |
Between the clitoris and vaginal opening. |
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What are the 3 parts of the male urethra? |
1) Prostatic urethra, 2) Membranous urethra, and 3) Spongy urethra. |
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The external opening of the urinary system. |
What is the external urethral orifice? |
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During the micturition reflex______________. |
Parasympathetic fibers conduct impulses from the spinal cord that cause contraction of the detrusor muscle.
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The urinary bladder in the female lies inferior to the_________. |
Uterus |
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Which waste management system binds excess hydrogen ions and thus prevents an increase in the acidity of body fluids? |
Body buffers |
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An embryonic tissue that develops into nephrons. |
What is mesoderm? |
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The ureteric bud give rise to__________. |
The collecting ducts, calyces, renal pelvis, and ureter. |
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The first kidney to form, is the most superior of the three and has associated pronephric duct. |
What is the pronephros? |
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The second kidney, replaces pronephros. |
What is the mesonephros? |
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What happens to sodium at the PCT? |
Na+ undergoes active transport from the filtrate to the blood at the proximal convoluted tubule. |
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What happens to sodium and Cl- at the PCT? |
Where Na+ goes, Cl- naturally follows. This situation creates an osmotic pressure gradient that pulls water out of the filtrate and into the blood. |
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Some substances, including K+ and some hormones, are secreted from the adjacent peritubular capillaries into the PCT. |
What is direct secretion? |
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What happens at the loop of Henle? |
Electrolytes and urea move out of the nephron into the medulla. |
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Once electrolytes and urea move out of the nephron the filtration remaining is what? |
Urine |
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What happens to the urine remaining in the nephron? |
Drains through the distal convoluted tubule into the collecting duct and then into the renal pelvis. |
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Water reabsorption at the DCT occurs under the control of what? |
ADH |
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When is renin-angiotensin system call into action? |
When the presence of toxins in the blood signals low blood pressure in the glomeruli. *Renin is also called angtiotensinogenase. |
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What happens when specialized kidney cells secrete the enzyme renin? |
It sets off a series of reactions that result in the production of the hormone angiotensin II. |
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What is important to remember about angiotensin II? |
It is a powerful vasoconstrictor. It also stimulates the secretion of the hormone aldosterone from the adrenal cortex. |
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What happens when aldosterone is secreted from the adrenal cortex? |
It causes Na+to be reabsorbed from the nephrons into the blood. |
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What happens without angiotensin II? |
No vasoconstriction takes pace, and the kidneys don't receive the signal to increase the water content of the blood. |
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Is a polypeptide hormone secreted by heart muscle cells in response to signals from sensory cells in the atria that blood volume is too high. |
What is atrial natriuretic hormone (ANH)? |
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What does ANH do to the kidneys? |
Prevents them from secreting renin. IMPORTANT: The overall effect of ANH is to counter the effects of renin. |
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ANH acts to reduce what? |
The water, sodium, and adipose loads on the circulatory system thereby reducing blood pressure. |
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A type of chemical that binds with either acid or base as needed to increase or decrease the solution pH |
What is a buffer? |
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Condition characterized by elevated blood levels of cholesterol, phospholipids and triglycerides with depressed blood levels of albumin. |
What is nephrotic syndrome? |
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Patient has symptoms that include painful, frequent urination, and low back pain. Further examination reveals inflammation of the mucosa and submucosa of the urinary bladder. |
What is cystitis? |
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The fraction of blood plasma in the afferent
arterioles of the kidneys that becomes glomerular filtrate. |
What is the filtration fraction?
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The glomerular capillaries and the podocytes, which completely encircle the capillaries, form a leaky barrier
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What is the filtration membrane? |
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What cannot pass through the filtration membrane? |
It prevents the filtration of most plasma
proteins, blood cells, and platelets. |
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What are the three filtration barriers? |
The glomerular endothelial cell, the basal
lamina, and a filtration slit formed by a podocyte. |
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A layer of acellular material between the
endothelium and the podocytes, consists of minute collagen fibers and proteoglycans in a glycoprotein matrix; negative charges in the matrix prevent filtration of larger negatively charged plasma proteins. |
What is the basal lamina? |
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What extends from each podocyte? |
Pedicels |
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What regulates how much surface area is available for filtration? |
The mesangial cells
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Glomerular filtration depends on three main pressures_________________. |
Glomerular blood hydrostatic pressure (GBHP)
Capsular hydrostatic pressure (CHP) Blood colloid osmotic pressure (BCOP) |
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Is the blood pressure in glomerular capillaries. Generally, it is about 55 mmHg. It promotes
filtration by forcing water and solutes in blood plasma through the filtration membrane. |
What is glomerular blood hydrostatic pressure? |
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Is the hydrostatic pressure exerted against the filtration membrane by fluid already in the capsular space and renal tubule. It opposes
filtration and represents a “back pressure” of about 15 mmHg. |
What is capsular hydrostatic pressure? |
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Is due to the presence of proteins such as
albumin, globulins, and fibrinogen in blood plasma, also opposes filtration. The average BCOP in glomerular capillaries is 30 mmHg. |
What is blood colloid osmotic pressure? |
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The amount of filtrate formed in all the renal corpuscles of both kidneys each minute.
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What is the glomerular filtration rate? |
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Renal autoregulation consists of two mechanisms. What are they? |
1) Myogenic mechanism 2) Tubuloglomerular feedback |
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How does blood enter into the nephron? |
Via the afferent arterial. |
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Where does blood go next after it has passed through the afferent arterial? |
The glomulerous |
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Blood exits the glomulerous via the? |
Efferent arterial |
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Where does the filtrate go when it has been filtered out of the glomulerous? |
The bowman's capsule- kind of the beginning of the nephron. |
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What gets put into filtrate? |
Na+, glucose, amino acids |
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What is the main job of PCT? |
REABSORPTION- we don't want to lose glucose, amino acids, and Na+ |
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What does the loop of Henle (particularly the ascending part) do to the medulla? |
Uses ATP to pump Na+ into the medulla and making it salty. The ascending part is only permeable to Na+ ion, potassium, Cl- (not water). Makes the medulla hypertonic! |
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What happens to water in the descending part of loop Henle? |
It is very permeable to water and the H20 will want to balance out the hypertonic conditions in the medulla. As a result, it will permeate through the descending loop of Henle and be reabsorbed into the body. |
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ADH does what to the collecting duct? |
It dictates how porous it will be-- which dictates how much water will leave (secreted) back into the medulla. Which will make the urine more concentrated. |
