Term
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Definition
| Removal of organic wastes from body fluids |
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Term
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Definition
| Discharge of waste products |
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Term
| 3 functions of the urinary system |
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Definition
1. Excretion
2. Elimination
3. Homeostatic regulation |
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Term
| 5 homeostatic functions of the urinary system |
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Definition
1. Regulates blood volume and blood pressure
-adjusts volume of water lost in urine
-Releases erythropoietin and renin
2. Regulates plasma ion concentrations
-Sodium, potassium, & chloride ions (controls quantities lost in urine)
-Calcium ion levels (through synthesis of calcitriol)
3. Helps stabilize blood pH
-Controls loss of hydrogen ions & bicarbonate ions in urine
4. Conserves valuable nutrients
-Prevents excretion while excreting organic waste products
5. Assists liver in detoxifying poisons |
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Term
| Goal of urine production- |
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Definition
| maintain homeostasis by regulating volume and composition of blood |
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Term
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Definition
Microscopic, tubular structures in cortex of each renal lobe
Where urine production begins |
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Term
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Definition
Consists of 50 intertwining capillaries
Blood delivered via afferent arteriole
Blood leaves in efferent arteriole
Flows into peritubular capillaries
Which drain into small venules
And return blood to venous system |
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Term
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Definition
Occurs in renal corpuscle
-Driven by blood pressure
-Forces water and dissolved solutes out of glomerular capillaries into capsular space
-Produces protein free solution (filtrate) similar to blood plasma |
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Term
| Three Functions of Renal Tubule |
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Definition
1. Reabsorb useful organic nutrients that enter filtrate
2. Reabsorb more than 90% of water in filtrate
3. Secrete waste products that failed to enter renal corpuscle through filtration at glomerulus |
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Term
| Proximal convoluted tubule function |
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Definition
| reabsorb ions, vitamins, water, organic molecules |
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Term
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Definition
| reabsorb water (down), reabsorb ions (up) |
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Term
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Definition
| reabsorb Na+ & Ca2+; secrete toxins, ammonia, drugs |
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Term
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Definition
Receive fluid from many nephrons
Each collecting duct
Begins in cortex
Descends into medulla
Carries fluid to papillary duct that drains into a minor calyx |
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Term
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Definition
85% of all nephrons
Located mostly within superficial cortex of kidney
Loop of Henle relatively short
Efferent arteriole delivers blood to a network of peritubular capillaries |
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Term
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Definition
15% of nephrons
Nephron loops extend deep into medulla
Peritubular capillaries connect to vasa recta
Vasa recta- capillaries wrap around Loop of Henle |
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Term
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Definition
1. The active secretion of ions, acids, drugs, and toxins into the tubule
2. The selective reabsorption of sodium ions and calcium ions from tubular fluid
3. The selective reabsorption of water |
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Term
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Definition
1. Urea-the most abundant waste
2. Creatinine-generated through the breakdown of creatine phosphate
3. Uric acid-formed during the recycling of the nitrogenous bases from RNA molecules. |
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Term
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Definition
| The transport of solutes from the peritubular fluid, across the tubular epithelium, and into the tubular fluid |
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Term
| Characteristics of Carrier-mediated transport |
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Definition
1. A specific substrate binds to a carrier protein that facilitates movement across the membrane.
2. A given carrier protein typically works in one direction only.
3. The distribution of carrier proteins can vary among portions of the cell surface.
4. The membrane of a single tubular cell contains many types of carrier proteins.
5. Carrier proteins, like enzymes, can be saturated. |
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Term
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Definition
A carrier protein transports a molecule across the plasma membrane without expending energy..
-Always follows the concentration gradient for the ion or molecule transported. |
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Term
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Definition
Driven by the hydrolysis of ATP to ADP
Can operate despite an opposing concentration gradient. |
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Term
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Definition
-not directly linked to the hydrolysis of ATP
-2 substrates cross the membrane while bound to the carrier protein
-always follows the concentration gradient of at least one of the transported substances. |
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Term
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Definition
| -resembles cotransport except the 2 transported ions move in opposite directions |
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Term
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Definition
| the plasma concentration at which a specific substance or ion begins to appear in the urine |
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Term
| Glomerular filtration rate |
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Definition
| The amount of filtrate the kidneys produce each minute. |
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Term
3 levels of control to stabilize the
GFR |
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Definition
1. Autoregulation at the local level
2. Hormonal regulation-initiated by the kidneys
3. Autonomic regulation-by the sympathetic division of the ANS |
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Term
| 3 triggers for the release of renin by the juxtaglomerular complex (JGC) |
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Definition
1. A decrease in blood pressure
2. stimulation by sympathetic innervation
3. a decrease in the osmotic concentration of the tubular fluid at the macula densa |
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Term
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Definition
1. Reabsorption of organic nutrients
2. Active reabsorption of ions
3. Reabsorption of water
4. Passive reabsorption of ions
5. Secretion |
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