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The urinary system has Three main functions:
- 1) Excretion, The removal of organic waste from the body fluids
- 2) Elimination, the discharge of these waste products into the environment
- 3) Homeostatic regulation of the volume and solute concentration of blood plasma.
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The urinary has several essential homeostatic functions that are often overlooked. They are:
- 1) Regulating blood volume and blood pressure
- 2) Regulating plasma concentrations of sodium, potassium, chloride, and other ions.
- 3) Helping to stabilize blood pH
- 4) Conserving valuable nutrients
- 5) Assisting the liver in detoxifying poisons
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Organ that produces urine
Kidney
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organ that transports urine toward the urinary bladder
Ureter
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Organ that temporarily stores urine prior to elimination
Urinary Bladder
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Conducts urine to exterior; in males, transports semen as well.
Urethra
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what is the renal corpuscle's primary function?
Filtration of plasma
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Primary Function:Reabsorption of ions, organic molecules, vitamins, water; secretion of drugs, toxins, acids
Renal Tubule
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what is the descending limb of the nephron loop's primary function?
The reabsorption of water from tubular fluid.
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What is the ascending limb of the nephron loop's primary function?
Reabsorption of ions; assists in creation of concentration gradient in medulla
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What is the primary function of the distal convoluted tubule (DCT)?
Reabsorption of sodium ions and calcium ions; secretion of acids, ammonia, drugs, toxins.
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In the collecting system, the primary function of the collecting duct is:
Reabsorption of water, sodium ions; secretion or reabsorption of bicarbonate ions or hydrogen ions
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In the collection system, the papillary duct has what primary functions?
Conduction of tubular fluid to minor calyx; contributes to concentration gradient of the medulla
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______ Nephrons perform most of the reabsorptive and secretory functions of the kidneys because they are more numerous than _____ Neprons.
- Cortical Nephrons
- Juxtamedullary Nephrons
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The ______ Nephrons enable the kidneys to produce concentrated urine.
Juxtamedullary
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Different segments of the nephron form urine in what 3 ways?
- 1) Filtration
- 2) Reabsorption
- 3) Secretion
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The goal of urine production is to maintain homeostasis by regulating the _______ and _______ of blood.
Volume & Composition
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Our bodies form form three important organic waste products:
- 1) Urea
- 2) Creatinine
- 3) Uric Acid
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This organic waste is the moste abundant; you generate approximately 21g of it each day, most of it through the breakdown of amino acids.
Urea
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Skeletal muscle tissues generate this organic waste through the breakdown of a high energy compound that plays an important role in muscle contraction; our bodies generate roughly 1.8 g of it each day; virtually all of it is excreted in urine.
Creatinine
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A waste product formed during the recycling of the nitrogenous bases from RNA Molecules. our bodies produce approximately 480 mg of this each day.
Uric Acid
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In this process, blood pressure forces water and solutes across the wall of the glomerular capillaries and into the capsular space. Solute molecules small enough to pass through the ____ membrane are carried by the surrounding water molecules.
Filtration X 2
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This process Involves the removal of water and solutes from the filtrate, and their movement across the tubular epithelium and into the peritubular fluid.
Reabsorption
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The transport of solutes form the peritubular fluid, across the tubular epithelium, and into the tubular fluid.
Secretion
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Hydrostatic forces water through membrane pores, and solute molecules small enough to pass though those pores are carried along; ____ takes place as larger solutes and suspended materials are left behind.
Filtration
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The processes of reabsorption and secretion at the kidneys involve a combination of what transport mechanisms?
- 1) Diffusion
- 2) Osmosis
- 3) Channel-mediated diffusion
- 4) Carrier mediated transport
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Type of Carrier-mediated transport where a carrier protein transports a molecule across the plasma membrane without expending energy.
Facilitated Diffusion
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Type of carrier-mediated transport that is driven by the hydrolysis of ATP to ADP on the inner membrane surface. Exchange pumps and other carrier proteins are active along the kidney tubules; can operate despite concentration gradients.
Active Transport
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Type of Carrier-Mediated Transport where protein activity is mot directly linked to the hydrolysis of ATP. Instead, two substrates (ions, molecules, or both) cross the membrane while bound to a carrier protein.
Cotransport
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Resembles cotransport except that the two transported ions move in opposite directions; operates in the PCT, DCT, and collecting system.
CounterTransport
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Characteristics of Carrier-Mediated Transport that are essential for kidney function:
- 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 cells 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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General functions are the filtration of plasma; generates approximately 180L/day of filtrate similar in composition to blood plasma without plasma proteins
Renal Corpuscle
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The general functions of the Proximal Convoluted tubule (PCT): Reabsorption of ______ of the water (108-116L/Day), and _____ of the organic substrates, and _________ of the sodium and chloride ions in the original filtrate.
- 60-70% of water
- 99-100% of organic Substrates
- 60-70% of Na & Cl ions
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General Functions of the nephron loop include: Reabsorption of ______ of the water (45 L/Day)and ______ of the sodium and chloride ions present in the original filtrate; creation of the concentration gradient in the medulla.
- 25%
- 20-25% of Na & Cl ions
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General functions of the Distal convoluted tubule (DCT) include: Reabsorption of a variable amount of water (usually ____, or 9 L/Day), under ADH stimulation, and a variable amount of sodium ions, under aldosterone stimulation
5% of water
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The General Functions of the collecting system include: Reabsorption of a variable amount of water (Usually ______, or 16.8L/Day) under ADH stimulation, and a variable amount of sodium ions, under aldosterone stimulation
9.3 % of water
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The general functions of the ________ _____ are the redistribution of water and solutes reabsorbed in the cortex.
Peritubular capillaries
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General functions of the ____ _____ are Redistribution of water and solutes reabsorbed in the medulla and stabilization of the concentration gradient of the medulla
Vasa Recta
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