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129 Cards in this Set
- Front
- Back
- 3rd side (hint)
What do the kidneys and their associated structures comprise?
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They comprise the “Urinary System”
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Pg. 270
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Where are the kidneys located?
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They are located posteriorly in the abdominal cavity, on either side of the vertebral column.
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Pg. 270
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Once urine has been produced in the kidneys what is the name of the structure it travels to next?
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The Ureters
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Pg. 270
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What structure does urine arrive at after it enters the ureter?
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The Urinary Bladder
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Pg. 270
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Once urine has been collected in the “Urinary Bladder” what is the final structure it travels through on its journey out of the body?
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The Urethra
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Pg. 270
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The Urethra
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1
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Pg. 270
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How many ureters does a normal person have?
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2
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Pg. 270
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Who has the shortest urethras?
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Females have the shortest urethras being approximately 4 cm in length.
It exits between the labia just above the vaginal opening |
Pg. 270
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What consequences result because of the urethra’s length in females?
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1. The short length of the female urethra makes bacterial invasion easier
2. Because of the short length of the urethra in females, and also because it’s external opening is so close to the rectum, helps explains why females are more prone to Urinary Tract Infections (UTIs). |
Pg. 270
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Who has the longest urethra?
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Males have the longest urethras.
Averaging approximately 20 cm in length when the penis is not erect. |
Pg. 270
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What structure encircles a males urethra as the urethra exits the urinary bladder?
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The Prostate Gland
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Pg. 270
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What can conditions can enlargement of the structure that encircles the male’s urethra as it exits the urinary bladder cause?
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Impedance of urination and emptying of the bladder
and Makes elderly males more susceptible to UTIs |
Pg. 270
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What is the name of the muscular wall of the structure located between the ureters and urethra called?
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The Detrusor Muscle
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Pg. 270
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How many associated sphincters does the urinary bladder have?
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2
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Pg. 270
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The detrusor muscle can generate action potentials in response to __________.
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Stretch
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Pg. 270
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The detrusor muscle receives parasympathetic axons, which release ______________.
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Acetylcholine (Ach)
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Pg. 270
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What does the release of Ach from the parasympathetic axons stimulate?
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It stimulates contraction and thus emptying of the bladder
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Pg. 270
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What type of muscle comprises the sphincters of the bladder?
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1. The Upper “Internal Urethral Sphincter” = Smooth Muscle
2. The Lower “External Urethral Sphincter” = Striated Skeletal Muscle |
Pg. 270
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What is the relaxation of the 2 sphincters of the bladder required for?
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It is required for urination
or Micturation |
Pg. 271
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What is another name for urination?
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Micturation
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Pg. 271
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What type of activity can strengthen the muscles of the pelvic floor and the external urethral sphincter?
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Kegel Exercises
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Pg. 271
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What is the inability to control Micturation called?
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Incontinence
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Pg. 271
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Micturation is controlled by a reflex center in the ______ regions of the spinal cord.
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Sacral
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Pg. 271
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What happens when a person wants to consciously urinate?
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Descending motor tracts to the micturation center produces inhibition of the somatic motor neurons to the external urethral sphincter (or to the sphincter that is composed of striated skeletal muscle) which causes it to relax.
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Pg. 271
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What would persons need who have damaged their spinal cord, which results in an interruption of voluntary signals to the pelvic muscles and external urethral sphincter, thus reverting to the spinal reflex of infancy and become incontinent?
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A Urinary Catheter
or Foley Catheter |
Pg. 271
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What do Nephrons consist of?
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Nephrons consist of tubules and associated blood vessels
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Pg. 271
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What is the inner region of the kidney called?
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The Renal Medulla
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Pg. 271
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What is the outer region of kidney called?
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The Renal Cortex
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Pg. 271
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Where are the renal pyramids located?
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The Renal Medulla
or The Inner portion of the kidney |
Pg. 271
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What are the cup-shaped structures that the narrow portions of the renal pyramids project into called?
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Calyces
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Pg. 271
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What is the structure called that the tip of each pyramid releases urine into?
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Minor Calyx (and several of these drain into a Major Calyx)
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Pg. 271
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What is the name of the structure the Major Calyces merge to form?
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The Renal Pelvis = A hollow cavity in each kidney
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Pg. 271
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What may occasionally form within the calyces or renal pelvis?
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Kidney Stones
or Renal Calculi |
Pg. 271
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What is it called when individual renal calculi merge?
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When individual stones or calculi merge a “Stag Horn Calculus” is formed.
|
Pg. 271
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The _________ receive plasma filtrate and then modify this filtrate to form the final urine.
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Nephron Tubules
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Pg. 272
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What is the name of the structure that is the bulbous beginning of the tubule that first receives the filtrate from plasma called?
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The Glomerular Capsule
or Bowman’s Capsule |
Pg. 272
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Why is it vitally important that most of the glomerular filtrate produced by the kidneys be immedeiately reabsorbed?
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To prevent an otherwise fatal drop in blood volume an pressure
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Pg. 274
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What region of the kidney are the Bowman’s capsules located?
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In the Renal Cortex
or The Outer region of the Kidney |
Pg. 272
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What is the name of the structure that receives the filtrate from the glomerular capsule?
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The Proximal Convoluted Tubule
|
Pg. 272
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What region of the kidney are the Proximal Convoluted Tubules located?
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In the Renal Cortex
or The Outer region of the Kidney |
Pg. 272
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What is the name of the structure that receives fluid from the proximal convoluted tubule?
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The Loop of Henle
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Pg. 272
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What is the first portion of the Loop of Henle called?
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What is the first portion of the Loop of Henle called?
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Pg. 272
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What is the first portion of the Loop of Henle called?
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It takes the fluid from the cortex into the medulla.
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Pg. 272
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It takes the fluid from the cortex into the medulla.
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It takes the fluid from the cortex into the medulla.
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Pg. 272
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It takes the fluid from the cortex into the medulla.
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They are sometimes referred to as the “Thick Segments”
Because, the upper portions of the loop have thicker walls and different transport properties than the lower portions. |
Pg. 272
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What is the name of the tubule that receives fluid from the ascending limb of the loop of Henle called?
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The Distal Convoluted Tubule
|
Pg. 272
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What region of the kidney are the distal convoluted tubules located?
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In the Renal Cortex
or The Outer region of the Kidney |
Pg. 272
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In the Renal Cortex
or The Outer region of the Kidney |
The Collecting Duct
|
Pg. 272
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What region of the kidney does the collecting duct begin and what is it sometimes separately identified as?
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The Renal Cortex
It is sometimes identified separately as the “Cortical Collecting Duct” |
Pg. 272
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_______ functions depend on interactions between the tubules and associated blood vessels.
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Nephron
|
Pg. 272
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Arterial blood arrives in the _________and passes through branches into smaller arteries that extend into the __________.
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Renal Artery
Renal Cortex |
Pg. 272
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What are the names of the blood vessels that deliver blood into the tightly wound capillary beds, and what are the tightly wound capillary beds called?
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Afferent Arterioles
Afferent = towards the center of activity Glomeruli |
Pg. 272
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Why is the vascular arrangement unique that is delivered to the glomeruli?
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Because blood from the glomeruli doesn’t pass into venules as it does elsewhere in the body.
|
Pg. 272
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Where does blood from the glomeruli enter?
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It enters Efferent Arterioles
Efferent = away from the center of activity |
Pg. 272
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What are the capillaries downstream from the glomerulus called?
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Peritubular Capillaries
(They are called Peritubular Capillaries because they surround the tubules) |
Pg. 272
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Peritubular Capillaries
(They are called Peritubular Capillaries because they surround the tubules) |
They are called Fenestrae
|
Pg. 272
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What does the Fenestrae of the capillaries allow for?
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It makes them far more permeable to plasma fluid and dissolved solutes than typical capillaries, such as those in the skeletal muscles.
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Pg. 272
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What is the name of the lining that is found just outside of the endothelial cells that comprise the walls of the glomerular capillaries?
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Glomerular Basement Membrane
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Pg. 273
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What is the Glomerular Basement Membrane a layer of?
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It is a layer of glycoproteins that may provide a filtration barrier for proteins.
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Pg. 273
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What is the name of the extensions of cells that surround the glomerulus and its basement membrane and compose the inner (visceral) layer of the glomerular capsule?
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Podocytes
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Pg. 273
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What force produces the glomerular filtrate?
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The forces that produce the glomerular filtrate are similar to those that act on other capillary beds to cause the formation of interstitial fluid.
The capillary blood pressure which is caused by left ventricular systole provides the force for filtering blood out of the glomerulus This is opposed by the colloid osmotic pressure of the plasma proteins which draws water into the capillaries by osmosis. |
Pg. 273
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What types of conditions might produce severe dehydration leading to hypotension?
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Persons who have severe:
Diarrhea Blood Loss Heart Failure Or who are simply deprived of water |
Pg. 273
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Reduction in what 2 things can lead to an increase in the transit time to move wastes from the tissues to the kidneys, increasing retention of metabolic wastes?
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Reduction in blood volume
and Reduction in blood pressure |
Pg. 273
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What are the end result(s) of severe dehydration?
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Acidosis
Uremia Impaired Cell Metabolism And Eventually Death |
Pg. 273
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What is the term for the volume of filtrate produced by both kidneys per minute?
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Glomerular Filtration Rate (GFR)
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Pg. 273
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True or False. Most of the salt and water in the glomerular filtrate are reabsorbed across the walls of the proximal tubules back into the blood.
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True
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Pg. 274
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What substances does the transport process of filtrate passing through the Loop of Henle cause to be accumulated in high concentrations in the renal medulla?
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Na+
Cl- Urea |
Pg. 274
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What does the accumulation of high concentrations of Na+, Cl- and urea provide for?
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This provides an osmotic force for water reabsorption out of the collecting ducts, which are made permeable to water by Antidiuretic Hormone (ADH) or Vasopressin
|
Pg. 274
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What term refers to the transport processes that allow substances in the glomerular filtrate to be returned to the vascular system?
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Reabsorption
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Pg. 274
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True or False. The glomerular filtrate is essentially hypertonic.
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False. The glomerular filtrate is essentially “Isotonic” (or has the same solute concentration as) to the surrounding interstitial fluid of the renal cortex and the blood plasma.
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Pg. 274
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What must be established in order for water to be reabsorbed into the blood of the surrounding peritubular capillaries?
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A concentration (osmotic) gradient across the wall of the tubule must first be produced.
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Pg. 274
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Which tubule reabsorbs most of the filtrate?
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The Proximal Convoluted Tubule
|
Pg. 274
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How is the osmotic concentration gradient established in order for water to be drawn out of the proximal convoluted tubules?
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This involves transport processes across the plasma membrane of the epithelial cells that form the walls of the proximal convoluted tubules. The plasma membrane actively transports Na+ from the cytoplasm into the surrounding interstitial fluid and blood plasma.
|
Pg. 275
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The higher ____ concentration of the fluid surrounding the proximal convoluted tubules serves as an osmotic gradient.
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NaCl
|
Pg. 275
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Why does water enter into the interstitial fluid and then into the peritubular capillaries?
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Because the walls of the proximal tubules are permeable to water and water passively follows the NaCl whose concentration have been increased in the interstitial fluid and the blood plasma of the peritubular capillaries.
|
Pg. 275
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Approximately what percent of the glomerular filtrate is immediately reabsorbed across the walls of the proximal convoluted tubule?
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Approximately 65% (almost two-thirds)
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Pg. 275
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Because the walls of the proximal tubules are __________to water, water passively follows the____ into the _________and then into the ___________________.
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Permeable
NaCl Interstitial fluid Peritubular capillaries |
Pg. 275
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What is responsible for maintaining a low Na+ concentration in the cytoplasm?
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The Na+/K+ (ATPase) pumps responsible for active transport maintain a low Na+ concentration in the cytoplasm.
|
Pg. 275
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____________ follows the Na+ passively by electrical attraction from the glomerular filtrate into the surrounding interstitial fluid and plasma.
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Chloride ion (Cl-)
|
Pg. 275
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What structure is responsible for reabsorbing approximately 20% of glomerular filtrate?
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The descending limb of the loop of Henle
|
Pg. 275
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What are the names of the 2 structures that are responsible for reabsorbing about 15% of the glomerular filtrate?
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The Distal Convoluted Tubule
and The Collecting Duct |
Pg. 275
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The loop of Henle produces a __________ renal medulla.
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Hypertonic
|
Pg. 275
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Where does an equal amount of water and NaCl removal occur, so that the filtrate’s volume is reduced but its concentration remains unchanged?
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The Proximal Convoluted Tubule
|
Pg. 275
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True or False. The filtrate that leaves the proximal convoluted tubule to enter the descending limb of the loop of Henle retains its same concentration as blood plasma.
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True. It was isotonic to blood plasma when it entered the glomerular capsule, and it is still isotonic when it leaves the proximal convoluted tubule to enter the descending limb of the loop of Henle.
|
Pg. 275
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What is Osmolarity?
|
It is a measurement of total solute concentration of solutions.
|
Pg. 275
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What is a solution that has a concentration of 300 milliosmolar (300mOsM) called?
|
Isotonic
|
Pg. 275
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Solutions with a higher osmolarity are more ________ .
and What are they referred to as? |
Concentrated
and Hypertonic |
Pg. 275
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Solutions with a lower osmolarity are more ________.
and What are they referred to as? |
Dilute
and Hypotonic |
Pg. 275
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True or False. The osmolarity of the fluid remains constant as it descends from the renal cortx to the medulla.
|
False. The osmolarity increases as the fluid descends from the cortex to the medulla, going from isotonic 300 mOsM to the very hypertonic 1,400 mOsM at the bottom of the loop.
|
Pg. 276
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What is the increasing concentration of the filtrate in the descending limb produced by?
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By the removal of water by osmosis into the surrounding Peritubular Capillaries.
|
Pg. 276
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Why is water drawn out of the descending limb?
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Because the interstitial fluid of the renal medulla is very hypertonic and thus has a higher osmotic pressure.
|
Pg. 276
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What does the thick segment of the ascending limb of the Loop of Henle actively pump out into the surrounding interstitial fluid of the renal medulla?
|
NaCl
|
Pg. 276
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True or False. Salt is removed from the filtrate into the surrounding fluid in both the Proximal Convoluted Tubule and the Ascending limb of the Loop of Henle.
|
True
|
Pg. 276
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If the Ascending limb of the Loop of Henle has salt removed from the filtrate as is done in the Proximal Convoluted Tubule, why does the filtrate not remain isotonic as is does in the Proximal Convoluted Tubules?
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Because the Ascending limb of the Loop of Henle is not permeable to water
|
Pg. 276
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How does the concentration of the interstitial fluid and the filtrate that ascends into the Distal Convoluted Tubule in the Renal Cortex change?
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As a result of the Ascending limb of the Loop of Henle not being permeable to water:
The interstitial fluid becomes Hypertonic and The filtrate that ascends into the distal convoluted tubule in the renal cortex becomes hypotonic |
Pg. 276
|
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What other structure in the renal medulla also forms loops, allowing them to carry away water but leave the NaCl to accumulate in the interstitial fluid of the medulla?
|
Blood Vessels
|
Pg. 276
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What is the name that refers to the interactions between the descending and ascending limbs that operates to increase the concentration of the renal medulla?
|
Countercurrent Multiplier System
|
Pg. 276
|
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What is occurring in the Countercurrent Multiplier System?
|
-The ascending limb pumps out salt and this action produces the hypertonic medulla.
- This draws water from the descending limb which produces a hypertonic filtrate that arrives at the ascending limb, which then allows it to pump out even more NaCl. |
Pg. 276
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Why does the renal medulla become increasingly salty and hypertonic?
|
Because of the transport processes in the loops of Henle (the countercurrent multiplier system).
|
Pg. 276
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What other substance besides salt contributes to the hypertonic concentration of the renal medulla?
|
Urea
|
Pg. 276
|
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What is Urea?
What structure produces urea? |
It is a waster product of the metabolism of amino acids
and Urea is produced by the Liver. |
Pg. 276
|
|
What does the breakdown of amino acids in the liver release?
|
Ammonia (NH3)
|
Pg. 276
|
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What does the liver rapidly combine the breakdown of amino acids with and what does this produce?
|
It combines the breakdown of amino acids (Ammonia or NH3) with Carbon Dioxide.
This produces Urea |
Pg. 276
|
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True or False. Ammonia is very toxic to cells but urea is much less toxic.
|
True
|
Pg. 276
|
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What is the name of the clinical test that can monitor levels of urea in the blood?
|
Blood Urea Nitrogen (BUN)
|
Pg. 276
|
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In which part of the medulla does some urea diffuse through channels in the collecting ducts to enter the interstitial fluid?
|
The Inner Medulla
|
Pg. 276
|
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What other substance besides salt is the Ascending limb of the Loop of Henle permeable to?
Where is this substance recycled? |
Urea
Urea can recycle between the ascending limb and the collecting duct as it accumulates in the interstitial fluid of the medulla. |
Pg. 276
|
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What 3 functions do the transport processes of the Loops of Henle?
|
1. Some water is reabsorbed across the walls of the descending limb.
2. The filtrate in the distal tubule in the renal cortex is made hypotonic (dilute, with a concentration as low as 100 mOsM 3. The interstitial fluid of the renal medulla is made very hypertonic (concentrated), with a concentration as high as 1,400 mOsM. |
Pg. 276-277
|
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What does water reabsorption from the collecting duct require?
|
ADH
|
Pg. 277
|
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What is the nature of the fluid and its concentration in the Distal Convoluted Tubules?
|
It is Hypotonic at a concentration of 100 mOsM
|
Pg. 277
|
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Why is the function of making the interstitial fluid of the renal medulla very hypertonic (concentrated), with a concentration as high as 1,400 mOsM the most important of the three functions accomplished by the transport processes of the Loops of Henle?
|
The hypertonic environment of the renal medulla provides the osmotic gradient for the reabsorption of water across the walls of the collecting ducts.
|
Pg. 277
|
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What does the hypertonic environment of the renal medulla allow us to produce?
|
It allows us to produce a small volume of very concentrated urine when we need to conserve water.
|
Pg. 277
|
|
What is the path of the Collecting Ducts?
|
The collecting ducts begin in the cortex and plunge into the medulla, all the way to the tips of the renal pyramids where they empty into the calyces.
|
Pg. 277
|
|
What part of the kidney do the Collecting Ducts receive hypotonic fluid from the distal tubules?
|
The Cortex
|
Pg. 277
|
|
What part of the kidney does the walls of the collecting ducts separate the hypotonic from the surrounding hypertonic interstitial fluid?
|
The Medulla
|
Pg. 277
|
|
Why is there a steep concentration gradient promoting the osmosis of water from the collecting ducts into the interstitial fluid and then into the peritubular capillaries?
|
Because the collecting ducts receive hypotonic fluid from the distal tubules in the renal cortex and the walls of the collecting ducts separate this dilute fluid from the surrounding hypertonic interstitial fluid in the renal medulla.
|
Pg. 277
|
|
Why is the reabsorption of water from the collecting ducts variable despite the constant concentration gradient between the collecting ducts, the surrounding interstitial fluid, and the peritubular capillaries?
|
Because the permeability of the collecting duct walls to water is dependent on Antidiuretic Hormone (ADH).
|
Pg. 277
|
|
Where is ADH manufactured?
Where is ADH stored? |
ADH is manufactured by the Hypothalamus
ADH is stored in the Posterior Pituitary Gland |
Pg. 277
|
|
How does ADH stimulate water reabsorption in the collecting ducts?
|
ADH stimulates the insertion of “Aquaporin” channels into the walls of the collecting ducts.
|
Pg. 277
|
|
When will the urine have a concentration of 1,400 mOsM and as a result an individual will excrete only about 400 ml of urine per day?
|
When ADH secretion and water reabsorption are at a maximum
|
Pg. 277
|
|
What occurs when ADH is absent?
|
Very little water can be reabsorbed across the walls of the collecting ducts, and an individual will excrete a large volume of dilute urine (with a minimum concentration of 100 mOsM).
|
Pg. 278
|
|
When is ADH secreted by the posterior pituitary?
|
It is secreted when stimulated by Osmoreceptor neurons in the hypothalamus.
|
Pg. 278
|
|
How are the neurons responsible for stimulating the secretion of ADH activated?
|
They are activated by an increase in the plasma osmolarity
(which can be produced by dehydration or eating too much salt) |
Pg. 278
|
|
What action can lower the osmolarity of the blood so that the osmoreceptors are less stimulated?
|
Drinking too much water
|
Pg. 278
|
|
What structure is known as the “Thirst Center?”
|
The Hypothalamus
|
Pg. 278
|
|
Why do people who loose excessive water through perspiration, blood loss, or who are denied normal intake of water become extremely thirsty?
|
Because of nerve impulses from the Hypothalamus
|
Pg. 278
|
|
Secretion of ________ accordingly so that the kidneys will retain water or excrete more water as needed is important to maintain homeostasis of the plasma osmolarity.
|
Antidiuretic hormone (ADH)
|
Pg. 278
|
|
Why should a person lost at sea not drink the salty seawater?
|
-The high salt content in seawater contains more sodium and chloride than the body needs and it must be excreted by the kidneys.
-This causes water to remain inside the tubules and be urinated out along with the sodium, chloride, and other salts in seawater. -More water is urinated out than the seawater taken in and you remain thirsty. (This is a losing equation because you will die quicker than if you didn’t drink at all) |
Pg. 278
|
|
What is the term used to describe when a solute causes water to remain inside the tubules and be urinated out along with the sodium and chloride?
|
Osmotic Diuresis
|
Pg. 278
|