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Chapter 26 Urinary System

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Urine leaving the kidneys travels along the following sequential pathway to the exterior
ureters -> urinary bladder -> urethra
Which organ or structure does NOT belong in the urinary system
gallbladder
The openings of the urethra and the two ureters mark an area on the internal surface of the urinary bladder called the
trigone
The initial factor that determines if urine production occurs is the
filtration
Along with the urinary system, the other systems of the body that affect the composition of body fluids are
integumentary, respiratory, and digestive
Seen in section, the kidney is divided into
an outer cortex and an inner medulla
The basic functional unit in the kidney is the
nephron
The three concentric layers of connective tissue that protect and anchor the kidneys are the
renal capsule, adipose capsule, renal fascia
Dilation of the afferent arteriole and glomerular capillaries and constriction of the efferent arteriole causes
elevation of glomerular blood pressure
Blood supply to the proximal and distal convoluted tubules of the nephron is provided by the
peritubular capillaries
In a nephron, the long tubular passageway through which the filtrate passes includes
proximal and distal convoluted tubules and loop of Henle
The primary site of regulating water, sodium, and potassium ion loss in the nephron is the
loop of Henle and collecting duct
The primary site for secretion of substances into the filtrate is the
distal convoluted tubule
The three pricesses involved in urine formation are
filtration, reabsorption, and secretion
The filtration of plasma that generates approximately 180 liters/day of filtrate occurs in the
renal corpuscle
Approximately 60-70 percent of the water is reabsorbed in the
proximal convoluted tubule
The portion of the renal segment that is under aldosterone stimulatino is the
distal convoluted tubule
The proximal convoluted tubule (PCT) and the distal convoluted tubule (DCT) are separated by a U-shaped tube called the
loop of Henle
The location and orientation of the carrier proteins determine whether a particular substance is reabsorbed or secreted in
active transport, cotransport, countertransport
The glomerular filtration rate is regulated by
autoregulation, hormonal regulation, autonomic regulation
The pressure which tends to draw water out of the filtrate and into the plasma, opposing filtration, is the
blood colloid osmotic pressure (BCOP)
The three primary waste products found in a representative urine sample are
ions, metabolites, nitrogenous wastes
The average pH for normal urine is about
6.0
The mechanism responsible for the reabsorption of organic and inorganic compounds from the tubular fluid is
cotransport
Countertransport resembles cotransport in all respects except
the two transported ions move in opposite directions
The primary site of nutrient reabsorption in the nephron is the
proximal convoluted tubular
In countercurrent multiplication, the countercurrent referes to the fact that an exchange occurs between
fluids moving in opposite directinos
The result of the countercurrent multiplication mechanism is
increased solute concentration in the descending limb of loop of Henle
When antidiuretic hormone levels rise, the distal convoluted tubular becomes
more permeable to water, water reabsorption increases
The results of the effect of aldosterone along the DCT, the collecting tubular and the collecting duct are
increased conservation of sodium ions and water
When urine leaves the kidney, it travels to the urinary bladder via the
ureters
The expanded, funnel-shaped upper end of the ureter in the kidney is the
renal pelvis
Contraction of the muscular bladder forces the urine out of the body through the
urethra
During the micturition reflex, increased afferent fiber activity in the pelvic nerves facilitates
parasympathetic motor neurons in the sacral spinal cord
Urine reaches the urinary bladder by the
peristaltic contractions of the ureters
In males, enlargement of the prostate gland compresses the urethra and restricts the flow of urine causing
urinary retention
The system that monitors distention of the urinary bladder and controls urination is the
nervous system
The vital function(s) performed by the nephrons in the kidneys is (are)
production of filtrate, reabsorption of organic substrates, reabsorption of water and ions
The renal corpuscle consits of
Bowman's capsule and the glomerulus
The filtration process within the renal corpuscle involves passage across three physical barriers, which include the
capillary endothelium, basal lamina, glomerular epithelium
The thin segments in the loop of Henle are
freely permeable to water; relatively impermeable to ions and other solutes
The thick segments in the loop of Henle contain
transport mechanisms that pump materials out of the filtrate
The collecting system in the kidney is responsible for
making final adjustments to the sodium ion concentration and volume of urine
Blood arrives at the renal corpuscle by way of an
afferent arteriole
Sympathetic innervation into the kidney is responsible for
decreasing the GFR and slowing the production of filtrate; stimulation of renin release; altering the GFR by changing the regional pattern of blood circulation
When plasma glucose concetrations are higher than the renal threshold, glucose concentrations in the filtrate exceed the tubular maximum (Tm) and
glucose appears in the urine
The outward pressure forcing water and solute molecules across the glomerulus wall is the
filtration pressure
The opposing forces of the filtration pressure at the glomerulus are the
capsular hydrostatic pressure and glomerular hydrostatic pressure
The amount of filtrate produced in the kidneys each minute is the
glomerular filtration rate
Inadequate ADH secretion results in the inability to reclaim the water entering the filtrate, causing
dehydration
Under normal circumstances virtually all the glucose, amino acids, and other nutrients are reabsorbed before the filtrate leaves the
proximal convoluted tubule
Aldosterone stimulates ion pumps along the distal convoluted tubule, the collecting tubule, and the collecting duct, causing a
reduction in the number of sodium ions lost in the urine
The high osmotic concentrations found in the kidney medulla are primarily due to
presence of sodium ions, chloride ions, and urea
The substances that influence the GFR by regulating blood pressure and volume are
renin, erythropoietin, ADH
Angiotensin II is a potent hormone that
causes constriction of the efferent arteriole at the nephron, triggers the release of ADH in the CNS, stimulates secretion of aldosterone by the adrenal cortex and epinephrine by the adrenal medulla
Sympathetic innervation of the afferent arterioles causes a
decrease in GFR and decrease of filtrate production
During periods of strenuous exercise, sympathetic activation causes the blood flow to
increase to skin and skeletal muscles; decrease to kidneys