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Anatomy of the Urinary System

The kidney is referred to as an excretory organ because it excretes _____ wastes.
The kidney is also a major homeostatic organ because it maintains the electrolyte, __1__, and __2__ balance of the blood.
1) Acid base, 2) fluid (water)
Urine is continuously formed by the __1__ and is routed down the __2___ by the mechanism of ____3___ to a storage organ called the ___4____.
1) kidneys, 2) ureters, 3) peristalsis, 4) urinary bladder
Eventually the urine is conducted to the body ______ by the urethra.
In the male, the urethra is __1__ centimeters long both urine and __2__.
1) 20 cm, 2) semen
The female urethra is ____ centimeters long and transports only urine.
4 cm
Voiding or emptying the bladder is called,
Voiding has both voluntary and involuntary components. The voluntary spinchter is the ____ spinchter.
External urethral
An inability to control this spinchter is referred to as ____.
What is the function of the fat cushion that surrounds the kidneys in life?
Perirenal fat capsules anchor the kidneys to the dorsal body wall in a retroperitoneal position & cushions it against blows.
Define ptosis.
Kidneys are less securely anchored and drop to a more inferior position.
Why is incontinence a normal phenomenon in the child under 1 1/2 to 2 years old?
Because they have not yet gained muscle control over their external spincter.
What events may lead to incontinence in adults?
Spinal cord injury, emotional problems, bladder irritability, or some other pathology of the urinary tract.
Smooth membrane, tightly adherent to the kidney suface
Fibrous capsule
Portion of the kidney containing mostly collecting ducts
Portion of the kidney containing the bulk of the nephron structures
Superficial region of kidney tissue
Basinlike area of the kidney, continuous with the ureter
Renal pelvis
A cup-shaped extension of the pelvis that encircles the apex of a pyramid
Minor calyx
Area of cortical tissue running between the medullary pyramids
Renal column
Site of filtrate formation
Primary site of tubular reabsorption
Proximal convulated tubule
Secondarily important site of tubular reabsorption
Distal convulated tubule
Structure that conveys the processed filtrate (urine) to the renal pelvis
Collecting duct
Blood supply that directly receives substances from the tubular cells
Peritubular capillaries
Its inner (visceral) membrane forms part of the filtration membrane
Glomerular capsule
Explain why the glomerulus is such a high-pressure capillary bed.
1) The bed is fed and drained by arterioles (high-resistant vessels), 2) The afferent arteriole (feeder) is larger in diameter than the efferent arteriole (draining).
How does its high pressure condition aid its function of filtrate formation?
The higher the capillary pressure, the more filtrate will be formed.
What structural modification of certain tubule cells enhances their ability to reabsorb substances from the filtrate?
Their possession of dense microvilli, especially the PCT cells.
Explain the mechanis of tubular secretion, and explain its importance in the urine formation process.
1) Its the process of moving substances (hydrogen, potassium ions, creatinine) from the tubule cells or from the peritubular capillary into the tubule filtrate. 2) It's important for adjusting pH and eliminating substances not already in the filtrate.
Compare and contrast the composition of blood plasma and glomerular filtrate.
1) Blood plasma contains red/white blood cells, blood proteins, glucose, water, nitrogenious wastes, and salt. 2) Glomerular filtrate contains everything blood plasma does without most of the blood proteins.
Trace a drop of blood from the time it enters the kidney via the renal artery until it leaves the kidney through the renal vein.
Renal artery-->segmental artery-->interlobular artery-->arcuate artery-->cortical radiate artery-->afferrent arterioles-->glomerulus-->efferent arterioles-->peritubular capillary bed and vasa recta--> arcuate vein-->interlobular vein-->renal vein
Define juxtaglomerular apparatus.
A region of the nephron that plays an important role in forming concentrated urine. Consists of juxtaglomerular & macula densa cells of the DCT.
Trace the anatomical pathway of a molecule of creatinine (metabolic waste) from the glomerular capsue to the urethra.
Glomerular capsule-->proximal convulated tubule-->loop of Henle-->distal convulated tubule-->collecting tubule-->papillary duct-->minor calyx-->major calyx-->renal pelvis-->ureter--> bladder-->urethra
What is imporant functionally about the specialized epithelium (transitional epithelium) in the bladder?
They have the ability to slide over one another, thus decreasing the thickness of the mucosal layer as the bladder fills & streches to accomadate the increased urine volume.
How does the position of the kidneys in the cat differ from their position in the humans?
Cat- the kidneys are located at the same level or the right kidney is anterior. Human- the left kidney is more superior.
In what way is the position of the kidneys in the cat and human similar?
Both are retroperitoneal
Carries urine from the kidney to the urinary bladder
Carries urine from the urinary bladder to the outside.
How does the site of urethra emptying in the female cat differ from its termination point in the human female?
Cat- empties into the "urogenital sinus" along with the vagina. Human- empties into the body exterior.
What is a urogenital sinus?
The common chamber into which both the vagina and urethra empty.
What gland encircles the neck fo the bladder in the male?
Prostate gland
Is the prostate gland apart of the urinary system?
No, its apart of the reproductive system.
What's the function of the prostate gland?
Produces a secretion, which contributes to seminal fluid.
Compare the location of the adrenal glands in the cat versus the humans.
Cat- It lies superior, separated and medial to the kidney, close to the inferior vena cava. Human- it lies directly on top of the kidneys
How many pyramids did the cat kidney have?