Term
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Definition
| Removal of electrolytes, nitrogenous waste (urea, uric acid), water, hydrogen ions etc... from the blood. |
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Term
| Basic Functions of the Urinary System |
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Definition
1. Waste elimination - Removal of electrolytes, nitrogenous waste (urea, uric acid), water, hydrogen ions etc... from the blood.
2. Maintain blood volume and composition.
3. Maintain blood pressure.
4. Regulate blood pH.
5. Regulate metabolism (ex. RBC production, glucose production and Vitamin D synthesis) |
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Term
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Definition
| - Two retroperitoneal structures located laterally to the spine, between T12 and L3. |
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Term
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Definition
| - Contains nephrons (blood filtering structures). Region deep to the capsule. |
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Term
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Definition
- Contains two distinct areas:
(a) Renal Columns - areas containing nephrons
(b) Renal Pyramids - areas containing the tubules that carry urine away from the nephron. |
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Term
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Definition
| - An expansion of the upper end of the Ureters. This receives urine from the Renal Pyramids. |
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Term
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Definition
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Term
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Definition
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Term
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Definition
- The functional unit(s) of the Kidney.
- Over 1 million.
- Two parts:
(1) Renal Corpuscle
(2) renal tubule |
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Term
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Definition
| - A tuft of capillary loops that are connected to arterioles. (i.e. Afferent Arterioles -> Glomerulus-> Efferent Arterioles -> capillary bed ->venous return) |
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Term
| ) Glomerular (Bowman's) capsule |
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Definition
- A double walled structure that surrounds the Glomerulus. This collects glomerular filtrate.
- parietal layer = simple squamous epithelium
- visceral layer is made up of Podocytes (modified simple squamous epithelium), these have pedicels (i.e. foot-like projections that wrap around the glomerular capillaries.) |
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Term
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Definition
(a) Proximal Convoluted Tubule
(b) Loop of Henle
- Descending and Ascending Limbs
(c) Distal Convoluted Tubule
- This drains into Collecting Tubules which ultimately drain into the Renal Pelvis.
(d) Juxtaglomerular apparatus (JGA) – consists of juxtaglomerular cells of the afferent arteriole and the Macula Densa of the ascending limb of the Loop of Henle
Help regulate blood pressure |
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Term
| Juxtaglomerular apparatus (JGA) – |
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Definition
consists of juxtaglomerular cells of the afferent arteriole and the Macula Densa of the ascending limb of the Loop of Henle
Help regulate blood pressure |
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Term
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Definition
| - This drains into Collecting Tubules which ultimately drain into the Renal Pelvis. |
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Term
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Definition
- 10 to 12 inches in length, extend from the Renal Pelvis to the Urinary Bladder, conveys urine
- Retroperitoneal
- Lined with mucous producing Transitional Epithelium
- As the Urinary Bladder fills it produces pressure on the distal end of the Ureter. This helps prevent the back flow of urine. |
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Term
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Definition
- A retroperitoneal, hollow, muscular organ that lies posterior to the Pubic Symphysis. For urine storage.
- Lined with mucous secreting Transitional Epithelium
- Detrusor muscle = 3 layers of smooth muscle that surrounds the Urinary Bladder
- Trigone = The triangular shaped area at the base of the Urinary Bladder. This is outlined by the two Ureters and the Urethra. |
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Term
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Definition
| The triangular shaped area at the base of the Urinary Bladder. This is outlined by the two Ureters and the Urethra. |
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Term
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Definition
| 3 layers of smooth muscle that surrounds the Urinary Bladder |
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Term
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Definition
- Extends from the floor of the Urinary Bladder to the external environment, drains the bladder.
- Two sphincters:
a. Internal Urethral Sphincter
- Smooth muscle, located at the base of the Urinary Bladder.
b. External Urethral Sphincter
- Skeletal muscle, located on the pelvic floor.
- Female urethra ~1 1/2 in. in length
- Male urethra ~8 in. in length
- Passes through the Prostate Gland, then joins the Reproductive system. |
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Term
a. Internal Urethral Sphincter
b. External Urethral Sphincter |
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Definition
- Smooth muscle, located at the base of the Urinary Bladder.
- Skeletal muscle, located on the pelvic floor. |
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Term
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Definition
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Term
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Definition
| Discharge of urine from the Urinary Bladder. Voiding. |
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Term
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Definition
Lack of voluntary control over urination
(and/or bowel movements) |
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Term
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Definition
- Blood pressure forces water and dissolved substances out of the Glomerulus into the Glomerular Capsule, forming Glomerular Filtrate.
- The Glomerular Filtration Rate is directly proportional to the pressure in the arterioles (Afferent, Efferent and Glomerulus), which is influenced by the SNS.
i.e. Net Filtration Pressure (NFP)
- Myogenic Mechanism: When the smooth muscle in the afferent arteriole is stretched this smooth muscle contracts to slow the rate of flow. These smooth muscle fibers relax when blood flow slows down.
- Tubuloglomerular Feedback: The Macula Densa detects high levels of sodium and chloride ions, and water and then provide feedback to the Glomerulus. This leads to constriction of the afferent arterioles, slowing blood flow to the Glomerulus.
- The average Glomerular Filtration Rate (GFR) is around 125 ml/min.
- The capillaries that make up the Glomerulus are more permeable than the other capillaries of the body.
- Except for protein, Glomerular Filtrate contains approx. the same substances (and amounts) as blood plasma |
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Term
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Definition
| When the smooth muscle in the afferent arteriole is stretched this smooth muscle contracts to slow the rate of flow. These smooth muscle fibers relax when blood flow slows down. |
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Term
| Tubuloglomerular Feedback: |
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Definition
| The Macula Densa detects high levels of sodium and chloride ions, and water and then provide feedback to the Glomerulus. This leads to constriction of the afferent arterioles, slowing blood flow to the Glomerulus. |
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Term
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Definition
Returning water and solutes back to the blood stream.
- Approx. 99% of glomerular filtrate is reabsorbed, leaving 1 to 2 liters of urine to be voided each day.
- Most reabsorption occurs in the PCT. |
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Term
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Definition
| The production and release of a substance from a cell. Generally, this is anything that enters the Renal Tubule, ex. penicillin, histamine, hydrogen ions, urea, potassium, etc.... |
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Term
| Tubular Reabsorption and Secretion |
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Definition
- Under normal conditions, all glucose and amino acids are reabsorbed in the PCT. When glucose concentration in the blood is 200 mg/ml or above, not all of the glucose is reabsorbed, causing Glucosuria. This may indicate Diabetes Mellitus, but you must be sure that the person with Glucosuria has not recently ingested large amounts of sugar.
- Most water is reabsorbed via osmosis as sodium and other ion are reabsorbed by the Nephron.
- Antidiuretic Hormone (ADH) is released from the Posterior Pituitary Gland when solutes in the blood are too high (i.e. concentrated, dehydration or loss of blood volume. ADH causes increased reabsorption from the Collecting Ducts (Tubules) and Renal Tubule. This action produces a concentrated urine, i.e. raises the Specific Gravity.
ADH also constricts arterioles which increases blood pressure, and decreases the activity of sweat glands (saving water).
- Atrial Natriuretic Peptide (ANP) is release by the Atria when blood volume is too high. This substance suppressed the PCT and Collecting duct, slowing water and sodium resorption. This hormone also inhibits ADH and Aldosterone.
- Blood pH is maintained by the secretion of hydrogen ions and the reabsorption of bicarbonate ions. |
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Term
| Antidiuretic Hormone (ADH) |
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Definition
is released from the Posterior Pituitary Gland when solutes in the blood are too high (i.e. concentrated, dehydration or loss of blood volume. ADH causes increased reabsorption from the Collecting Ducts (Tubules) and Renal Tubule. This action produces a concentrated urine, i.e. raises the Specific Gravity.
ADH also constricts arterioles which increases blood pressure, and decreases the activity of sweat glands (saving water). |
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Term
| Atrial Natriuretic Peptide (ANP) |
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Definition
is release by the Atria when blood volume is too high. This substance suppressed the PCT and Collecting duct, slowing water and sodium resorption. This hormone also inhibits ADH and Aldosterone.
- Blood pH is maintained by the secretion of hydrogen ions and the reabsorption of bicarbonate ions. |
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Term
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Definition
| - Reduced ADH secretion or the inability of tissue to respond to ADH. This leads to high urine volume, dehydration and thirst. This may lead to bed wetting in children. |
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Term
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Definition
| - Any substance that reduces the reabsorption of water, i.e. increasing urine volume. Often used by dieters, and to lower blood pressure. These substances can affect the ion concentration in the blood, especially potassium. |
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Term
| Blood Urea Nitrogen (BUN) |
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Definition
| - A blood test measuring the Nitrogen in Urea (from protein metabolism). An increased BUN may indicate Kidney Disease or Urinary Tract obstruction (failure to remove Urea from the blood). |
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Term
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Definition
| - A measure of how effectively the Kidneys are at removing a substance from the blood plasma. One way to test this is to inject the polysaccharide Inulin into the blood. Inulin is not reabsorbed or secreted by the Renal Tubule, therefore is should steadily build up in the urine. |
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Term
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Definition
| - Separating large solutes from smaller ones by using a selectively permeable membrane, i.e. artificially cleaning the blood. |
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Term
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Definition
| - The average Kidney in a 20 year old is ~260 grams. By the age of 80 this weight is less than 200 grams. Renal blood flow and filtration decreases by 50%. As a person ages they are more susceptible to dehydration and Kidney disorders. |
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Term
| Renal Calculi = Kidney Stones |
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Definition
| - Salt crystals form in the passage ways of the Kidneys. This is often caused by excess calcium or low water intake. Calculi can grow large enough to block the flow through the Ureters. Calculi cause severe pain and metabolic disturbances. |
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Term
| Polycystic Kidney Disease |
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Definition
| - Inherited. Many fluid filled cysts form in the Kidneys. Cysts and defects may also develop in other organs, ex. Cerebral aneurisms, heart valve defects, diverticuli. |
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