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Urinary Elimination
Physiology of Urine Elimination
•Urinary Elimination depends on effective functioning of:
- 1.Upper urinary tract (kidneys and ureters)
- 2.Lower urinary tract (bladder, urethra, and pelvic floor)
- 3.Cardiovascular system
- 4.Nervous system
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Kidneys
- •Right and left kidneys are located on either side of the spinal column and behind the peritoneal cavity (retro-peritoneal)
- •Located at the level of T12 through L3
- •The right kidney is lower than the left because of the liver
- •They are the primary regulators of fluid and acid–base balance in the body
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Nephron
- •The functional unit of the kidney
- •Filters blood and removes metabolic wastes
- •Urine is formed here
- •Urine is formed through a process of filtration, reabsorption, and secretion
- •Each kidney contains approximately 1 million nephrons
- •Each nephron has a glomerulus
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• A tuft of capillaries surrounded by the Bowman’s capsule
• The endothelium of the ________ are very porous which allows fluids and solutes to easily flow through. It moves across that membrane into the Bowman’s capsule.
Glomerulus
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Filtrate moves from here into the tubule of the nephron
* Bowman’s Capsule
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Where most of the water and electrolytes are reabsorbed
* Proximal Convoluted Tubule
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• Solutes such as glucose are reabsorbed here
• Other substances secreted (they concentrate the urine)
* Loop of Henle
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Additional water and sodium are reabsorbed here under control of hormones (ADH/anti diuretic hormone and aldosterone). This control reabsorption allows for fine regulation of fluid and electrolyte balance in our body.
* Distal Convoluted Tubule
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Formed Urine
• Once the urine is formed in the kidneys it moves through the collecting ducts in the calyces of the renal pelvis. From there it goes into the ureters and then into the urinary bladder. From the urinary bladder it travels to the urethra and is excreted from the body.
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Bladder
- • Also called the vesicle
- • It is a hollow, muscular organ that serves as a reservoir for urine and as the organ of excretion (because it holds the urine then excretes the urine)
- • When it is empty it lies behind the synthesis pubis
- • In men it lies in front of the rectum above the prostate gland
- • In women it lies in front of the uterus and vagina
- •Capable of a considerable amount of distention because of the folds (rugae). These folds are in the mucous membrane lining and they are very elastic
- •Normal bladder capacity is between 300 and 600 mL of urine
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Urination
- •All these terms refer to the process of emptying the urinary bladder-micturition, voiding, and urination
- •Urine collects in the bladder, the urine stimulates the stretch receptors in the bladder wall, the stretch receptors send an impulse to the spinal cord voiding reflex center, and the internal sphincter will relax and stimulate the urge to void. If time and place are appropriate for urination, the conscious portion of the brain relaxes the external urethral sphincter muscle and urination takes place. (some pt with neurological or spinal disorders may not be able to hold it because of the impulses that are sent to the spinal cord)
- •The micturition reflex usually won’t subside until you urinate
- •Women can hold urine longer than men because they have a longer urethra
- •In an adult urination usually occurs after 250 to 400 mL of urine has been collected in the bladder
- •In children urination usually occurs after 50 to 200 mL of urine has been collected in the bladder
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Developmental Factors:
- •An infant may urinate as many as 20 times a day
- •The urine of a neonate is colorless and odorless because the kidneys of the newborn are immature and are unable to concentrate urine very effectively
- •Infants are born without urinary control. Control is normally gained between the ages of 2 to 5 yrs. Usually have more control during the daytime than at night no matter what the age.
- •The kidneys will double in size between the ages of 5 to 10 yrs.
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Developmental Factor that is defined as the involuntary passing of urine when control should be established (about 5 yrs of age)
* Enuresis
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Developmental Factors: _______ or (bed-wetting) is the involuntary passing of urine during sleep (this shouldn’t be considered a problem until after the age of 6)
• Nocturnal enuresis
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Developmental Factors:
• As you get older the excretory function of the kidney decreases (they won’t work as affectively) and the capacity of the bladder and its ability to empty completely will also diminish (this is the reason many elderly people have to get up many times during the night to urinate).
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Psychosocial Factors
- •For many people, they have to be in familiar settings or feel comfortable to urinate. This includes privacy, normal position (it is harder for a man to urinate in a bed pan lying down), sufficient time (women can usually urinate much easier than men…the majority of men cannot urinate on demand but most women can), and occasionally running water.
- •When a person becomes anxious in regards to urination, they will be unable to relax abdominal and perineal muscles and the external urethral sphincter, and will not be able to void.
- •People often suppress the urge to urinate due to time measures (this can increase the risk of urinary tract infections)
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Medications
• Medications will play a role in how frequently a pt will urinate. If they are taking lasix or some type of anti diuretic then they will urinate frequently.
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is known as excessive thirst
• Polydipsia
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is low urine output, usually less than 500mL a day or 30 mL an hour for an adult (if you don’t have at least 30 mL an hour then notify physician because this can indicate that there is impaired blood flow to the kidneys or impending renal failure)
• Oliguria
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Altered Urine Production: _________refers to the production of abnormally large amts of urine by the kidneys, often several liters more than the client’s usual daily output (can cause you to lose a lot of fluid and can lead to an intense thirst, dehydration, and weight loss)
Polyurea (diuresis)
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refers to a lack of urine production
• Anuria
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Altered Urinary Elimination: ___________ is voiding two or more times at night
• Nocturia
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Altered Urinary Elimination:
_________ is voiding at frequent intervals, that is, more than 4 to 6 times per day (4-6 times per day is normal for an adult)
• Urinary frequency
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Altered Urinary Elimination:
_________ is the sudden strong desire to void
•Urgency
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Altered Urinary Elimination:
_____________ means voiding that is either painful of difficult
• Dysuria
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Altered Urinary Elimination:
___________ is involuntary urination (this is a symptom, not a disease). This can have a significant impact on a pt life, causing embarrassment, skin breakdown, isolation, and social withdrawal.
• Urinary Incontinence
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Altered Urinary Elimination:
______________is where the bladder is impaired and urine accumulates and the bladder becomes overdistended. (During a physical assessment if you palpate over a distended bladder you may cause the client to urinate on themselves or you may cause them pain)
• Urinary Retention
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Altered Urinary Elimination:
_____________ is impaired neurologic function that can interfere with normal mechanisms of urine elimination.
• Neurogenic Bladder
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Altered Urinary Elimination:
If the kidneys don’t function appropriately then your client will probably have to have ___________. This is a mechanism of filtering the blood and its necessary to prevent illness or death. Its technique by which fluids and molecules pass through a semipermeable membrane.
• Renal Dialysis
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Altered Urinary Elimination:
__________ is where the client’s blood flows through vascular catheters which allow for the exchange of fluid and solutes. They go in and out of the catheter and into a dialysis machine with dialysis solution. The solution is regulated on the client’s electrolytes. (So before the physician orders the dialysis the client will have blood drawn and if they are low on potassium, magnesium, etc then they will increase the potassium, magnesium, etc in the dialysis solution)
*Hemodialysis
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Altered Urinary Elimination:
________ is where the dialysis solution is instilled into the abdominal cavity through a catheter. The solutes and solution go into the abdominal cavity and sit there and mix around and pull out and put in what they need to in the abdominal cavity. Then the solution is removed through the dialysis machine.
*Peritoneal dialysis
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Excess water and toxic waste in the form of urine leaves the kidney via the __________.
ureter
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Blood without waste or excess water leave the kidney through the ___________.
Renal Vein
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Blood, waste & water enter the kidney at the _____________.
Renal Artery
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