Transcript The Urinary Bladder

Composition of the Urinary System
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Functions of the kidney
1.
Removes nitrogenous wastes
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2.
1.
2.
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3.
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Juxtaglomerular
apparatus
RAA system
» Renin
» Angiotensin
» Aldosterone
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4.
Occurs in proximal
convoluted tubule
Also occurs in distal
convoluted tubule
It takes things back into
blood
Secretion
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Via blood filtration &
formation of urine
Occurs in renal corpuscle
Reabsorption
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Regulation of Blood
Pressure
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Filtration
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Fluid balance
Electrolyte balance
Acid-base balance
Excretory Organ
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4.
Urine formation
Maintains homeostasis
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3.
Urea
Uric acid
Creatinine
Ammonia
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Occurs in distal
convoluted tubule
Blood gives things up to
the urine
Concentration
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Occurs in collecting
tubules
See next slide
URINE FORMATION
The Filtration Membrane
From the plasma to the
capsular space, fluid passes
through three barriers.
foot processes
fenestrated
epithelium
basement
membrane
The Filtration Membrane
Almost any molecule smaller
than 3 nm can pass freely
through the filtration membrane
into the capsular space.
These include:
Water, electrolytes, glucose, amino acids,
lipids, vitamins, and nitrogenous wastes
Kidney infections and trauma commonly damage
the filtration membrane and allow plasma
proteins or blood cells to pass through.
Glomerular Filtration Rate (GFR)
- is the amount of filtrate formed per minute
by the two kidneys combined.
- For the average adult male, GFR is about
125 ml/min.
- This amounts to a rate of 180 L/day.
- An average of 99% of the filtrate is
reabsorbed, so that only 1-2 L of urine per
day is excreted.
GFR must be precisely
controlled.
a. If GFR is too high
- increase in urine output
- threat of dehydration and electrolyte
depletion.
b. If GFR is too low
- insufficient excretion of wastes.
c. The only way to adjust GFR from
moment to moment is to change
glomerular blood pressure.
Urine Properties
Composition and Properties of Urine
Fresh urine is clear, containing no blood
cells and little proteins. If cloudy, it could
indicate the presence of bacteria, semen,
blood, or menstrual fluid.
Urine Volume
An average adult produces 1-2 L of urine per
day.
a. Excessive urine output is called
polyuria.
b. Scanty urine output is oliguria. An
output of less than 400 mL/day is
insufficient to excrete toxic wastes.
Diuresis
refers to excretion of large amount of urine.
Natriuresis
refers to enhanced urinary excretion of sodium
Hemodialysis
artificially clearing wastes from the blood
Urine Storage and Elimination
The Ureters
The ureters are muscular tubes leading from the
renal pelvis to the lower bladder.
The Urinary Bladder
- is a muscular sac on the floor of the pelvic cavity.
- is highly distensible and expands superiorly.
The openings of the two ureters and the urethra mark a
triangular area called the trigone on the bladder floor.
The Urethra
- conveys urine from the urinary bladder to the
outside of the body.
Females
3-4 cm
greater risk of
urinary tract
infections
male
~18 cm
• Appearance
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Clear = normal
Cloudy = ? Infection
If sediment = kidney disease
Dark = ?blood, ?bilirubin,
?concentrated
• Color
– Urochrome pigment = yellow
• comes from breakdown of
hemoglobin
– Concentration
• More Concentrated =
Deeper Yellow
– Change of Color From:
• Meds
– Vitamin = yellow
• Diseases
– Blood = red-brown
– Liver = Orange
• Foods
– Rhubarb = red-brown
• Odor
– Normal = ammonia-like smell
• from breakdown of urea
– Unpleasant = ? infection
• Quantity
– Average per 24 hours = 1500 cc
• 60 cc per hour
• GFR = 125 cc/min
– Thus, 7500 cc/ hour
• Urine Made Per Hour = 60 cc
• Urine GFR Per Hour = 7500 cc
– KEY: 1 % of filtered urine
remains urine; 99 % becomes
reabsorbed back into blood
– Oliguria = 100 - 400 cc per day
– Anuria = less than 100 cc per day
– Polyuria = diabetes, nerves, diuretics
Renal Calculi (Kidney Stones)
• Made of crystals of calcium
phosphate and uric acid
• Gradually they get larger until
they block ureters
• First sym severe pain
• Other sym nausea and
vomiting, frequency, chills,
fever, hematuria
• Diagnosis by symptoms,
ultrasound, or x-ray
• Rx –increase fluids to flush out
stone, medications, and if
needed LITHOTRIPSY
Nephritis
• Inflammation of the
kidney (kidney
infection)
• Incontinence –
involuntary urination
Cystitis
• Inflammation of the
mucous membrane lining
of the urinary bladder
• Most common cause –
E.Coli
• Sym- DYSUIA (painful
urination) and frequency
• Usually in females
(shorter urethra)
• Rx - antibiotics
Hematuria
• Hematuria is the presence
of red blood cells in the
urine. Often, the urine
appears normal to the
naked eye, but In gross
hematuria, the urine is red
or the color of cola, which
can be seen with the naked
eye.
Urinary Tract Infection
• What are urinary tract
infections?
• Urinary tract infections are a
serious, but common, health
problem that affects millions of
people each year. With the
reason remaining unclear,
women are especially prone to
urinary tract infections.
• What causes urinary tract
infections?
• Normal urine is sterile and
contains fluids, salts, and waste
products. It is free of bacteria,
viruses, and fungi. An infection
occurs when microorganisms,
usually bacteria from the
digestive tract, cling to the
opening of the urethra, the
hollow tube that carries urine
from the bladder to the outside
of the body, and begin to
multiply.