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Chapter 26
Urinary System
Functions:
1. Excretion: removal of waste products from body fluids
2. Elimination: discharge of waste products from body
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Chapter 26
Urinary System
Consists of the
• Kidneys: produce urine
• Ureters: pathway of urine
from kidneys to bladder
• Urinary bladder: muscular
sac for temporary storage of
urine
• Urethra: urine removal
pathway
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Location of Kidneys
Located on either side of the vertebral column (T12-L3)
Superior surface is capped with the adrenal gland.
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Protection of Kidneys
Renal capsule: inner layer of collagen
Adipose capsule: thick layer of adipose tissue
Renal Fascia: outermost layer of collagen
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Kidney Structure
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Kidney Structure
2 layers:
1.Cortex: superficial portion, contains nephrons
• Nephron: microscopic, tubular structures that beings
urine production
2. Medulla: consists of 6-18 renal pyramids
• Renal lobe: renal pyramid + renal cortex
• where urine is produced
• Renal Pelvis: large chamber which connects the renal lobes
to the ureter
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Functions of the Kidneys
• Removal of metabolic wastes from the blood and excretion to
the outside of the body
• Regulation of blood pressure, calcium ion absorption, and the
volume, composition, and pH of the blood
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Renal Blood Vessels
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Renal Blood Vessels
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Renal Blood Vessels
• Kidneys receive 20-25% of total cardiac output
•Receives blood from the renal artery  segmental arteries 
interlobar arteries  arcuate arteries  interlobular arteries
 afferent arterioles  deliver blood to nephrons 
interlobular veins  arcuate veins  interlobar veins  renal
vein
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Structure of a Nephron
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Structure of a Nephron
•Renal tubule: long pathway that starts at the renal corpuscle
•Renal corpuscle: contains a glomerulus, where the capillaries
are found, where filtration takes place
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Pathway of filtration of a
Nephron
•Blood filters into the afferent arteriole  Renal corpuscle
(Glomerulus and Bowman’s capsule)  Proximal convoluted
tubule (where reabsorption of water, ions, organic nutrients)
 down Renal tubule  Loop of Henle ( further reabsorption
 of water)  up Renal tubule  Distal convoluted tubule
 (secretion of acids, drugs, toxins)  collecting duct 
Papillary duct (all excess waste—urine– to minor calyx 
major calyx  ureter
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Glomerular Capsule
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stop
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Juxtaglomerular Apparatus
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Cortical and Juxtamedullary Nephrons
• cortical nephrons
• 80% of nephrons
• located close to the surface
of the kidney
• juxtamedullary nephrons
• regulate water balance
• located near the renal
medulla
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Urine Formation
• nephrons remove wastes from the blood and
regulate water and electrolyte concentrations
• urine is the final product of the processes of:
• glomerular filtration
• tubular reabsorption
• tubular secretion
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Urine Formation
• Glomerular Filtration
• substances move from blood to glomerular capsule
• Tubular Reabsorption
• substances move from renal tubules into blood of
peritubular capillaries
• glucose, water, urea, proteins, creatine
• amino, lactic, citric, and uric acids
• phosphate, sulfate, calcium, potassium, and sodium ions
• Tubular Secretion
• substances move from blood of peritubular capillaries into renal
tubules
• drugs and ions
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Urine Composition
• about 95% water
• usually contains urea, uric acid, and creatinine
• may contain trace amounts of amino acids and
varying amounts of electrolytes
• volume varies with fluid intake and environmental
factors
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Ureters
•Leave the kidneys
•25-30 cm long
•parallel to vertebral column
• in pelvic cavity, join
urinary bladder
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Urinary Bladder
• hollow, muscular organ located within the pelvic cavity,
posterior to the Symphysis pubis
•Can hold up to a liter of urine (rugae)
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Urinary Bladder
• the internal floor of the bladder includes a triangular
area called the trigone
•Internal urethral sphincter: provide control over
bladder
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Urethra
• tube that conveys urine from the urinary bladder to the
outside of the body
• Men: 18-20 cm
• Connects to the prostate/ejaculatory ducts
• Female: 3-5 cm
•External urethral sphincter
•UTI
•Incontinence
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Life-Span Changes
• kidneys appear scarred and grainy
• kidney cells die
• by age 80, kidneys have lost a third of their mass
• kidney shrinkage due to loss of glomeruli
•harder for kidneys to clear certain substances
• bladder, ureters, and urethra lose elasticity
• bladder holds less urine
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Formal Lab Write-up  DUE
• Heading
• Name, title (be creative),
date
• Experiment
• STEP BY STEP instructions
on what happened
• Problem
• What are you testing and
why?
• Observations
• What did you see, smell,
hear?
• Hypothesis
• What do you think you will
discover after the
experiment?
• Discussion
• What do you know NOW?
• Materials
• LIST of every tool required
• Conclusion
• Summary of what
happened, what errors
occurred, why this
experiment was useful
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Matching
a. Functional Unit of the Kidney
1. Cortex
2. Bowman’s Capsule
3. Loop of Henle
4. Renal Pelvis
5. Nephron
6. Ureter
b. Transports Urine to Bladder
c. U-shaped tubule
d. Covers the surface of the
e.
f.
g.
7. Hilus
8. Renal Capsule
h.
kidney
Surrounds glomerulus
Outer layer of kidney
Area on kidney where blood
vessels, nerves, lymphatics,
and ureters enter/exit
Drains major calyx
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Matching
1. Cortex (F)
2. Bowman’s Capsule (E)
3. Loop of henle (C)
4. Renal Pelvis (H)
5. Nephron (A)
a.
b.
c.
d.
e.
f.
g.
6. Ureter (B)
7. Hilus (G)
8. Renal Capsule (F)
h.
Functional Unit of the Kidney
Transports Urine to Bladder
U-shaped tubule
Covers the surface of the kidney
Surrounds glomerulus
Outer layer of kidney
Area on kidney where blood vessels,
nerves, lymphatics, and ureters
enter/exit
Drains major calyx
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Short Answer
• What are some anatomical differences with
the male versus female urinary structures and
how do they affect the physiology?
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Short Answer
• What are some anatomical differences with
the male versus female urethra and how do
they affect the physiology?
• Males have longer urethra = fewer UTI’s, less
urgency for urination
• Ejaculatory/prostate ducts connect to males
urethra = urethra doesn’t just carry urine
How do the following tests relate to a urinalysis?
Leukocytes
Nitrites
Protein
pH
Blood
Specific Gravity
Ketone
Bilirubin
Glucose
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Meaning
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Leukocytes
Only found in individuals who are fighting a bacterial/viral
infection
Nitrites
Only found in individuals with significant infections
Protein
Found in individuals with kidney disease/damage
pH
If increased ketone levels, there will be a more acidic
urine
Blood
Only present if trauma, UTI, or recent menstruation
Specific Gravity
Degree of concentration/dilution of urine (amount of
excess water)
Ketone
Positive with excessive lipid breakdown
Bilirubin
Rare-breakdown of hemoglobin
Glucose
Excess-hyperglycemia