Lecture 24
Urinary System
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Urinary System Anatomy
Anterior
Kidney
Ureter
Stomach
Pancreas
Large intestine
Abdominal aorta
Liver
Renal vein
Renal artery
Inferior vena
cava
Right kidney
Renal hilum
Fibrous capsule
Spleen
Fat
Urinary
bladder
Urethra
(a) Anterior view
Rib
Left kidney
Posterior
Fig. 27.2
Fig. 27.1
External Anatomy of Kidneys
•Renal capsule
–surrounds each kidney
•Hilum
–renal artery and nerves enter and renal vein and ureter exit kidneys
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Internal Anatomy of Kidneys
• Renal cortex: Outer area
– Renal columns
• Renal medulla: Inner
area
– Renal pyramids
• Calyces
Fig. 27.3
– Major: Converge to
form renal pelvis
– Minor: Collects urine
from individual renal
pyramid
• Nephron: Functional
unit of kidney
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• Renal corpuscle
The Nephron
– Bowman’s capsule
– Glomerulus
• network of capillaries
• Arterioles
– Afferent
• blood to glomerulus
– Efferent
• drains
• Tubules
– Proximal (convoluted) tubule
– Loops of Henle
• Descending limb
• Ascending limb
Fig. 27.5
– Distal (convoluted) tubule
• Collecting ducts
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Ureters and Urinary Bladder
• Ureters
– tubes through which urine
flows from kidneys to
urinary bladder
• Urinary bladder
Ureter
Peritoneum
– stores urine
• Urethra
– transports urine from
bladder to outside of body
– difference in length
between males and females
– sphincters
• Internal urinary
• External urinary
Ureteral openings
Neck of urinary bladder
Internal urethral
sphincter
External urethral sphincter
Fig. 27.9
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Review Question
Think back for a moment to the lectures on histology.
What type of epithelium would line the inside of the
ureters and urinary bladder?
(a) Stratified squamous
(b) Pseudostratified columnar
(c) Simple cuboidal
(d) Transitional
(e) Simple squamous
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Points to Remember
• Kidney filters blood to eliminate metabolic wastes
(e.g. urea formed from ammonia that is removed
from blood by liver) and reabsorb substances such
as sugars, amino acids, sodium and chloride
• Functional unit of kidney is nephron
• Ureters, urinary bladder and urethra transport
urine (product of nephron) outside of body
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Questions?
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