The document provides an overview of the urinary system, including its key components and functions. It describes the kidneys, nephrons, and how they filter waste from the blood and produce urine. It then explains how the ureters, urinary bladder, and urethra work together to transport, store, and eliminate urine from the body. The document features several diagrams labeling the structures and pathways of the urinary system.

1. © 2012 Pearson Education, Inc.
26
The Urinary System
PowerPoint® Lecture Presentations prepared by
Steven Bassett
Southeast Community College
Lincoln, Nebraska

2. Introduction
The urinary system includes the kidneys, the ureters,
the urinary bladder, and the urethra.
 Performs vital excretory functions:
 Regulating plasma concentrations of ions
 Regulating blood volume and blood pressure by
adjusting the volume of water lost in the urine,
releasing erythropoietin, and releasing renin
 Contributing to the stabilization of blood pH
 Conserving valuable nutrients
 Eliminating organic waste products
 Synthesizing calcitriol.
 Assisting the liver in detoxifying poisons
© 2012 Pearson Education, Inc.

3. Introduction
• The urinary system consists of:
• Kidneys
• And the associated nephrons
• Ureters
• Urinary bladder
• Urethra
© 2012 Pearson Education, Inc.

4. Figure 26.1a An Introduction to the Urinary System
Kidney
Produces urine
Ureter
Transports urine
toward the
urinary bladder
Urinary bladder
Temporarily stores
urine prior
to elimination
© 2012 Pearson Education, Inc.
Anterior view showing the
components of the urinary system
Urethra
Conducts urine to
exterior; in males,
transports semen
as well
Suprarenal gland
Renal artery
and vein
Inferior
vena cava
Aorta

5. The Kidneys
Urine-producing organ of the urinary system
 Two kidneys in the retroperitoneal area
 Left kidney is higher than the right kidney
On top of each kidney a suprarenal gland is sitting.
 Contain millions of tiny nephrons
Blood is provided to the nephrones for filtration through
afferent arterioles.
The filtrate passes through the renal tubules and final
product (urine) reaches the collecting duct. The urine
leaves the collecting ducts towards minor and major
calyces. Urine from major calyces enter into the renal
pelvis, before leaves the kidney through ureters to the
bladder.
© 2012 Pearson Education, Inc.

6. Figure 26.1c An Introduction to the Urinary System
Diagrammatic cross section, as viewed from above, at
the level indicated in part (b)
External
oblique
Stomach
Parietal
peritoneum
Ureter
Spleen
Anterior
renal
fascia
Left
kidney
© 2012 Pearson Education, Inc.
Renal vein
Renal artery
Inferior
vena cava
Aorta
Adipose
tissue
Spinal
cord
Psoas
major
Quadratus
lumborum
Pararenal
fat
Perinephric
fat
Posterior
renal fascia
Fibrous
capsule
Pancreas
Vertebra

7. Figure 26.2a The Urinary System in Gross Dissection
Diaphragm
Inferior vena cava
Celiac trunk
Right suprarenal
gland
Right kidney
Hilum
Quadratus
lumborum
muscle
Iliacus muscle
Psoas major
muscle
Peritoneum
(cut)
Rectum (cut)
Urinary bladder
Diagrammatic anterior view of the abdominopelvic cavity showing
the kidneys, suprarenal glands, ureters, urinary bladder, and blood
supply to the kidneys
© 2012 Pearson Education, Inc.
Esophagus (cut)
Left suprarenal gland
Left kidney
Left renal artery
Left renal vein
Superior
mesenteric
artery
Left ureter
Abdominal
aorta
Left common
iliac artery
Gonadal artery
and vein

8. Figure 26.3a Structure of the Kidney
Inner layer of
fibrous capsule
© 2012 Pearson Education, Inc.
Medulla
Hilum
Ureter
Frontal section through the left kidney showing
major structures. The outlines of a renal lobe and a
renal pyramid are indicated by dotted lines.
Renal sinus
Adipose tissue
in renal sinus
Renal pelvis
Hilum
Renal papilla
Ureter
Major calyx
Cortex
Medulla
Renal
pyramid
Connection to
minor calyx
Minor
calyx
Renal lobe
Renal columns
Outer layer of
fibrous capsule
Outer layer of
fibrous capsule
Renal
pyramids
Renal sinus
Inner layer of
fibrous capsule
Renal pelvis
Major calyx
Minor calyx
Renal papilla
Renal lobe
Fibrous capsule

9. Figure 26.4a Blood Supply to the Kidneys
Interlobular
veins
Cortical
radiate
arteries
Interlobar
arteries
Segmental
artery
Suprarenal
artery
Renal
artery
Renal
vein
© 2012 Pearson Education, Inc.
Sectional view showing major arteries and
veins. Compare with Figures 26.3 and 26.8.
Arcuate
veins
Arcuate
arteries
Interlobar
veins

10. © 2012 Pearson Education, Inc.

11. The Kidneys
• Structure and Function of the Nephron
• Waste (glomerular filtrate) material leaves the
glomerular capillaries and enters:
• Glomerular capsule
• Proximal convoluted tubule (PCT)
• Nephron loop
• Distal convoluted tubule (DCT)
© 2012 Pearson Education, Inc.

12. The Kidneys
• Structure and Function of the Nephron
• Filtrate enters the DCT of several nephrons and
empties into a common tube called the
collecting duct
• Filtrate enters the papillary duct
• Minor calyx
• Major calyx
• Ureter
• Urinary bladder
• Urethra
© 2012 Pearson Education, Inc.

13. Figure 26.7a Histology of the Nephron
© 2012 Pearson Education, Inc.
Cortical
nephron
Juxtamedullary
nephron
Orientation of cortical and juxtamedullary
nephrons
Proximal convoluted
tubule
Renal corpuscle
Distal convoluted
tubule
Connecting tubules
Nephron
loop
Thin descending
limb
Thick ascending
limb
Collecting duct
Papillary duct
Renal papilla
Minor calyx
Cortex
Medulla

14. Figure 26.7ac Histology of the Nephron
Orientation of cortical and juxtamedullary
nephrons
© 2012 Pearson Education, Inc.
Cortical
nephron
Juxtamedullary
nephron
Proximal convoluted
tubule
Renal corpuscle
Distal convoluted
tubule
Connecting tubules
Nephron
loop
Thin descending
limb
Thick ascending
limb
Collecting duct
Papillary duct
Renal papilla
Minor calyx
Cortex
Medulla
Renal corpuscle LM ´ 140
The renal corpuscle
Visceral epithelium
Parietal epithelium
Capsular space
Distal convoluted
tubule
Proximal convoluted
tubule
Glomerulus

15. Figure 26.6 A Typical Nephron
© 2012 Pearson Education, Inc.
NEPHRON
PROXIMAL CONVOLUTED TUBULE
DISTAL CONVOLUTED TUBULE
RENAL CORPUSCLE
NEPHRON LOOP
COLLECTING SYSTEM
Connecting tubules
CONNECTING TUBULES
AND COLLECTING DUCT
Variable reabsorption
of water and
reabsorption or
secretion of
sodium, potassium,
hydrogen, and
bicarbonate ions
PAPILLARY DUCT
Nucleus
Microvilli
Mitochondria
Reabsorption of water, ions, and
all organic nutrients
Secretion of
ions, acids,
drugs, toxins
Variable reabsorption of water,
sodium ions, and calcium ions
(under hormonal control)
Renal tubule
Efferent arteriole
Afferent arteriole
Ascending
limb of
loop ends
Ascending
limb
Descending
limb of
loop ends
Descending
limb
Parietal (capsular)
epithelium
Capsular space
Visceral
(glomerular)
epithelium
Capillaries of
glomerulus
Production of filtrate
Thin
descending
limb
Thick
ascending
limb
Further reabsorption of water (descending limb) and
both sodium and chloride ions (ascending limb)
Minor
calyx
Delivery of
urine to
minor calyx
Collecting duct

16. Figure 26.8c The Renal Corpuscle
Macula densa
© 2012 Pearson Education, Inc.
The renal corpuscle.
Arrows show the
pathway of blood
flow.
Efferent
arteriole
Distal convoluted
tubule
Juxtaglomerular
complex
Juxtaglomerular
cells
Extraglomerular
mesangial cells
Afferent
arteriole
Glomerular capsule
Tubular
pole
Proximal
convoluted
tubule
Capsular space
Glomerular
capillary
Parietal
epithelium
Visceral
epithelium
(podocyte)
Vascular pole

17. © 2012 Pearson Education, Inc.

18. Structures for Urine Transport, Storage, and
Elimination
 Ureters
 Urinary bladder
Contains detrusor muscle, which compresses the
urinary bladder to eliminate the urine.
Voluntary urination needs compression of detrusor
muscle and relaxation of external sphincter.
 Urethra
There are significant differences between the male and
female urethra.
The parts of urethra in male:
 Prostatic urethra
 Membranous urethra
 Penile urethra
© 2012 Pearson Education, Inc.

19. Figure 26.10 Organs Responsible for the Conduction and Storage of Urine
Peritoneum Left ureter Rectum
Urinary
bladder
External
urethral
sphincter
Spongy
urethra
Median umbilical
ligament (urachus)
Ureter
Lateral
umbilical
ligament
Detrusor
muscle
Ureteral
openings
Internal urethral
sphincter
© 2012 Pearson Education, Inc.
Anatomy of the urinary
bladder in a male
Position of the ureter, urinary
bladder, and urethra in the female
Right
ureter
Base of
urinary
bladder
The male urinary bladder and accessory reproductive
structures as seen in posterior view
Position of the ureter, urinary
bladder, and urethra in the male
Pubic
symphysis
Prostate
gland
Urogenital
diaphragm
Urethra
[see part c]
External
urethral
orifice
Vestibule
Rectum
Right ureter
Uterus
Peritoneum
Urinary
bladder
Pubic
symphysis
Internal urethral
sphincter
Urethra
External urethral
sphincter (in
urogenital diaphragm)
Vagina
Peritoneum
Ductus
deferens
Seminal
gland
Posterior surface
of prostate gland
Prostatic
urethra
Trigone
Center of
trigone
Neck of
urinary
bladder
Prostate
gland
Prostatic
urethra
Membranous
urethra
External urethral
sphincter (in urogenital
diaphragm)
Rugae

20. Aging and the Urinary System
A decline in the number of functional nephrons
 A reduction in glomerular filtration
 Reduced sensitivity to ADH
 Problems with the micturition reflex related to the
following factors:
 Loss of tone in sphincter muscles leading to
incontinence
 Strokes, Alzheimer’s disease, or other CNS problems
impair ability to control micturition
 Urinary retention may develop in men whose prostrate
glands are enlarged
© 2012 Pearson Education, Inc.