THE URINARY SYSTEM
Stuctures
• THE KIDNEYS
• THE URETERS
• THE URINARY
BLADDER
• THE URETHRA
Kidney
1. Location and external anatomy
Retroperitoneum
2. Internal anatomy
E
4. Physiology
Renal corpuscle
Nephron
Renal tubes
The tubule
Collecting duct
=> Renal papilla
=> Calyx
=> Ureter
The ureters
Ureterovesical
valve
3. Blood supply
The urinary bladder
• Shaped: A Sac-like hollow organ -> store urine
• Location: Along the body’s midline at the inferior
end of the pelvis
• Volume: Hold 600-800 milliters of urine from ureters
because of the elastic walls
Internal urethral
sphincter
External urethral
sphincter
Urination
• 3-step process
The walls of the
bladder stretch
when urine fills the
bladder
Spinal cord
Relaxation of the
internal urethral
sphincter
Sensation of needing
to urinate
• People can choose when to urinate because the external urethral
sphincter is controlled to close and open.
The urethra
A tube through which urine passes from the bladder to the
exterior of the body
Male ( 8-10 inches and ends at the tip of the penis )
Female (2 inches, ends inferior the clitoris and superior
to the vagina opening)
The urethra
• The flow of urine through the urethra is controlled by the internal and
external urethral sphincter muscles.
1) The internal urethral sphincter
+ smooth muscle
+ open involuntarily
2) The external urethral sphincter
+ skeletal muscle
+ open voluntarily
FUNCTIONS
The nephrons.
• Inside each kidney are
around a million tiny
structures called nephrons.
• The nephron is the
functional unit of the kidney
that filters blood to produce
urine.
The
glomerulus
• Arterioles in the kidneys
deliver blood to a bundle of
capillaries surrounded by a
capsule called a glomerulus.
• As blood flows through the
glomerulus, much of the
blood's plasma is pushed
out of the capillaries and
into the capsule, leaving the
blood cells and a small
amount of plasma to
continue flowing through
the capillaries.
The cells surrounding the
tubules selectively absorb
water and substances
from the filtrate in the
tubule and return it to the
blood in the capillaries. At
the same time, waste
products present in the
blood are secreted into
the filtrate. By the end of
this process, the filtrate in
the tubule has become
urine containing only
water, waste products, and
excess ions.
The proximal
convoluted tubule or
PCT
• The proximal
convoluted tubule or
PCT which is a coiled
area that extends from
the Bowman's capsule.
Proximal
convoluted
tubule
The loop of Henle
• The loop of Henle
connects the proximal
convoluted tubule or
PCT to the distal
convoluted tubule or
DCT.
The loop
of Henle
The distal convoluted
tubule or DCT.
• The distal convoluted
tubule which is a coiled
area that extends from
the loop of Henle to
the collecting duct.
The distal
convoluted
tubule
The blood exiting the capillaries has reabsorbed all of the nutrients along with most
of the water and ions that the body needs to function. The kidneys maintain the
homeostasis of several important internal conditions by controlling the excretion of
substances out of the body.
Ions
• Ions can control the excretion of
potassium, sodium, calcium,
magnesium, phosphate, and
chloride ions into urine.
• When these ions reach a higher
than normal concentration, the
kidneys can increase their
excretion out of the body to
return them to a normal level.
• Conversely, the kidneys can
conserve these ions when they
are present in lower than normal
levels by allowing the ions to be
reabsorbed into the blood during
filtration.
pH
• The kidneys monitor and
regulate the levels of
hydrogen ions (H+) and
bicarbonate ions in the
blood to control blood pH.
• The kidneys excrete excess
H+ ions into urine for
elimination from the body.
The kidneys also conserve
bicarbonate ions, which act
as important pH buffers in
the blood.
Osmolarity
• The kidneys maintain the body’s osmotic balance: Control the
amount of water that is filtered out of the blood and excreted into
urine.
Osmolarity
• The changes in excretion of water are controlled by antidiuretic
hormone (ADH)
Osmolarity
• The changes in excretion of water are controlled by antidiuretic
hormone (ADH)
Blood Pressure
• The kidneys monitor the body’s blood pressure to help maintain
homeostasis.
Blood Pressure
High blood pressure
Low blood pressure
Reducing the reabsorption of water
into the blood
Producing the enzyme renin to
constrict blood vessels
Producing watery, dilute urine
Producing concentrated urine
EXERCISES
EXERCIES A.
Answer the following questions.
1. What is the function of the urinary system?
The purpose of the urinary system is to eliminate
waste from the body, regulate blood volume and
blood pressure, control levels of electrolytes and
metabolites, and regulate blood pH.
2. What does the urinary system consist of?
The urinary system consist of the kidneys, the
ureters, the urinary bladder, the urethra.
3. Where are the kidneys located?
The kidneys are a pair of bean-shaped organs
found along the posterior wall of the abdominal
cavity.
4. What is the renal medulla made up of?
The renal medulla is made up of triangular areas
called pyramids.
5. How many nephrons do the kidneys
contain?
Each kidney contains about one million nephrons.
=> Each kidney contains about 2 million nephrons.
6. Where is urine stored before it is
eliminated from the body?
Urine stored in the urinary bladder before it is
eliminated from the body.
7. What is the function of the urethra in
males?
In males, the
urethra carries
sperm out of the
body through the
penis.
8. How do the kidneys maintain the body
homeostasis?
The kidneys maintain the body homeostasis by
controlling the excretion of substances out of the
body.
9. What is ADH and its function?
ADH is a hormone produced in the hypothalamus
and released by the posterior pityutary gland
ADH help the body retain water.
10. What is the role of the enzyme renin?
Enzyme renin constrict blood vessels and produce
concentrated urine.
EXERCIE B
Complete the sentences with the words or phrases given
kidney
urinary
bladder
secrete
renal
pelvis
urethra
beanshaped
ureter
renal
pelvis
system
urine
kidney
secrete
ureter
renal
pelvis
urinary
bladder
urethra
beanshaped
urinary
system
urine
waste
products
kidney
secrete
urinary
bladder
urethra
beanshaped
1. The _________ is a muscular tube carrying
urine from a kidney to bladder.
ureter
renal
pelvis
urinary
system
urine
waste
products
kidney
secrete
urinary
bladder
urethra
beanshaped
2. The _______ is the place where urine
accumulates, waiting for urination.
renal
pelvis
urinary
system
urine
waste
products
kidney
secrete
urethra
beanshaped
3. _______ is waste liquid that collects in the
bladder and is discharged from the body.
renal
pelvis
urinary
system
urine
waste
products
kidney
secrete
urethra
beanshaped
4. The ________ lead urine out of the body
from the bladder.
renal
pelvis
urinary
system
urine
kidney
beanshaped
secrete
5. The __________ disposes of waste
products and toxins from the blood.
renal
pelvis
urinary
system
urine
kidney
beanshaped
secrete
6. A _________ is one of a pair of organs in the
abdomen that separates waste liquid from the
blood.
renal
pelvis
urinary
beanshaped
secrete
7. The kidney is a __________ structure with
a convex and concave border.
renal
pelvis
urinary
secrete
8. The tip, or papilla, of each pyramid empties
urine into a minor calyx; minor calyces emty into
major calyces, and major calyces emty into the
____________.
renal
pelvis
urinary
secrete
9. The kidneys excrete a variety of _________
produced by metabolism into the urine.
urinary
secrete
10. The kidneys ______ a variety of hormones,
including erythropoietin, calcitriol, and renin.
EXERCISE C.
Add names of organs to the descriptions of their functions. Rearrange
the descriptions of functions to reflect the actual sequence of stages
in urine production and excretion.
1.Kidneys
2.The external urethral sphincter
3.The urethra
4.urine
5.The detrusor mucle
6.The urinary bladder
7. The ureters
Rearrangement
1
7
6
4
5
2
3
EXERCISE D.
Choose the best answer to complete each of the following sentences
1. D
2. A
3. D
4. B
5. C
6. A
7. D
8. D
9. C
10. D
Exercise F
1-A
2-C
3-A
4-D
5-A
6-B
7-D
8-A
EXERICISE G. Match the terms on the left with their definitions on the
right.
1. Nephron
A. A cluster of capillaries
2. Proximal
B. Voiding
3. Distal
C. Excessive urine production
4. Convoluted
D. Renal system
5. Urination
E. Near
6. Urinary system
F. Coiled
7. Eliminate
G. A person treating diseases of the urinary tract
8. Polyuria
H. Far
9. A urologist
I. Get rid of
10. Glomerulus
J. Functional unit of the kidney
EXERCISE H. Choose the correct word or phrase to complete each sentence below.
• 1. The urinary bladder is a sac-like hollow organ used for the storage / production of urine.
• 2. Renin causes an increase / decrease in blood volume.
• 3. The ureters are a pair of tubes that carry urine from the kidneys to the urinary bladder / exterior of the
body.
• 4. The internal / external urethral sphincter is made of smooth muscle and opens involuntarily when the
bladder reaches a certain set level of distention.
• 5. The internal / external urethral sphincter is made of skeletal muscle and may be opened to allow urine to
pass through the urethra or may be held closed to delay urination.
• 6. Excretion / Secretion is a term used to describe urination.
• 7. Pain during urination is most likely a symptom of incontinence / urinary tract infection.
• 8. The left kidney is located slightly higher / lower than the right kidney because the right side of the liver is
much larger than the left side.
• 9. The ureter / urethra is the tube that carriers urine to the outside of the body.
• 10. The urethra is longer / shorter in males than in females.
Excerise I
• 1- Filter
• 2- Molecular
• 3- Eventually
• 4- Selective
• 5- Completely
• 6- Secretion
• 7. Tubular
• 8.Excretion
• 9.Called
• 10. Transport
Exercise J
• 1-A
• 2-C
• 3-A
• 4-C
• 5-C
• 6-B
filter-> elimination
filter-> filters
enters-> entering
moves-> move
that-> which
urinating-> to urinate