The document discusses the structure and function of the urinary system. It describes the location and roles of the kidneys, ureters, bladder, and urethra. The kidneys filter waste from the blood to produce urine, and contain nephrons that remove waste and regulate chemical balances before urine passes through the ureters to the bladder for storage and eventual expulsion through the urethra.

1. Urinary System Structure and
Functions
Science V

2. What are the parts of the urinary
system?
What are the parts of the kidney?
Review

3. Checking of Assignment
Answer the following question:
1. How can you take good care of our
urinary system?
2. What foods are good to the urinary
system?
3. Why are salty foods not good to eat?

4. Motivation
• What is the shape of the kidney?
• Where are the kidneys located?
• Would you like to find out about their
structure and function/s?

5. Presentation
Watch the video clip
Excretory System Parts and Functions
Animation video for kids

6. The kidneys are two
bean-shaped organs
about the size of a
clenched fist.
Can you point where
the kidneys are?
Concept Formation

7. Each kidney is divided into three regions.

8. The outermost
region is the
Cortex

9. The middle region
is the
Medulla
which consists of
collecting ducts that
carry the urine

10. The inner region is
the
Pelvis
a cavity connected
to the ureter, into
which the urine
drains

11. The
Renal Artery
delivers oxygenated
blood to the kidney

12. The
Renal Vein
receives
deoxygenated blood
from the peritubular
veins within the
kidney

13. Their vital functions include:
• Removal of extra water and waste products
from the blood in the form of urine.
• Keeping a stable balance of salts and other
substances in the body.
• Releasing hormones that help maintain the
normal number of red blood cells and
regulate blood pressure.
Concept Formation

14. Interesting fact:
The right kidney is slightly
lower than the left because
the liver displaces it
downward.
Concept Formation

15. Concept Formation
The functional and
structural units of the
kidneys are the
nephrons. Each
kidney contains about
1.25 million
nephrons.

16. Concept Formation
Each nephron consists of two parts: a cup
shaped structure called the Bowman’s
capsule and a network of tubules.
Proximal
tubule

17. Concept Formation
The Bowman’s capsule
encloses a bundle of tiny
capillaries called the
glomerulus—where actual
sifting or filtering of blood
occurs. Connected to the
Bowman’s capsule are the
network of convulated
tubules divided into four
kinds.

18. Concept Formation
The Proximal convulated
tubules, the Henle’s loop,
the distal convulated
tubule, and the collecting
tubule. The collecting
tubule receives the
nitrogen waste from many
nephrons.

19. Concept Formation
Impure blood enters
the kidney through the
renal artery.
Purified blood exits the
kidneys through the
renal vein.

20. Concept Formation
At first, the tubules receive a combination
of waste materials and chemicals that your
body can still use. Some of these chemicals
include sodium, phosphorus, and potassium.
If your body is lacking any of these
chemicals, your kidneys can release them
back to the blood to maintain their normal
levels.
If these chemicals are in excess, the kidneys
will release it to become a part of the urine.

21. Concept Formation
This is how the kidneys maintain the
normal levels of chemicals inside your
body. The right balance is necessary for life,
but excess levels can be harmful too.
If the kidneys fail to function, a
condition called renal failure, this would
cause an excessive build up of toxins in the
body. You will need dialysis to rid of these
toxins.

22. Concept Formation
The kidneys also release important hormones
that help to maintain balance in the body.
Erythropoietin (eh-RITH-ro-POY-eh-tin) or EPO,
stimulates the bone marrow to make red blood
cells
Renin (REE-nin) regulates blood pressure
Calcitriol (kal-suh-TRY-ul), the active form of
vitamin D, helps maintain calcium for bones and
for normal chemical balance in the body

23. Each kidney has a drainage tube
called ureter. The walls of the
ureter have a thick layer of
smooth muscle which contracts.
The contraction of the muscle in
the ureter move urine to the
bladder.
Can you point where the ureters
are?
Concept Formation

24. Constant tightening and relaxing of
muscles in the ureter wall forces urine
downward away from the kidneys. These
muscles help to maintain a one-way flow of
urine from the kidneys to the bladder. If
urine is allowed to stand still, or to flow
back into the kidneys, a kidney infection
may develop.
Concept Formation

25. The urinary bladder is a
balloon-shaped, hollow,
muscular sac inside the
pelvis (hip bones). It is
held in place by
ligaments attached to
other organs and the
pelvic bones.
Concept Formation

26. The bladder stores urine until it is
released when you urinate. As urine flows
into the bladder, it becomes larger and the
shape becomes more rounded or spherical.
When it is empty, its size becomes smaller.
Small amounts of urine are emptied into
the bladder from the ureters about every
10 to 15 seconds.
Concept Formation

27. A normal adult
bladder can store up
to 2 cups of urine for
as long as 2 to 5
hours.
Concept Formation

28. Sphincter muscles are
two circular muscles
around the opening of
the bladder into the
urethra. They help keep
urine from leaking into
the urethra.
Concept Formation

29. Concept Formation
The urethra is the tube
that allows urine to pass
outside the body. The
urethra has a ring of
skeletal muscle around
its opening. The male
and female urethra are
different in some ways.

30. Concept Formation
In females, their urethra are much shorter
than in males. In addition to urine, the male
urethra is also where semen passes through.

31. Application
Your mother sent you to the market to
buy a cow's kidney. Would you be able to
buy a cow's kidney by pointing the kidney
to the meat vendor? Can you tell the
function of the kidney?

32. Evaluation
Choose the letter of the correct answer:
1. What carries waste from the kidney to
the bladder?
a. Urethra c. Cortex
b. Ureter d. Medulla
2. What protects the kidney?
a. Nephron c. Cortex
b. Ureter d. Medulla

33. Evaluation
3. Which of the following are the filter
devices of the kidneys?
a. Nephron c. Ureter
b. Glomerulus d. Cortex
4. What is the cuplike structure of the
nephon called?
a. Pelvis c. Urethra
b. Glomerulus d. Bowman’s
capsule

34. Evaluation
5. What kind of blood is in the renal artery?
a. Clean c. Purified
b. Unclean d. Sometimes
clean

35. Key
1. b
2. c
3. b
4. d
5. c

36. Assignment
1. Do most people have two (2) kidneys?
2. Can a person live normally with only
one kidney?
3. What is the function of the kidney?
4. What part of the urinary system stores
urine?