OVERVIEW
The Urinary (Excretory) System
The Urinary (Excretory)
System



The urinary system also
known as the excretory
system is responsible for
removing wastes and
excess water from the body.
This system also maintains
the acid-base balance of
the body.
The organs in this system
are 2 kidneys, 2 ureters, the
bladder and a urethra.
Kidneys



The kidneys are two
bean shaped organs,
located on either side
of the vertebral column
behind the abdominal
cavity.
They are protected by
the ribs and a cushion
of fat.
The outer section of
the kidney is the
cortex, which contains
the nephrons.


The inner section of
the kidney is the
medulla, containing the
tubules which are a
series of tubes draining
the urine from the
cortex.
The pelvis of the
kidney, like the upper
part of a funnel drains
the urine into the
ureters.



Nephrons, the
functional unit of the
kidney, are tiny filtering
units, numbering over
one million in each
kidney.
The Renal Artery
carries the blood to the
kidney which separate
into smaller vessels.
In each nephron, blood
vessels form balls of
capillaries called
glomeruli.



As the blood passes
through this cluster of
capillaries, water, salt,
sugar, and wastes are
filtered out of the blood.
This filtered blood returns
to the bloodstream by
way of the renal vein.
Each glomeruli is
surrounded by a tube with
a cuplike end called
Bowmans capsule.


The material filtered
out of the blood
gathers in this capsule
and pass into the
tubules.
The tubules twist and
coil where substances
needed by the body to
maintain the proper
water and acid base
balance are
reabsorbed by the
capillaries.



The substances that are
not reabsorbed drain into
the pelvis of the kidney.
Under ordinary
circumstances, only a
portion of the glomeruli
are used.
If one kidney is unable to
function, more glomeruli
open up and assume the
work of the nonfunctioning or absent
kidney.
Ureters



The pelvis of the kidney
forms the uppermost part
of the ureter.
The ureters (one from
each kidney), are tubes
about 10-12 inches long
and only ¼ inch wide
which connect the
kidneys to the bladder.
The urine produced in the
kidneys flows through the
ureters by means of
peristalsis to the bladder.
Urinary Bladder



The bladder, a hollow,
muscular, organ made of
elastic fibers and
muscles.
The bladder stores the
urine until the urge to
urinate or void is felt,
usually when the bladder
holds 200-300cc.
The elasticity of the
bladder allows it to hold
more urine than this
amount.


Nerve receptors in the
wall of the bladder
sends a reflex action to
a series of sphincter
muscles which control
the bladder opening.
This action becomes
under voluntary control
in childhood.
Urethra



The urethra is the tube
which carries the urine
outside of the body.
The external opening is
called the Urinary
Meatus.
In females the urethra
is one and a half
inches long, that opens
in front of the vagina
and carries only urine.



In males the urethra,
also part of the
reproductive system, is
about 8 inches long
and passes through
the prostrate gland and
out through the penis.
In males the urethra
carries both urine and
semen, although not at
the same time
The urinary meatus is
guarded by a sphincter
muscle that relaxes to
release urine.
Urine



Urine is the liquid waste product produced by the
urinary system.
It is about 90%-95% water and contains urea, uric
acid, creatinine, salts and pigments.
The presence of sugar, pus, blood, acetone or
protein in the urine are an indication of disease,
infection or trauma. About 1500 to 2000 cc. of
normally light straw colored urine are produced
daily.
Diseases Affecting the Urinary
System




Nephritis – inflammation of the kidney.
Cystitis – inflammation of the bladder.
Renal Calculi – formation of stones in the kidney.
Tumors may also affect the urinary system although
infections are the most common affliction of the
urinary system
Additional Body Systems
Integumentary System –
 Organs in this system are
the skin, sweat glands and
sebaceous (oil) glands and
the hair.
 The functions of this system
include protection, sensory
reception, regulation of
body temperature and
excretion of certain waste
products through
perspiration.
Special Senses
 Included in this system
are the eye, ear, taste
buds and sense of
smell.
 This system works in
cooperation with the
nervous system. The
functions of the special
senses are to receive
sensations which
sends messages to the
brain which interprets
and responds.
Endocrine System
 The endocrine system is a
collection of glands which
secrete hormones directly
into the blood. These
hormones called “chemical
messengers” regulate
growth and development
and metabolism, maintain
chemical and fluid balance
and control various sex
process.
 The pituitary gland, called
the master gland produces
hormones which regulates
many of the other glands.
Reproductive System


The function of the
reproductive system is
to reproduce another
human being.
The anatomical parts
are different in the
male and female,
however both have the
same types of organs:
sex glands, ducts or
tubes to carry the sex
cells and secretions
and accessory organs.
Male Organs
 Testes – Produce sperm
and the male hormone
testosterone.
 Seminal Vesicles – Form
most of the secretion in the
semen.
 Prostrate Gland - produces
secretion; the muscles in
the prostrate gland produce
ejaculation.
 Penis – contains erectile
tissue and urethra which
transports semen.
Female Organs
 Ovaries – produce ova
(eggs), estrogen and
progesterone.
 Fallopian Tubes –
conduct the ova from
the ovary to the uterus;
fertilization occurs in
the fallopian tubes.
 Uterus – lined with
endometrium which is
prepared by hormones
for pregnancy; embryo
grows in the uterus.



Vagina – Canal for
reception of semen
and serves as birth
canal.
Vulva – External area
of female contains the
labia folds and clitoris.
Mammary Glands –
Breasts of the female
are accessory organs
of the reproduction
system.