The Urinary and Reproductive Systems
Lab 12—7-11
• Excretion refers to the processes that remove
wastes and excess materials from the body.
• Urine is essentially water and solutes.
– Some of the solutes excreted in urine are:
• excess elements, drugs, vitamins, toxic
chemicals, waste produced by the liver
and cellular metabolism, salt
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The Urinary and Reproductive Systems
Lab 12
• The urinary system is composed of the organs
that produce, transport, store and excrete
urine:
– 2 kidneys, 2 ureters, one bladder and one
urethra
• The Kidneys
– are bean shaped organs about the size of a
clenched fist
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The Urinary and Reproductive Systems
Lab 12
– are located in the abdominal cavity*, lateral
to the 2nd lumbar vertebrae and close to
the posterior wall of the body (our back).
*some people believe the kidneys are located
retroperitoneally (behind the abdominal
cavity lining and part of the posterior body
wall)
– a renal artery and vein connect each kidney
to the aorta and inferior vena cava.
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The Urinary and Reproductive Systems
Lab 12
Gross anatomy of the kidneys:
• the capsule is the protective outer covering of
the kidney
• the interior of the kidney has 2 distinct areas:
the cortex and the medulla
• the cortex is the outer portion. It has most of
the capillary blood flow, and contains the renal
corpuscles, which contain the nephrons, the
functional unit of the kidney .
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The Urinary and Reproductive Systems Lab 12
– The nephron is the functional unit of the
kidney. It is divided into several different areas:
• the glomerular or Bowman’s capsule which
surrounds the glomerulus,
• the proximal convoluted tubule (a thin
hollow tube of epithelial cells),
• loop of Henle, composed of a descending
tubule, a loop, and an ascending tubule
• distal convoluted tubule,
• collecting tubule
• blood vessels that supply the tubules,
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The Urinary and Reproductive Systems
Lab 12
• How a Nephron works to produce urine:
• The glomerular capsule surrounds the
glomerulus which is a network of capillaries.
– blood plasma fluid is filtered out of the capillaries and
into the space between the 2 layers of the glomerular
capsule
• A tubule exits from the back of the glomerular
capsule and continues as a long, thin tube with 4
distinct regions:
– the proximal tubule
– The loop of Henle
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The Urinary and Reproductive Systems
Lab 12
– the distal convoluted tubule
– The collecting duct - up to 1,000 distal
tubules can join together to become a
collecting duct
– The collecting duct leads into the renal
pelvis where the final urine is deposited.
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The Urinary and Reproductive Systems
Lab 12
• The kidney medulla is composed of cone
shaped pyramids. The base of each
pyramid faces toward the cortex and the
point faces toward the middle of our body.
– The pyramids appear striped because
they are formed of parallel bundles of
microscopic urine collecting tubules, the
loop of Henle and the collecting ducts.
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The Urinary and Reproductive Systems
Lab 12
• The tips of the pyramids are called the
papillae. These insert into the
opening of a tube called the calyx.
• Filtered urine is transported to the
kidney pelvis, the innermost hollow,
muscular part of the kidney.
• The pelvis empties into the ureters.
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The Urinary and Reproductive Systems
Lab 12
• The smooth muscle of the ureters create
peristaltic waves which move the urine into the
bladder.
– The bladder can usually hold between 2-3.5 ounces.
– Women typically have smaller bladder capacity than
men because the uterus compresses the bladder.
• The external and internal urethral sphincter
prevent the bladder from emptying until we are
ready to do so.
• During urination, urine passes into the urethra, a
muscular tube that extends from the bladder to
the body’s opening.
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The Urinary and Reproductive Systems
Blood vessels and filtration
How does the kidney filter our blood?
• Blood enters the interlobular artery. This
branches into afferent arterioles which enter the
glomerular capsule where they divide many times
to become the network of capillaries that make
up the glomerulus.
• The blood pressure in the glomerular capsule is
high in order to allow filtration of plasma fluid
and solutes from the blood into the capsular
space.
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The Urinary and Reproductive Systems
Lab 12
• The filtered material is called the glomerular
filtrate. It contains urea, amino acids, vitamins,
hormones, salts, glucose, ions and water, but no
large proteins or blood cells.
• Reabsorption of water, glucose, amino acids,
hormones, ions, vitamins and some salts occurs
mainly in the walls of the proximal convoluted
tubule.
– Approximately 65% of water is reabsorbed here.
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The Urinary and Reproductive Systems
Lab 12
• The Loop of Henle and the Distal Convoluted
Tubule also perform reabsorption and secretion
of ions.
– Tubular excretion or secretion refers to the process in which cells
in the proximal and distal tubules pass materials into and remove
substances from the filtrate.
• The Collecting Tubule or Duct receives filtrate
from several distal convoluted tubules and
empties into the calyces and pelvis. Some
reabsorption and secretion, especially ions and
urea, may occur.
– Regulation of water reabsorption happens
here.
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The Urinary and Reproductive Systems
Lab 12
• An important pituitary hormone, the antidiuretic hormone (ADH) regulates the
reabsorption of water in the kidney
tubules.
– Diuretics are substances that increase
the flow of urine.
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The Urinary and Reproductive Systems
Lab 12
• The kidney reabsorbs water and ions and thus
prevents the loss of substances which the body
needs. It adjusts the composition of blood and
body fluids through this filtration process.
• Urine is the final product of the filtration process.
It leaves the distal tubules, empties into the renal
pelvis and then travels through the ureters to the
bladder.
• From the bladder, it goes into the urethra and
then exits the body when we choose to urinate.
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REMINDER, page 1 of 2:
Urinary System
1. Using figures 16.1 and 16.2 as a guide, learn parts
of the urinary system on the model.
2. In the fetal pig, find the kidneys, ureters, and
urinary bladder.
3. On the SHEEP kidney, identify the bulleted items
listed on page 153.
4. 4. Do the urine hydrometer and Combistix test.
In the hydrometer we actually have yellow food color,
water, and other “stuff” to approximate urine. The
yellow food color may stain so don’t spill it on
yourself.
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Lab 12
REMINDER, page 2 of 2: Urinary System
– The more solute in urine, the more
buoyant it is (like swimming in salt vs
fresh water). The more concentrated
urine is, the higher the hydrometer will
float.
– The hydrometer is no longer used in
doctors' offices; a dipstick test is used
now.
5. Observe the kidney stones in the jar.
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Lab 12 The Urinary and Reproductive Systems
The Reproductive Systems-Male
• The term genitalia refers to reproductive organs.
Anatomy of the Male Reproductive System
look at picture on page 161
• The scrotal sac contains 2 testes which produce
sperm (the male reproductive cells).
– The testes are located outside of the body
because sperm need lower temperatures to
survive.
• The seminiferous tubules, in the testes produce
sperm.
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Sperm
• Consist of 3 major parts: a head, midpiece, and a
tail
• The head contains the nucleus and ½ the number
of chromosomes of the parent
• The midpiece contains mitochondria and ATP
which produce the energy to power the tail
• The tail propels the sperm
• The process of sperm formation is called
spermatogenesis.
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The Urinary and Reproductive Systems Lab 12
• In between the seminiferous tubules are interstitial cells
which produce testosterone, the male hormone.
• Sperm production involves a series of cell divisions called
meiosis and produces sperm with ½ the number of
chromosomes of the parent
• Many seminiferous tubules join to become the
epididymus which is located at the rear of the
testes. Sperm are stored here.
• They enter the vas deferens (the sperm duct)
which passes through an opening in the wall of
the body called the inguinal canal.
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The Urinary and Reproductive Systems
Lab 12
– The ability of newly formed sperm to swim
develops in both the epididymis and the vas
deferens.
– A vasectomy ties off the vas deferens so sperm
are no longer available for fertilization.
• The vas deferens connects to the ejaculatory
duct.
• When the male ejaculates semen, rhythmic
contractions of smooth muscle propel the sperm
through the ejaculatory duct and then through
the urethra.
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The Urinary and Reproductive Systems
Lab 12
• The penis is the male organ of sexual intercourse. It
contains erectile tissue that fills with blood and
causes the erection during sexual stimulation.
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Lab 12 The Urinary and Reproductive Systems
Glands which help sperm survive:
• Prostate gland: surrounds the urethra and
produces an alkaline fluid which is added to the
seminal fluid. This raises the pH of the vagina to a
more optimal pH for sperm survival.
• Seminal vesicles produce seminal fluid which is a
watery mixture containing fructose which
provides energy for the sperm.
• Cowper’s or bulbourethral glands secrete mucus
into the urethra during sexual arousal. This
provides lubrication for intercourse and nelps
neutralize the acidity of the urethra.
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Lab 12 The Urinary and Reproductive Systems
The Female Reproductive System
Anatomy:
• The external female genitalia or vulva (page 166)
• the mons pubis, a fatty, rounded tissue area,
covers the pubic symphysis. It becomes covered
with hair during puberty.
• The labia majora are 2 elongated, pigmented, hair
covered, fat padded skin folds which surround
and enclose the labia minora.
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The Urinary and Reproductive Systems
Lab 12
• The Labia minora are 2 smaller, highly
vascular, hair free folds.
• The clitoris is a small organ partly enclosed
by the labia minora. It is composed of
erectile tissue and is highly sensitive.
• The urethral opening lies between the
clitoris and the vaginal opening.
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The Urinary and Reproductive Systems
Lab 12
Internal female reproductive organs (page 168)
• 2 Ovaries are the primary reproductive organs.
They lie near the ends of the fallopian tubes (also
called oviducts) in the upper pelvic cavity. They
are held in place by several ligaments.
• The ovaries produce eggs called oocytes at
regular intervals during the reproductive years.
Eggs have 1/2 the number of chromosomes as the
parent.
• They also produce the hormones estrogen and
progesterone.
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The Urinary and Reproductive Systems
Lab 12
• The distal ends of the fallopian tubes are funnel
shaped and have fingerlike projections called
fimbriae. These create waves or currents which
sweep the egg from the ovary into the pelvic
cavity into the fallopian tube. They do not touch
the ovary itself.
• The egg is propelled toward the uterus by the cilia
on the walls of the fallopian tubes.
• If fertilization by a sperm occurs, it usually takes
place in the upper third of the fallopian tube.
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The Urinary and Reproductive Systems
Lab 12
• The uterus is a pear shaped, muscular organ
which is located between the bladder and the
rectum. It will “incubate” the fertilized egg.
– Its narrow, lower end is called the cervix. The
middle part of the uterus is called the body
and the upper part is called the fundus.
• The vagina is a muscular tube that extends from
the cervix to an opening on the exterior of the
body.
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The Urinary and Reproductive Systems
Lab 12
– It serves as a birth canal and the female organ
for sexual intercourse.
– It also permits the passage of menstral blood
to the outside of the body.
• Note that in the pig, the urethra merges with the
vagina. In humans, these openings are separate.
• Pigs (and most female mammals who bear young
in litters) have uterine horns. This allows linear
uterine distance for the young to develop.
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The Urinary and Reproductive Systems
Lab 12
The Breasts (page 167)
• are considered to be part of the reproductive
organs
• are really modified sweat glands which produce
milk to nourish newborn infants.
• milk production is stimulated by hormones only
when birth has actually occurred.
• the nipple is at the center of each breast. It
contains smooth muscles that can contract and
cause the nipple to become erect.
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The Urinary and Reproductive Systems
Lab 12
• Surrounding the nipple is the pigmented areola.
• Internally, the breasts contain mammary glands that
produce milk.
– The glands consist of many milk producing
lobules. Contractile cells around each lobule allow
the milk to be released and ducts deliver the milk
to the nipple.
– Most of the breast consists of adipose tissue so breast
size doesn’t indicate the potential for milk production.
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Lab 12
REMINDER page 1of 2:
Reproductive Systems
1. For the TOP activity on page 164, do not do
number 1 and 2. Do number 3.
2. Do the bottom activity on page 164: The Male
Reproductive System of the fetal pig. You are
responsible for finding the following organs:
the testes, epididymis, and urethra
3. In the female pig, you are responsible for finding
the ovaries, uterine horns, body of uterus and
vagina.
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REMINDER, page 2of 2:
Reproductive Systems
4. You are responsible for these organs in both male
and female pigs. Look at each other’s pigs to see
an opposite sex pig.
5. For humans, use figure 17.3 as your guide for the
male model and figures 18.3 and 18.4 for the
female model. Find the comparable human
organs as you located on the pigs.
6. There are suitcases on the table with models.
Look at these.
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