URINARY AND REPRODUCTIVE SYSTEMS
Introduction:
Organs of the urinary and reproductive system lie in close proximity to each other within the abdominopelvic
cavity. Because of their close proximity, and in some cases, overlapping functions, these two body systems are
commonly studied together.
Activity 1: Urinary System
The urinary system includes the kidney, ureters, (urinary) bladder and urethra.
The major structures of the kidney is an external connective tissue capsule that surrounds the kidney as it lies
dorsal to the peritoneum. The kidney is ‘bean’ shaped, with an indentation or hilum which is where the renal
artery, renal vein and ureter enter into the kidney.
As seen in cross section, the renal cortex (outer layer) surrounds the inner renal medulla.
Within the renal medulla, it is organized into cone shaped structures, renal pyramids, where urine forms through
microscopic tubules called nephrons and enters into the renal pelvis before it passes out of the kidney through
the ureter. Between the renal pyramids are the renal columns.
As urine forms, it passes through the renal pelvis, ureter and is temporarily stored in the (urinary) bladder.
When it is full, under nervous control, it is emptied out of the body through the urethra. The urethra carries only
urine out of the human female, however, in the human male both urine and semen pass through to exit the body.
Procedure:
Before lab draw a diagram of a kidney and label it in your lab notebook including the bold-faced terms.
During Lab, observe a model of a kidney and identify the structures as identified in your diagram.
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Activity 2: Male Reproductive System
The major structures of the male reproductive
system are designed to produce and deliver the
male gamete, sperm, to the female vagina, as well
as, produce the hormone testosterone.
The testes are the primary sex organs of the male
which are suspended within sacs, scrotum, to
maintain a cooler than body temperature for
optimum sperm production.
Sperm are produced within microscopic tubules of
the testes, seminiferous tubules. Immature
sperm are transported by peristaltic waves to the
epidiymis for maturation. The epididymis is also
composed of microscopic tubules that are
approximately 6 meters in length uncoiled.
Mature sperm are conducted through the vas deferens, a muscular tube approximately 45 cm long, toward the
urethra where they eventually exit the body.
There are three accessory glands, whose secretions contribute to sperm viability as semen. These glands include
the seminal vesicles, bulbourethral glands and prostate gland. As men age, the prostate gland may enlarge.
It’s position surrounding the urethra making urination difficult.
Procedure: Observe the model of the Human Male Reproductive system
1) Before Lab, draw a diagram of the male reproductive system and urinary system structures in your notebook,
complete with labels.
2) During Lab, compare your diagrams to the model(s) available in lab and identify the indicated structures.
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Activity 3: Female Reproductive System
The female reproductive system functions to produce eggs (ova) and sex hormones within the ovaries; transport
the ovum, receive sperm and contribute to the maturation of the fertilized egg (zygote) or expel an unfertilized
ovum.
The ovaries are the female gonad.
Each ovary is held in place to the
pelvic cavity walls by several
ligaments. Extending between
the uterus and the ovaries are the
oviducts (uterine tubes). Cilia
lining the lumen of the oviduct and
muscular contractions propel the
ovum toward the uterus. It is
within the oviduct that fertilization
is most likely to occur.
The fertilized egg is called a
zygote, which immediately begins
to divide and then ultimately forms
the embryo. Once the embryo
enters into the thick-walled
muscular uterus, the embryo will implant into the wall of the uterus and the placenta forms.
If the ovum is not fertilized, the uterine lining is shed (menstruation) and the unfertilized ovum is shed from the
female body through the vagina.
The vagina is a fibromuscular structure that can stretch to receive the penis and also serves as a birth canal.
Procedure: Observe the Model of the Human Female Reproductive System
1) Before Lab, draw a diagram of the female reproductive system in your lab notebook with labels.
2) During lab, observe the model(s) of the human female reproductive system.
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Activity 4: Histology of the Reproductive System
Sperm are produced in microscopic tubules, seminiferous
tubules, of the teste. As you look at a cross section of the testes,
identify the different layers of cells that contribute to sperm
formation.
The outermost layer are the spermatogonia cells that divide by
mitosis—these are a type of stem cell. Between the seminiferous
tubules, there are cells called interstitial cells which produce
testosterone affecting sperm maturation and anterior pituitary
function.
The cells produced by spermatogonium are
the primary spermatocytes which begin a
specialized nuclear division called Meiosis I
giving rise to the secondary spermatocytes.
Meiosis is responsible for producing
gametes (sex cells—sperm and eggs) that
have half the number of chromosomes as the
parent. As you observe the cells lining the
seminiferous tubule, you can identify the
different cell types as you move inward
toward the lumen. The secondary
spermatocytes also divide by the second
half of meiosis, Meiosis II, which give rise to
the immature gamete a spermatid.
Spermatids are propelled through the
seminiferous tubule by peristalsis toward the
epididymis to complete their maturation
process and become motile.
Mature sperm are completely motile by
flagella. The body of a mature sperm includes
the acrosome (head) containing an enzyme
that helps the sperm to penetrate an egg to
achieve fertilization. Most of the head is the
nucleus containing 23 DNA molecules, half
the number of a normal human. (The ovum
contributes the other 23 DNA molecules.)
Between the head and the flagella, is the
midpiece, this is where there are many
mitochondria which generate ATP for flagellar
movement.
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Looking at ovarian tissue, there are commonly a great many oocytes (ovum) in various stages of development.
The most immature oocytes are those that are a component of the primary follicles. A primary follicle includes
follicular cells which are small cells that surround the very large oocyte. These primary follicles are under
hormonal influence. As you observe a human ovarian slide, there will be quite a few primary follicles and very few
secondary follicles or vesicular follicles which are nearing ovulation
Primary
Follicle
Antrum
Secondary
Follicle
The secondary follicles have reached a more mature state due to hormones produced by the pituitary gland.
The follicular cells have divided, so there are more cells surrounding the oocyte. These follicular cells are
secreting hormones which are filling the space between the follicular cells and the ovum. The hormone filled
space is the antrum. When the anterior pituitary gland reaches peak production of leutenizing hormone the
vesicular follicle erupts releasing the ovum which moves through the oviduct. The follicular cells remain as part of
the ovary (corpus luteum) temporarily continuing the production of progesterone.
Procedure: Microscopic Observation of Reproductive Tissues
1) Note: If you have a choice, choose animal reproductive tissues over human reproductive tissue slides—
rats and rabbits produce many more progeny so produce many more reproductive cells which is
commonly easier to locate and identify on a slide.
2) Before lab, update your histology atlas by drawing and labeling a diagram of the seminiferous tubule.
Label the different cell types as described (bold-faced) above. During lab, observe the seminiferous
tubule slide using your High Power Objective lens and compare your diagram to the slide.
3) Before Lab, update your histology atlas by drawing and labeling a diagram of a mature sperm from the
human sperm smear slide. During lab, observe the sperm smear slide under High Power or Oil Immersion
and compare your diagram to the slide.
a. Calculate the average cell size of a typical mature sperm (do not include the flagella as part of
your measurement). Record your work and measurement in your lab notebook.
4) Before lab, update your histology atlas by drawing and labeling a diagram of the ovarian tissue, including
labeling the different cells of both the primary follicle and secondary follicle.
5) During lab, observe the ovary slide under scanning and low power. You should be able to easily see the
secondary follicles and antrum using minimal magnification. Under high power, identify the primary
follicles.
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