Lab Practical Reproductive System

Testis

Produces sperm (spermatogenesis) and testosterone.

Tunica albuginea

Dense fibrous capsule surrounding the testis; protects and helps divide the testis into lobules.

Septa

Extensions of the tunica albuginea that divide the testis into lobules.

Lobules

Compartments within the testis that contain seminiferous tubules.

Seminiferous tubules

Site of sperm production (spermatogenesis).

Epididymis (head, body, tail)

Site where sperm mature, are stored, and transported.

Ductus deferens (with ampulla)

Transports mature sperm from epididymis to ejaculatory duct; ampulla stores sperm temporarily.

Ejaculatory duct

Formed by union of ductus deferens and seminal vesicle duct; carries semen to urethra.

Seminal gland / Seminal vesicle

Produces fructose-rich fluid that nourishes sperm and contributes most of semen volume.

Spermatic cord

Suspends testis and contains ductus deferens, vessels, nerves, and lymphatics.

Testicular artery

Supplies oxygenated blood to the testis.

Venous plexus (pampiniform plexus)

Helps cool arterial blood before it reaches the testis for proper sperm production.

Lymphatic vessels

Drain lymph from the testes.

Nerves

Provide autonomic and sensory innervation.

Prostate

Produces prostatic fluid that helps activate and protect sperm.

Urethra

Passageway for urine and semen to leave the body.

Prostatic urethra

Portion of urethra passing through the prostate.

Membranous urethra

Short portion passing through pelvic floor; narrowest part.

Penile (spongy) urethra

Portion running through the penis to external opening.

Penis

Organ of copulation and pathway for urine/semen excretion.

Corpus cavernosum (corpora cavernosa)

Erectile tissue responsible mainly for penile rigidity during erection.

Corpus spongiosum

Erectile tissue surrounding urethra; keeps urethra open during ejaculation.

Cremaster muscle vs Dartos muscle

Cremaster elevates testis for temperature regulation; Dartos wrinkles scrotal skin to reduce heat loss.

Crura vs Bulb

Crura are proximal extensions of corpora cavernosa attached to pubic arch; bulb is proximal expanded part of corpus spongiosum.

Glans vs Prepuce

Glans is enlarged distal tip of penis; prepuce (foreskin) is fold of skin covering the glans.

Vestibule

Space between labia minora containing urethral and vaginal openings.

Clitoris

Erectile structure involved in sexual arousal.

Urethral orifice

External opening for urine excretion.

Vaginal orifice

External opening of vagina; passage for menstruation, intercourse, and childbirth.

Labia minora

Inner folds protecting vestibule openings.

Labia majora

Outer folds protecting external genital structures.

Vagina / Vaginal canal

Muscular canal for intercourse, menstrual flow, and childbirth.

Uterus

Site of implantation and fetal development.

Cervix

Lower narrow portion of uterus opening into vagina.

Body of uterus

Main central portion where implantation commonly occurs.

Fundus

Rounded superior portion of uterus above uterine tube openings.

Ovary

Produces oocytes (eggs), estrogen, and progesterone.

Uterine tubes / Fallopian tubes

Transport oocyte to uterus; usual site of fertilization.

Fimbriae

Finger-like projections that sweep ovulated oocyte into uterine tube.

Male Reproductive Pathway (Sperm Pathway)

Seminiferous tubules → Epididymis → Ductus deferens → Ejaculatory duct → Urethra (prostatic → membranous → penile/spongy) → External urethral orifice

Male Urine Pathway

Bladder → Prostatic urethra → Membranous urethra → Penile/spongy urethra → External urethral orifice

Female Reproductive Pathway (Egg Pathway)

Ovary → Fimbriae → Uterine tube → Uterus → Cervix → Vagina → Vaginal orifice

Female Urine Pathway

Bladder → Urethra → Urethral orifice

What is spermatogenesis?

Continuous process of sperm production beginning with mitosis of spermatogenic cells and ending with meiosis producing immature sperm that mature into sperm with acrosome and tail.

Structures associated with spermatogenesis

Testis, seminiferous tubules, spermatogenic cells, Sertoli cells, lumen of seminiferous tubules, epididymis (for sperm maturation/storage)

Primary oocyte

Immature egg cell in the ovary; appears like a water balloon with a knot facing you and is the cell that will eventually undergo ovulation.

Primordial follicle

A primary oocyte surrounded by a single flat layer of follicular cells; earliest follicle stage.

Primary follicle

A primary oocyte surrounded by more than one layer of follicular cells; zona pellucida begins to appear around the oocyte.

Zona pellucida

Clear layer surrounding the oocyte that appears between the oocyte and surrounding follicular cells.

Secondary follicle

Follicle stage with fluid-filled vesicles developing inside and thecal cells surrounding the structure; zona pellucida is still present.

Thecal cells

Outer supporting cells surrounding the secondary follicle that help produce hormones.

Tertiary follicle (Mature/Graafian follicle)

Large mature follicle with one large clean fluid-filled space called the antrum; oocyte is pushed toward one side and is ready for ovulation.

Antrum

Large fluid-filled cavity seen in the mature (Graafian) follicle.

Corpus luteum

Structure formed after ovulation from the remaining follicle; secretes progesterone and some estrogen and enlarges if pregnancy occurs.

Corpus albicans

Degenerated form of the corpus luteum; smaller white-yellow scar-like structure after hormone production ends.

Ovulation

Release of the oocyte from the mature Graafian follicle into the uterine tube.

Follicular progression

Primordial follicle → Primary follicle → Secondary follicle → Tertiary (Graafian) follicle → Ovulation → Corpus luteum → Corpus albicans

What is average length of menstrual cycle?

28 days

What days are involved in menstruation?

1-7

What days are involved in the follicular phase?

1-13

What days are involved in ovulation?

13-15

What days are involved in the luteal phase?

15-28

What occurs to the endometrial histology during menstruation?

shedding of the functional layer of endometrium out of the body

What occurs to the endometrial lining during the follicular phase?

blood lining formed sheds out of the body and the endometrium begins to rebuild

What occurs to the endometrial lining during ovulation?

the endometrium continues to rebuild

What occurs to the endometrial lining during the luteal phase?

the endometrium continues to rebuild before plateauing

What hormones are associated with the menstrual cycle?

• follicle-stimulating hormone (FSH)

• estradiol (estrogen)

• luteinizing hormone (LH)

• progesterone

What releases FSH?

anterior pituitary

Function of FSH

stimulates ovarian follicles to grow & helps dominant follicles mature

When does FSH peak and by how much?

ovulation (day 13-15) and only slightly compared to other hormones

What releases LH?

anterior pituitary

Function of LH

triggers ovulation

When does LH peak and by how much?

ovulation (day 13-15) by the most significant amount

What releases estradiol?

developing follicles

Function of estradiol

thickens endometrium

When does estradiol peak and by how much?

starts off the highest vs other hormones, peaks right before ovulation (day 12-13), then only slightly decreases before returning to day 1 level

What releases progesterone?

corpus luteum after ovulation

Function of progesterone

maintains and prepares the uterine lining for implanation

When does progesterone peak and by how much?

starts slightly lower than estradiol, begins steep incline as ovulation begins (day 13-15), peaks days 20-21, then decreases back to normal by day 28

Body temperature trend through menstrual cycle

days 1-14 it stays slightly above 36C, at day 14 it spikes to a little under 37C until day 17, decreases very slightly until day 25 when it begins its decrease back to slightly above 36C

Ovarian histology: days 1-13

(follicle growing in size, follicle → mature follicle around day 7)

• Primordial → primary → secondary → Graafian follicle

• Follicles grow under FSH stimulation

• One dominant follicle becomes mature

Ovarian histology: days 13-15

(ovulation)

• Mature follicle ruptures

• Secondary oocyte is released

Ovarian histology: days 15-28

(corpus luteum → degenerate corpus luteum, aka corpus albicans around day 25)

• Remaining follicle becomes the corpus luteum

• Corpus luteum secretes progesterone + some estrogen

What is the proliferative phase?

(after menstruation) when estrogen causes rebuilding of the uterine lining and the endometrium thickens → days 6-14

What is the secretory phase?

(after secretory phase) when progesterone makes the endometrium thick, vascular, and glandular to prepare uterus for implantation → days 15-28