Reproductive System Flashcards
Gonads (Testes/Ovaries)
Produce gametes and hormones
Ducts
Transport and store gametes
Accessory Glands
Produce secretions that support the gametes
Structure of the Testicular Reproductive System
- Gonads = testes
- Ducts
- Penis
- Accessory Glands
Gonads = testes
- Located within the scrotum (skin and connective tissue)
- Surrounded by 2 layers (tunics):
- Tunica vaginalis
- Tunica albuginea
Tunica vaginalis
- Outer (superficial) layer
- Serous membrane derived from peritoneum
Tunica albuginea
- Inner fibrous connective tissue capsule
- Extends inward to divided testis into lobules (small lobes)
What does each lobule contain?
- Seminiferous tubules
- Interstitial endocrine (Leydig) cells
Seminiferous tubules
- Produce sperm (spermatogenesis)
- Tubules unite to form rete testis on posterior side of each testis (rete = network)
- Walls of the tubules are composed of:
- Spermatogenic cells
- Sustentocytes (nurse) cells
Spermatogenic cells
Germ cells in various stages of development that
will become sperm
Sustentocytes (nurse) cells
- Surround, nourish and protect developing gametes
- Extend from basement membrane to lumen
- Are connected to one another by tight junctions that form the blood-testis barrier
- Protects developing sperm from immune system, toxins and drugs
- Produce testicular fluid
- For sperm transport in tubule lumen during
Interstitial endocrine (Leydig) cells
- In connective tissue between seminiferous tubules
- Secrete testosterone (hormone)
Ducts
- Sperm formed in the seminiferous tubules enter the rete testis, and then move into a series of
ducts:- Epididymis
- Vas (ductus) deferens
c) Ejaculatory Duct
formed by union of vas deferens and duct from seminal vesicle
d) Urethra
transports urine and semen out of the body
3 regions:
i. prostatic urethra – runs through prostate gland
ii. intermediate (membranous) urethra – runs through the urogenital
diaphragm (muscular floor of pelvis)
iii. spongy (penile) urethra – runs through the corpus spongiosum of the
penis and ends at an opening at the tip of the glans penis called the
external urethral orifice
Epididymis
- Posterior border of testis
- Site of sperm storage and maturation (develop ability to swim)
Vas (ductus) deferens
- Transports sperm from the epididymis during ejaculation
- Part of the spermatic cord which carries the vas deferens, nerves, blood supply, lymphatic vessels through the body wall
- Enters anterior pelvic cavity and loops over posterior wall of bladder
Ejaculatory Duct
Formed by union of vas deferens and duct from seminal vesicle
Urethra
- Transports urine and semen out of the body
- 3 regions:
- Prostatic urethra
- Runs through prostate gland
- Intermediate (membranous) urethra
- Runs through the urogenital diaphragm (muscular floor of pelvis)
- Spongy (penile) urethra
- Runs through the corpus spongiosum of the
penis and ends at an opening at the tip of the glans penis called the external urethral orifice
- Runs through the corpus spongiosum of the
- Prostatic urethra
Penis
- Urinary and copulatory organ
- Parts:
- Root
- Body (shaft)
- Glans penis (enlarged tip)
- Has three cylindrical bodies of erectile tissue (blood sinuses bound by connective tissue):
- 2 corpora cavernosa
- Dorsal/posterior (in the erect position)
- Form most of the root and shaft - 1 corpus spongiosum
- Midventral/anterior (in the erect position)
- Surrounds urethra and forms the glans penis
- 2 corpora cavernosa
Accessory Glands
- Contribute secretions during sexual arousal
- ~95% of semen comes from the following glands, listed in order of highest to lowest
contribution:- Seminal vesicles (2)
- Prostate gland (1)
- Bulbourethral glands (2)
Seminal vesicles (2)
- Posterior to bladder
- Secrete a fluid that provides sperm with a source of nutrients
Prostate gland (1)
- Inferior to bladder and encircles prostatic urethra
- Secretes a fluid that nourishes and activates sperm motility
Bulbourethral glands (2)
- Below prostate in urogenital diaphragm (in contact with external urethral sphincter)
- Secretes thick mucus that helps lubricate the urethra and the glans penis
Spermatogenesis
Spermatogenesis refers to sperm production within the seminiferous tubules
Spermatogenesis Flow
Type A Spermatogonia (2n)
↓ (Mitosis)
Type B Spermatogonia (2n)
↓ (Mitosis + growth)
2 Primary Spermatocytes (2n)
↓ (Meiosis I)
4 Secondary Spermatocytes (n)
↓ (Meiosis II)
8 Spermatids (n)
↓ (Spermiogenesis)
8 Spermatozoa (n)
Spermiogenesis
- A part of spermatogenesis
- Is the differentiation of the spermatids into sperm:
- Develop flagella and acrosomes
- Lose most cytoplasm
Structure of Spermatozoa
- Head
- Body
- Tail = flagellum
Head (Spermatozoa)
- Nucleus (23 chromosomes (n))
- Top of nucleus is covered by the acrosome
- A modified lysosome
- Contains enzymes required to penetrate secondary oocyte
Body (Spermatozoa)
Contains a large number of mitochondria that produce the ATP required for movement
Tail = Flagellum (Spermatozoa)
- Propel sperm
- Made of microtubules
Semen
- Sperm and testicular fluid (5%), and accessory gland secretions (95%)
- 2-5mL released during ejaculation
- Contains 20-150 million sperm/ml
- pH is slightly alkaline = 7.2 – 7.6
- Provides sperm with transportation medium, nutrients, and protection
Structures of the Ovarian Reproductive System
- Gonads = ovaries
- Uterine (Fallopian) Tubes
- Uterus (“womb”)
- Vagina (birth canal)
- Vulva
Gonads = Ovaries
Located in pelvic cavity on lateral sides of uterus and connected to body wall by ligaments that are continuous with the peritoneum