Reproductive System Flashcards
Define gonads and give examples for both sexes.
Organs where gametes a produced.
- testes produce spermatozoa
- ovaries produce oocytes
Define coitus and its function.
Sexual intercourse- enabling gametes to fuse and form an embryo.
What are the differences between the pelvic inlet and outlet (2)?
The inlet is open, while the outlet is closed by muscles. The inlet is larger than the outlet.
Name the two pelvic subdivisions, their location, and what they contain.
False/ greater pelvis- above pelvic inlet, containing GI organs
True/ lesser pelvis- below pelvic inlet, containing reproductive organs
Name three ways in which female and male pelvises differ.
Females have a broader subpubic angle.
Female- oval inlet, male- heart inlet
Females have a straighter coccyx, pointing more inferiorly, while males have a curved coccyx which points more anteriorly.
Describe the pelvic floor/ diaphragm.
Two muscles- levator ani and coccygeus- that close over the pelvic outlet.
Describe the male perineum.
An anatomical region inferior to the pelvic floor, between upper region of the thighs. Two divisions:
- urogenital triangle- includes urethral opening and external genitalia
- anal triangle- includes anal canal and fat
Name the two functions of the male reproductive system.
To produce spermatozoa, and to transport them into the female reproductive tract.
What structures does the scrotum enclose?
Two testes, two epididymides, and two spermatic cords (containing part of the ductus deferens).
What do testes produce (3)?
Spermatozoa
Testosterone
Inhibin
What are the testes surrounded by?
Tunica albuginea- dense fibrous capsule
In which structures of the testes are sperm produced?
Seminiferous tubules (1-4 within each lobule of the testes)
Where do sperm undergo maturation? Name the three parts of this structure.
Epididymis
Head, body, tail
Through which structures does sperm travel to get to the epididymis?
Seminiferous tubules join to form rete testis (series of canals), which join to form efferent ductules leading to the epididymis.
Name three cell types within the seminiferous tubules, and their functions.
Interstitial endocrine cells (in tissue surrounding tubules)- produce testosterone
Nurse cells- produce inhibin and support developing spermatozoa
Spermatogenic cells- spermatozoa at various developmental stages (get pushed into the lumen)
Which structure continues from the tail of the epididymis?
Ductus deferens
Where does the ductus deferens run?
- up and out of the scrotum
- through the inguinal cavity in the abdominal wall
- continues superior and posterior to the bladder
- dilates to form the ampulla
What covers the ductus deferens?
Smooth muscle Spermatic cord (until inguinal canal)
Which duct joins the ampulla to form the ejaculatory duct? And where does the ejaculatory duct open?
Duct from the seminal vesicle
Into the prostatic urethra
What is the function of the bulbourethral gland?
Produces a component of seminal fluid- along with the prostate gland and seminal vesicle
What causes retrograde ejaculation?
The internal urethral sphincter doesn’t close during ejaculation, so sperm ends up in the bladder.
Where do the epididymides join to the testes?
At their posterior borders
Why is the scrotum located outside the body?
Because it holds the testes which need to maintain a temperature of 34 degrees celsius- slightly lower than internal body temperature.
Which muscle lines the scrotum, and what is its function?
Dartos muscle
Contracts to wrinkle the skin and reduce the SA for heat exchange
Which muscle surrounds the testes and spermatic cord? What occurs when it contracts?
Cremaster muscle
Brings testes closer to the body for heat conservation
Where does the spermatic cord run, and what does it contain?
From the testes to the abdomen.
Ductus deferens, testicular arteries and veins (venous plexus), nerves, lymphatics
Where does the spermatic cord run, and what does it contain?
From the testes to the abdomen.
Ductus deferens, testicular artery, venous plexus, nerves, lymphatics
What are the two functions of the penis?
Urination
Copulation- transporting sperm into female reproductive tract
Name the three parts of the penis.
Root/ bulb (attaches penis to the body wall)
Body (motile)
Glans
What covers the glans of the penis?
Prepuce/ foreskin
Which region separates the body and the glans of the penis?
Neck of glans
Which state of the penis are the ventral and dorsal terms based on?
Erect state
Describe the three erectile tissues of the penis.
2 corpora cavernosa (one on each side)
- main erectile tissue, on dorsal aspect
1 corpus spongiosum
- contains urethra, forms bulb and glans, on ventral aspect
Why are the corpora cavernosa the main erectile tissue of the penis?
Because the corpus spongiosum contains the urethra, and further erectile movement may block it off.
Which three accessory glands produce seminal fluid? Name the components they produce and their functions.
Seminal vesicles- alkaline viscous secretion (60% of semen) protects sperm against acidic environment in urethra and vagina
Prostate gland- slightly acidic, milky fluid (30% of semen) contributes to sperm activation, viability and motility
Bulbourethral glands- secretion (5% of semen) lubricates and neutralises acidity in urethra prior to ejaculation
Where are the seminal vesicles located?
Posterior to the bladder, lateral to the ampulla.
Where is the prostate gland located?
Inferior to bladder, wraps around prostatic urethra.
Which protein is secreted by the prostate gland?
PSA prostate-specific antigen
Where are the bulbourethral glands located?
In the urogenital diaphragm, opening into the penile urethra.
Describe a vasectomy.
A surgical method of sterilisation in males which involves cutting the ductus deferens- has no effect on volume of seminal fluid (-5% on volume of semen).
Define gametogenesis. What is it called in each sex?
Formation of gametes.
Females- oogenesis
Males- spermatogenesis
What is the basis of spermatogenesis?
Spermatogonia maturing into spermatozoa via mitosis and meiosis.
When and where does spermatogenesis occur?
From puberty onwards, in the seminiferous tubules.
Describe spermatogenesis 1.
Mitosis divides spermatogonia (stem cell) into 2 diploid daughter cells. One stays at the basement membrane of the seminiferous tubule (type A) while the other moves away (type B).
Describe spermatogenesis 2.
Type B spermatogonia differentiates into a diploid primary spermatocyte which undergoes meiosis I to form 2 haploid secondary spermatocytes.
Describe spermatogenesis 3.
Secondary spermatocytes undergo meiosis II to form 4 haploid spermatids, which differentiate into spermatozoa by spermiogenesis. Spermatozoa are released into the lumen.
What changes to the spermatids as they undergo spermiogenesis to become spermatozoa?
- nucleus condenses into head of spermatozoon
- (enzyme-containing) acrosomal vesicle becomes acrosome
- lots of mitochondria form to produce ATP for tail production
- excess cytoplasm is discarded
Define gonadotropin.
A hormone that acts on the gonads.