Lecture 35 Flashcards
What are the accessory structure os the MRS?
Penis and Scrotum
Why does the scrotum house the testis outside the body?
To maintain their optimum temperature at 34 degrees away from normal body temperature
What muscles are found in the scrotum?
Lined by Dartos muscle and cremaster muscle contracts for heat conservation.
Location of spermatic cords?
There are two spermatic cords what run between the abdomen and testis.
What does the spermatic cords contain?
Ductus deferens
Blood vessels (testicular arteries and veins)
Nerves
Lymphatics
Functions of the penis?
Urination and copulation
General structure of the penis?
A cylindrical organ consisting of the root (bulb), body and glans covered by prepuce/foreskin
Erectile tissues of the penis?
Two corpora Cavernosa: Main erectile tissue found on the dorsal aspect.
One corpus spongiosum: Contains urethra, forms bulb and glans, found on ventral aspect.
What is semen?
Spermatozoa carried to FRT in seminal fluid
What accessory glands mainly produce seminal fluid?
Seminal vesicles
Prostate gland
Bulbourethral glands
What are seminal vesicles?
Two glands located posterior to bladder and lateral to ampulla. Role is to produce viscous secretion
What is Viscous secretion?
Makes up 60% of semen, it’s alkaline pH protects sperm from acidic environment in vagina and urethra.
Location of prostate gland?
Inferior to bladder, wraps around prostatic urethra.
Function of prostate gland?
Produces secretion • 30% of semen • Slightly acidic, milky fluid • Contains PSA: prostate-specific antigen • Contributes to sperm activation, viability and motility
Location of Bulbourethral glands?
Two glands located in the
urogenital diaphragm. Open into spongy/penile urethra
Function of Bulbourethral g;and?
Contribute 5% of semen
volume. Secretions lubricate and
neutralise acidity in urethra
Bulbourethral prior to ejaculation
What are the components of semen?
- ~60% from seminal vesicles
- ~30% from prostate
- ~5% from bulbourethral glands
What is a vasectomy?
Surgical method of sterilisation. Cut the ductus deferens (cut ends tied or
cauterised)
What is Gametogenesis?
- Formation of the gametes (sex cells)
- Spermatogenesis in males
- Oogenesis in females
- Under hormonal control
- Occurs via mitosis and meiosis
- Cells need to be haploid (23 chromosomes)
Brief overview of meiosis?
• Meiosis I
–2 haploid cells produced from 1 original diploid cell
• Meiosis II
–Each cell produced from Meiosis I divides to produce
two haploid cells with 23 chromosome cells
What is spermatogenesis?
• Formation of the male gamete
• The process by which spermatogonia are transformed
to mature spermatozoa (sperm)
• Occurs continuously from puberty onwards
Where does spermatogenesis occur?
• Occurs in the seminiferous tubules
What is Gonadotropin?
hormone that acts on the gonads
What is GnRH?
gonadotropin releasing hormone produced by the hypothalamus
What is LH?
• Luteinizing hormone (a gonadotropin) produced by the anterior pituitary
What is FSH?
Follicle stimulating hormone (a gonadotropin) produced by the anterior pituitary
What is testosterone?
• Type of androgen
• Group of steroid hormones
• Responsible for male characteristics
(maturation of sex organs, spermatogenesis,
secondary sex characteristics, libido)
• Synthetic androgens (steroids) - therapeutic
purposes
Describe the negative feedback loop?
• LH stimulates production of testosterone (interstitial endocrine [Leydig] cells) • FSH and testosterone control spermatogenesis • FSH stimulates Inhibin production (nurse [Sertoli] cells)
Negative feedback of Inhibin?
• Inhibin suppresses FSH
• Testosterone suppresses LH
& GnRH
