Male reproductive system Flashcards
Male reproductive system
- Scrotum
- Two testes
- Two epididymides • Two vas deferens • One prostate
- Penis
- Prepuce
- Urethra
Functions of the male reproductive system
- Produces male sex hormones
- Develops spermatozoa
- Deliver the spermatozoa to the female system
Scrotum
- Dogs - Lies between the hind legs
- Cats – On perineum below anus
- Membranous pouch containing testicles divided by a septum into two halves
- Located outside of the body to promote spermatogenesis
- Cremaster muscle allowing position to change
Testicles
• Two testicles (gonads or testes) • Descend through the abdomen
through the inguinal ring
• If the testicles do not descend the animal is termed:
Cryptorchid - One or both testicles retained
Monorchid - Only one testicle developed/ descended at birth
*Neither monorchids or cryptorchids should be used for breeding
produce sperm by spermatogenesis
• To secrete the hormone testosterone which influences sperm development and male behavioural patterns
The testis tissue contains numerous blind ending tubules known as seminiferous tubules
• Drain into efferent ducts which lead to epididymis - maturation of sperm
• Epididymis drains into the vas deferents or spermatic cord to urethra
During castrations
... Eight layers: 1. Skin (scrotum) 2. Dartos 3. External spermatic fascia 4. Cremaster muscle (only in one part) 5. Internal spermatic fascia 6. Parietal vaginal tunic (Vaginal cavity) 7. Visceral vaginal tunic 8. Tunica abuginea (Testis)
Spermatic cord
• Blood – testicular artery and vein
• Lymphatic vessels, nerves, and the vas
deferens (deferent duct)
• Pampiniform plexus - meshwork of veins that surrounds testicular artery. To keep testicle cool and to warm blood when it goes up into the abdomen!
Urethra
Urethra
• Pelvic portion - entry point of deferen duct and accessory reproductive glands
• Penile portion:
• Spermatozoa from vas deferens and secretions from accessory reproductive glands
• urine from the urinary bladder outside the body
Urine flow temporarily blocked when ejaculation occurs
Accessory reproductive glands
• Enter pelvic portion of the urethra • ≠ species ≠ accessory reproductive
glands
• Produce alkaline fluid that helps counteract the acidity of the female reproductive tract and provides energy to sperm
Accessory glands - prostate
- Small walnut that hugs the urethra
- Dog, cat and stallion
- Produces a large part of the seminal fluid that makes up the volume of ejaculate in the dog
Bulbourethral (Cowper’s glands)
- Only in the cat and the stallion
- Caudal to the prostate gland
- Secretes a thick mucous substance that forms part of the seminal fluid
- Clears the urethra of debris prior to full ejaculatio
Penis & prepuce
- A tubular organ.
- Root, body and glans
- Two strips of erectile tissue known as corpus cavernosum and corpus spongiosum which expand proximally when engorged with blood along the penis and is known as the bulb of the penis
- It extends towards the tip and is known as the glans penis
The functions of the penis are to:
• Convey sperm and fluids from the testis into the female reproductive tract
• Convey urine from the bladder to the outside via the urethra
Penis DOGS
• Points cranially
• Distal part within prepuce
(epithelial tissue)
• Os penis
Penis CATS
• Points caudally and it is shorter
• Distal part (glans) covered in barbs
– induced ovulation
• Barbs develop with testoterone
Hormone control
• Formation of spermatozoa begins at puberty • Interstitial cell stimulating hormone (ICSH)/
Luteinizing hormone (LH)
• Stimulation of the cells of Leydig results in the production of testosterone
• Rising levels of testosterone > production of spermatozoa > male characteristics
- Follicle Stimulating Hormone (FSH)
- Sertoli cells→support and nourish the spermatozoa • Inhibin: negative feedback on the production of FSH
Sperm formation
Testosterone produced interstitial space
Stimulates production of sperm in seminiferous tubules
Secretions from Sertoli cells nourishes sperm
Sperm grow and mature, detach and travel to epididymis
