Week 1 - Male Reproductive Physiology Flashcards
Label the Diagram
What are the 4 major Functional Components of the Male Reproductive System?
- Sites for production of male gametes and androgens -> Testes
- A paired system of ducts to collect, store and transport sperm from each testis -> efferent ducts, epididymis & vas deferens
- Exocrine glands that secrete most of the fluid in which ejaculated sperm are suspended -> Seminal vesicles, prostate and bulbourethral glands
- A means for copulation and delivery of semen to the female reproductive tract -> Penis
What are the 3 cylindrical columns of erectile tissue within the penis?
2 corpus cavernosa (dorsal)
1 corpus spongiosum (ventral)
What causes an erection?
NO relaxes smooth muscles -> vessels dilate, increased blood flow to penis, vascular channels become engorged with blood, erection of penis occurs
What is the optimal temp for sperm production?
34 degrees C
What muscles in scrotum regulate temperature? and how do they work?
Dartos muscle (smooth muscle) -> contracts in cold and wrinkles scrotal skin to decrease heat loss
Cremaster muscles (skeletal muscle) -> contracts in cold and elevates scrotum and testes closer to body
What 2 tunics are the testes surrounded by?
Tunica vaginalis (outer layer derived from peritoneum)
Tunica albuginea (fibrous connective tissue)
Diagram of Testes
What does testicular blood supply consist of?
- Arteries arising from abdominal aorta
- Veins arising from pampiniform venous plexus
How many seminiferous tubules are within a lobule?
1-4
What do Seminiferous tubules consist of?
Sertoli cells and germ cells
What do Seminiferous tubules produce?
Produce sperm
What cells are within the interstitial compartments?
Leydig cells
What do Leydig cells within the interstitial compartment produce?
Produce testosterone
Spermatogenesis process
Describe the steps in Spermatogenesis (7 steps)
- Type A spermatogonia are found only in the basal compartment of the seminiferous tubule
- Type A spermatogonia gives rise to type B spermatogonia
- Type B spermatogonia divide and differentiate to form primary spermatocytes
- Tight junction remodelling allows primary spermatocytes to cross the blood-testis barrier
- Primary spermatocytes undergo the first meiotic division to form two secondary spermatocytes
- Secondary spermatocytes undergo a second meiotic division to form four spermatids
- Spermatids differentiate into spermatozoa in a process known as spermiogenesis
Describe the steps in Spermiogenesis
- Packaging of the acrosomal enzymes by the Golgi
- Positioning of the acrosome and centrioles
- Microtubules elongate to form flagellum
- Mitochondria multiply and surround the flagellum
- Sloughing of excess cytoplasm
- Structure of immature sperm released into the lumen
- Structure of mature sperm in the epididymis
Three parts of the structure of sperm
Head
Midpiece
Flagellum (tail)
What does the Epididymis do in terms of transport of sperm?
- Monitors and adjusts the composition of fluid produced by the seminiferous tubules
- Acts as a recycling centre for damaged sperm
- Stores and protects spermatozoa while facilitating function maturation
- Ejects sperm in to the vas deferens
What is the Vas Deferens?
Tube that runs from scrotal sac to inguinal canal then descending down towards the urethra
What do Seminal Vesicles do?
- Attach to vas deferens to form Ejaculatory duct
- Also releases a fluid which makes up 70% of semen and enhances sperm motility
What does the Urethra do?
- conveys both urine and semen
- lined with Bulbourethral glands producing a thick mucus which lubricates the glan s penis and neutralises acidic urine
What does the Prostate gland do?
- plays a role in activating sperm by producing a fluid that accounts for 1/3 of semen volume containing a citrate, enzymes and prostate-specific antigen
