Functions of the Reproductive Organs

Functions of the reproductive organs Male ● Produce sperm and introduce it to the female body Female ● Produce eggs ● Receive sperm ● Site for union and development ● Carry and nourish foetus ● Give birth ● Nourish offspring Primary sex organs: gonads produce gametes ● M = testes for sperm production ● F = ovaries for egg production Secondary sex organs: internal (accessory organs) and external genitalia ● Accessory organs are important for the passageway of gametes through the reproductive canal ● Makes sure that sperm meets the egg but they are not the primary organ Male reproductive system ● Gonads develop inside the abdominal cavity during fetal development and go down to the scrotum before birth ● Testes have to push through the anterior abdominal wall through a weakness in the fascia ● Make a tunnel inguinal canal to go towards the sacs of the scrotum ● Push through and brings with it muscle and fascia from the innermost layers of the anterior abdominal wall ● The coverings of the scrotum and the anterior abdominal wall are the same ● Hole in the abdominal wall = increased intra abdominal pressure (e.g. long term coughing, opening into the inguinal canal is abnormally wide = intra abdominal organs can push their way down to the scrotum (hernia) ● Male external genitalia is the penis Primary sex organs ● Testes produce testosterone (male sex hormone) and sperm ● Transportation of sperm out of the male body Scrotum ● External casing or the external sac that houses the testes ● Paired - L and R sides are separated ○ There is a septum which physically divides the two ○ Raphe = Indentation on the external surface ● House the testes and the spermatic cord (which is burrowed down with the inguinal canal) ● They are located outside the body to keep them at a temperature below body temperature ● Sperm cannot develop at 37 degrees, optimal is 35 degrees ● L testes is lower than the R testes so that they are not compressed between the thighs ● 2 muscles: dartos and cremaster ● Dartos ○ Thicken and wrinkle skin of scrotum ○ Located in the wall of the scrotum, directly underneath the skin ○ Part of the scrotum itself (not just surrounding) ○ Smooth muscle ○ Contracts when its cold by thickening the skin and subcutaneous tissue (space between the external environment and testes) to trap the warm air ○ Increases the thickness for protection (e.g. blunt force trauma) ● Cremaster ○ ○ ○ Immediately surrounds the testes and spermatic cord Slips of the internal oblique muscle that the testes brought with them when they went to the scrotum (continuation of the abdominal sac) Raises and lowers testes (raise when its cold to get them warmer, lower it when its reached 35 degrees) Testes ● Male gonads ● Paired ● External to the body (for optimum temperature) ● Divided into multiple segments ● Internal structures: seminiferous tubule, rete testis ● Seminiferous tubule (70cm) is tightly coiled within each segment and this is where sperm production occurs ● Cilia and lubrication produced will transport the sperm along the coil to the rete testis ● Rete testis = network of tubes that allows multiple pathways to the next ducts (beginning of maturation) Spermatic cord ● A duct that the sperm has to travel through ● Connection between the testes on the outside of the body to where it needs to go on the inside of the body ● Covered by cremaster muscle (part of internal abdominal wall) and fascia ● Contains supply structures of the testis ○ Ductus deferens ○ Testicular artery --> provides testes with oxygen to increase likelihood of sperm surviving ○ Pampiniform plexus --> veins that wrap around all of the structures, drain the blood away from the testis Epididymis ● ● ● ● ● ● ● ● Ducts that transport the sperm from the testes (external) to internal Wormlike structure (6m but condensed to 3m) On the posterior surface of the testes Tightly coiled tube located within Head is continuous with the rete testis (where maturation of the sperm begins) Sperm is produced in the seminiferous tubule --> cilia transports it --> rete testis (maturation) --> epididymis Epididymis: Starts at the head --> body --> tail (continuous with the ductus deferens) ○ Head --> sperm is not mature and cannot fertilise an egg ○ Tail --> is where it becomes mature and it stays here until ejaculation (can stay here for 40 to 60 days) ○ If no ejaculation = reabsorbed by the epididymis into the body (high chance because a lot of sperm is produced) 74 days in total for production of sperm in the seminiferous tubule to maturation of the sperm in the tail of the epididymis Ductus deferens (vas deferens) ● Located within the spermatic cord ● Continuous with the tail of the epididymis ● 45cm long ● Goes from the tail of the epididymis, up the inguinal canal (into the pelvic cavity) ● Inguinal canal is located in the fascia of the abdominal wall (circled), pierces through the abdominal wall and enters into the abdominal cavity ● Goes to the back of the urinary bladder ● On the posterior surface of the bladder, it widens into the ampulla of the ductus deferens ● Unites with the seminal vesicle at the prostate gland (glands will provide secretions to the sperm to help nourish it) ● Where the ductus deferens and seminal vesicle meet = merge into the ejaculatory duct ● Sperm can leave but some can stay in the ductus deferens but can stay alive until there is the secretion from the accessory glands Seminal glands ● Paired ● Posterior to the bladder ● Superior to prostate gland ● Secretions to nourish the sperm and keep it alive ● Wakes the sperm up out of its suspended animation and nourishes it on its way through the rest of the ducts ● Secretes 60% of seminal fluid during ejaculation ● Wake up inactive 'suspended animation' sperm and the flagella begins to beat ● Secretions: ○ Fructose to nourish the sperm ○ Enzymes to thin out the cervical mucus = undisturbed path to the egg (viscus yellow fluid) Ejaculatory duct ● Where the ductus deferens and seminal vesicle unite ● Empties into the prostatic urethra ● Single duct on each side ● Brings sperm covered in fluid from the seminal gland to the prostate until it gets to the prostatic urethra