Lecture 1: Male Reproductive System Flashcards
Lecture 1 and chapter 27
What is meant by the statement: The female system is cyclical whereas the male system is not.
The female system runs on a regular monthly cycle. If fertilization doesn’t occur the cycle resets and starts again; whereas the male reproductive system works continuously in a steady fashion with no cycle.
ie. Women’s fertility window is limited while a man is fertile everyday
The testes are located within
The Scrotum
The testes are responsible for:
- producing sperm
- maintain a temperature 3C lower than the body for optimal sperm production
Tunica vaginalis is:
two-layered serous membrane surrounding the testes
Tunica albuginea is:
the fibrous capsule of the testes
Pampiniform plexus is a
blood supply that helps with thermoregulation of the testes to maintain homeostasis
Why is the scrotum located outside of the body?
Functions to maintain optimal temperature for Sperm production
What are the muscles that have the abilities to raise the testes into the abdominal cavity?
the cremaster muscle (lift testes inside the body when cold)
How does dartos muscle work to maintain appropriate temperature of the testes
Dartos muscle contracts in cold and wrinkles the skin of the scrotum reducing the surface area and pulling the testes closer to the body
In heat the muscle relaxes and increases the surface area prmoting heat loss
Why is it critical that the testes maintain a temperature 3 degrees lower than the internal temperature of the body?
Maintain optimal temperature for sperm production.
What is the pathway sperm takes to get to the ductus vas deferens?
- Seminiferous Tubules
- Tubules Rectus
- Rete Testes
- Efferent Ductules
- Epididymis
What is the function of the epididymis?
Location where sperm matures and is stored
What are the 3 sections of the epididymis?
- Head
- Body
- Tail
Where does the head of the epididymis receive sperm from?
Seminiferous Tubules
Sperm are mature when they get to the epididymis.
True or False
False.
Sperm not immature and nonmotile
How many days does it take sperm to transverse the epididymis and gain their ability to swim
Approx. 20 days
What happens to the epididymis during ejactulation?
smooth muscle walls of the epididymis contract and push sperm from the tail of the epididymis to the vas derferens
Does the epdidymis add any secretions to the sperm?
No.
Secretions are added to the sperm by seminal vesicles, the prostate and the bulbourethral
What happens to the sperm that do not get ejaculated after several weeks?
They are phagocytized
What is the function of the Ductus (Vas) Deferens?
To transport mature sperm from the epididymis to the ejactulatory duct
The ejactulatory duct passes into the _____ before being expelled into the urethra.
Prostate Gland
Describe the secretions produced by the seminal vesicles
Excretes a thick yellow fluid that contains: Fructose, Citric acid, coagulating enzymes and prostaglandins.
What is the purpose of the secretions produced by the seminal vesicles?
Increases sperm motility or fertilizing ability
Describe the secretions produced by the Bulbourethral Gland:
produce thick clear mucous
What is the function of the secretions produced by the bulburethral gland?
lubricates the glans penis during sexual excitement
Describe the secretions produced prostate gland
Milky white appearance
What is the purpose of the secretions produced by the prostate gland
Activate sperm
Contains nutrients (citrate) and Prostate Specific Antigens (PSAs)
What happens to the prostate gland during ejactulation?
muscles contract and force secretions into the prostatic urethra
Explain the Function of the Uretha (2)
Teminal portion of the penis that serves both urinary and reproductive systems
Explain the Spongy urethra
Runs through the penis and opens to the outside of the body. It secretes lubricating mucus into the lumen just before ejaculation
How is urine prevented from entering the urethra during ejactulation?
The internal sphinchter in the bladder constricts and this prevents urine from leaving the bladder
How is semen prevented from entering the bladder
The internal sphinchter in the bladder constricts and this prevents semen from entering the bladder
The seminal vesicles contribute ___% of the semen volume
70%
What accounts for the yellowing colour of the secretions produced by the seminal vesicle?
Flavin Protein
Explain the purpose pf the bulbourethral gland (copwers gland)
pre-cum to help lubricate the urethra and the tip of the penis to make passage of semen smoother during ejaculation.
It neutralizes the acidity of the urethra from urine
Do the secretions produced by the bulbourethral gland contain sperm?
no - however, it can carry left over sperm from the urethra
Explain how the penis is a copulatory organ?
because its main function during sexual intercourse is reproduction by delivering sperm into the vagina
External male genitialia consist of?
- Penis - root - shaft - glans penis
- Scrotum
The internal penis consists of:
- spongy urethra
- 3 corpora of erectile tissue
- 2 corps cavernosa
- mid ventral corpus spongiosum
Describe the function of the Corpus Cavernosa
Allows the penis to fill with blood becoming erect and enabling it to enter the vagina
Describe the composition of semen
secretions the provide:
1. transport medium
2. nutrients (fructose, citrate)
3. chemicals (PGs, ATP, Antibiotic)
Protects and activates sperm
What is the pH of semen
7.2-7.6
Why is the pH of semen significant
to neutralize the acidity of the vagina and help sperm survive passge through the female reproductive tract
Describe the Hypothalamic-Pituitary-Gonadal Axis
- the hypothalmus releases GnRH
- GnRH stimulates the anterior pituitray
- the anterior pituitary releases FSH and LH
- FSH and LH act on the gonads to stimulate gamete production and sex hormone secretion
What hormone initiates the negative feedback mechanims of the Hypothalamic-Pituitary-Gonadal Axis
Inhibin
how does inhibin work on the Hypothalamic-Pituitary-Gonadal Axis
inhibits FSH stimulation at the pituitray
how does the hormone testosterone contribute to the negative feedback mechanism of Hypothalamic-Pituitary-Gonadal Axis
at the anterior pituitary testosterone inhibits LH and FSH
At the hypothalamus testosterone inhibits GnRH
What is the purpose of the negative feedback mechanims of Hypothalamic-Pituitary-Gonadal Axis
prevents overproduction of testosterone and sperm
maintains hormonal balance
What is the location of the sertoli cells
inside the seminferous tubules
What is the main function of the Sertolic cells?
support and nourish developing sperm
Sertoli cells are stimulated by:
FSH
Sertoli cells stimulated by FSH stimulate
inhibin
What are Sertoli cells role in spermatogenesis?
Directly help sperm develop and mature
What is another name for Sertoli cells?
Nurse cells
Where are Leydig cells located?
Interstitial space
What is the main function of Leydig cells?
produce testosterone
Leydig cells are stimulated by:
LH - Lutenizing Hormone
The hormone secreted by the Leydig cell is:
Testosterone
What is the role of Leydig cells in spermatogenesis?
indirectly supports it by producing testosterone. which is necessary for sperm development
What is another name for Leydig cells?
Factory cells
What is an easy way to remember how to differentiate Sertoli and Leydig cells?
Sertoli = support (sperm)
Leydig = Libido (testosterone)
How do Sertoli and Leydig cells work together?
leydig cells produce testosterone (with LH stimulation) and Sertoli cells respond to FSH and testosterine to nurture the sperm cells
What are the Gonadal effects of testosterone?
Growth and maturation of gonads and accessory glands
essential for spermatogenesis
What are the somatic effects of testosterone?
adolescent growth spurts
growth of the larynx and vocal cords
secretion of sweat
hair growth (chest/armpits/face/groin)
What are the metabolic effects of testosterone?
Anabolic: hematopoiesis
Basal Metabolic Rate
What are the CNS effects of testosterone?
Maintenance of libdo
aggression
The CNS activates the
parasympathetic nervous system.
When a male reaches climax (orgasm) what reflex is initiated?
visceral spinal reflex is initiated
Ejaculation is followed by
Ejaculation is followed by resolution
what is resolution
– a period of muscular and psychological relaxation.
During resolution the activation of the sympathetic nerve fibers
constrict penile arterioles reducing blood flow to the penis
Penis
. Organ that delivers semen to the ♀ reproductive tract.
ductus vas deferens
Passageway for sperm from epididymis to ejaculatory duct.
Conveys both sperm & urine down length of the penis.
Urethra
Organs that contribute to the formation of semen.
prostate gland
seminal vesicles
External sac that houses the testes
scrotum
Cuff of skin encircling the glans penis.
prepuce
Surrounds the urethra at the base of bladder; produces a milky, alkaline secretion.
Prostate Glands
Produces over half of the seminal fluid.
seminal vesicles
Empties a lubricating mucus into the urethra
bulbourethral glands
CT sheath enclosing vas deferens, blood vessels & nerves.
spermatic cord
