Lecture 21 - Male Reproductive System Flashcards
primary sex organ of the male reproductive system
testes
organ of copulation
penis
What is the scrotum and it is composed of which structures
- > skin-covered sac that provides the testes with a cooler environment than body temp (sperm develop better 3degrees below normal body temp)
- > a raphe separates the two scrotal sacs
- > the dartos muscle is a layer of smooth muscle that is part of the wall of the scrotum
what makes up the Spermatic cord
testicular artery - > branch of the abdominal aorta
Pampiniform plexus - > a network of veins surrounding the testicular artery
Cremaster muscle and fascia - > formed from muscle fiber extensions of the internal oblique muscle
Autonomic nerves - > travel with plexus and return to testes
Ductus Deferens
where does the spermatic cord originate
the spermatic cord originates ath the inguinal canal
Functions of the testes
- production of sperm
- production and secretion of androgens (male sex horomones, most common = testosterone)
tunicas of the testes
- > each testes is covered anteriorly and laterally by a serous membrane called the tunica vaginalis
the tunical vaginalis has an outter parietal layer and an inner visceral layer
- > located deep to the visceral layer (in contact with the testis) there is a whitish fibrous capsule covering the testis called the tunica abluginea
tunica albuginea projects into the interior of the testis as the mediastinum testis through which blood vessels, lymphatic vessels and some nerves enter and leave the testis
Types of cells of the seminiferous tubules
- Sustentacular cells
- > nondividing support cells that assist with sperm development
- > connected to each other by tight junctions and form blood-testis barrier - A populaiton of dividing germ cells that continuously produce sperm beginning at puberty
Name all the ducts in the male reproductive system; beginning at the testis
- > rete testis
- > efferent ductules
- > epididymis
- > ductus deferen (or vas deferens)
- > ejactulatory duct
- > urethra
rete testis
- > receives sperm from seminiferous tubules
efferent ductules
- > connect rete testis to epididymis
Epididymis
- > internally, the epididymis contains a long convoluted duct of the epididymis
- > the epididymis stores sperm and serves in the maturation process of sperm
regions of the epididymus
- > head
- > body
- > tail
Ductus deferens
- > sperm leaving epididymis enters the ductus deferens (vas deferens)
- > this tube travels within the spermatic cord and enters the pelvic cavty through the inguinal canal
- > as the ductus deferens approaches the prostate gland, it enlarges to form the ampulla
- > the ampulla unites with the proximal portion of the seminal vesicle to form the ejaculatory duct
ejaculatory duct
formed by a uniting/merger of the ductus deferens (spcifically the ampulla) and the seminal vesicle
- > located within the prostate gland and conducts sperm from the ductus deferns to the prostate urethra
function of male urethra
transports semen from both ejaculatory ducts and urine from the bladder to the outside of the body
Three regions of the male urethra
- Prostatic urethra
- membranous urethra
- spongy urethra
accessory glands of the male reproductive system
- > these glands secrete fluid to mix with sperm to create seminal fluid
- > these secretions nurish the sperm and neutralize the acidity of the vagina
1. seminal vesicles
2. prostate gland
3. bulbourethral glands
Seminal vesicles
- > paired structures located on the posterior surface of the urinary bladder and lateral to the ampula of the ductus deferens
- > they secrete a viscou, whitish-yellow, alkaline fluid containing fructose and prostaglandins
Prostate gland
- > located immediately inferior to the urinary bladder
- > it produces substances that are secreted directly into the prostatic urethra
Prostatic secretions
PS is slightly acidic and contains…
- > mucin
- > citric acid (nutrient for sperm)
- > seminal plasmin (antibacterial)
- > prostatic-specific antigen; PSA (an enzyme that helps liquefy semen, can’t move if it’s too thick)
Bulbourethral glands
- > located in the urogenital diaphragm on either side of the membranous urethra
- > mucin is secreted from theses glands and enters the spongy urethra at the base of the penis
penis
- > penis and scrotum for the external genitalia of males
- > internally, the attached portion of the penis is the root forming both the bulb and the crura of the penis
- > body/shaft is the long part; tip is called the glands
structures of the body of the penis
- Paired corpora cavernosa (fills with blood=erection)
- A single corpus spongiosum surrounded by the corpora cavernosa
- > the corpus cpondiosum contiues into the glands and the corpora cavernosum stops where the body and glands meet
Pathway of sperm through and out the body
Spermatogenesis vs Spermiogenesis
Spermatogenesis - > formation of sperm cells from stem cells via mitosis and meiosis (60-75 days)
Spermiogeneis
- > final maturation phase/ last phase of spermatogenesis where spermatids differentiate into motile sperm cells (24 days)
Semen vs sperm vs ejaculate
Semen = sperm + accessory/seminal fluid from accessory glands
When semen is still in the body = semen
when semen leaves the body = ejaculate
Sperm count for optimum fertility
semen normally measures about 3-5ml and contains 200-500 million sperm
Normal sperm count: > 40 million/ml
Minimum for fertility: 20 million/ml
poor: < 10 million/ml
Componants of a mature sperm cell
- > nucleus, golgi apparatus, mitochondria, microtubules
How long can sperm survive in the fallopian tubes prior to ovulation
up to 5 days
urogenital diaphragm
- > triangle shaped muscle layer created by sphincter urethrae
- > separates the deep perineal sac from the upper pelvis
