18. UPDATED: Male Reproductive System
glans penis
enlarged end of hte penis
where is sperm matured?
epididymis
what happens if sperm are not immediately ejaculated after full maturation?
eventually die & are phagocytized
differentiate the exocrine/endocrine features of the testes
exocrine=sperm production endocrine=hormone production
septum
extensions of the tunica albuginea that divides the testis into lobules
seminiferous tubules
filling most of the testis, these long tubes are the location of actual sperm formation
what does the function of the sperm tail?
flagellum to propel the sperm thru the female tract
primary organs of the reproductive system
gonads (testes)
Describe the 3 parts of a mature sperm
head, midpiece, tail
function of scrotum
holds the testes in a location so the temperature allows proper sperm development/maturation
where is testosterone produced?
interstitial cells in the testes
Why does sterility occur if the testes do not descend?
normal sperm production is inhibited at body temperature and require a cooler temperature
location of seminal vesicles
posterior to bladder at the base; anterior to the rectum
Location of epididymis
posterior to the testis
when does spermatogenesis begin and end?
puberty to death
circumcision
removal of the foreskin
what 2 systems is the urethra involved in?
reproductive & urinary
Why is this maturation time needed by sperm?
required for the sperm to gain the ability to swim.
location of scrotum
sac suspended from the pelvic floor; surrounds the testes
where are the testes located
scrotum
secondary organs of the male reproductive system
scrotum, epididymis, vas deferens, ejaculatory duct, urethra, penis, glands
what happens if the sperm is stored in the epididymus longer than 40-60 days?
the body will reabsorb them bc they're infertile; they are replaced by new sperm
spermatic cord
the collection of structures (ductus deferens, testicular artery, pampiniform plexus, and nerves) which travel through the inguinal canal, wrapped in a CT covering
acrosome
the crown of the sperm that contains the enzymes that breakdown the membrane of the egg to allow the sperm to penetrate
function of prostate gland
-1/3 of semen volume - secretes a milky alkaline fluid believed to activate or increase the motility of the sperm
function of seminal vesicles
-60% of ejaculate volume -viscous yellow secretion contains nutrients like fructose, vitamin C, and prostaglandins to assist sperm in reaching ovum
List and describe the location of the 3 sections of the male urethra
-Prostatic urethra: Surrounded by the prostate gland -Membranous urethra: Begins at the end of the prostatic urethra & travels to the penis -Spongy urethra: Runs through the penis & opens to the outside at the external orifice
list the components of semen
-fructose (fuel) -prostaglandins (facilitates movement) -relaxin (enhances motility) -alkaline pH (protective & motility enhancement) -antibiotic seminalplasmin (kills bacteria)
what are the 3 dif't types of cells in the testes
-spermatogenic cells -sustentocytes (AKA Sertoli cells) -interstitial cells (AKA cells of leydig)
what are the main parts of the testes
-tunica vaginalis -tunica albuginea -septum -seminiferous tubules
how long is the sperm maturation period?
20 days
how many chromosomes does the spermatid have
23
what is the final result of spermatogenesis
4 spermatids
how many sperm are in a single ejaculation of semen
50-100 million
What length of time is required for the production of sperm?
64-72 days
prepuce
AKA foreskin; the retractable skin covering the glans penis
Describe the difference in production of sperm by males and eggs by females
Production of sperm in males begins at the onset of puberty and continues during their lifetime. Women have all their eggs at birth
Describe, in detail, the production of spermatids.
Sperm are formed from spermatogonia in the seminiferous tubules located in the testes. The spermatogonia are stem cells that go through mitotic divisions beginning at birth until puberty. Once a male enters puberty his anterior pituitary gland begins to secrete follicle stimulating hormone (FSH). When FSH is secreted the spermatogonia undergo cell division; one of the cells continues the stem cell line (so you'll never run out of spermatogonia). The other cell, known as the primary spermatocyte, undergoes meiosis 1, dividing into 2 spermatocytes, then meiosis 2, becoming 4 spermatids
Trace the path of sperm from their site of production to the outside of the body.
Sperm produced by the testes mature within the epididymis. -Once the sperm have matured, they are propelled into the vas deferens by muscular contractions. -The vas deferens connects with the duct of the seminal vesicle to form the ejaculatory duct. -The ejaculatory duct then connects with the urethra to provide a means for the sperm to exit the body.
describe the structure of the scrotum
Superficial fascia (CT) Dartos Muscle (a layer of smooth muscle) Cremaster muscle (skeletal muscle fibers)
Describe the structure of the penis and how it functions during sexual intercourse
The penis is a cylindrical organ that contains spongy, erectile tissue containing distensible blood spaces. During sexual arousal, nerve system reflexes cause an increase in arterial blood flow to the penis. This fills the blood spaces in the erectile tissue and the penis, which is normally limp, stiffens and increases in size. This allows the penis to be inserted into the vagina when sexually excited and deposit semen into the female's reproductive tract.
Describe the formation and function of testosterone
The production of testosterone begins during puberty when the anterior pituitary gland secretes luteinizing hormone.
Describe the action of the scrotum in maintaining the proper condition of sperm.
The skin of the scrotum can adjust to outside temperature, contracting when outside temperatures are cold, allowing the sperm to get some heat from the body and expanding when temperatures are warm to keep sperm away from the higher body temperature
describe the location of the vas deferens
Travels superiorly through the inguinal canal & then turns posteriorly over the bladder & descends inferiorly to the base of the prostate gland, connecting with the duct of the seminal vesicle to form the ejaculatory duct
tunica vaginalis
a serous sac found anterior to the testes. formed from the serous membranes of the peritoneum
corpus spongiosum
a single shaft of tissue that surrounds the spongy urethra; also forms the glans
What is semen?
a thick, whitish fluid that contains sperm & accessory gland secretions
tunica albuginea
a tight, which protective CT capsule around each testis
where do the testes develop?
abdominal cavity
what does the head contain
almost entirely nucleus containing the cell CNA + the acrosome
location of the male urethra
begins at the bladder outlet & connects to the exterior
Describe a male vasectomy and how it prevents fertilization
In a vasectomy, the vas deferens is cut and tied off which permanently prevents sperm from exiting the body to fertilize an egg
corpora cavernosa
a dorsal pair of columns of the penis
how do the sperm reach the epididymis from the seminiferous tubules?
by way of the tubulus rectus & rete testis
interstitial cells
cells in the testes that produce the male sex hormones (testosterone)
location of the ejaculatory duct
connects the ductus deferens to the prostatic urethra
what are the 3 columns of erectile tissue of the penis?
corpus spongiosum corpora cavernosa (2)
what muscles of the scrotum are involved in drawing the scrotum closer/pushing it away from the pelvic floor?
cremaster muscle
location of prostate gland
just below the bladder
sustentocyte
larger, cells in the testes that help to protect & "nurse" the developing sperm
spermiogenesis
maturation of spermatids to sperm
function of the bulbourethral glands
minimal contributor to the volume of semen clear, mucous secretion released prior to ejaculation helps neutralize the traces of acidic urine in the urethra
what does the midpiece contain?
mitochondria to generate locomotive energy
what is the function of the pampiniform plexus
network of veins that surround the testicular artery that absorbs heat from the arterial blood, cooling it as it enters the testes
Does a vasectomy change testosterone levels?
no
are the spermatids mature at this point?
no
can you ejaculate and pee at the same time?
no
what 3 glands contribute to the semen
seminal vesicles prostate gland bulbourethral glands
where is sperm produced?
seminiferous tubules
what are the 2 parts of the penis
shaft and glans
Location of bulbourethral glands
small, paired glands in the pelvic floor
functions of the testes
sperm & testosterone production
spermatogenic cells
sperm cells in various developmental states
spermatogenesis
sperm formation from spermatogonia to spermatids
describe the function of testosterone
stimulates the sex drive and growth in males. It also stimulates secondary sex characteristics such as broad shoulders, deep voice, increased muscle size and bone density, and increased hair.
gametogenesis
the general process of gamete formation
sterility
the inability to produce offspring
shaft
the long cylindrical part
Why do older men have difficulty urinating?
the prostate gland enlarges, constricting the urethra & making urination difficult
Epididymis
tightly coiled tubules that start at the superior end of the testes & then travel inferiorly along the posterior lateral side of the testes
function of the ejaculatory duct
transports sperm & the fluids of the seminal vesicles to the prostatic region of the urethra
what is the function of the urethra in the male reproductive system?
transports sperm to the outside world