Packet 31 Flashcards
Gonads, ducts, sex glands & supporting structures
Semen contains sperm plus glandular secretions
Male reproductive system
Sac of loose skin, fascia & smooth muscle divided into two pouches by septum
Skin contains dartos muscle causes wrinkling
Temperature regulation of testes
- -sperm survival requires 3 degrees lower temperature than core body temperature
- -cremaster muscle in spermatic cord
scrotum
elevates testes on exposure to cold & during arousal (‘shrinkage muscle’)
warmth reverses the process
cremaster muscle in spermatic cord
Paired oval glands measuring 2 in. by 1in.
Surrounded by dense white capsule
testes
the testes are surrounded by dense white capsule called __
–septa form 200 - 300 compartments called lobules
tunica albuginea
lobules in testes are filled with 2 or 3 seminiferous tubules where __ are formed
sperm
Descent of testes
Develop near kidney on posterior abdominal wall
Descends into scrotum by passing through inguinal canal
- -during 7th month of fetal development
- -Guevedoches in D.R.
Testes do not descend into the scrotum
–3% of full-term & 30% of premature infants
–Descend spontaneously 80% of time during the first year of life
surgical treatment necessary before 18 months
Cryptorchidism
Untreated bilateral cryptorchidism results in
sterility & a greater risk of testicular cancer
all stages of sperm development: spermatogonia, primary spermatocyte, secondary spermatocyte, spermatid, spermatozoa
supporting cells called sertoli cells
Leydig cells
seminiferous tubules
__ in between tubules secrete testosterone
leydig cells
extend from basement membrane to lumen
- -form blood-testis barrier
- support developing sperm cells
- produce fluid & control release of sperm into lumen
- secrete inhibin which slows sperm production by inhibiting FSH
sertoli cells
Testosterone & DHT bind to receptors in cell nucleus & change genetic activity
Prenatal effect is born a male
At puberty, final development of 2nd sex characteristics and adult reproductive system
sexual behavior & libido
male metabolism (bone & muscle mass heavier)
deepening of the voice
hormonal effects of testosterone
On Test
how does testosterone effect development
testosterone organizes reproductive system before birth and at puberty testosterone activates development of sexual behavior, male metabolism, voice deepening.
Secondary spermatocytes are formed
4 spermatids are formed
spermatogenesis
23 chromosomes of which each is 2 chromatids joined by centromere
Secondary spermatocytes
each is haploid & unique
all 4 remain in contact with cytoplasmic bridge
accounts for synchronized release of sperm that are 50% X chromosome & 50% Y chromosome
4 spermatids
maturation of spermatids into sperm cells
Spermiogenesis
release of a sperm cell from a sertoli (sustentacular) cell
Spermiation
Hormonal control of spermatogenesis
Puberty
LH
FSH
hypothalamus increases its stimulation of anterior pituitary with releasing hormones
anterior pituitary increases secretion LH & FSH
puberty
stimulates Leydig cells to secrete testosterone
LH
stimulates Leydig cells to secrete testosterone
an enzyme in prostate & seminal vesicles converts testosterone into dihydrotestosterone (DHT-more potent)
LH
stimulates spermatogenesis
–with testosterone, stimulates sertoli cells to secrete androgen-binding protein (keeps hormones levels high)
testosterone stimulates final steps spermatogenesis
FSH
Male sterilization Vas deferens cut & tied off Sperm production continues Sperm degenerate 100% effective 40% reversible
vasectomy
Formed from duct of seminal vesicle & ampulla of vas deferens
About 1 inch long
Adds fluid to prostatic urethra just before ejaculation
ejaculatory ducts
Ejaculatory ducts are made of
ampulla of ductus defrens and seminal vesicle
Passageway for urine & semen
Prostatic urethra (1 inch long)
Membranous urethra (passes through UG diaphragm )
Penile (spongy) urethra (through corpus spongiosum)
urethra
Pair of pouchlike organs found posterior to the base of bladder
Alkaline, viscous fluid (seminal fluid)
seminal vesicles
functions of seminal vesicles and their alkaline, viscous fluid
neutralizes vaginal acid & male urethra
fructose for ATP production
prostaglandins stimulate sperm motility & viability
clotting proteins for coagulation of semen
Single organ the size of chestnut found inferior to bladder
Many duct openings
Enlarges with age
secretes milky fluid
prostate gland
function of prostate gland
increases sperm motility and viability
-citric acid for ATP production & enzymes for seminal liquefaction
Paired, pea-sized gland within the UG diaphragm
Bulbourethral or Cowper’s Gland
function of Bulbourethral or Cowper’s Gland
Secretes alkaline mucous into spongy urethra
-Neutralizes acids and lubricates
Mixture of sperm & seminal fluid
semen
semen contains
nutrients, clotting proteins & antibiotic seminalplasmin
Typical ejaculate is 2.5 to 5 ml in volume
Normal sperm count is 50 to 150 million/ml
actions of many are needed for one to enter
Coagulates within 5 minutes – reliquefies in 15 due to enzymes produced by the prostate gland
Semen analysis—-bad news if show lack of forward motility, low count or abnormal shapes
semen
