Male Reproductive Chap 32 Flashcards
Male reproductive system is comprised of
a) Penis
b) Testes
c) Genital ducts
d) Accessory glands
Male reproduct function
Hormone and sperm production
Spermatogenesis: 4 sperm cells
Spermatogonium (2N) -> 1 prime spermatocyyte (2N) - > 2 prime spermatocyte (N) - > Spermatid (N) - > Sperm (N)
Temperature regulation of spermatogenesis
Occurs only below 37 C. 34 C is maintained in the scrotal sac.
Testes consist of
Seminiferous tubules. Spermatozoa form here. These tubules are surrounded by loose connective tissue rich in blood vessels, lymphatics, nerves, and Leydig cells.
Leydig cells produce
Testosterone
2 types of cells in the seminiferous epithelium
Spermatogenic cells and sertoli cells
Sertoli cells
“Nurse cells”. Protect, support, and give nourishment to the spermatogenic cells. Phaocytosize cytoplasm eliminated during sperm production.
Testosterone Synthesis occurs
Puberty in males, then hypothalamus begins production GnRH.
GnRH tells the _______ pituitary gland to release __ and __.
Anterior pituary gland to release LH and FSH.
LH causes the ____ cells to secrete _____ in males
Leydig, testosterone
FSH binds to the _____ cells and aids in ______ in males
Sertoli cells, spermatogenesis.
Negative feedback mechanism in males reproductive
Elevated levels of testosterone inhibit the secretion of GnRH.
High sperm counts also induces sertoli cells to secrete inhibin which inhibits production of FSH.
Epididymis
Mature of sperm. Sperm attains maturation, motility, and membrane receptors for the zona pellucida protein (acrosomal maturation).
Prostate gland
Secretes and stores significant contribution to the seminal fluid. White, slightly alkaline fluid that makes up a portion of the semen. Semen is made alkaline to help neutralize acidity of the vaginal tract.
Smooth muscle
PSA - Prostate specific antigen
Secreted in blood. PSA conc increases during malignancy. One possible treatment is to remove the testes the main source of testosterone and administer estrogen.
Vas deferens
Tube that conveys the sperm to the ejaculatory duct. Which empties into the urethra.
Male accessory glands
A) Bulbourethral or Cowper’s glands
B) Seminal Vesicles
Seminal Vesicles (paired structure)
60% of semen volume. Contains, aa, proteins, prostaglands, Vit C, but fructose is the main constituent. Fructose i the fuel needed for motile sperm.
Bulbourethral Gland
Secretes thick mucus that aids in neutralizing acidic urine in the urethra, and aids in lubricating urethral lining.
Fluid from these glands are release in response to sexual stim. Can carry some sperm, thus pregnancy from this fluid alone is possible.
pH 7.5
Mature Sperm Head
Contains nucleus and small part of the acrosome. The acrosome contains digestive enzymes hyaluronidase and arcrosin to break down the zona pellucida. This will allow haploid sperm and haploid egg to join in syngamy. A zygote is totipotent.
Exocytosis from the acrosome.
The acrosome is an organelle derived from the Golgi apparatus.
Process of fertilization involves
1) Acrosomal reaction: Hydrolytic enzyme release
2) Cortical reaction: hardening of jelly coat to prevent potential polyspermy
3) Capacitation: Biochemical changes which allow for sperm to swim better
Neck
Contains sperm cnetrioles and connects head to the midpiece
Midpiece
Contains many mitochondria that provide energy for sperm movement
Tail
Flagellum with 9 +2 microtubule arrangement. Flagellum movement requires ATP, microtubulues, dynein (motor protein with ATPase activity).
Inside cilia and flagella is a microtubulue
9+ 2 with a cytoskeleton called axoneme.
Leydig cells are steroid producing cells
Large accumulation of smooth endoplasmic reticulum, and a well developed Golgi Apparatus.
Testosterone
Involved in muscle growth, development of male secondary sex characteristics such as growth of male genitalia, increased body hair, thickening of skin, thickening vocal chords, and something decreased growth of hair on scalp.
After 25 years, gradual decline in testosterone levels occur.
Precursor for testosterone
Cholesterol
Androgens
Class of homrones. Include Testosterone, Androstenedione, Dehydroepiendrosterone (DHEA): early pubic heath growth, increased oiliness of skin and acne