Exam 1 - Male Reproductive System Flashcards
Corpus Cavernosum
- upper paired
- erectile tissue masses
Corpus Spongiosum:
- lower erectile tissue mass
- surround urethra
- ends as glans penis
Scrotum
- Sac skin, fascia, and smooth muscle divided into two pouches by septum
- Cremasteric muscle - changes testis elevation
-** Pampiniform plexus - blood vessel anastomosis - Temperature - regulation of testis
- Sperm survival requires 3 degrees lower temp than core body temp.
Testis
- paired oval glands - 2 in. x 1 in.
- seminiferous tubules for sperm production
- Rete testis
- Epididymis: sperm maturation/ storage
Vas deferens
- in testis
- conducting tubule - duct which conveys sperm from the testicle to the urethra
Urethra
the duct which urine is conveyed out of the body from the bladder, and which in male vertebrates also conveys semen
Prostate Gland
40% of seminal fluid volume, acid phosphatase, zinc, citric acid, cholesteral
Acessory Sex glands
- Seminal vesicle
- Prostate gland
- Bulbourethral (Cowper’s) gland
Seminiferous Tubules
- For sperm production
Leydig Cells
Sertoli Cells
Overview of Spermatogenesis
- Spermatogonium (2N, 4C)
- primary spermatocyte (2N, 4C)
- Secondary spermatocyte (1N, 2C)
- Spermatids (1N, 1C)
- Spermatozoa (1N, 1C)
- Haploid (1N, 1C)
Spermatogonia
stem cells
- gives rise to 2 daughter cells by mitosis
- 46XY, 2N, 4C
Spermatogenesis
formation of sperm cells from spermatogonia
64 day cycle
generates mature sperm
What are the three types of Spermatogonia stem cells?
Dark A: noncycling reserve
Light A: mitotically active, derives Type Bs
Type B: derive primary spermatocytes
Primary Spermatocytes
(46XY) goes through meiosis I
DNA replication
2N, 4C
tetrad formation
crossing over
Hormonal Control
GnRH from hypothalamus - triggers - LH and FSH from Anterior Pituitary
LH triggers….
testosterone from Leydig cells
FSH stimulates….
Sertoli cells
Effects of Testosterone
skeletal and muscle growth
stim. erythropoiesis (prod. of red blood cells)
*stimulates metabolic rate
*stimulates sebaceous gland activity
*growth on distribution of body hair
*anabolic effect: nitrogen, phosphorus, sodium sparing
*enlargement of genitalia, accessory repro glands
*gametogenesis, development of sperm and ducts
*dominance and aggressive behavior
Treatments for hair loss:
Minoxidol (Rogaine): increases vascular supply to hair follicle
Treatments for hair loss:
Minoxidol (Rogaine): increases vascular supply to hair follicle
Propecia: blocks the enzyme 5 aloha reductase - prevents production of dihydro testosterone
Hair transplant surgery
Andropause
- gradual decline in hormonal function in men as they age
- hormones known to decline: testosterone, DHEA, Growth Hormone
Semen
- Spermatozoa: 100-120 million/ml
- 6-8 ml of ejaculate = 600-800 million
- Functionally sterile w/ only 20% of this
- Sperm live for 48 hours in female reproductive tract
- Glycolytic pathway, require basic pH
- The odds of the conception happening is like winning the lottery
Erection
- Parasympathetic nervous system
- Dilation of arteries, construction of venous outflow
- Blood is trapped in corpus cavernosa and spongiosa
- No bons involved
- Dilation of arteries, causes by Nitric Oxide release
- Triggers cGMP second messenger
- Erectile Dysfunction drugs (Viagra, Levitra, Cialis) stimulate itric oxide release by preventing breakdown of cGMP – erections longer tan 4 hours seek medical help
- Blue Haze
Ejaculation
- Spinal Mediated reflex
- Contraction of bulbocavernosus muscle
- Contraction of smooth muscle in vas deferens
Cryptorchidism
- Testes don’t descend into scrotum
- 3% of full term and 30% of premature infants
- Untreated bilateral cry. Results in sterility and a greater risk of testicular cancer
- Descend spontaneously 80% of time during the first year of life
o surgical treatment necessary before 18 months
Testosterone production:
- Principle circulation form – testosterone
- Most potent activated form – dihydrotestosterone
o Is weakly active - Androstenedione is weakly active
- Estradiol
- 80%
Spermatogenesis
- formation of sperm cells from spermatogonia
- 64-day cycle
- generates mature sperm
- Male = heterogametic sex (XY)
- Female = homogametic sex (XX) (reverse in birds, reptiles) – faster sperm
- Some lower vertebrates lack sex chromosomes (amphibians, reptiles, monotremes) egg incubation temp imp.
- Bc human males have XY genotype, (females XX), the sperm determines the gender of the offspring
