Male Reproduction 🍆 Flashcards
Testosterone, DHT, or Estradiol?
Muscle mass💪🏼
Testosterone
What is the product of meiosis in spermatogenesis
two divisions create 16 spermatids
single strand of one chromosome
What is the role of testosterone in embryonic/ fetal development
masculinize reproductive tract and external genitals
promotes descent of testes into scrotum
What fluid is secreted by sertoli cells that aids in flushing sperm to epididymus
seminiferous tubule fluid
Testosterone is converted to dihydrotestosterone (DHT) by:
5a-reductase
Testosterone, DHT, or Estradiol?
Libido
Testosterone
Propecia (finasteride) MOA
5a-reductase antagonist, does not let testosterone convert to DHT
tx of hair loss and enlarged prostates
We don’t use male endocrine contraception because it has these kinda terrible side effects:
acne
increased body weight
decreased HDL
FAT AND PIMPLE-Y 🤮
compression of the _______ reduces venous outflow
subtunical venules
What is the role of testosterone in sex-specific tissue after birth
promotes maturation of reproductive system at puberty
required for spermatogenesis
maintains reproductive tract throughout life
three main cavities of of the penis:
2 corpus cavernosa
1 corpus spongiosum
why do the testes need to be kept 1-2 C cooler than body temperature❄️❄️
prevents lysosomal destruction
What is a vasectomy reversal surgery called?
vasovasostomy
What is the process called by which mature sperm are extruded from Sertoli cells, into the lumen of the seminiferous tubules
Spermiation
Testosterone, DHT, or Estradiol?
Sperm production
all three!
GnRH acts on gonadotrophs in the anterior pituitary to release
FSH
LH
concurrent sympathetic inhibition and parasympathetic stimulation can create an erection in ____
as little as 5 seconds
signs of androgen deficiency (ADAM)
⬇️bone formation ⬇️muscle ⬇️sex drive ⬇️body height ⬇️hematocrit ⬆️cardiovascular disease ⬇️facial hair
changes in mood and energy
changes in appetite
Since sperm cells aren’t mature enough and capable of movement while traveling to the epididymis storage site, how do they get there?
transferred under pressure and by smooth muscle contractions
Testosterone, DHT, or Estradiol?
Pubertal growth spurt
Testosterone
Developing sperm cells do not complete cytokinesis during meiosis, therefore the four daughter cells remain connected, forming a ___________
syncytium
What is the difference between spermatogenesis and spermiogenesis
spermatogenesis: spermatogonia (diploid) —> spermatozoa (sperm)
spermiogenesis : packing and maturation of spermatozoa
Testosterone, DHT, or Estradiol?
Differentiation of epididymis, vas deferens and seminal vesicles
Testosterone
What are the two phases of ejaculation
Emission
Expulsion
What hormone mediates the process of spermatogenesis?`
testosterone
Which gland, seminal vesicles, prostate, or bulbourethral?
fructose to nourish sperm
Seminal vesicle
Describe the sperm cells in the storage area of the epididymis
Not capable of movement
require further maturation
concentrated
Fluid from the bulbourethral glands account for ___% of ejaculate
10%
Stertoli cells secrete was 4 things
- Antimüllerian hormone
- Androgen binding protein
- inhibin
- Seminiferous tubule fluid
What provides nourishment to developing sperm
sertoli cells
Where is the site of spermatogenesis
seminiferous tubules
Which gland, seminal vesicles, prostate, or bulbourethral?
Clotting factors
Seminal vesicle
tonic sympathetic stimulation results in a
flaccid penis
What is the process of releasing permatozoa from sertoli cells into the lumen of the seminiferous tubules
spermiation
What allows XY sperm to transport necessary gene product to XX sperm
cytoplasmic bridges
What forms the blood-testes barrier
tight junctions between Sertoli cells
How long does Spermatogenesis take?
74 days
Fluid from the prostate accounts for ____% of ejaculate
20%
How does the head of the sperm change in spermiogenesis
elongates, most of cytoplasm is lost
nucleus remodels- chromatin condensation
lysosomes aggregate to form acrosome
Sertoli cells are stimulated by: (2 things)
testosterone
FSH
Where are gametes produced in males?
Where are gametes produced in females?
males = testes females = ovaries
PRIMARY REPODUCTIVE ORGANS
The final release of spermatids requires the breakdown of what
tight junctions (between sertoli cells) gap junctions (between sertoli cells and spermatocytes)
The testes have 2 compartments:
And 3 cell types:
compartments = seminiferous tubules, connective tissue
cells = germ, sertoli, leydig
Testosterone, DHT, or Estradiol?
Beard growth, sebum formation 🧔🏽
DHT
Testosterone, DHT, or Estradiol?
red blood cells
Testosterone
How does the secretion of prostaglandins into the ejaculate facilitate reproduction
stimulates motility of sperm to help transport within the male and the female
Scalp hair growth is attenuated by DHT and:
transforming growth factor ß1 (TGF-ß1)
The male erection is due to _____ and
NOT due to _______
due to vasocongestion of the penis with blood
NOT due to skeletal muscle contraction 💪🏼
Testosterone, DHT, or Estradiol?
Differentiation of penis, scrotum, and prostate
DHT
What regulates LH and FSH by negative feedback
testosterone
Receptors where both testosterone and DHT can bind have a greater affinity for
DHT
why is secretion of LH and FSH low during prepubertal phase
hippocampal inhibition of GnRH
the average sperm count is ____ per mL of ejaculate
20-40 million
Three forms of male contraception
- condoms
- “withdrawal method”
- vasectomy ✂️
Further maturation of the spermatids create :
spermatozoa
What is cut in a vasectomy
each vas deferens
Where are all the mitochondria in sperm cells
midpiece- to power the centriole
Beard growth is stimulated by synergism between 🧔🏽
DHT and IGF-1
Proper erectile function requires coordinated involvement of (3 things)
- intact central and peripheral NS
- Corpora cavernosa/ spongiosa
- normal arterial blood supply/venous drainage
How long are the seminiferous tubules
250 m
How does testosterone circulate within the peripheral circulation?
bound to sex-hormone binding globulin (SHBG)
ejaculation pathway:
vas deferens –> ampulla –> urethra –> out 💦💦
decreased production of testosterone and sperm later in life is called
senescence 👴🏽
What is the role of testosterone in reproduction-related effects (Sexy time)
increases sex drive
controls secretion of gonadotropins
Temporal organization of the spermatogenic cycle for continuous production is called
the spermatogenic wave
How can testosterone be conventrated within the seminiferous tubules
by binding to androgen=binding protein (ABP) produced by Sertoli cells
What are the 3 stages of spermatogenesis
- mitosis (proliferation)
- meiosis (2 divisions)
- Spermiogenesis (packaging)
erection is achieved by three things:
- higher brain activity 🧠
- mechanical stimulation of the glands (feedback to the sacral S2-S4 reaction generating center) 🍆
- periodic parasympathetic impulses from sacral erection generating center (night boners) 😴
In the testes, seminiferous tubules make up ____% by weight and connective tissue makes up ____% by weight
seminiferous tubules = 80%
connective tissue = 20%
Which gland, seminal vesicles, prostate, or bulbourethral?
Lubrication fluid
Bulbourethral glands
how many seminiferous tubules per testis?
500
Testoserone is converted to Estradiol (E2) by:
Aromatase
What absorbs excess cytoplasm and wastes from developing sperm
sertoli cells
How many mature sperm are produced daily
128 million
Testosterone, DHT, or Estradiol?
prostate growth
DHT
DHEA from the adrenal cortex is sufficient to stimulate
pubic and axial hair growth
What does a syncytium ensure?
that haploid cells that contain either an X or Y chromosome, have access to all the gene products available in a complete diploid genome
sperm storage area
epididymis
Parasympathetic release of NO vasodilates penis arterioles—-> NO activates _______
guanylyl cyclase and the production of cGMP —-> lowering INTRACELLULAR Ca2+
Testosterone, DHT, or Estradiol?
Negative-feedback on anterior pituitary
Testosterone
FSH does what during spermatogenesis
sensitizes sertoli cells to testosterone
promotes inhibin and androgen binding protein secretion from Sertoli cells
What part of the sperm is in the head that is like a big packet of digestive enzymes that “eat” thru the egg to get in
acrosome
LH does what during spermatogenesis
stimulates cholesterol desmolase within Leydig cells to produce testosterone
(rate limiting step)
Testosterone can be peripherally converted to _____ or _____ in target tissues
dihydrotestosterone (DHT)
Estradiol (E2)
What are 4 male secondary sexual characteristics
- facial and body hair
- larger muscle mass
- masculine jaw
- body height
what is in the wall of the scrotum that can act as a temperature sensor and can relax and contract muscles
rugae
luminal migration to ejaculatory ducts takes ~___ days
14
parasympathetic stimulation of an erection stimulates what two things to occur
vasodilate penile arterioles
stimulates secretion of lubrication from bulbourethral glands
How many spermatogonia begin the spermatogenic cycle daily
2 million
What is the tole of testosterone in non-reproduction effects
increased protein anabolic effect (muscle mass) 💪🏼💪🏼💪🏼
promotes bone growth at puberty 🦴🦴🦴
closes epiphyseal plates
may induce aggressive behavior 🤼♂️
male-specific brain delveopment (pre-optic area, hippocamous, amygdala)
What keeps the testes cool?
- air around scrotum
- rugae contraction/relaxation
- countercurrent venous blood flow
what selectively regulates FSH
Inhibin
What type of patients do NOT go bald
castrated males
eunuchoidal patients with androgen-insensitivity syndrome
5a-reductase deficiency
Hair follicle miniaturation occurs with ______ conversion of testosterone to DHT
5a-reductase
in the flaccid state, blood flow into penile tissue is limited by
contraction of helicine arteries
and
trabecular smooth muscle
What type of cells secrete testosterone in the testes
Leydig cells in the connective tissue
Sperm travels from the Sertoli cells and pass through the _________ on their way to final processing and storage in the epididymis
Rete testes
Testosterone, DHT, or Estradiol?
Cholesterol regulation in the liver
Testosterone
side effects of Propecia (finasteride)
ED
loss of libido
reduced ejaculate
What is the product of mitosis in spermatogenesis
two divisions create 4 diploid primary spermatocytes
double strands of DNA
Testosterone, DHT, or Estradiol?
male pattern baldness
DHT
Fluid from the seminal vesicles account for ___% of ejaculate
60%
Which gland, seminal vesicles, prostate, or bulbourethral?
Secretes an alkaline fluid to counter acidic vaginal environment and pH triggers clotting to keep sperm in vagina
Prostate
During embryonic development germ line cells help form the gonad and become ________________
Spermatogonia
What is the relationship between BPH and prostate cancer?
none
Testosterone, DHT, or Estradiol?
Deepening of voice
Testosterone
What is the “motor” of the spermatozoa
centriole of the midpiece
what is the most widespread environmental factor producing low sperm counts
interference with ability of scrotum to cool the testes
What is the role of testosterone in secondary sexual characteristics
male-pattern hair growth
deepening of voice
promotes muscle growth and male adiposity
Filling of the urethra in ejaculation triggers
somatic nervous impulses with rhythmic activation of skeletal muscles at the base of the penis
Which gland, seminal vesicles, prostate, or bulbourethral?
prostaglandins to stimulate male and female reproductive tract
Seminal vesicle
