male repro Flashcards
gametes
46 chromosomes-
Diploid cell- complete number of chromosomes
Haploid is half the amount of chromosomes
Differentiate pools of cells- males stem cells go through differentiation, the rest go back into the unlimited pool, never a depletion until their 70 or 80
chromosomes
Autosomes- comes in pairs- 22 of these pars
Sex chromosomes- one pair - XX or XY
X chromosome is essential for living
Males give one X or Y, female always give off an X
22 autosomes
1 sex chromosomes
gonads
Testes
Essential organs- sperm is produced and matured, sex hormones released here
The rest is accessory- (mating) the rest
Transport of gamete
Secrete fluids into reproductive tract- glands
Sperm isn’t fully matured when exiting the gonads
Fluid and peristalsis help move things along
Enzymes help with clotting in males and declotting in females
Acidity needs to be neutralised which is potentially damaging to sperm
Events following fertilization
Wolffian ducts- precursor to male tract
Mullerian ducts- precursor to female tract
Sex differentiation controlled by hormones
Y variant is present, male reproductive tract develops
Sex differentiation
Embryo has not testes yet, precursor will be there, testosterone is released to stimulate the development of the wolffian ducts
Same cells release mullerian inhibiting substance, no females
Without these female develops
Male reproductive tract
Testes- prime hormone producer, testosterone allows sperm to produce properly
Need to be out of the body so they can be colder than core body temp
Epididymis- sperm travel after they leave the testes, excess fluid is absorbed, sperm gain motility (with the flagella), doesn’t work fast until in contact with the female
Smooth muscle contractions- peristalsis
Tail that’s moving- means needing energy- mitochondria supply atp
The prostate can neutralize the urethra
3 types of spongy tissue- can soak up something- blood, part of the process of copulation, get to the spot close as possible to the cervix, corpora cavernosa, corpus spongiosum
External genitalia
At rest there is not a lot of blood inside- flaccid
When aroused the pressure is higher, compression of veins allows blood to stay there- during ejaculation process
scrotum on the outside- they need to stay cold or they do not develop good sperm
testes
250-300 compartments
Seminiferous tubules within them
Sperm production occurs here
Leydig cells (interstitial cells) - secrete testosterone
Sertoli cells (epithelial cells) - support sperm development
Enter the lumen and are stored into the posterior testes
They don’t have the ability to use tail yet- stored in protective fluid have proteins
Smooth muscle- peristalsis: propel sperm
blood-testis barrier
Blood-testis barrier: basal compartment, lumenal compartment- tight junctions between sertoli cells
Tight junction most likely has a chemical signal to temporarily open to let sperm go through and go through meiosis
Sperm need to split through meiosis to have 23 rather than 46 chromosomes, this is protection from the immune system
Sertoli cells
Support sperm development
Secrete lumenal fluid
Secrete androgen-binding protein- to bind androgen which is released (pulsitile- released in bursts- testosterone) binds excess and slowly releases so it is smooth throughout the day.
Target cells of testosterone and FSH
Secrete inhibin
Secrete MIS (mullerian inhibiting substance) - embryonic development
FSH targets sertoli cells and increases sperm development
LH stimulates testosterone release
Inhibin inhibits FSH only- negative feedback to limit spermatogenesis, but not testosterone levels
Spermatogenesis
Diploid (2 made, 1 goes back to the pool), primary spermatocyte → haploid- secondary spermatocytes → haploid- spermatids → sperm- spermatozoa
Sperm and development
Sperm maturation
Spermatozoa released into lumen of seminiferous tubules- immotile
Move into epididymis- method of movement, acquire motility
Move to vas deferens- method of movement: energy requiring process (mitochondria supply atp), moves faster once in the female reproductive tract, stay in vas deferens
Seminiferous tubules → Rete testis → efferent ductules → epididymis → vas deferens (last stop until needed/aroused)
Accessory glands:
Seminal vessels- secrete alkaline fluid with protein, fructose, and prostaglandins- neutralise urethra and provide energy, prostaglandins for protection while in female, clotting factor for sperm
Prostate gland- secretes citrate- which is fuel, and enzymes that un-clot the sperm
Bulbourethral glands- secrete viscous fluid and helps line urethra
Sexual response in males
Controlled by ANS
Spinal reflexes
Phases:
-Erection: PSNS- relax smooth muscle in the arterioles, blood flow increases
-Emission: SNS
-Ejaculation: SNS
Stimuli
Mechanoreceptors
Brain
erection
PSNS- increase blood flow and nitric oxide to increase vasodilation, increase pressure to fill spongy tissue
