male reproductive system

pouch of skin, muscle and connective tissue that houses the teste and epidydidmis

scrotum

what wrinkles the skin of the scrotum when contracted

dartos muscle and fascia

layers of muscle and CT that wrap around ducts and neurovasculature that is dragged through the inguinal canal during testicular descent

spermatic cord

what connects the scrotum to the pelvic cavity

spermatic cord

what are the major components of the spermatic cord

cremaster muscle, ductus deferens, testicular artery, and pampiniform venous plexus

provides blood to the testicle

testicular artery

surrounds the testicular artery

pampiniform venous plexus

has both endocrine and exocrine functions and produces sperm and sex hormones; oval shaped

testicles

what covers the testicles

tunica albuginea

what is the testicles divided into internally

250-300 lobules each containing 1-3 seminiferous tubules

ver long, slender ducts that is the site of sperm production

seminiferous tubules

located on the posterior side of the testicle and collects immature sperm produced in the seminiferous tubules

rete testis

where does sperm start its maturation process

rete testis

what are the three main types of cells within the testicles

germ cells, sertoli/nurse cells, and leydig/interstitual cells

what cell ultimately becomes sperm and resides in several layers within the tubules, each in differing maturity phases

germ cells

protects and promotes the development of germ cells by providing nutrients, waste removal, growth factors, etc

nurse cells

produces inhibin to regulate FSH secretion and androgen-binding protein to concentrate local testosterone levels; form tight junctions between each cell to create a blood-testes barrier to protect the sperm

nurse cells

produces and secretes testosterone and is surrounds the seminiferous tubules

interstitial cells

where are the more mature cells located

closer to lumen of tubule

why are the testes housed outside of the abdominopelvic cavity

require temps less than body temp (35 C)

what are the three mechanisms in which the temp of the testes is regulated

cremaster muscle, dartos muscle, and pampiniform plexus

cold stimulates it to contract to draw the testes closer to body and vice versa

cremaster muscle

contracts when cold and relaxes when too warm

dartos muscle

acts as a countercurrent heat exchanger where heat transfers from the warmer arterial blood to the venous

pampiniform plexus

single coiled spermatic duct located on the posterior part of the testicle and is the site of sperm maturation and storage while also resorbing fluid made from testis

epididymis

if the sperm within the epididymis is not ejaculated, what happens to it

disintegrated and reabsorbed

spermatic duct that carries sperm to the ejaculatory duct and is contained within the spermatic cord

ductus deferens (vas deferens)

what two parts merge to form the ejaculatory duct

ductus deferens and seminal vesicle

spermatic duct that passes through the prostate and empties into the urethra

ejaculatory duct

accessory gland that lies posterior to the bladder and is responsible for 65-75% of the contents of semen by providing fructose, citrate, and ascorbic acid for nutrients

seminal vesicles

accessory gland inferior to the bladder that secretes a milky prostatic fluid, makes semen sticky at first before liquifying it, and contributes 25-30% of semen

prostate

accessory gland within the perineum that produces pre-ejaculate to neutralize the acidity of the urethra and lubricate the head of penis

bulbourethral glands

internally made up of erectile tissues that are covered with muscles

penis

what is the purpose of the 2 corpus cavernosum of the penis

houses the deep artery of penis

what is the purpose of the singular corpus spongiosum of the penis

houses the urethra

loose skin that covers the glans (external end of penis) in a flaccid penis

prepuce (foreskin)

purpose is for growth, repair, and replacement of somatic cells and results in 2 daughter cells through one division, each with identical copies of cell’s DNA and has 2 copies of each chromosome (diploid)

mitosis

purpose is to produce gametes to make sperm or eggs through 2 divisions to result in four daughter cells, each with unique copies of the original cell’s DNA through crossing over and independent assortment (haploid

meiosis

separates homologous chromosomes (sisters stay together) and after division each cell has 23 total chromosomes that are unpaired

meiosis I

all 23 chromosomes are separated at the sister chromatids

meiosis II

what is the sex of a zygote determined by

dad’s sperm

the organs that produce the gametes

primary sex organs

organs that are needed for reproduction

secondary sex organs

at what age are all embryos sexually undifferentiated: all have the same parts

< 5 weeks

what are the three parts of an embryo when it is still sexually undifferentiated

gonadal ridges, mesonephric duct, paramesonephric duct

develops around 5-6 weeks and becomes the gonads

gonadal ridges

becomes the male reproductive tract and degenerates in females

mesonephric duct

becomes the female reproductive tract and degenerates in males

paramesonephric duct

what signals the embryo to develop male genetials

y chromosome has gene called sex-determining region (SRY) that signals the gonads to turn into testes

by what week is the gonadal ridges a rudimentary testis and begins to secrete testosterone and mullerian-inhibiting factor

8-9 weeks

what stimulates the mesonephric duct to develop into male reproductive tract

testosterone

what causes atrophy of the paramesonephric duct

MIF

when should external genitalia be distinct

12 weeks

what does the genital tubercle develop into

penis or clitoris

what does the urogenital folds develop into

encloses urethra within penis or the labia minora

what does the labioscrotal folds develop into

scrotum or labia majora

where do the gonads of males initially develop

high in posterior abdominal cavity near kidneys

cord-like CT structure that anchors to the teste and draws it down through the inguinal canal into the scrotum; ultimately makes the spermatic cord

gubernaculum

is a slow process (begins 28-32 wks) and is stimulated by the presence of testes and should be complete by birth (ends 32-35 weeks)

descent of testes

onset of pituitary gonadotropin secretion (LH & FSH)(10-12) until age of first ejaculation of viable sperm (14)

puberty

puberty to full adult development

adolescence

what are the two main androgens responsible for changes in males

testosterone and dihydrotestosterone

what is the first sign of puberty in males

enlargement of testes and scrotum around 13 years old

what is the order of the male events of puberty after testes and scrotum enlargement

pubic hair, penile growth, growth spurt, spermarchy

when do the testes become dormant up until puberty

after the first 3 months of pregnancy

what is the reproductive function regulated by the hormonal

what stimulates the anterior pituitary to secrete gonadotropins

gonadotropin releasing hormone from the hypothalamus

tells interstitial cells of testes to secrete androgens (testosterone) to eventually produce sperm

luteinizing hormone

stimulates nurse cells to secrete androgen binding protein which makes it more sensitive to testosterone

follicle stimulating hormone

what is the effect of androgen binding protein

accumulates testosterone in seminiferous tubules and epididymis to allow the testes to concentrate testosterone in appropriate areas and absorb it

testosterone has no effect on the testes if what is absent

FSH and ABP

what is inhibin secreted by

nurse cells

inhibits the FSH release from anterior pituitary when there is enough spermatogenesis (negative feedback)

inhibin

if a male was castrated what hormone would be decreased

testosterone

if a male was castrated, how would the FSH and LH levels be affected

they would rise

when does testosterone secretion peak

20

by age 80, how does testosterone decline

1/5 of peak level

has a Y chromosome but the body is unable to response to testosterone

complete androgen insensitivity syndrome

process of sperm production and occurs within the seminiferous tubules

spermatogenesis

where do mature sperm come from

primordial germ cells called spermatogonia

primordial germ cells that remain dormant in the periphery of the seminiferous tubules until puberty

spermatogonia

how are spematogonia reactivated

rise in testosterone

germ cell that remains to divide by mitosis and provides the lifetime supply of stem cells

type A spermatogonium

dublicate copy that goes on to make 4 spermatids by meiosis

type B spermatogonium

what happens in step 1 and 2 of spermatogenesis

spermatogonia divide by mitosis to create one daughter cell (type A) that remains near the basement membrane and serves as the lifetime supply of stem cells

what happens in step 3 of spermatogenesis

type B cell enlarges and undergoes meiosis I to form two secondary spermatocytes

what happens in step 4 of spermatogenesis

secondary spermatocytes undergo meiosis II to make 2 spermatids each

what happens in step 5 of spermatogenesis

each spermatid becomes 1 spermatozoon by sprouting a tail and discarding the cytoplasm

how long does it take for a type B spermatogonium to become a mature spermatozoa

70 days

mature sperm cell that has two parts- head and a tail

spermatozoon

part of spermatozoon that contains a nucleus, acrosome, and flagellar basal body

head

part of the sperm that contains a haploid set of chromosomes

nucleus

part of the sperm that is a lysosome containing enzymes used to penetrate the egg

acrosome

part of the sperm that is a solitary centriole surrounded by a centromere; plays important role in fertilization and allows the tail to swim

flagellar basal body

section of the tail of the sperm that contains numerous mitochondria that produce ATP needed for the long journey up the female reproductive tract

middle piece

what are the sections of the tail of the spermatozoon

middle piece, principal piece, and endpiece

what is the source that provides the semen with prosemogelin that is a fibrinogen-like clotting protein that coagulates the semen

seminal vesicles

what are the 4 phases of male intercourse

excitement, plateau, orgasm and ejaculation, and resolution

what is the major artery to the penis that comes from the internal iliac artery

internal pudendal artery

what fills the erectile tissues of the penis to cause engorgement and erection when stimulated

smaller branches called helicine arteries