The Male Reproductive System

Explains the hormones involved in the male reproductive system

GnRH in the hypothalamus → anterior pituitary → produces LH and FSH → acts on the gonads

initially males and female embryos are ________

homologous

What are the two ducts involved in development of the reproductive system

Mesonephric ducts (woffian ducts)and paramensonephric ducts (mullerian ducts)

What is SRY

the sex determining region on the y chromosome

during the first 7-8 wks of gestation the male and female develop a ___________ that eventually differentiates into the testes and clitoris

genital tubercle

For the genital tubercle to differentiate into male genitalia what hormone has to be present

Testosterone

what is the order of development for important structures in utero

ant pituitary (4-5 wks), LH & FSH (10th wk), vascular connection bwn pituitary and hypothalamus (12th wk)

Near the end of pregnancy gonadotropin releasing hormone is released in a ________ flow

pulsatile

What happens to gonadotropins after birth

they are suppressed until puberty

Explain the process of the SYR gene affect on indifferntiated gonad to

indifferent gonad → primordial germ cell → spermatogonia → spermatozoa

The male SRY gene results in the production of TDF (Testis-determining factor) results in the creation of

seminiferous tubules

TDF acts on the seminiferous tubles resulting in the production of what cells

sertoli cells and leydig cells

The sertoli cells and leydig cells produce/ support the production of what hormone

testosterone

Testosterone acts on the wofflan ducts results in what structures

epididymis, vas deferens, seminal vesicles, and ejaculatory duct

Testosterone increases DHT affecting the production of what

prostate, bulbourethral glands, penis, and scrotum

testosterone results in the brain being _________

masculinized

The absence of the SRY gene results in the production of what cells

Thecal cells and granulosa

the abscence of testosterone results in the differentiation into which structures

clitoris, labia majora, labia minora

What does high levels of Anti- mullerian horomone do

prevent the formation of the mullerion ducts

What does low levels of Anti- mullerian horomone do

allow for the formation of mullerion ducts

What structures do the mullerion ducts develop into

oviducts, uterus, cervix, vagina

When does puberty begin and end in males

begins around 11yrs old and is complete with the first ejaculation that contains mature spern

when does puberty begin and end in females

begins at 8-9yrs with thelarche (breast development) and complete at the first ovulatory menstrual period

How can obesity affect the onset of puberty

earlier onset

in general when a person is capable of ___________ puberty is complete

reproduction

Which hormone is responsible for breast development, maturation of the vagina, uterus, and ovaries; also fat deposits in the hips of girls

Estradiol

increased _________ results in rapid skeletal growth in boys and girls

estrogen and growth factors

hormone that is responsible for the growth of testes, scrotum, and penis

testosterone

causes the hypothalamus to secrete gonadotropin-releasing hormone (GnRH)

extrahypothalamic factors

hormones that stimulates the gonads to secrete male or female sex hormones

LH, FSH

Testosterone, FSH, and LH utilize what to increase growth and development during puberty

positive feedback loop

What is described at an increased production of adrenal androgens

Adrenarche

During puberty there is a pulsatile release of _____ during sleep

LH

As puberty progresses, the ________ and _________ of LH peaks increase

frequency, amplitude

The LH surge during puberty is triggered by what

inc activity of neurons releasing GnRH

What is the essential male organ of reproduction that produces the gametes and sex hormones

testes

sperm production requires an temperature that is

1-2 degrees cooler than body temp

What is the outer covering of the testes called

tunica vaginalis

what is the inner covering of the testes called

Tunica albuginea

What is the bulk of the male reproductive structures and the site of sperm production (spermatogenesis)

Testes

which cells produce androgens, primarily testosterone

Leydig cells

the comma shaped structure the curves over the posterior part of the testes and is the location of sperm maturation

Epididymis

Is a ducts with muscular layers capable of powerful peristalsis that transports sperm toward the urethra; is the location of sperm storage

vas deferens

forms the septum that separates the two testes; tightens and relaxes based on temperature

scrotum

part that delivers the sperm to the vagina and eliminates urine

penis

contains the opening of the urethra in males

glans penis

what structures are responsible for conducting sperm and glandular secretions from the testes to the urethral opening

vas deferentia, ejaculatory duct, and urethra

what secretes fluids for sperm transport and creates an alkaline nutritious medium for sperm motility and survival

prostate gland, seminal vescles, and cowper (bulbourethral) glands

what is semen composed of

sperm and glandular fluids

a pair of glands that provide fructose as source of energy for ejaculated sperm

seminal vesicles

the seminal vesicles secrete ____________ that promote smooth muscle contraction, assisting with sperm transport

prostaglandins

an alkaline substance that helps sperm survive in the acidic environment of the female reproductive tract

prostatic fluid

prostatic fluid also include _______ and _________ which help to mobilize sperm after ejaculation

clotting enzyme; fibrinolysin

Luteinizing hormone acts on the Leydig cell to

regulate testosterone secretion

follicle stimulate hormone acts on the sertoli cells to

promote spermatogenesis

what hormone maintains biosynthesis of testosterone

prolactin

Explains how the LH actss on the Leydig cells to increase testosterone

increases the activity of cholesterol

testosterone has what type of communication effects

local paracrine and distal endocrine

testosterone is the primary __________

androgen

what does testosterone affect

sexial differentiation, nervous and skeletal tissue development, libido

Dihydrotestosterone is necessary for what

external virilization (development of male physical characteristics)

SRY encodes what kind of protein

testes determining factor (aka SRY protein)

testosterone is responsible for the differentiation of the internal male genitalia except what

the prostate

Closing of the epiphyseal plates is influenced by what

estrogen converted from testosterone

FSH acts on the Sertoli cells which increases the synthesis and secretion of

androgen-binding protein (ABP)

explain the actions of androgen-binding protein (ABP)

binds testosterone to maintain high local testosterone levels, this increases synthesis of growth factors and supports the development of spermatogonia and spermatogenesis

Inhibin is secreted by what cells and does what action

Sertoli; inhibits FSH secretion which inhibits the proliferation of spermatoginua

What facilitates LH stimulation of androgen biosynthesis in the Leydig cells

inhibin

explain the negative feedback loop of testosterone

inhibits GnRH at the hypothalamus and FSH at the anterior pituitary

the biological process of maturing sperm

spermatogenesis

final stage where spermatids physically transform into mature spermatozoa

spermiogenesis

Where does spermatogenesis and spermiogenesis occur

seminiferous tubules

testosterone is essential for growth and division of ___________

spermatogonia

explain the process of going from spermatogonia to spermatozoa

spermatogonia → mitosis → Primary spermatocyte → meiosis I → secondary spermatocyte → meiosis II → secondary spermatocyte → spermatozoa

during which stages of spermatogenesis are cells diploid and haploid

diploid spermatogonia/ primary spermatocyte; haploid secondary spermatocyte/ spermatozoa

what stage:
lubrication secretions from vaginal canal and bulbourethral glands increase; clit and penis become engorged with blood

arousal

which stage:
clit lifts up, canal expands, labia darken; testes elevate, penis darkens

plateau

which stage:
rhythmic contractions leading to ejaculations

orgasm

which stage:
all changes resolve/ return to normal

Resolution

Erection is _______ mediated

Ejaculation is _______ mediated

parasympathetic, sympathetic

parasympathetic nerves causing the arterioles to dilate through the release of nitric oxide; the corpora cavernosa and corpus spongiosum become engorged with blood

Erectile reflex

contraction of vas deferens/ ampulla causes expulsion of sperm into prostatic urethra and contraction of prostate/ seminal vesicles releasing fluid

emission

triggered by filling urethra with semen, contraction of ischiocavernous and bulbocavernous muscles; also triggered by pressure in penile erectile tissue and urethra

Ejaculation

What is the pathway of sperm during ejaculation

seminiferous tubules, epididymis, vas deferens, ejaculatory ducts, urethra, penis

erection is controlled by the _________ devision of the autonomic nervous system

parasympathetic

___________ breaks down cGMP and limits vasodilation

cGMP specific phosphodiesterase

__________ division of the autonomic nervous system (hypogastric nerve) control emission

sympathetic

the ________ nervous system (pudendal nerve) controls ejaculation

somatic

what is the composition of seminal fluid

60% seminal vesicle secretion, 30% prostate secretionn, and 10% sperm

what is seminal vesicle secretions composed of

fructose, ascorbic acid, prostaglandins, phosphorylcholine, and flavins

__________ division of the autonomic nervous system (hypogastric nerve) controls resolution

sympathetic

__________ in the prostate secretions liquefies seminal fluid

fibrinolysin

When secondary sex characteristics have not appeared in males by 14yrs of age

delayed puberty

what are the two physiologic factors that are the causes of delayed puberty 95% of males

hormonal delay, HPG axis delay

What is classified as precocious puberty

sexual maturation prior to age 9

is GnRH dependent and caused by normal HPG axis working normally but prematurely

central precocious puberty

is GnRH independent and develops when sex hormone are produced by some mech other than stimulation by the gonadotropins

peripheral puberty

feminization of a boy; development of some secondary sex characteristics of the opposite sex

mixed precoious puberty

males that present with an underdeveloped penis and scrotum, overdeveloped mammary glands, infertility, low libedo, and minimal facial hair have what condition and why does it occur

primary male hypogonadism; impaired ability to synthesize/secrete testosterone