Module 3: Male Reproductive Anatomy and Physiology Flashcards
list the functions of the male genitalia
- produce sperm
- produce androgens
- transport sperm from the site of production to the vagina of a female
- eliminate urine
- provide sexual pleasure
what is the analogous tissue of testicles
ovaries
what structure produces sperm
testicles
what androgen is created by the testicles
testosterone
list the components of the external male genitalia
- penis
- scrotum
list the components of the external penis
- glans penis
- corona
- frenulum
- shaft
what tissue is the penis made of
erectile tissue
describe the glans penis
- head of the penis
- distal portion of the penis
- covered by foreskin in uncircumcised males
- made of erectile tissue
- richly innervated
what is the analogous structure to the glans penis
clitoris
what does corona mean
crown/ring
describe the corona
- band of tissue where the shaft of the penis meets the head of the penis
- surrounds the circumference of the head of the penis
describe the frenulum
- on the backside/underside of the penis
- connects the glans penis/head of the penis to the shaft of the penis and runs down to the scrotum
- helps pull the foreskin over the glans of the penis
describe the scrotum
sac that suspends/holds the testicles
describe why testicles are suspended outside the body in the scrotum
testicles need to be 1-2 degrees cooler than the rest of the body to produce sperm
describe what the scrotum does when it is hot or cold outside
- draw up towards the body when it is cold
- suspend down away from the body when it is hot
define testicular torsion
one testicle twisting around itself inside of the scrotum
what is the average length of the penis erect in the US
5.16 inches
what is the average girth/circumference of the penis in the US
4.5 inches
which testicles is said to hang lower
the opposite testicle of the dominant hand hangs lower
what percent of male babies are circumcised before they leave the hospital
80%
define circumcision
removal of foreskin
describe how circumcision is performed
- protective metal device is placed under foreskin around the head of the penis
- the foreskin is draw back and a cut is made parallel to the penis
- the foreskin is cut around the circumference of the head of the penis until fully removed
list medical benefits of circumcision
lower risk of UTI, penile cancer, and STIs (especially HIV)
describe why circumcision can protect against infection
- the foreskin can hold pathogens against the head of the penis
- removal of the foreskin can made the head of the penis easier to clean
what often causes penile cancer
HPV
list the risks of circumcision
- pain
- bleeding
- infection
what happens to the risks of circumcision as you age
risks increase with age
what does the American Academy of Pediatrics say about circumcision
- benefits outweigh the risks
- benefits not great enough to recommend universal circumcision
what impacts the decision to circumcise your child
- culture
- religion
- personal preference
list the components of male internal genitalia
- testes
- epididymis
- vas deferens
- seminal vesicles
- prostate gland
- cowper’s/bulbourethral glands
what is the average size of one testi
2 in x 1 in
what is the analogous structures of the testes
ovaries
what are the main functions of the testes
- produce male sex hormone (testosterone)
- produce sperm
define seminiferous tubules
- structures inside of the testicle
- produce sperm
what is the length of seminiferous tubules inside 1 testicle unravled
28 inches
where is the epididymis located
on the backside (posterior) of the testicle
define epididymis
- consists of tubing that holds sperm after it’s production
- site of sperm maturation
what is the length of the tubing in 1 epididymis unraveled
20 feet
how long are sperm stored in the epididymis
2-6 days
what happens to sperm in the epididymis if ejaculation does not occur
they die and are reabsorbed into the body
define the vans deferens
connects the epididymis to the prostate
define a vastectomy
- permanent sterilization for men
- tying of the vans deferens
how long is the vas deferens
14-16 inches
what is the analogous structure of the vas deferens
fallopian tubes
what is the purpose of cilia in the vas deferens
move sperm towards the prostate
define seminal vesicles
- before the prostate gland
- 2 small sacs on each side that secrete fructose for semen
what is the purpose of fructose in sperm
gives sperm nutrients
what is the majority of semen made of
fructose
what is the purpose of the liquid component of semen
- fructose is nutrients for sperm
- helps sperm motility
describe the size of the prostate gland
size of a chestnut
where is the prostate located
below the bladder
where do the renal and reproductive system join in males
prostate gland
what does the prostate gland do
- where renal and reproductive systems meet in men
- secretes prostaglandins
what is the purpose of prostaglandins in semen
- propel sperm
- cause uterine/cervix contractions
where are cowper’s/bulbourethral glands located
below the prostate
describe the size of a cowper’s/bulbourethral gland
size of a pea
what do cowper’s/bulbourethral glands do
- secrete liquid to lubricate the urethra and balance the pH of the urethra so sperm don’t die
- secretions are also called precum/pre-ejaculate
how many sperm are in ejaculate and how many are in pre-ejaculate
- ejaculate: 300 million sperm
- pre-ejaculate: 50,000 sperm
are the secretions from the bulbourethral glands included in the contents of semen
no
how long is the urethra in males
12 inches
what are the two types of erectile tissue in the penis
- corpus sponginosum
- corpus cavernosum
what does corpus mean
body
where is the corpus sponginosum found
surrounding the urethra
what is the purpose of the corpus sponginosum in the penis
- vasocongests when aroused
- protects the urethra
what tissue does the urethra run through in the penis
corpus sponginosum
what is the majority of penile tissue
corpus cavernosum
what is the corpus cavernosum responsible for in the penis
- rigidity
- length
- circumference
what runs through the corpus cavernosum in the penis
penile arteries
list the path of sperm in the male reproductive system
- seminiferous tubules in the testicles
- epididymis
- vas deferens
- prostate
- urethra
- urethral opening
are the seminal vesicles a passage for sperm
no, sperm do not move through the seminal vesicles
is the incidence of testicular cancer increasing or decreasing in the US and many other countries
increasing
is testicular cancer common
no
how many males will develop testicular cancer
- 1in 250
- 9300 cases per year in the US
what is the average age of diagnosis for testicular cancer
33
who usually gets testicular cancer
young and middle-aged men
what percent of testicular cancer cases do men aged 25-44 make up
90%
what are signs of testicular cancer
swelling of the testicle or scrotum
describe the growth of testicular cancer
- slow growing
- doesn’t often metastasize
how many men will be diagnosed with prostate cancer in their life
- 1 in 9
- 160,000 cases per year in the US
how many women will be diagnosed with breast cancer in their life
1 in 8
who usually gets prostate cancer
- older men
- african american men
what percent of prostate cancer cases are men over the age of 65
60%
what is the average age of diagnosis for prostate cancer
66
what are the signs of prostate cancer
- trouble peeing as the prostate inflames and cuts off the urethra
- blood in urine/semen
- erectile dysfunction
describe how to perform a testicle self-check
- in a warm shower to relax the scrotum
- hold the top of the testicle between the thumb and forefinger and roll gently, feeling for any lumps
what is the risk of dying from testicular cancer
- 1 in 5000
- 400 men die a year from testicular cancer in the US
what is the treatment for testicular cancer
removal of the testicle
does removing one testicle impact fertility
- no
- the remaining testicle will compensate
what is the name of testicle replacements
neuticles
what are the two prostate cancer screeners
- digital rectal exam
- prostate-specific antigen test
at what age should a man start getting digital rectal exams to screen for prostate cancer
- age 40
- earlier if they have a family history or are experiencing problems
describe a digital rectal exam
- patients leans over the exam table
- one finger is inserted into the rectum
- the physician will palpate downwards towards the stomach to feel the prostate
what is the prostate-specific antigen test
blood test
what is prostate-specific antigen (PSA)
- a substance naturally produced by the prostate gland
- normal to have a small amount of PSA in the bloodstream
what would high PSA levels indicate
- prostate infection
- prostate inflammation
- prostate enlargement
- prostate cancer
what is the second leading cause of cancer death in men behind lung cancer
prostate cancer
how many men will die from prostate cancer
- 1 in 41
- 2.5%
how many women will die from breast cancer
2.6%
do most men who are diagnosed with prostate cancer die from it; why or why not
- most men do not die from it
- prostate cancer in slow to metastasize and it usually occurs in older men
- older men will probably die from something else before they die from prostate cancer
how many men in the US are alive with prostate cancer
2.9 million
what is the treatment for prostate cancer
- won’t remove prostate in older men; may cause pain, incontinence, erectile dysfunction
- medications used to reduce inflammation
what is used to gauge the sexual response cycle in men
penis: length, diameter, rigidity
what are the 4 phases of the sexual response cycle
- excitement
- plateau
- orgasm
- resolution
define refractory period
- in men not women
- resolution time needed before a second orgasm for the contents of semen to be remade
what are the physical changes that occur during the excitement phase of the sexual response cycle
- increase in heart rate, blood pressure, and respiration
- penis begins to engorge with blood, partial erection
is it possible for a man to have an orgasm and not ejaculate
yes
does a man have to be aroused to have an erection
no
does a man having an erection always mean he is aroused
no
what are the physical changes that occur during the plateau phase of the sexual response cycle
- penis increases in length and diameter
- testes increase in size
- glans of the penis vasocongests and turns a deep purple color
what is the average length of a flaccid and erect penis
- flaccid: 5 inches
- erect: 50-100% growth
what happens 2-3 seconds before orgasm occurs in men
- fluids are added to the sperm as it reaches the prostate
- a feeling of inevitability
describe the penile contractions that occur during male orgasm
- contractions in 0.08 second intervals
- first 3-4 are the strongest and expel the semen
what is the average duration of orgasm for men
25 seconds
what are the physical changes that occur during the resolution phase of the sexual response cycle
- vasocongestion dissipates rapidly (30-60 seconds)
- erection decreases 50% and then goes back to pre-excitement phase
what happens to the refractory period in men if they are younger and healthier
shorter refractory period
