Chapter 4: Male Reproductive Anatomy Flashcards
The penis is made up of what structures? (5)
- glans
- shaft
- foreskin
- corpora cavernosa
- corpus spongiosum
The penis is homologous to what?
-the clitoris
The penis functionally corresponds with what?(3)
L> and why?
- clitoris, urethra and vagina since it involves sexual arousal, excretion of urine and the transfer of gametes.
- foreskin huh?
- loose tubular fold of skin that partially or completely covers the glans
Describe Circumcision of foreskin
- nerve blocker used to reduce pain
- ## usually right after birth but can be done in adult hood ( stitches required and 4 weeks of no sex/masturbation)
Circumcision is prescribed religiously to whom
- Muslims and jews
about ___ of men are circumcised
30%
Superincison?
L> huh?
L> location?
- exposes the top surface of the glans and lest the foreskin droop below them…no tissue is removed
- Polynesian and Philippines
Subincision ?
L> huh
L> location?
- slit along the underside of the penis exposing the urethra and allowing the glans and part of the shaft to flare outward giving the penis a flat appearance
- Australia
The Shaft of the penis contains what three erectile structures?
- two corpora cavernosa : account for the bulk of the erectile capacity of the penis side by side
- single corpus spongiosum : midline near the undersurface of the penis
- tough layer of connective tissue surrounds the corpora cavernosa only….= tunica albuginea
What extends from the shaft of the penis and balloons in the glans?
corpus spongiosum
L> fills entire glans
The corpus spongiosum and cavernosa both extend where?
- back into the body under the pubic symphysis forming the root of the penis
Penile bulb?
-the corpus spongiosum expands into a rounded mass of erectile tissue called this……
Crura?
- corpus cavernosa diverge forming these….
Ischiocavernousus and Bulbospongiosus muscles?
- much larger in males
- assist in erection and ejaculation.
Bulbospongiosus muscles an integral part of what?
- external anal sphincter which contracts rhythmically during ejaculation
Urethral meatus?
- opening of the urethra
Corona?
the rim of the glans
Frenulum?
- strip of loose skin running btwn the glans and shaft
What two regions of the penis are the most erotically stimulating?
- corona and frenulum
Describe the following issues with the penis?
- Balanitis
- Phimosis
- Paraphimosis
- Peyronie’s disease
- inflammation of the glans via poor hygiene …common in uncirc
- inability to retract foreskin far enough to expose the glans
- entrapment of a retracted foreskin behind the corona of the glans….via forced retraction usually of phimosis foreskin. EMERG can cause necrosis of the glans
- unnatural curvature of the erect penis…via scar formation in the capsule of the corpora cavernosa possibly as a late consequence of trauma.
L> can cause pain during and prevent sex (surg)
What is koro?
- fear of penile retraction…..common in Asia
L> prevention? attaching clamps and string to the penis to prevent its complete disappearance.
Is penile cancer common?
NO
predisposed to penile cancer via ?
- infection with certain types of HPV
Scrotum?
loose bag of skin that hangs below the penis and contains the two testicles.
Why does the scrotum possess numerous sweat glands?
to help regulate temperature
Dartos muscles?
lies under the skin of the scrotum..constriction causes thickening and wrinkling of the skin in response to cold…brings testicles closer to the body…warming them..better insulation.
Testes?
- two glands that produce sperm and secrete sex steroids
Epididymis?
- a tube that carries sperm btwn testes and vas deferns
Vas deferns?
- duct that convey sperm from the epidiymes to the ejaculatory duct
L> storage of mature sperm as well
Seminiferous tubules?
- internal structure of the testes…site of spermatogenesis within the testes
Leydig cells?
testicular cells that secrete certain hormones..found btwn seminiferous tubules
L> mainly testosterone
Ejaculatory duct?
- empties into the urethra within the prostate
Semen is composed of what?
- sperm
- fluids from the seminal vesicles and prostate gland
Bulbourethral gland ?
root of the penis secretions appear prior to ejeculation
L> DOES NOT CONTAIN SPERM
L> may have remains from previous ejac though
Sertoli cells?
in the seminiferous tubules and nurture developing sperm and secrete hormones (peptide)
Hormones produced via sertoli cells?(2)
- a role in embryonic sex determination
- others help regulate testicular function
Rete testis?
-sperm leaves the seminiferous tubules to this network that enters the epididymis
What syndrome predisposes men to testicular cancer?
klinefelter
What gives a definite diagnosis of testicular cancer?
- orchiectomy
L> removal of a testicle
Prostate gland?
- surrounds the urethra as it exits the bladder….secrets cloudy alkaline fluid..
Seminal vesicles?
- two small glands that lie behind the bladder close to the Vas Def
L> they add secretions to the semen
NO STORAGE
Erections can be mediated by ___.
spinal reflex
The involvement of the brain is essential or not essential in having an erection?
- not
The penis and the clitoris possess a unique class of sensory nerve endings called? L> describe
- genital end bulbs
L>in the penis they are in high [ ] around the corona of the glans and the frenulum…the two more erotically stimulating parts.
L> specialized to sense the kind of tactile stim of sexual behaviour
The genital end bulbs cannot do what?
cannot make fine discriminations
Sympathetic and parasympathetic fibers compete for what?
control of erectile tissue
Sympathetic NS?
Divison of the ANS that actively inhibit erection but helps trigger ejaculation
Parasympathetic NS?
division of the ANS that actively promotes erections of the penis and clitoris
ANS?
- controls smooth muscles and glands without our conscious control
The erectile tissue forms a hydraulic system:
1. Corpora cavernosa contain
L> Sinusoids
L> Trabeculae
- collapsible spaces which are part of the vascular system (containing arterioles and veins)
- walls of connective tissue which contain smith muscle cells
The erectile tissue forms a hydraulic system:
- Sympathetic fivers release the NT called???
- norepinephrine
L> contract arterioles and trabecular walls
The erectile tissue forms a hydraulic system:
- Parasympathetic Activity releases what three things?
- acetylcholine
- vasoactive intestinal peptide
- nitric oxide (most important NT)
L> causes the relaxation of smooth muscle cells of arterioles and the trabecular walls…aka more blood goes into the sinusoids and the erectile tissue expands…expansion compresses and closes the veins and the erectile tissue expand further…
Priapism?
- complete erection blood cannot enter the sinusoid…..the pooled blood loses O2….because of the stasis an erection that won’t go down causes this…which can cause damage to the erectile tissue if on more than a few hours.
Striated Muscles are also involved in erections:
1. Ischiocavernous and bulbospondiousus muscles
- squeeze and pull at the root of the penis
voluntary
Striated Muscles are also involved in erections:
2. Onuf’s Nucleus
- motor neurons in this
- innervate these muscles releasing acetylcholine…which can cause voluntary contraction and penile movement
The Brain also influences erection:
1. Erections can occur without ___
- tactile stimulation
L> REM - can occur in erotic dreams but it occurs in all rem regardless of the dream content
The Brain also influences erection:
2. Regions of the brain can promote via ____ or inhibit via____ erections.
- parasympathetic
- sympathetic
The Brain also influences erection:
3. The reduction of activity in the ____ promotes an increase in the parasympathetic activity and promotes nocturnal erections in men and women.
- locus coeruleus
The Brain also influences erection:
4. Arousing ___ and ___ can cause erections by suppressing the activity go the _____ of the hypothalamus causing the prevention of the release of ___ which activates the parasympathetic neurons.
- sights and thoughts
- paragigantocellular nucleus
L> serotonin
NT related drugs can influence erection :
- Fluoxetine ( Prozac)
- raises lvld of serotonin and inhibits the parasympathetic neurone..impotence can result
NT related drugs can influence erection :
- Sildenafil ?
- viagra
- increases the effect of nitric oxide on the erectile tissue but depends upon arousal to be effective.
Ejaculation requires the coordination of muscles and glands.
- Seminal emission is what?
- loading of semen into the urethra
1. first prostatic fluid
2. semen
3. fluid from seminal vesicles
Ejaculation requires the coordination of muscles and glands.
- Why is the separation of prostatic fluid and fluid from the seminal vesicles impotent?
- if they weren’t they would cause semen to be coagulated in the vagina…which does occur but this prevents it from happening too soon.
Ejaculation requires the coordination of muscles and glands.
- Ejaculation?(cause?)
- expulsion of semen
- contractions of many muscles of the pelvic floor resulting from sympathetic innervation
Ejaculation requires the coordination of muscles and glands.
- Ejaculation?
L> length of condition/
l. intervals btwn contractions
- urethral sphincter at the bladder becomes?
- 0.8 s it lasts
- 0.7
- closed
Ejaculation requires the coordination of muscles and glands.
- Some women also ejaculate?
- 40%
- discharge via urethra
- two types: low volume from the paraurethral gland…high volume from the bladder (dilute urine)
Orgasm is a subjective sensation with physiological correlates.
- There are ____ sensations in men and women minus?
- similar
L> no refractory time in women as in males
Orgasm is a subjective sensation with physiological correlates.
- Spasmodic contractions cause what in males?
- tightening of what in females?
- of muscles of the pelvic floor and anal sphincter
- tightening of the outer third of vagina.
Orgasm is a subjective sensation with physiological correlates.
L> There are __ types of female orgasm
two
Orgasm is a subjective sensation with physiological correlates.
L> Hormone oxytocin is involved in subjective feelings or orgasm
- surge occurs before and during orgasm
- higher lvld the greater perceived orgasm
- pleasurable quality of orgasm is reduced by drugs that block oxy
Orgasm is a subjective sensation with physiological correlates.
- barin imaging suggests where orgasms may be experienced?
-men…a general decrease in blood flow to the cerebral context has been found except in the right prefrontal cortex which increases
Semen breakdown:
-rank contribution of the three!
Seminal vesicles ( fructose fibrinogen) > prostate gland (citric a and enzymes ) > bulborethral gland (precum) > testis (`~1%)
Epididymis Inositol does what?
- removes water
Erectile reflexes?(4)
- stimulation of genitals kin
- activation of sensory fibbers in the pudendal nerve
- signals pass to the dorsal horn of the sacral spinal cord
- activate interneurons
Nudity and Culture Regulation:
- Most cultures require?
- the genitals remain covered in public
Nudity and Culture Regulation:
- social prohibitions against nudity are primarily concerned with?
- reducing men’s arousal
Nudity and Culture Regulation:
- evidence suggests a strong and specific response to the sight of a ___
- vulva
Nudity and Culture Regulation:
- social rules concerning exposure of the body are ?
- indicators of general attitudes towards sexuality
Nudity and Culture Regulation:
- contradictory?
VERY SUBJECTIVE
- public reaction to Janet J
- (-) attention towards public breast feeding
- (+) attentudes toward nudity beaches…
