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Flashcards in fertilization and sex Deck (49)
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when does the sperm gain its capability of movement?

once in the tail of the epididymis


what else happens in the epididymis?

it adds secretery products on surface of sperm to protect it from the harsh environment if the female reproductive tract!

Dependent on support of the epididymis by androgens 


what is semen?

what is it composed of?

Semen, also known as seminal fluid, is an organic fluid that may contain spermatozoa.


• Spermatozoa
• Seminalplasma


describe the functions of the main constituents of semen.

Seminal plasma derived from accessory glands of the male reproductive tract.


• Function:
– Transport (vehicle) 

– Nutrition

–  Buffering capacity (bc vagina is so acidic)



describe the source of the main constituents of semen.

Seminal vesicles-60%

  • alkaline fluid (neutralizes the acid: male urethra & female reproductive tract)
  • fructose, prostaglandins, clotting factors (particularly semenogelin)

Prostate gland-25%

  • milky, slightly acidic fluid
  • proteolytic enzymes (breakdown clotting proteins, re-liquefying semen in in 10-20 minutes )
  • citric acid, acid phosphotase

Bulbourethral glands (Cowper’s glands)

–  Very small volume

–  alkaline fluid

–  a mucous that lubricates the end of the penis and urethral lining. 


what gives the semen its milky appearence?

the prostate gland


what is the volume and pH of seminal fluid?

volume= 2–6 mL 

pH= 7–8 


Describe the phases of the human sexual response?

 4 phases


list the stages of the male sexual act (4)

stimulation, erection, emission and ejaculation.


what r the Stimulants in the male sexual response? (2)

  1. Psychogenic
  2. Tactile (sensory afferents of penis and perineum) 


what is the most important source of sensory nerve signals for intitiating the male sexual act?

Glans penis

slippery massaging action of intercourse on the glans stimulates sensory end organs > sexual signals pass through PUDENDAL NERVE

then through sacral portion

then brain


what nerves r the efferents of the male sexual response going to the spinal cord?

pelvic and pudendal nerve


what happens during erection

caused by Parasympathetic impulses through pelvic n.

release NO and ach

increase amounts of cyclic GMP

  1. this relaxes arteries of penis
  2. and trabecular meshwork of SM fibers in corpus cavernosa & corpus spongiosum


how does the penis eject (boner)

as vascular smooth muscle relaxes, BF to penis increases> causing release in NO> further vasodilation


erectile tissue of penis consists largely of cavernous sinosoids that r normally empty of blood, but now blood is rushing to them under high pressure! (compress on venous outflow)


role of parasympathetic 

via what nerves

needed for erection and lubrication!

• Fibres
– Lumbar and sacral spinal levels

Pelvic nerve and pelvic plexus

Cavernous nerve to corpora and vasculature 


(if doesnt lubricate, its painful)


explain role of NO in erection?

NOS= nitric oxide synthase


what can be reasons for erectile dysfunction?


How can you treat erectile dysfunction?


slows rate at which cGMP is degraded

there fore 


what happens after erection has acheived?

when the sexual stimulus becomes extremely intense...reflex centers of spinal cord begin to emit

sympathetic impulses!

then emission and ejaculation can take place!


how does emission take place?

contraction of vas deferens & ampulla causes expulsion of sperm into the urethra!

then SM of prostate & contraction of seminal vesicles release fluid also in urethra!>> forcing sperm FORWARD!


all these fluids mix in the internal urethra to form

the semen!


hoe does ejaculation take place?

filling of semen in the urethra send sensory signals through pudendal nerve to low spinal cords>> giving feeling of fullness in the internal genital organs>>these senspry signlas further excite rythmateical contractions of ischiocavernous and bulbocavernousus muscles that compress the base of the erectile tissue of penis.

ejeaculate sperm to exterior


once muscles start squeezing, a guy cant stop the semen frrom not coming out "thats why they cant stop"


what makes sure the ejaculate doesnt retrograde?

bladder internal sphincter contract!


what is orgasm?

period of both ejaculation and erection


explain the autonomic control of sexual function

erection> parasympathetic

Ejection & ejaculation> sympathetic


so if u give sympathetic antagonist ex: when treating high BP, u can get a dry orgasm


describe how the character of cervical mucus changes over the course of the menstrual cycle. and the hormoes responisble for this change!

what is the term which refers to the stringy or stretchy property found to varying degrees in mucus?

estrogen make it thin>>so perm can get in>> up to the point of OVULATION




where is Semen deposited in the female repro tract?

and where does fertilization occur?


what happens to the semen when it gets into the cervix of the female repro tract?

it undergoes temporary coagulation to make sure it doesnt get out of the vagina!


(stay in bitch)


what is the primary method that allows spermatozoa to get to the site of fertilisation?

under their own control! their motility tail!


describe the physiological changes in the female which facilitate coitus 


Define fertilization?

fertilization is the union of a human egg and sperm