fertilization and sex Flashcards
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)
- Psychogenic
- 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
- this relaxes arteries of penis
- 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?
ViagraTM
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
what is the fertile window in sperm and egg?
• Spermatozoa >> 48-72 hr
• Oocytes >> 6 – 24 hr (max)
Describe the process involved in sperm transport through the cervix and uterus
Describe the processes of capacitation of sperm and the acrosome reaction
sperm tail in capacitation also starts to move vigoursly!
where is the acrosome on the sperm derived from?
Derived from golgi region of developing spermatid
how does transport of oocyte and sperm differ?
• Gamete transport
- – Oocyte:* beating cilia & peristalsis of uterine tube
- – Sperm:* own propulsion
descrobe processes of cortical reaction and its importance?
functions of Ca+ surge? (2)
what happens after zygote is formed?
cleavage and blastocyst formation!
36 hrs after fertilization, the 1st cleavage division of zygote has made 2 IDENTICAL cells called blastomeres
- these divide and become 4 cells>> then 8>>so on*
- AFTER 3 days of fertilisation> MORULA!*
Morula is totipotent
what does this mean?
capable of giving rise to any cell type
its identical to parent cell
when the ZP starts to break down an inner strucutre is now formed called the_____
describe its structure.
why does it need to hatch from the ZP?
Blastocyst!
so it can implant! no longer contrained!
IMMM FREEEE AND IMMA BLAST OFF!
Describe processof implantation
what happens if u get Implantation in lower uterine segment?
can cause placenta praevia
placenta is your baby’s ‘life support’ system during pregnancy. It is shaped a bit like a pancake attached to the inside of your womb (uterus)
what part of the blastocyst interacts with the endometrium?
the trophoblsts!
Hyperprolactinaemia may lead to infertility.
What clinical sign may indicate a diagnosis of hyperprolactinaemia?
Production of small quantities of milk
what drug could be used to treat hyperprolactinaemia. How does it work?
Bromocryptine
Dopamine agonist – mimics effects of prolactin inhibitory hormone
How might you test whether uterine tubes are patent? (opened up and normal)
Passage of radio-opaque dye from uterine cavity, hysterosalpingography
is an x-ray examination of a woman’s uterus and fallopian tubes that uses a special form of x-ray called fluoroscopy and a contrast material.
How might you establish whether cervical sperm transport is disturbed?
Post coital test – collect cervical mucus from women soon after intercourse
