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72 terms

Ch 27 The reproductive system

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What is fertilization?
the fusion of a sperm from the male and an immature ovum from the female to form a zygote (fertilized egg).
The reproductive system includes
-reproductive organs (gonads)
-reproductive tract (ducts)
-accessory glands (secrete fluid)
-external genitalia
In a male, testes produce sperm which are then expelled from body as
semen during ejaculation
The ovaries (gonads) produce an egg that travels through
-the uterine tubes to reach the uterus.
-the vagina connects the uterus with the exterior
The spermatozoa travels along
the epididymis, the ductus deferens, the ejaculatory duct and the urethra before leaving the body.
Male accessory glands are
-seminal glands (vesicles)
-prostate gland
-bulbourethral glands
*these secrete into the ejaculatory ducts of the urethra.
The scrotum & penis
-scrotum encloses the TESTES
-the penis is an erectile organ
The descent of the testes is
-through the inguinal canals that occur during development.
-before this time the testes are held in place by the gubernaculums testis.
during the seventh month of developmental growth, differential growth and contraction of the ______ _______ causes the testes to descend.
gubernaculums testis
-a cord of connective tissue and muscle fibers
the testes remain connected to the abdominal cavity through the
The spermatic cords
*consist of layers of fasia, tough connective tissue, and muscle.
The perineal raphe
marks the boundary between the the two chambers of the scrotum.
Each testis lies in its own
scrotal cavity
The dartos muscle
gives the scrotum a wrinkled appearance
The cremaster muscles
pulls the testes closer to the body
The tunica vaginalis
is a serous membrane that covers the tunica albuginea, the fibrous capsule that surrounds each testis.
Semiferous tubules
-are within each lobule
-the sites of sperm production
from the semiferous tubules the Sperm passes through a straight tubule to the
rete testis
Efferent ducts
connect the rete testis to the epididymis
between the semniferous tubules, interstitual cells
secrete male sex hormones called androgens
Seminiferous tubules contain
spermatogonia
spermatogonia (stem cells) form during embryonic development.. they are involved in:
spermatogenesis (production of sperm)
Spermatogonia produce
primary spermatocytes and diploid cells ready to undergo meiosis
How many spermatids are produced for every primary spermatocyte
4
The spermatids remain embedded within
sustentacular cells while they mature into a spermatozoon
Each spermatozoon has
a head, neck, middle piece and tail
the tip of the head & the tail of each spermatozoon
the tip of the head: acrosomal cap
the tail: single flagellum
*since the sperm lacks most intracellular structures, it must absorb nutrients from environment.
The epididymis-
-monitors and adjusts the composition of the tubular fluid
-serves as a recycling center for damaged spermatozoa
-stores spermatozoa
-facilitates functional maturation (capacitating)
The ductus deferens (vas deferens)
begins at the epididymis and passes through the inguinal canal as one component of the spermatic cord
The ampulla is
near the prostate
*the junction of the base of the seminal vesicle and the ampulla creates the ejaculatory duct (empties into the urethra)
The ductus deferens functions to
transport and store spermatozoa
The urethra extends from
the urinary bladder to the tip of the penis
The urethra can be divided into 3 regions
-prostatic urethra
-membranous urethra
-spongy urethra
The accessory glands function
to activate and provide nutrients to the spermatozoa and to produce buffers to neutralize the acidity of the urethra and vagina
Each seminal vesicle
-is an active secretory gland that contributes about 60% of the volume of the semen
-secretions are high in fructose (produce ATP)
The prostate gland
secretes a weakly acidic fluid (prostatic fluid) that contains about 20-30% of the volume of semen
Seminalplasin is
an antiobotic which may help prevent urinary tract infections in men
A typical ejaculation release is
2-5 ml which contains sperm count of 20 to 100 million sperm per mililiter
The penis can be divided into
-root(made of Crura)
-body (shaft)
-glans (end)
The prepuce (foreskin)
surrounds the tip of the penis.
Erectile tissue
-surround the body of the penis
-consists of 3 masses
*when the smooth muscles in the arterial walls relax, the erectile tissue becomes engorged with blood, producing an erection.
The female reproductive system includes
-ovaries
-uterine tubes
-uterus (myometrium)
-vagina
-external genitalia
The ovaries are held in the position by
-the ovarian ligament
-suspensory ligament (connects ovary to the pelvic wall)
Oogenisis has the following steps
1. formation of primary ovarian follicles
2. formation of secondary ovarian follicles
3. formation of tertiary ovarian follicle
4. ovulation
5. formation of the corpus luteum
6. formation of the corpus albicans (degeneration of the corpus luteum)
the decline in progesterone and estrogen triggers the secretion of GnRH, which in turn triggers a rise in:
-FSH & LH production, and then the entire cycle begins again.
Each uterine tube has
-an infundibulum (expanded funnel)
-an ampulla
-an isthmus
-uterine part (intramural part that opens into uterine cavity)
For fertilization to occur, the ovum must encounter spermatozoa during the first
12-24 hours of its passage from the infundibulum to the uterus
The uterus provides
mechanical projection and nutritional support to the developing embryo
normally the uterus bends anteriorly near its base (anteflexion). It is stabilized by broad ligaments:
uterosacral ligaments
round ligaments
cardinal ligaments
The uterus is divided into the
-body (largest portion)
-fundus
-isthmus
-cervix
-external os
-uterine cavity
-cervical canal
-internal os
The uterine wall can be divided into
-endometrium (inner)
-myometrium (muscular)
-perimetrium (superficial)
a typical 28 day uterine cycle (menstrual cycle) begins with:
-the onset of menses and the destruction of the functional zone of the endometrium
*this process of menstruation continues from 1-7 days
after menses, The proliferative phase begins & the functional zone:
undergoes repair and thickens
*menstrual activity begins at menarche (first uterine cycle) and continues until menopause.
The vagina is
-an elastic, muscular tube extending between the uterus and external genitalia.
-it serves as a passage way for menstrual fluid, receives the penis during sexual intercouse, and forms the lower portion of the birth canal.
The hymen is
-a thin epithelial fold
-partially blocks the vagina entrance.
The structures of the vulva (pudendum) include
vestibule, labia minora, clitoris, prepuce (hood), and labia majora.
The lesser and greater vestibular glands
keep the area moistened in and around the vestibule.
The fatty mons pubis
creates the outer limit of the vulva (labia majora)
The mammary glands lie
in the subcutaneous layer beneath the skin of the chest and are the site of milk production or lactation.
Milk production is stimulated by
a combination of hormones:
-prolactin (PRL)
-growth hormone (GH)
-human placental lactogen (HPL)
The ducts of the underlying mammary glands open
onto the body surface of a nipple
The placenta (special embryonic organ) that develops functions as
a temporary endocrine organ, producing several important hormones and facilitate gas and nutrient exchange
Menopause
-typically occurs around the age 50
-is it the time when ovulation and mestruation cease & also is is due to shortage of primordial follicles)
Premature menopause
-occurs before age 40
-production of GnRh, FSH, and LH rise, while circulating concentrations of estrogen and progestrins decline
The male climacteric (comparable to menopause) occurs
-between age 50-60
-involves in the decline in circulating testosterone levels and rise in FSH and LH levels
the human reproductive system produces, stores, nourishes, and transports...
-functional gametes
-is haploid reproductive cells that have 1/2 the normal number of chromosomes.
gonads
-reproductive organs
-produce gametes & hormones
the testes hang within the scrotum and each measure:
-about 2 inches long and 1 inch in diameter
-the compartments within the testes are lobules.
the SEPTA extends from the tunica albuginea to the mediastinum, creating a series of
lobules
Oogenesis (ovum production)
occurs monthly in ovarian follicles as part of the ovarian cycle
menstrual activity begins at ______ and continues until _________
menstrual activity begins at MENARCHE (first uterine cycle) and continues until MENOPAUSE
three stages of the uterine cycle (menstrual cycle)
1. menses
2. proliferative phase
3. secretory phase
the placenta produces & secretes:
Produces: relaxin
Secretes: estrogen & progesterone