REPRODUCTIVE SYSTEM.pdf

1. FUNCTIONS
1. Production of gametes.
2. Fertilization.
3. Development and
nourishment of a new
individual.
4. Production of sex hormones.
FORMATION OF GAMETES
Gametes – sex cells; sperm in males;
oocytes(eggs in females) Each sperm cell
and each oocyte contains 23
chromosomes
Meiosis – a type of cell division in
which formation ofgametes occur
Synapsis – chromosomes align as pairs
Crossing over – allows exchange of
genetic material bet.chromosomes
Reduction division – 1st meiotic
division; from 16 to 23chromosomes
2nd Meiotic division – similar to mitosis
M A L E R E P R O D U C T I V ES Y S T E M
SCROTUM
▪ Saclike structure containing the
testes
Dartos muscle – layer
of SM beneath the
skin of thescrotum
Cremaster muscles –
extensions of
abdominal muscles
into the scrotum
TESTES
▪ Also called male
gonads; oval organs within the
scrotum
Seminiferous tubules – where sperm
cells develop
Interstitial cells /
Leydig cells –
endocrine cells that
secrete testosterone
Sustentacular cells /
Sertoli – are large
and nourish the
germ cells; produce a number of
hormones
SPERMATOGENESIS
▪ Formation of sperm cells
Spermatogonia – most peripheral germ
cells that dividethrough mitosis
Primary spermatocytes – other
daughter cells that divide by meiosis
and become sperm cells
Secondary spermatocytes – product of
first meiotic division
Spermatids – product of secondary
meiotic division
Sperm cell / Spermatozoon –
developed spermatid with a head,
midpiece, and flagellum
DUCTS
Epididymis
▪ A tightly coiled series of
threadlike tubules thatform a
comma-shaped structure
Rete testis – each seminiferous tubule
empty into in tubular networks
Efferent ductules – carry sperm cells
from the testis to the epididymis
Capacitation – final changes in sperm
cells that occur after ejaculation of
semen into the vagina and prior to
fertilization
REPRODUCTIVE SYSTEM
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2. Ductus Deferens / Vas deferens
▪ Emerges from the epididymis
and ascends along the
posterior side of the testis
Spermatic cord – consists of the ductus
deferens, testicular artery and veins,
lymphatic vessels, and testicular nerve
Ampulla of the ductus deferens –
ductus deferens increases in diameter
Seminal Vesicle Ejaculatory Duct
DuctSeminal vesicle –
sac-shaped gland
Ejaculatory duct – formed by the ducts
from the seminal vesicle and the
ampulla of the ductus deferens
Urethra
Prostatic urethra – passes through the
prostate gland
Membranous urethra – passes through
the floor of thepelvis; surrounded by
the external urinary sphincter
Spongy urethra – extends the length
of the penis andopens at its end
PENIS
▪ Male organs of copulation
▪ Functions in transfer of sperm
cells from the male to the
female
Erection – process of the engorgement
of the erectile tissue with blood that
causes the penis to enlarge and become
firm
Corpora cavernosa – two columns of
erectile tissue that form the dorsal
portion
Corpus spongiosum – third, small
erectile column thatoccupies the ventral
portion of the penis
Glans penis – a formed cap
External urethra orifice – spongy
urethra that opens to the exterior
Prepuce / foreskin – lose fold of skin
that covers the glans penis
GLANDS
Seminal
Vesicles – next
to ductus
deferens help
form
ejaculatory
duct
Prostate gland
– consists of
glandular _
muscular tissue & empties into the
urethra
Bulbourethral glands / Cowper glands
– a pair of small, mucus-secreting
glands that empty into the urethra
SECRETIONS
Semen – mixture of sperm cells + gland
secretions; provides a transport medium
and nutrients that
protect and activate sperm
- 60% of fluid is from seminal
vesicles
- 30% of fluid is from prostate
gland
- 5% of fluid is from
bulbourethral gland
- 5% of fluid is from testes
Prostate fluid – contains nutrients and
proteolyticenzymes; neutralizes the pH
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3. of the vagina
Bulbourethral + urethral mucuous
glands – produce mucus that
neutralizes the acidic pH of the urethra
PATH OF SPERM
1. Sperm develop in seminiferous
tubules (testes)
2. Epididymis (mature)
3. Ductus deferens
4. Receive secretions from seminal
vesicles, prostate gland, and
bulbourethral gland
5. Urethra where semen (sperm)
exit body
PHYSIOLOGY OF MALE
REPRODUCTION
Regulation of Sex Hormone Secretion
Gonadotropin-releasing hormone
(GnRH) – produced in hypothalamus;
stimulates release of LH and FSH from
the anterior pituitary
Luteinizing hormone (LH) – stimulates
interstitial cells to produce testosterone
Follicle-stimulating hormone (FSH) –
binds to sustentacular cells and
stimulates spermatogenesis and
secretion of inhibin
Testosterone – has a negative-feedback
effect on GnRH, LH, and FSH
Inhibin – has a negative-feedback effect
on FSHsecretion
PRODUCTION OF SPERM CELLS
1. Germ cells
2. Spermatogonia
3. Primary spermatocytes
4. Secondary spermatocytes
5. Spermatids
6. Sperm cells
SPERM CELL’S STRUCTURE
• Head:
contain a
nucleus and DNA
• Midpiece:
contain
mitochondria
• Tail:
flagellum
for movement
Puberty in Males
▪ Before puberty; small
amounts of testosterone
inhibit GnRH release.
▪ During puberty; testosterone
does not completely suppress
GnRH release, resulting in
increased prod. of FSH, LH,
and testosterone.
Puberty – sequence of events by which
a child is transformed into a young
adult
Effects of Testosterone
▪ Enlargement of the genitals;
necessary for spermatogenesis
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4. ▪ Responsible for the
development of secondary
sexual characteristics (hair
distribution and growth, skin
texture, fat distribution,
skeletal muscle growth,
changes in the larynx)
Male Sexual Behavior and the Male Sex
Act
Testosterone – required for
normal for sex drive
Emission – movement of sperm cells,
mucus, prostatic secretions, and
seminal vesicle secretions into the
prostatic, membranous, spongy urethra
Orgasm / climax – result of
pleasurable, intensesensation
Resolution – penis becomes flaccid; an
overall feeling ofsatisfaction exists
Erection – first major component of the
male sex act
Erectile dysfunction (ED) –
impotence; failure toachieve erections
Infertility in Males
▪ Common cause is a low sperm
cell count
Artificial insemination – concentrating
the sperm cellsand inserting them into
the female’s reproductive tract
F E M A L E R E P R O D U C T I V E S Y S T E M
Broad ligament – spreads out on both
sides of the uterusand attaches to the
ovaries and uterine tubes; Produce
female oocytes
• (sex cells)
• Produce female sex hormones
• Receive sperm from males
• Develop and nourish embryos
OVARIES
Suspensory ligament – extends from
each ovary to thelateral body wall
Ovarian ligament – attaches the ovary
to the superiormargin of the uterus
Mesovarium – folds of peritoneum
OOGENESIS AND FERTILIZATION
Oogonia – the cells form which oocytes
develop
Primary oocyte – oogonia that has
stopped I prophase I
Ovulation – release of an oocyte from an
ovary
Secondary oocyte – released when the
first meioticdivision is complete
Fertilization – when a sperm cell
penetrates thecytoplasm of a secondary
oocyte
Zygote – 23 chromosomes from the
sperm + 23 chromosomes from the
female gamete
Follicle Development
Primordial follicle – primary oocyte
surrounded by granulosa cells (single
layer of flat cells)
Primary follicles – oocyte enlarges and
the single layer of granulosa cells
become enlarged and cuboidal
Zona pellucida – a layer of clear
material that is deposited around the
primary oocyte
Secondary follicle – fluid-filled
vesicles appear and a theca form
around the follicle
Fluid filled spaces – vesicles
Theca – a capsule that forms around the
follicle Antrum – a single, fluid-filled
chamber Graafian follicle – mature
follicle
Cumulus cells – mass of granulosa cells
Corpus luteum – remaining cells of the
ruptured follicleare transformed into a
glandular structure
Human chorionic gonadotropin
hormone (hCG) – the corpus luteum
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5. enlarges in response to this hormone
UTERINE TUBES
▪ Fallopian tube or oviduct
▪ Receive the secondary oocyte
Fimbriae – long, thin processes that
surrounds each the opening of each
uterine tube
➢ Cilia on fimbriae – sweep the
oocyte into theuterine tube
Ampulla – where fertilization usually
occurs
Implantation – process wherein the
fertilized oocyte embeds itself in the
uterine wall
UTERUS
Fundus – superior to the entrance of the
uterine tubes
Body – main part of the uterus
Cervix – inferiorly, narrower part
Uterine cavity & cervical canal –
spaces formed by theuterus
Perimetrium – outer layer; serous
layer of the uterusformed from visceral
peritoneum
Myometrium – middle layer; muscular
layer hat accounts for the bulk of the
uterine wall
Endometrium – innermost layer;
consists of simple columnar epithelial
cells with an underlying CT layer
Spiral glands – simple tubular glands
formed by foldsof endometrium
Prolapsed uterus – occurs when the
uterus extendsinferiorly into the vagina
VAGINA
▪ Female organs of copulation
▪ Allows menstrual flow and
childbirth
Muscular layer – smooth muscle +
elastic fibers
Mucous membrane – moist
stratified squamous
epithelium that forms a protective surface
Hymen – thin mucous membrane
EXTERNAL GENITALIA
Vulva – pudendum; external female
genitalia
Vestibule – the space into which the
vagina and urethra open
Labia minora – thing, longitudinal
skin folds
Clitoris – small, erectile structure; well
supplied with sensory receptors, made
up of erectile tissue
Greater vestibular glands – produce a
lubricating fluid that helps maintain
the moistness of the vestibule
Labia majora – prominent, rounded
folds of skin
Mons pubis – an elevation of tissue
over the pubic symphysis
Pudendal cleft – space bet. the labia
majora
Clinical perineum – region bet. the
vagina and the anus
Episiotomy – an incision made I the
clinical perineum to avoid tearing
during childbirth
MAMMARY GLANDS
▪ Organs of milk production
▪ Located in the breasts
▪ Modified sweat glands
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6. Areola – a circular, pigmented area
that surrounds the nipple
Gynecomastia – occurs when the
breasts of a male become permanently
enlarged; results from hormonal
imbalance and the abuse of anabolic
steroids
Glandular lobes – covered by adipose
tissue; gives the breast its form
Lactiferous duct – opens
independently to the surface of the
nipple
Myoepithelial cells – surround the
alveoli and contract to expel milk from
the alveoli
OVULATION
• when a mature follicle rupture
forcing oocyte into peritoneal
(pelvic) cavity
• due to LH (anterior pit. gland)
PHYSIOLOGY OF FEMALE
REPRODUCTION
Puberty in Females
Menarche – first episode of the
menstrual bleeding
Menstrual cycle – series of changes
that occur in sexually mature, non-
pregnant females, and that culminate
in menses
Menses – a period of mild
hemorrhage; part of the endometrium
is sloughed and expelled from the
uterus; day 1 – 4: menstrual fluid is
produced by degeneration of the
endometrium
Proliferative phase – day 5 –
ovulation: epithelial cells multiply and
form glands
Secretory phase – day of ovulation –
28: endometrium becomes thicker,
endometrial glands secete
Blastocyst – a collection of cells
produced by the zygote
Ectopic pregnancy – implantation
occurs anywhere other than in the
uterine cavity
STAGES OF MENSTRUAL CYCLE
Days 1-5 Menses (shedding of
endometrium)
o menstrual bleeding
(menses)
o estrogen and
progesterone levels are
low
o follicle begins to mature
Days 6-13 Proliferative (between end
of menses and ovulation)
- endometrium rebuilds
- estrogen levels begin to
increase
- progesterone levels
remain low
- follicle matures
Day 14 Ovulation
- oocyte is released due to
LH
- estrogen levels high
- progesterone levels are
increasing
- cervical mucus thins
Days 15-28 Secretory (between
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7. ovulation and next menses)
- endometrium is
preparing for
implantation
- estrogen levels decrease
(low)
- progesterone levels high
- cervical mucus thickens
MENOPAUSE
▪ Cessation of menstrual cycles
(Female) Climacteric – the whole time
period from the onset of irregular cycles
to their complete cessation
FEMALE SEXUAL BEHAVIOR AND
THE FEMALE SEX ACT
Orgasm / climax – triggered by tactile
stimulation of the female’s genitalia
during intercourse or psychological
stimuation
Resolution – the overall sense of
satisfaction and relaxation after the sex
act
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