Transcript The Reproductive System

The Reproductive System
Reproduction
Primary function: to produce
offspring
 genetic material passed from
generation to generation
 Sharing intimate feelings with another
person
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Some terms to know
Gonads: the organs in the body that
produce the sex cells (GAMETES)
 Male = testes --> Sperm
 Female = ovaries --> Ova or Egg cells
 Ducts: transport and secrete
 Glands: secrete
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Testes
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Paired organs
located inside the
scrotum
Located outside the
body to ensure
proper temp for
sperm production
Function of the testes
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Produce and mature
sperm
maturation of sperm
takes approximately 74
days
Protect sperm and
sperm development-Sertoli cells
Produce testosterone:
Leydig cells
Functions of Testosterone
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the principle male hormone
produced by Cells of Leydig
responsible for the male secondary sexual
characteristics:
growth and development
maintenance of sex organs
bone growth
influences sexual behavior
influences final maturation of sperm cells
Seminiferous Tubules
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tightly coiled tubules in
testes
Spermatogenesis occurs
Spermatogonia =
immature Sperm Cell
Spermatozoa = mature
Sperm Cell
Interstitial Cells (Cells of
Leydig) = endocrine cells
produce and secrete
testosterone
Epididymis
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7 m long
Head - superior,
receives
spermatozoa
Body
Tail - leads to
ductus deferens
Epididymis
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Functions:
1) Monitors and
adjusts tubular
fluid
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2) Recycles
damaged
spermatozoa
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3) Stores sperm and
facilitates
maturation
Ductus (Vas) Deferens
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long duct (18
inches) passageway
for sperm from
epididymis to
urethra
enters the body
through the pelvic
floor called the
Inguinal Canal
Ejaculatory Ducts
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union of seminal
vesicles and the
ductus
(vas)deferens
eject sperm into the
prostatic urethra
prior to ejaculation
Urethra
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passageway for sperm
and urine to the
external environment
measures about 8
inches in length
4 sections of the
Urethra
Urethra
1. prostatic
1
urethra
2.
Membranous 2
urethra
3
3.
spongy
urethra
Urethra
4
4. external urethral orifice
Accessory Male Sex Glands
secrete most of the liquid portion of
Semen
 provides a liquid, nutrious medium
for the support of sperm cells
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Seminal Vesicles
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Paired, on posterior
wall of urinary
bladder
Tubular (~ 15 cm)
Produce 60% of
semen, hormones,
fructose, etc.
Activate sperm
(leading to motility)
Prostate Gland
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about the size of a
chestnut located
inferior to the urinary
bladder - surrounds the
urethra
secretes a fluid rich in
citric acid, prostatic
acid, phosphatase, and
prostaglandins
makes up about 13% of the semen
often site of cancerous
growth in males
Bulbourethral Glands (Cowper’s Glands)
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Pea size, paired, at
base of penis
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Produce about 10%
of semen
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Alkaline mucus neutralize acidic
nature of female
vagina
Semen (Seminal Fluid)
mixture of sperm and secretions of
accessory glands
 2.5 - 5.0 ml of semen per ejaculation
(1/2 tsp)
 300-500 million sperm per ejaculation
 if less than 100 million sperm-- male is
considered infertile
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MALE: EXTERNAL
GENITALIA
SCROTUM
supports and
protects testes
 continuation of
abdominal wall
skin
 Separated by a
structure called
the raphe
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SCROTUM
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Cremaster muscle
Dartos muscle in dermis
Cremaster muscle - continuous with abdominal
wall muscles
Involuntary contraction in response to TEMP
changes
Temp must be 2-3o Lower than body temp
Penis
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used to introduce
sperm into the
female vagina
during intercourse
Voids urine
(urination)
cylindrical in shape
Three parts of penis
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Body : 3 cylindrical
masses of tissue
Corpora Cavernosa
Penis ( 2)
Corpus
Spongiosum Penis
Made of erectile
tissue filled with
blood sinuses
Penis (cont)
Root--portion
attached to
pubic area
 Bulb--attached
to abdominal
wall
 Crus--Attached
to muscles that
aid in erection
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Glans penis
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Slightly enlarged
portion of the
corpus spongiosum
Separated from
body by corona
Contains many
nerve endings
Uncircumcised
glans contains
prepuce or foreskin
Penis erection
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With sexual
stimulation, arteries
dilate, veins
constrict, large
quantities of blood
enter sinuses and
an erection occurs
Erections occur also
to maintain health
of penis
End of male
REPRODUCTIVE System
QUESTIONS?
FEMALE REPRODUCTIVE
SYSTEM
Ovaries
the female
gonads
 oogenesis occurs
 females are born
with all egg cells
as they will ever
have (500,000)
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Oogenesis
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Maturing of an oocyte (egg)
Begins with primary follicles, ends with secondary
ooctye
other primary follicles donate material to
developing egg
Ovarian follicles
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each month about
20 primary oocytes
are stimulated to
undergo meiosis
usually only one of
these 20 completes
the process of
oogenesis &
develops into a
secondary oocyte
Graffian Follicle
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Oocyte continues to
mature before
released by ovary
during ovulation
Contains two parts
Antrum and oocyte
Secretes estrogen
Ovulation
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Process where
secondary oocyte is
released from ovary
About day 14 of
cycle
Corpus Luteum and Corpus Albicans
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Glandular body that
develops after release
of egg
Secretes progesterone,
estrogen, relaxin,
inhibin
Becomes corpus
albicans if egg is
NOT fertilized
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Stays in tact during
pregnancy
Uterine (Fallopian) Tubes
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ducts transport ova
from site of
ovulation to uterus
Infundibulum =
funnel shaped,
open distal end
– Fimbriae = “little
fingers” on distal
end
Uterine (Fallopian) Tubes
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Ampulla = widest,
longest portion of
the uterine tubes
– fertilization usually
occurs in this region
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Isthmus = narrow,
constricted,
proximal end where
the tubes attach to
the uterus
Uterus
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serves as the site of
menstruation,
implantation of a
fertilized ovum, and
development and
maintenance of fetus
during pregnancy
inverted pear shaped
muscular organ
has 3 sections or areas
– Fundus
– Body
– Cervix
Tissue Layers of the Uterus
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3 tissue layers
Perimetrium =
outermost layer
Myometrium = middle,
muscular layer
– majority of the uterus
– consists of three layers
of smooth muscle
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Endometrium =
innermost layer of the
uterus
Made of stratum
functionalis and
stratum basalis
Vagina
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tubular fibromuscular organ lined with mucous
membrane
passageway for sperm & menstrual flow
receptacle for penis during sexual intercourse
lower portion of birth canal
FEMALE: EXTERNAL
GENITALIA
Female External Genitalia
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Vulva = term used to
describe female
external genitalia
Mons Pubis = adipose
tissue above the pubic
symphysis, covered by
skin and coarse pubic
hair
Labia Majora = an area
of longitudinal folds of
tissue
Labia Minora = medial
longitudinal folds of
tissue
Female External Genitalia (cont)
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Vestibule: the space
between the Labia
Minora
Bulb of vestibule
contain:
Greater Vestibular
Glands (Bartholin’s)
produce mucoid
substance
Provide lubrication for
sexual intercourse
Female External
Genitalia (cont)
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Clitoris: small
cylyndrical
mass of nervous
and erectile
tissue
Prepuce: layer
of skin from
labia minora
covers clitoris
Hymen: thin
membrane
partially
covering the
vagina
Mammary Glands (Breasts)
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modified sudoriferous
glands (Sweat Glands)
each gland contains 15
- 20 lobes or
compartments
separated by adipose
tissue
amount of adipose
tissue between lobes
determines breast size
breast size is not
related to milk
production
Mammary Glands (Breasts)
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each lobe has
compartments called
lobules
Inside lobules are milk
secreting cells
Nipple = the raised
area on the breast that
an infant suckles to
receive milk and
stimulate lactation
Areola = the dark,
circular, pigmented
area that encircles the
nipple
Lactation
the process of milk production,
secretion, and ejection
Menstrual and Ovarian Cycles
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Ovarian Cycle =
maturation and
ovulation of an ovum
Menstrual Cycle =
changes of the
endometrial lining of
the uterus
– preparation for
implantation of a
fertilized ovum
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correlated with each
other and are under the
influence of hormones
Endocrine influence
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Hypothalamus
stimulates pituitary
FSH and LH
FSH : ovarian follicles
LH: ovulation-stimulates production
of estrogen,
progesterone and
relaxin
Ovaries produce
estrogen and
progesterone
Estrogen
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different types
 development and maintenance of
the female reproductive system
 helps control fluid and electrolyte
balance
 Keeps heart strong
 Keeps bones strong
Progesterone
 hormone of maturation
 prepares the endometrial lining
for implantation
 stimulates milk production and
secretion
 Drop in progesterone starts
menstrual cycle
Relaxin and Inhibin
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Relaxin = produced by the corpus luteum
during pregnancy
Relaxin = most prominent during the final
trimester of pregnancy
relaxes the pubic symphysis and helps
dilate the cervix
Inhibin = is the negative feedback
hormone for estrogen and progesterone
DEVELOPMENT
and
INHERITANCE
HUMAN DEVLOPMENT
The continuous process of body
changes
 Begins at fertilization
 Continues until death
 Two periods
 Prenatal: Conception until birth
 Postnatal: birth until death
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Spermatogenesis vs.
Oogenesis
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Spermatogenesis:
production &
maturation of
sperm
Oogenesis:
production &
maturation of egg
Prenatal Development
changes that occur prior to Birth
 Divided into Two Periods
 The Embryonic Period
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– fertilization until eight weeks
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The Fetal Period
– eight weeks until birth
Fertilization
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also called
“Conception”
union of sperm &
oocyte
one sperm cell
penetrates layers of the
egg
aided by enzyme on
head of sperm
oocyte cell membrane
changes biochemically
The Embryonic Period
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first 8 weeks of life
fertilized egg called
Zygote
first cell divisions of
Zygote are called:
CLEAVAGE --result in
ball of cells called
Morula
Morula turns into a large
mass of cells called
Blastocyst
Blastocyst Stages of
Development
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Implantation =
attachment of the
Blastocyst to the
endometrium
about 6 days after
fertilization
Blastocyst
differentiates into
primary Germ Layers
(Endoderm, Mesoderm,
Ectoderm)
Trophoblast Development
and Implantation
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Becomes
Trophoblast-layers form
(Chorion, Amnion,
and Yolk Sac) begin
to form around the
embryo
Called pregnancy
when implanted
Embryonic Period
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5 weeks after
conception
Bones begin to form,
major blood vessels
form
other systems form
Heart forms & starts to
beat
Nervous system forms
Embryonic Development
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Development of Body
Form
– weeks three to eight
– the embryo resembles a
human like figure
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Development of
Organs
– most major organs
appear during the first
eight weeks of
development
Embryonic Period
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8 weeks
Resembles a
human and is
called a
FETUS—Latin
word for
OFFSPRING
Fetal Development
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18 weeks
Face looks
human
Joints form
Bones ossify
Rapid
development of
body organs
Fetal Development
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Can recognize
sounds
Urine forms
Fetal Development
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18 weeks
Rapid
development
of body organs
Fetal Development
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20 weeks
Lanugo appearsprotects fetus from
waste in amniotic
fluid
Fetal movements
felt by mother
Hair appears on
head
Fetal Development
20 weeks
Fetal Development
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24 weeks
Sense of taste
develops, lungs are
ready to produce
surfactant
Substantial weight
gain
Eyelashs form
Can survive outside
womb (viable)
Fetal Development
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30 weeks
Head and body more
proportionate
In male, testes descend
Fetus assumes upside
down position
Subcutaneous fat
deposited
Fetal Development
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40 weeks
Additional
subcutaneous fat
accumulates
Lungs secrete
oxytocin
Lanugo is shed
Fetus is full term
Is ready at 38
weeks
Fetal Development
Labor
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movement of the fetus through birth canal
in response to uterine contractions
Three Stages of Labor
Stage One = dilation & effacement
contractions push fetus against cervix
amniotic sac ruptures
cervix dilates
Once cervix dilates to 10 cm Stage Two
begins
Fetal Development
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Stage Two =
delivery and
birth
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Stage Three =
expulsion of the
placenta
Stages of Physical
Development
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Neonate - “newborn”
Infancy
Toddlerhood
Childhood
Adolescence – puberty
Adulthood
Middle Age
Advanced Age