Transcript Ch. 27 Presentation.ppt

Chapter 27 Reproduction and Embryonic
Development (Ch. 18)
 Both sexes in humans have
– a set of gonads where gametes are produced,
– ducts for gamete transport, and
– structures for copulation including the penis and the vulva
surrounding the vaginal opening.
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27.3 The human female reproductive system
 Ovaries contain follicles that
– Surround and nurture eggs and when egg is ejected
remaining surrounding tissue forms the corpus luteum
– Follicles and corpus luteum produce sex hormones.
 An immature egg is ejected from the follicle in a
process called ovulation.
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27.3 The human female reproductive system
 Oviducts convey eggs to the uterus where a
fertilized egg develops.
 The uterus, which thickens its endometrium monthly
and breaks down causing menstruation if an embryo
does not develop, opens into the vagina through the
cervix.
 The vagina
– receives the penis during sexual intercourse and
– forms the birth canal.
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Figure 27.3A
Ovaries
Oviduct
Follicles
Corpus luteum
Uterus
Wall of uterus
Endometrium
(lining of uterus)
Vagina
Cervix
(“neck” of uterus)
Figure 27.3B
Egg
cell
Ovary
27.3 The human female reproductive system
 The external female genitalia are collectively called
the vulva and consist of skin folds that surround the
vagina called labia minora and labia majora
 The clitoris plays a role in female sexual arousal
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Figure 27.3C
Oviduct
Ovary
Uterus
Rectum
(digestive system)
Cervix
Vagina
Anus
(digestive system)
Urinary bladder
(excretory system)
Pubic bone
(skeletal system)
Urethra
(excretory system)
Shaft
Prepuce Clitoris
Glans
Labia minora
Labia majora
Vaginal opening
Vulva
27.4 The human male reproductive system
 Testes (singular, testis) produce
– sperm and
– male hormones.
 The epididymis stores sperm as they develop further
and the vas deferens leads to the urethra.
 Several glands contribute fluids to semen. These are
the
– seminal vesicles (sugar solution),
– prostate gland (nutrient and alkakline solution), and
– bulbourethral glands (alkaline mucous).
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Figure 27.4A
Urinary bladder
(excretory
system)
Seminal
vesicle
(behind
bladder)
Prostate gland
Bulbourethral
gland
Urethra
Erectile tissue
of penis
Vas deferens
Scrotum
Epididymis
Testis
Glans of
penis
Figure 27.4B
Rectum
(digestive
system)
Urinary bladder
(excretory system)
Seminal vesicle
Vas deferens
Pubic bone
(skeletal system)
Ejaculatory
duct
Prostate gland
Erectile
tissue
Bulbourethral gland
Anus
(digestive system)
Vas deferens
Testicle
Urethra
(excretory
system)
Epididymis
Testis
Glans of penis
Scrotum
Prepuce
Penis
27.4 The human male reproductive system
 During ejaculation
– sperm is expelled from the epididymis,
– the seminal vesicles, prostate, and bulbourethral glands
secrete into the urethra, and
– semen is formed and expelled from the penis.
 Sperm production
– is regulated by hormones in testes
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27.15 The embryo and placenta
 Pregnancy, or gestation, is the carrying of
developing young within the uterus.
 Human pregnancy
– Averages 40 weeks (9 months) from the start of the last
menstrual period.
 Embryonic development begins with fertilization,
– the union of sperm and egg form a diploid zygote which
becomes the embryo (chapter 18) and is in a fluid filled
amnion. It is surrounded by the placenta and by the 9th
week is called a fetus having the major human features.
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