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Chapter 26b. Reproduction and Development. Male Reproductive Structures. External genitalia Penis and scrotum Common passageway Urethra Accessory glands and ducts Prostate gland Seminal vesicle Bulbourethral gland. Male Reproductive Structures - Overview. Figure 26-8 (1 of 2). - PowerPoint PPT Presentation
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Chapter 26b
Reproduction and Development
Male Reproductive Structures
• External genitalia• Penis and scrotum
• Common passageway• Urethra
• Accessory glands and ducts• Prostate gland• Seminal vesicle• Bulbourethral gland
Figure 26-8 (1 of 2)
Male Reproductive Structures - Overview
Figure 26-8 (2 of 2)
Male Reproductive Structures - Erectile Tissues
Male Reproductive Structures
• Testes (sperm production)• Seminiferous tubules
• Epididymis (sperm maturation)• Vas deferens (aka “ductus deferens”, a
passageway into abdomen and delivery to the urethra)
Figure 26-9a
Male Reproductive Structures - Sagittal View
Urethra
ScrotumTestis
Rectum
UreterUrinarybladder
Prostategland
Ejaculatoryduct
Bulbourethralgland
Vas deferens
Pubicsymphysis
Epididymis
Seminalvesicle
Penis
(a)
ANATOMY SUMMARYTHE MALE REPRODUCTIVE SYSTEM
Figure 26-9b
Male Reproductive Structures - Scrotal Structures
Head ofepididymis
Seminiferoustubule
Vas deferens
Epididymis
Scrotal cavity(b)
ANATOMY SUMMARY
THE MALE REPRODUCTIVE SYSTEM
Figure 26-9c
Seminiferous Tubule - Cross-Section
Spermatogonium
Capillary
Leydig cell
(c)
Sertoli cell
ANATOMY SUMMARY
THE MALE REPRODUCTIVE SYSTEM
Spermatogenesis in the Testes
• Seminiferous tubules• Sertoli cells surround and support developing
sperm• Spermatogonia divide and produce all sperm
cells• Primary and secondary spermatocytes• Spermatids• Spermatozoa
• Interstitial tissues support spermatogenesis• Leydig cells testosterone• Capillaries deliver nutrients and remove wastes
Figure 26-9d
Seminiferous Tubule - Detail
Sertoli cells
SpermatozoaSpermatidsSecondary spermatocyte
Primary spermatocyteSpermatogonium
Leydigcells
CapillaryFibroblast
Basallamina
Lumen ofseminiferous tubule
(d)
Tight junctionbetween Sertoli cells
ANATOMY SUMMARY
THE MALE REPRODUCTIVE SYSTEM
Figure 26-10
Spermatozoa Structure
Tail(flagellum)
Mid piece
Head
Microtubules
Mitochondrialspiral
Centrioles
Nucleus
Acrosomecontainsenzymes
Regulation of Spermatogenesis
• Hormones control the production of sperm• GnRH stimulates the release of LH and FSH• LH Leydig cells testosterone • FSH Sertoli cells cell products
Figure 26-11
Regulation of Spermatogenesis
LH
GnRHHypothalamus
Anteriorpituitary
Inhibin
Testes
Leydigcells
Testosterone (T)
To bodyfor secondary
effects
FSH
Sertolicell
Cellproducts
Secondmessenger
Sertolicell
ABP TAndrogen-binding
protein (ABP)
Spermatogonium
Spermatocyte
Accessory Glands Contribute to Semen
• Accessory glands contribute 99% of semen volume, as well as the following• Seminal vesicles – fructose, vitamin C,
prostaglandins• Prostate gland – buffers, citric acid, enzymes• Bulbourethral gland – mucus, buffers
Table 26-3
Accessory Glands Contribute to Semen
Female Reproductive System
• Female reproduction is a cyclic process• Hormones from the hypothalamus and
anterior pituitary stimulate the ovaries• The ovaries release estrogen and
progesterone in varying patterns during each cycle
• Ovulation releases a mature oocyte monthly• Estrogen and progesterone prepare the
uterus for possible pregnancy
Female Reproductive Structures
• External genitalia (aka vulva, or pudendum)• Labia majora• Labia minora• Clitoris• Vagina• Hymen
• Urethral opening is inside the labia minora
Figure 26-12a
Female Structures - External Genitalia
Vagina Hymen(stretched)
Anus
Labiummajora
Labiumminora
ClitorisUrethralopening
THE FEMALE REPRODUCTIVE SYSTEM
ANATOMY SUMMARY
(a)
Female Structures - Internal Organs
• Vagina• Uterus• Cervix• Endometrium and myometrium
• Fallopian tube• Fimbriae
• Ovary
Uterus
Ovary
Urinarybladder
Fallopian tube
Rectum
Cervix
Anus
Clitoris
Labiummajora
Labiumminora
VaginaUrethra
THE FEMALE REPRODUCTIVE SYSTEM
ANATOMY SUMMARY
(b)
Figure 26-12b
Female Structures - Sagittal View
Ovaries: Cells and Tissues
• Follicle - structure where oocytes develop• Granulosa cells• Oocyte
• Thecal cells surround all follicles• Corpus luteum
Figure 26-12c–e
Structure of the Uterus and Ovary
Figure 26-12c, f
Structure of the Uterine Wall
Phases of the Ovarian Cycle
• Follicular phase• Proliferation of granulosa cells• Development of antrum• Maturation of oocyte
• Ovulation• Ripened follicle bursts, releasing oocyte
• Luteal phase• Ruptured follicle develops into corpus luteum
Figure 26-13 (1 of 2)
The Ovarian Cycle
Endometrial Lining: the Uterine Cycle
• Menses (occurs if pregnancy is not achieved)• Bleeding from uterus as endometrium is shed
• Proliferative phase• Endometrium grows in preparation for
pregnancy• Secretory phase• Endometrial secretions promote implantation
Figure 26-13 (2 of 2)
The Uterine Cycle
Figure 26-13 (1 of 4)DAYS
36.4
36.7
7 14 21 28/028/0
Follicular Phase
Phases of theUterine Cycle
Phases of theOvarian Cycle
Basal bodytemperature
(–C)
Uterinecycle
Ovarianhormone
levels
Ovariancycle
Gonadotrophichormone
levels
Primaryfollicle Theca
MENSES
InhibinEstrogen
LH
FSH
Progesterone
Follicular Phase and Menses
Figure 26-13 (2 of 4)DAYS
36.4
36.7
7 14 21 28/028/0
Follicular Phase
Phases of theUterine Cycle
Phases of theOvarian Cycle
Basal bodytemperature
(–C)
Uterinecycle
Ovarianhormone
levels
Ovariancycle
Gonadotrophichormone
levels
Primaryfollicle Theca
MENSES PROLIFERATIVEPHASE
InhibinEstrogen
Antrum
LH
FSH
Progesterone
Follicle Maturation and the Proliferative Phase
DAYS
36.4
36.7
7 14 21 28/028/0
Follicular Phase Ovulation Luteal Phase
Phases of theUterine Cycle
Phases of theOvarian Cycle
Basal bodytemperature
(–C)
Uterinecycle
Ovarianhormone
levels
Ovariancycle
Gonadotrophichormone
levels
Primaryfollicle Theca Ovulation
Corpusluteum
formation
MENSES PROLIFERATIVEPHASE
SECRETORY PHASE
InhibinEstrogen
Antrum
LH
FSH
Progesterone
Figure 26-13 (3 of 4)
Ovulation, Luteal Phase, and Secretory Phase
DAYS
36.4
36.7
7 14 21 28/028/0
Follicular Phase Ovulation Luteal Phase
Phases of theUterine Cycle
Phases of theOvarian Cycle
Basal bodytemperature
(–C)
Uterinecycle
Ovarianhormone
levels
Ovariancycle
Gonadotrophichormone
levels
Primaryfollicle Theca Ovulation
Corpusluteum
formation
Maturecorpusluteum
Corpusalbicans
Progesterone
MENSES PROLIFERATIVEPHASE
SECRETORY PHASE
InhibinEstrogen
Antrum
LH
FSH
Figure 26-13 (4 of 4)
Corpus Luteum Degenerates and Ceases Hormone Production
Complex Hormonal Control of Two Cycles
• Ovarian and uterine cycles are controlled by several hormones, which display complex interactions
• Extra-ovarian hormones• GnRH from the hypothalamus• FSH and LH from the anterior pituitary
• Ovarian hormones• Estrogen• Progesterone
Figure 26-14
LHFSH
GnRH
Androgens
Estrogens
(a) Early to mid-follicular phase
Follicle
Granulosacells
Thecalcells
(b) Late follicular phase and ovulation (d) Late luteal phase
FSH LH
New folliclesbegin todevelop
Corpusluteum
dies
Tonic secretionresumes
Corpus luteum
Progesterone
Ovum
LHFSH
Follicle
Estrogen andprogesterone
FSH LH
Corpus luteum(from ovulated
follicle)
EstrogenProgesteroneInhibin
GnRHGnRH
secretes
(c) Early to mid-luteal phase
EstrogenInhibin
Follicle
Granulosacells
Thecalcells
Inhibin
High estrogenoutput
Small amount ofprogesterone
Androgens
LHFSH
GnRH
Pituitary Hypothalamus
Hormonal Control of the Menstrual Cycle
Hormonal Control of the Menstrual Cycle: Follicular Phase
• FSH stimulates follicular development• Maturation to secondary and tertiary follicles• Granulosa cells produce estrogen• Negative feedback decreases FSH and LH
secretion• Positive feedback allows continued estrogen
production
• LH stimulates thecal cells to produce androgens• Aromatase converts androgens into estrogens
• Antrum fills with fluid
LHFSH
GnRH
Androgens
Estrogens
(a) Early to mid-follicular phase
Follicle
Granulosacells
Thecalcells
Corpus luteum
Progesterone
Ovum
LHFSH
FollicleEstrogen
Inhibin
Pituitary Hypothalamus
Figure 26-14 (1 of 4)
Hormonal Control of the Menstrual Cycle: Follicular Phase
Hormonal Control of the Menstrual Cycle: Late Follicular Phase and Ovulation
• Late follicular phase• Secretion of inhibin and progesterone begins• Estrogen changes from negative to positive
feedback• Enhanced secretion of LH - the LH surge• Meiosis resumes in developing follicles
• Ovulation• Mature follicle secretes collagenase• Inflammatory reaction produces prostaglandins• Follicle ruptures releasing mature oocyte• Theca and granulosa cells change into luteal
cells
LHFSH
GnRH
Androgens
Estrogens
(a) Early to mid-follicular phase
Follicle
Granulosacells
Thecalcells
(b) Late follicular phase and ovulation
Corpus luteum
Progesterone
Ovum
LHFSH
FollicleEstrogen
Inhibin
Follicle
Granulosacells
Thecalcells
Inhibin
High estrogenoutput
Small amount ofprogesterone
Androgens
LHFSH
GnRH
Pituitary Hypothalamus
Figure 26-14 (2 of 4)
Hormonal Control of the Menstrual Cycle: Late Follicular Phase and Ovulation
Hormonal Control of the Menstrual Cycle: Early to Mid-Luteal Phase
• Corpus luteum develops and secretes progesterone and estrogen
• Progesterone and estrogen exert negative feedback on hypothalamus
• Effects of progesterone• Endometrium develops further• Cervical mucus thickens
LHFSH
GnRH
Androgens
Estrogens
(a) Early to mid-follicular phase
Follicle
Granulosacells
Thecalcells
(b) Late follicular phase and ovulation
Corpus luteum
Progesterone
Ovum
LHFSH
Follicle
FSH LH
Corpus luteum(from ovulated
follicle)
EstrogenProgesteroneInhibin
GnRH
secretes
(c) Early to mid-luteal phase
EstrogenInhibin
Follicle
Granulosacells
Thecalcells
Inhibin
High estrogenoutput
Small amount ofprogesterone
Androgens
LHFSH
GnRH
Pituitary Hypothalamus
Figure 26-14 (3 of 4)
Hormonal Control of the Menstrual Cycle: Early to Mid-Luteal Phase
Hormonal Control of the Menstrual Cycle: Late Luteal Phase
• If no implantation• Corpus luteum undergoes apoptosis after 12
days• Lack of progesterone leads to death of
endometrium• Menses = sloughing of the dead endometrium• FSH and LH secretion resumes
• Following implantation• hcG maintains corpus luteum• Corpus luteum secretes progesterone and
estrogen
LHFSH
GnRH
Androgens
Estrogens
(a) Early to mid-follicular phase
Follicle
Granulosacells
Thecalcells
(b) Late follicular phase and ovulation (d) Late luteal phase
FSH LH
New folliclesbegin todevelop
Corpusluteum
dies
Tonic secretionresumes
Corpus luteum
Progesterone
Ovum
LHFSH
Follicle
Estrogen andprogesterone
FSH LH
Corpus luteum(from ovulated
follicle)
EstrogenProgesteroneInhibin
GnRHGnRH
secretes
(c) Early to mid-luteal phase
EstrogenInhibin
Follicle
Granulosacells
Thecalcells
Inhibin
High estrogenoutput
Small amount ofprogesterone
Androgens
LHFSH
GnRH
Pituitary Hypothalamus
Figure 26-14 (4 of 4)
Hormonal Control of the Menstrual Cycle: Late Luteal Phase
Female Secondary Sex Characteristics
• Secondary sexual characteristics are traits, other than genitalia, that distinguish males from females
• Characteristics controlled by estrogen• Breast development• Distribution of body fat
• Adrenal androgens control some female traits• Growth of pubic and axillary hair• Sex drive (libido)