4. Scrotum
Pouch that supports the testes
Septum separates into separate sections for
each testis
Sperm requires temperatures 2-3°C below
body temperature
Allows raising and lowering testes to adjust
temperature
Copyright 2010, John Wiley & Sons, Inc.
5. Testes
Paired oval glands
Develop on embryo’s posterior wall and
descend into scrotum
Starts in 7th month
200-300 lobules containing seminiferous
tubules
Lined with spermatogenic cells: spermatagonia
& sertoli cells
Copyright 2010, John Wiley & Sons, Inc.
8. Spermatogenesis
Stages: meiosis I, meiosis II, spermiogenesis
Occurs in seminiferous tubules
Cell types involved: spermatagonia, sertoli
cells & interstitial cells (leydig cells)
Move through rete testes
epididymis
Copyright 2010, John Wiley & Sons, Inc.
9. Meiosis
Cells have 23 pairs of chromosomes
Gametes are Haploid
Diploid = paired homologous chromosomes
Unpaired chromosomes
Meiosis is the process by which this can
happen
Required for gamete production
Copyright 2010, John Wiley & Sons, Inc.
10. Spermatogenesis Stages
Takes ~65–75 days from first division to
release
Spermatogonium divides: mitosis
One cell is stem cell other differentiates into
primary (1o) spermatocyte
Meiosis I: chromosomes replicate
Line up as pairs of homologous chromosomes
Chromosomes twist and some exchange of
material between chromosomes can occur
Each homologous pair separates and a member
moves to opposite end of cell
After cell division each cell is haploid
Copyright 2010, John Wiley & Sons, Inc.
11. Spermatogenesis Stages
The cells from meiosis I are: secondary
spermatocytes
Meiosis II: divide again
Each cell is haploid- has two copies of each
chromatid
One copy of each chromatid in each new cell
Cells are: spermatids
Copyright 2010, John Wiley & Sons, Inc.
12. Spermatogenesis Stages
Spermiogenesis- each spermatid develops
into a sperm cell
Process requires support of Sertoli cell
Often called “nurse cell”
Copyright 2010, John Wiley & Sons, Inc.
18. Androgen Effects
Prenatal: male pattern of development:
Puberty: enlargement of organs, secondary
characteristics
Male ducts, descent of testes, external genitals
and brain regions
Muscular and skeletal growth, hair patterns,
thickening of skin
Sexual function: sexual behavior,
spermatogenesis and libido
Stimulation of anabolism: stimulate protein
synthesis and muscle and bone growth
Copyright 2010, John Wiley & Sons, Inc.
19. Ducts: Sperm Route
Epdidymis vas (ductus) deferens
ejaculatory duct (by seminal vesicles)
urethra in prostate
Pass bulbourethral glands (alkaline + mucus
fluid)
penis and ejaculation
Copyright 2010, John Wiley & Sons, Inc.
20. Accessory Glands
Seminal vesicles: seminal fluid
Prostate: surrounds upper urethra
Fructose (sperm ATP production
+ alkalinity (neutralize acid in tracts)
+ prostaglandins-activation of sperm
Increases volume + adds antibiotics
Bulbourethral glands
More alkalinity + mucus fluid
Copyright 2010, John Wiley & Sons, Inc.
21. Penis
Contains urethra- root, body & glans penis
Root: attached portion
Body: 3 cylindrical masses erectile
Passage for semen and urine
Dorsal: Corpora Cavernosa Penis
Midventral: Corpus Spongiosum penis- contains
urethra
Glans penis has external urethral oriface
Uncircumcised glans covered by prepuce
Copyright 2010, John Wiley & Sons, Inc.
22. Arousal & Ejaculation
Parasympathetic impulses erection
Dilation of penile arteries
Volume compresses veins so outflow is slowed
Ejaculation is a Sympathetic reflex
Peristaltic contractions in ductus deferens,
seminal vesicles, ejaculatory ducts & prostate
emission
Sphincter at urinary bladder closes
Forceful release of semen from urethra
Copyright 2010, John Wiley & Sons, Inc.
23. Female Reproductive System
Ovaries: paired organs- produce
Secondary oocytes ova (after fertilization)
Hormones: progesterone & estrogens
From same embryonic tissue as testes
Uterine (fallopian) tubes & uterus
Vagina
External organs (vulva or pudendum)
Copyright 2010, John Wiley & Sons, Inc.
27. Oogenesis
Begins before birth
Meiosis I- start before birth & finish at puberty
Oocytes not continually produced
During fetal development form oogonia
Before birth some primary oocytes
Monthly hormones some to complete meiosis I
Two uneven haploid cells = secondary
oocyte & polar body (discarded)
Copyright 2010, John Wiley & Sons, Inc.
28. Oogenesis
Secondary oocyte has most of cytosol
Then begins meiosis 2 & stops
Then ovulation into uterine tube
If fertilization then meiosis II is completed
ovum + 2nd polar body
Nuclei of sperm & ovum unite
Diploid zygote
Copyright 2010, John Wiley & Sons, Inc.
30. Uterine Tubes
Two tubes- extend laterally from uterus
End in fringe fimbriae
Fimbriae sweep secondary oocyte into tube
Oocyte moved by cilia lining wall
Zygote reaches uterus in ~7 days
Copyright 2010, John Wiley & Sons, Inc.
31. Uterus
Pathway for sperm & site of implantation
Fundus: dome-shaped area above tubes=
Body: tapering central portion
Cervix: narrow opening into vagina
Uterine cavity: interior of body
Copyright 2010, John Wiley & Sons, Inc.
32. Vagina
Extends from exterior to cervix
Receptacles for penis and outlet for
menstrual flow
Fornix- recess surrounds cervix
Acid environment- prevents bacterial growth
Smooth muscular layer- adjusts for
intercourse or birth
Thin membrane fold can cover vaginal orifice
= hymen
Copyright 2010, John Wiley & Sons, Inc.
34. Perineum and Vulva
Perineum: Diamond-shaped area between
thigh & buttocks of both males & females
Vulva or pudendum = external genitalia
Mons pubis- elevation of adipose tissue
Labia majora- extends back from mons pubis
Same fetal tissue as scrotum
Labia minora- internal to majora
Copyright 2010, John Wiley & Sons, Inc.
35. Perineum and Vulva
Clitoris: small cylindrical mass of erectile
tissue & nerves
Vestibule: between labia minora
External urethral oriface: anterior to vaginal
oriface
Paraurethral glands: either side of urethra
Also contains prepuce & glans
Same embryonic tissue as prostate
Secretes mucus
Greater vestibular glands- adds to mucus
Comparable to bulbourethral glands
Copyright 2010, John Wiley & Sons, Inc.
43. Hormones
Estrogen development & maintenance of
reproductive structures & secondary
characteristics
protein synthesis & growth
Lower blood cholesterol level
Progesterone maintains myometrium for
implantation
Relaxin: relaxes uterus- inhibits myometrium
Inhibin: inhibits FSH release
Copyright 2010, John Wiley & Sons, Inc.
44. Phases of Cycle
Menstrual phase: ~1st 5 days of cycle
Several Ovarian follicles enlarge
Decreased progesterone & estrogen uterine
arteries constrict endometrium sloughs off
Preovulatory: between menstruation &
ovulation
Ovaries: follicles grow & secrete estrogen &
inhibin one dominates
Uterus: growth of new endometrium
Copyright 2010, John Wiley & Sons, Inc.
45. Phases of Cycle
Ovulation
Release of 2o oocyte with LH surge
Postovulatory
Ovaries: follicle collapses corpus luteum (luteal
phase)
If no fertilization FSH & LH corpus albicans
& decreased Progesterone menstruation
Copyright 2010, John Wiley & Sons, Inc.
46. Phases of Cycle
If fertilization & division human chorionic
gonadotrophin (hCG) stimulates corpus
luteum secretion
Uterus: Progesterone & estrogens
complete development of uterus for
implantation
Copyright 2010, John Wiley & Sons, Inc.
48. Birth Control Methods
Surgical: vasectomy in males
Tubal ligation in females
IUD, condoms, cervical cap
Timing
Oral hormones, implants, injections, spermicide
Blocking physically
Close uterine tubes
Chemical interference
Ductus deferens segment removed
Temperature, mucus charting, calendar
Abortion
Copyright 2010, John Wiley & Sons, Inc.
49. Aging
Puberty- pulses of LH & FSH
Rise in sex steroids
Follicles become exhausted menopause
Growth & secondary characteristics
Start of female reproductive cycle
Estrogen secretion declines
Lose feedback on pituitary high FSH & LH
Decline in estrogen supported functions
In males: slower decline of function
Copyright 2010, John Wiley & Sons, Inc.
50. End of Chapter 23
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