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Male repro system functions

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Male repro system functions ... Male repro anatomy Functions of each structure Scrotum ... muscular contraction in female reproductive tract clotting ... – PowerPoint PPT presentation

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Title: Male repro system functions


1
Male repro system functions
  • Testes- produce sperm male sex hormone-
    testosterone
  • Ducts transport, store, assist in maturation
    of sperm
  • Accessory sex glands- secrete most of liquid
    portion of semen
  • Penis- contains urethra
  • passageway for ejaculation of semen
  • excretion of urine

2
Male repro anatomy
3
Functions of each structure
  • Scrotum- bag
  • supporting structure for testes
  • loose skin superficial fascia
  • hangs from root of penis
  • Testes- paired oval glands
  • develop near kidneys descend into scrotum in
    latter half of 7th fetal month
  • Sperm produced in seminiferous tubules
  • Adjacent to seminiferous tubules are
  • Leydig cells -secrete testosterone.

4
Structure/Functions (2)
  • Epididymis- lies along posterior border of each
    testis
  • each consists of tightly coiled ductus epididymis
  • where sperm motility ? over 10-14 day pd
  • ductus stores helps propel sperm by peristaltic
    contraction of it smooth muscle
  • Sperm may be stored for a month or more

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6
Structure/Functions (3)
  • Ductus deferens or vas deferens- ?18 in
  • stores sperm, can remain viable several months
  • sperm not ejaculated are reabsorbed
  • (as can happen in epididymis)
  • Cut during vasectomy
  • Ejaculatory ducts- ?1 in, formed by union of
    seminal vesicle ampulla of vas deferens
  • eject sperm seminal vesicle secretions just
    before ejaculation - powerful propulsion of semen
    from urethra to exterior of body

7
Structure/functions (4)
  • Urethra- shared terminal duct of reproductive
    urinary system
  • Passes thru
  • prostate gland (prostatic urethra)
  • urogenital diaphragm (membraneous urethra)
  • penis (spongy urethra)
  • Penis- passageway for ejaculation of semen
    excretion of urine

8
Glands (1)
  • Seminal vesicles- lies posterior to urinary
    bladder, anterior to rectum
  • Function secrete an
  • alkaline (neutralize acidic environment of male
    urethra), viscous fluid that contains fructose
    (ATP production), prostaglandins (contribute to
    sperm motility viability)
  • may also stimulate
  • muscular contraction in female reproductive tract
  • clotting proteins
  • About 60 of volume of semen

9
Glands (2)
  • Prostate gland- inferior to urinary bladder
    surrounds prostatic urethra
  • Secretes milky fluid that contains
  • 1. Citric acid- used in ATP production
  • 2. Acid phosphatase- function unknown
  • 3. Proteolytic enzymes- pepsinogen, lysozyme,
    amylase, and hyaluronidase
  • About 25 volume of semen

10
Glands (3)
  • Bulbourethral (Cowpers) glands- inferior to
    prostate on either side of membraneous urethra
  • During sexual arousal secrete an alkaline
    substance that protects passing sperm by
    neutralizing acids from urine in urethra
  • Also secrete mucus- lubricating end of penis
    lining urethra to ? of sperm damaged during
    ejaculation

11
Descent of Testes
  • In both sexes, gonads originate in lumbar region
    descend caudally during fetal development
  • In male fetus, testes descend toward scrotum,
    followed by their blood vessels nerves
  • testes require a cool location for sperm
    formation
  • testes reach pelvis near inguinal region in month
    3
  • testes proceed no further until month 7, when
    they suddenly quickly pass thru the inguinal
    canal enter the scrotum

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13
Parts of spermatozoan
  • Head- contains nuclear material acrosome
  • Acrosome- dense lysosome-like body in head of
    sperm cell
  • contains enzymes that facilitate penetration of
    sperm cell into secondary oocyte
  • Midpiece- contain numerous mitochondria
  • provides ATP for locomotion
  • Tail- typical flagellum
  • propels sperm

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15
Gametes are haploid
  • Haploid- (n) having half the of chromosomes
    characteristically found in somatic cells of an
    organism
  • Sperm
  • Oocyte
  • Diploid- (2n) having the of chromosomes
    characteristically found in the somatic cells of
    an organism

16
Meiosis vs. Mitosis
  • Meiosis- cell division during production of
    gametes
  • 2 successive nuclear divisions resulting in
    daughter cells with haploid number chromosomes
  • 2n ? n
  • Mitosis- division of nucleus that ensures each
    new daughter nucleus has same number kind of
    chromosomes as original parent nucleus
  • Process includes the 2 full sets of chromosomes
    sent into 2 separate equal nuclei
  • Daughter cells have diploid number of chromosomes
  • 2n ? 2n

17
Maturation of sperm
18
  • Hormonal control of spermatogenesis

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20
Hormone producing cells
  • Sertoli cells- supporting cell of seminiferous
    tubules
  • secretes fluid for supplying nutrients to sperm
  • Secrete hormone inhibin
  • phagocytizes excess cytoplasm for spermatogenic
    cells
  • mediates effects of FSH testosterone
  • Secrete Mullerianinhibiting substance during
    fetal development
  • Leydig cells- secretes testosterone
  • located in CT between seminiferous tubules

21
  • Negative feedback loop for testosterone

22
Female repro structures
  • Ovaries produce 2 oocytes and hormones
  • Estrogens, progesterone, inhibin, relaxin
  • Uterine tubes transport 2 oocyte to uterus.
    Also, site of fertilization
  • Uterus- implantation, fetal development, labor
  • Vagina receives penis during intercourse,
    passageway for childbirth
  • Mammary glands- synthesize, secrete, eject milk
    for nourishment of newborn

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24
Oogenesis
  • During fetal development, primordial germ cells
    migrate yolk sac? ovaries
  • Germs cells in ovary oogonia
  • Are diploid
  • Most degenerate atresia
  • Few develop into primary oocytes which enter
    prophase I of meiosis during fetal development do
    not complete until puberty
  • 1 oocyte surrounded by follicular cells
    primordial follicle

25
Primary oocyte development
  • 200,000 2,000,000 oocytes/ovary at birth
  • 40,000 still present at puberty
  • ? 400 will mature and ovulate
  • Monthly FSH LH stimulate development of
    several primordial follicles, typically only one
    matures enough to be ovulated
  • Primary follicle ? secondary follicle ? Graafian
    follicle? follicle ruptures ovulation
  • See figure 28.13

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29
Oogenesis
  • One female gamete (haploid) forms from one
    oogonium (diploid)
  • How many male gametes are formed from one diploid
    spermatogonium?
  • Table 28.1 summarizes

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31
Hormonal Control of Ovulation
32
Female hormone functions
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35
Human sexual response
  • 4 stages
  • Excitement arousal, ParasympNS causes
    vasocongestion
  • HR bp?, skeletal muscle tone, hypervent
  • Plateau excitement sustained intensely, sex
    flushredness of face chest
  • Orgasm- briefest, ejaculation, muscular
    contractions in both sexes. SympNS causes smooth
    muscle contraction of genitals
  • Resolution- relaxation return to unaroused
    state
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