Transcript Sperm Release Pathway: The Parasympathetic Step

Sperm Release Pathway:
The Parasympathetic Step
1. Brain perceives sexual stimulus
2. NO (nitrous oxide) released in smooth
muscle lining arterioles of erectile tissue
3. Arterial muscles relax, arterioles dilate
4. Arterioles fill with blood
5. Engorged arterioles compress venules
6. Blood is trapped in erectile tissue
arterioles. Erection achieved.
Sperm Release Pathway:
The Sympathetic Step
7. Prolonged sexual stimulus results in spinal
reflex impulse…
8. Causes contraction of:
*vas deferens *bulbourethral gland
*prostate gland * seminal vesicles
9. Semen empties into urethra
10. Urethral sphincter muscles contract
11. Semen forcefully ejected from urethra
Ejaculation
Female Reproductive System
I. Female Reproductive
Structures
 Ovaries
 Oviducts
 Uterus
 Cervix
 Vagina
 Brain
A.
Ovaries
 Primary Reproductive Organ/Female Gonad
 Paired
 Attached medially to uterus by ovarian
ligament
 Filled with ovarian follicles
 Each ovarian follicle contains an immature
oocyte (gamete)
Follicle
membrane
Immature
oocyte
OVARIAN FOLLICLE
Onset of Puberty
 Hypothalamus released GnRH (Gonadotropin
Releasing Hormone)
 Pituitary Gland releases:
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FSH
LH
ESTROGEN
RELEASE
Release of Estrogen at onset of
Puberty…
 SECONDARY SEX CHARACTERISTICS
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Breast development
Widening of pelvic girdle
Body hair
 MENARCHE
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First ovulation followed by menstrual period
The Ovarian Cycle
 Results in the release of:
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gamete
hormones required for pregnancy
 Repeats ~ 28 days
OVULATION:
 major event of Ovarian Cycle!
 release of mature oocyte from ovary
3 Phases of Ovarian Cycle
Follicular Phase
2. Ovulation
3. Luteal Phase
1.
1. Follicular Phase
 Days 1 - 14
 Granulosa cells (Epithelium/CT) of follicle
provide nutrition/support/protection to
oocyte
 Follicle increases in size around oocyte
 Follicle secretes Estrogen hormone
 Zona pellucida forms around oocyte

Thick protective, nutritive membrane
 Increased granulosa cells surround oocyte
“Corona radiata”
nucleus
Corona Radiata
Zona
pellucida
2. Ovulation Day
• Day 14 Wall of ovary bulges and bursts
• Oocyte (w/ corona radiata) expelled from
ovary!
Ovulation
Identify:
Ovary
Follicle
Oocyte
Corona Radiata
3. Luteal Phase
 Days 15 – 28
 Follicle remains in ovary after ovulation
 Granulosa cells secrete hormones:
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Progesterone
Estrogen
 Follicle has been transformed into…
CORPUS LUTEUM!
The fate of the Corpus Luteum…
 If sperm are present and oocyte becomes
fertilized…
Corpus Luteum continues production of
progesterone (pregnancy hormone) for 1st
three months of pregnancy!
 If fertilization of oocyte does NOT occur…
Corpus luteum stops hormone production
and breaks down
B. It Starts with the Brain…
C.
Fallopian Tubes
 Aka: oviducts / uterine tubes
 Attached medially to uterus
 Lateral region surrounding ovary…
Ampulla : common site of fertilization
 Possesses ciliated finger-like projections that hang
over ovary…
Fimbriae !
Ampulla
Fimbriae
D.
The Uterus
 “womb”
 Thick muscular lining
 Resembles a pear in shape and size
 Functions to receive, retain, and nourish the
fertilized ovum
The Uterus is…
 Divided into regions
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Fundus:
Body:
Cervix:
rounded superior region
largest region
narrow inferior region
Fundus
Body
Cervix
The Uterus is…
 Composed of three layers:
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Perimetrium:
Myometrium:
Endometrium:
outer visceral layer
middle muscular thickest layer
inner epithelial layer
site of implantation of fertilized ovum
The Uterus is…
 Highly vascular!
 Uterine Arteries: branch to provide blood to
myometrial and endometrial layers of uterus!
The Vagina
 Extends from cervix to external environment
 Functions to:
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Allow for passage of infant (“birth canal”)
Allow for passage of menstrual flow
Receive penis during intercourse
(female organ of copulation)
 Acidic pH in adults protection against
infection
 hostile environment for
sperm
The fate of the Ovum...
Post-Ovulation
Menstruation
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Occurs ~ 14 days post ovulation
Occurs ONLY if fertilization of ovum does NOT occur
Endometrium layer of uterus is shed
Results in bleeding from vagina for ~3-5 days
Endometrial layer will immediately begin rebuilding
vascular tissue during days 1-14 of Ovarian Cycle (due
to
estrogen!)