Transcript REPRODUCTIVE SYSTEM - Fox Valley Lutheran High School

REPRODUCTIVE SYSTEM
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Reproductive system: carries out the process so organisms can produce
new individuals of their own kind.
It stores, nourishes, and releases gametes
SEXUAL DEVELOPMENT
During 7th week, if male testes develop and produce androgens
developing into male reproductive organs.
If female, the ovaries produce estrogens which develop female
reproductive organs.
Puberty: Period of rapid growth and sexual maturation when sexual
reproductive organs become fully functional.
Gonads: Male and female reproductive organs.
Puberty begins w/a change in the hypothalamus telling the pituitary
to release the hormones FSH and LH affecting the gonads.
MALE REPRODUCTIVE SYSTEM
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Scrotum: Sac where the testes remain after birth regulating temp.
Seminiferous tubules: Tightly compacted forming the testes where
sperm are produced.
FSH and LH stimulate production of testosterone and sperm.
Secondary sex characteristics: deep voice, beards, muscles??
SPERM DEVELOPMENT
See fig. 43-4
Epididymis:comma-shaped structure for storing mature sperm
From the epididymis the sperm travel into the vans deferens tube
From there the vas deferens passed into the abdominal cavity where
three glands produce seminal fluid for sperm storage.
Semen: combination of sperm and seminal fluid (fig. 43-4)
100-200 million sperm/ ml or 5,000,000/drop (2-3 ml/ejaculation)
The vas deferens merges into the urethra then to penis
Ejaculation: Contraction of smooth muscle lining vas deferens
FEMALE REPRODUCTIVE SYSTEM
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Fig. 43-5
Ovary: Primary reproductive organ located in the abdominal cavity
Produce usually only one egg/month (ovum;ova) which signals the need
to nourish a developing embryo.
Puberty is signaled when the hypothalamus signals the release of FSH
and LH
FSH signals the production of estrogen causing reproductive system to
develop
Secondary sex characteristics: enlarged breasts, wide hips,
controlled hair growth
OVA DEVELOPMENT: (FSH completes the meiosis for an ova)
An ovary has about 400,000 primary follicles surrounding an ovum
Born w/400,000 immature ova but fewer than 500 actually release
OVULATION
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OVULATION: Follicle has completely matured and ovum is released.
Follicle ruptures, ovum moves into one of two Fallopian Tubes. (43-6)
Cilia move ovum along. Fertilization can take place during this time.
After a few days the ovum moves into the Uterus, which is designed
to receive a fertilized ovum. This opens into the vagina.
Menopause: Follicle development no longer occurs, no babies possible
THE MENSTRUAL CYCLE:
The interaction of the endocrine and reproductive systems
Average occurrence every 28 days
Controlled by hormones on the negative feedback mechanism
Follicle Phase:
Level of estrogen in low causing a releasing hormone released by the
hypothalamus (FSH & LH to cause a follicle to develop into maturity.
Level of estrogen goes up dramatically, uterus thickens, (10 days)
MENSTRUAL CYCLE
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Leteal Phase:
corpus luteum: ruptured follicle continues to release estrogen
progesterone: hormone released increasing blood supply, tissue
matures, and lining is fully prepared to accept fertilized egg.
During first 2 days egg fertilization is greatest
If fertilized a zygote develops and attaches to uterus
MENSTRUATION:If egg is not fertilized, the corpus luteum begins to
disintegrate, and less & less estrogen and progesterone are released.
When level of estrogen is below a certain point, lining of uterus
detaches. The tissue along with blood and the unfertilized ovum are
discharged through the vagina.
Lasts 3-7 days;
After a few days estrogen levels are low enough, so hypothalamus
produces releasing hormones, secreting FSH and LH etc…..
FERTILIZATION
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FERTILIZATION
When sperm unites with the egg in the Fallopian tube.
Sperm are released during sexual intercourse.
Sperm swim actively through the uterus and up into the Fallopian
tubes.
Hundreds of millions of sperm are released only a few reach the
ovum, and it only takes one to fertilize the egg.
The ovum has receptor sites for sperm. Once a sperm cell reaches
it, the sperm head ruptures, release an enzyme that breaks down the
wall creating a pathway for the sperm nucleus.
Once this happens, cell membrane changes; no other sperm enters
Zygote: fertilized ovum after two haploid fuse into a single diploid.
After a few divisions the zygote attaches to wall of the uterus and
begins to grow.