Reproductive System
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Meiosis
The process of MEIOSIS is reproduction
The purpose is to continue the human
species through the production of children
Male and female produce gamates
Sperm and Egg cells
Union of gamates = fertilization
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Meiosis
Cell division process of meiosis produces
gamates – sperm or egg cells
One cell with a diploid # of chromosomes
(46), divides twice to form 4 cells, each
with a haploid # of chromosomes (23)
Male has XY chromosomes, female has
XX
Fertilization merge the egg and sperm
(zygote) to have 46 chromosomes
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Male Spermatogenesis
Takes place in the testes
Starts in the Seminiferous Tubules
Contain sperm-generating cells which
divide via mitosis  produce primary
spermatocytes
For each spermatocyte undergoing
meiosis, 4 sperm cells are produced
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Male Spermatogenesis
Sperm production begins at puberty (1014 yrs)
Million of sperm are formed each day
No complete cessation of sperm
production takes place
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Male Hormones
FSH – follicle stimulating hormone from the
anterior pituitary gland. Initiates sperm
production.
LH - luteinizing hormone from anterior pituitary
gland. Aide in production of testosterone
Testosterone – secreted by the testes when
stimulated by LH. Testosterone is responsible
for secondary sex characteristics
Inhibin - secreted by testes. Decreases FSH
secretion, controls rate of spermatogenesis
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Testes
Located in the scrotum
Temperature is 96°F, ideal temperature for
sperm production
The scrotum rises and lowers depending
on the need to cool or warm testes
Decent of testes in the fetus before birth
The testes are an endocrine gland testosterone
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Male Anatomy
Spermatogenesis occurs in the
Seminiferous Tubules
Sperm anatomy –
head – acrosome, enzyme to digest egg
cell wall has 23 chromosomes
middle – mitochondria produce ATP
(energy)
tail/flagellum – cell movement
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Male Anatomy
Epididymis – tube 20 feet long, posterior surface
of testis. Sperm complete maturation here and
flagella become functional
Vas Deferens – extends from the epididymis into
abdominal cavity. Goes through the inguinal
canal “weak spot”, over the bladder to the
ejaculatory duct. Contracts in peristalsis “waves”
during ejaculation.
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Male Anatomy
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Male Anatomy
Ejaculatory duct – receives sperm from
the Vas Deferens
Seminal Vesicles – secretions contain
fructose to provide sperm energy. Is also
alkaline to enhance sperm mobility
Semen – each ejaculate (2-4 ml) contain
100 million sperm per 1 ml. Alkalinity is
important – female vagina very acidic (not
conducive to sperm)
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Male Anatomy
Prostate gland – below the bladder.
Surrounds the first inch of the urethra.
Also secretes more alkaline fluid.
Contracts during ejaculation. Helps move
semen.
Bulbourethral glands/Cowper’s gland –
secretes alkaline fluid to coat the urethra
before ejaculation
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Male Anatomy
Urethra – semen and urine pass through.
Is the last duct for semen and the longest
portion of the penis
Urinary meatis – opening of the urethra
Penis –external organ. Distal end is the
glans penis. Covered with a
prepuce/foreskin (circumcision is the
removal of the foreskin)
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Male Anatomy
Penis – 1 corpus cavernosum, 2 corpus
spongiosums are blood sinuses that fill
with blood during an erection
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Male Anatomy
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Female Anatomy
Oogenesis – meiosis for egg cell formation
Regulated by hormones
FSH – initiates growth of ovarian follicles,
containing an egg generating cell.
Stimulates follicle cells to secrete……
Estrogen – which promotes the maturation
of the ovum
Inhibin - secreted by corpus luteum, inhibits
FSH and LH secretion
Relaxin - inhibit myometrium contractions
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Female Anatomy
Only one functional egg/ovum cell is
produced
The other 3 cells are polar bodies which
deteriorate
Puberty – starts at 10 to 14 yrs.
(menarche is 1st period), ends with
menopause at 45 to 55 yrs. Ovaries
atrophy and stop producing eggs.
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Female Anatomy
Cyclic egg production produces a mature
ovum every 28 days
Mistakes with meiosis – trisomy 21 Downs
Haploid egg and sperm with 23
chromosomes, when fertilized the nucleus
of the egg and sperm merge and produce
a zygote with 46 chromosomes
Oophor = bearing eggs
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Human Ovum
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Female Anatomy
Ovaries –
1.5 inches long on each side of the uterus
Ovarian ligament suspends the ovaries
Broad ligament keeps in place
Follicle maturation requires FSH and estrogen
Mature follicles rupture, releasing ovum
Follicles become corpus luteum and secrete
progesterone as well as estrogen
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Female Anatomy
Fallopian Tubes (salpingo=tubes)
4 inches long, one end around the ovary
with fimbrae (fringed edges)
The other end opens into the uterus
Tubes lined with ciliated epithelial tissue
that sweeps the ovum to the uterus as
well as peristaltic movement.
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Text
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Female Anatomy
Fertilization usually happens in the
fallopian tubes
If no fertilization, the ovum dies within 24
to 48 hrs and disintegrate
Ectopic pregnancies are when the embryo
implants in the fallopian tube, ovary,
abdominal cavity, and can cause
bleeding\pain. May need surgery, or may
go to term.
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Female Anatomy
Uterus
3 inches long by 2 inches wide
Located above the bladder in the pelvic
cavity
Broad ligament covers it
Suspended by the round ligament (can
cause back ache in pregnancy)
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Female Anatomy
Uterus
Fundus – upper portion
Body – central portion
Cervix – opens to vagina
Outer layer – epimetrium/serosa is a fold
of the peritoneum
Middle layer – myometrium is smooth
muscle layer, contracts in labor
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Female Anatomy
Inner layer – endometrium, 2 layers
Basilar – vascular layer, is the permanent
layer
Functional layer – regenerates, lost during
menstrual cycle, influenced by estrogen
and progesterone, thickens to prepare for
embryo
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Female Anatomy
Vagina
Muscular tube approx. 4 inches long
Lined with rugae, and is a continuous
mucous membrane from vagina to
fallopian tubes
Function is to receive sperm, exit for
menstrual flow, birth canal for baby
High acidic pH helps inhibit pathogen
growth
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Female Anatomy
Perineum – muscle structure at the floor of
the pelvis
External genitals/vulva
clitoris – erectile tissue (sensory)
mons pubis – fat pad over pubis
symphysis
labia majora & labia minora – lateral skin
folds
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Female Anatomy
External genitals/vulva cont.
vestibule – urethra and vaginal opening
(introitus)
Bartholin’s glands – lubricating secretions
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Female Anatomy
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Female anatomy
Female pelvis – 4 bones of the pelvis: 2
hip bones, sacrum and coccyx
3 parts of the true pelvis: inlet, pelvic
cavity and outlet (1st and last most
important during birth)
Bony circumference of the true pelvis
determines size and shape adequate to
pass baby
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Female Pelvis
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Female Pelvis
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Female Pelvis
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Female Pelvis
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Female Anatomy
Breasts/Mammary glands
Accessory organ of reproduction
Alveolar glands – produce milk after
pregnancy
Lactiferous ducts converge at the nipple to
carry milk
Areola is the pigmented tissue of the
nipple
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Female Anatomy
Breast/Mammary glands
Hormonal control of milk production
estrogen and progesterone prepare for
milk production
prolactin – formation of milk
oxytocin – release of milk
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Menstrual Cycle
Hormones
FSH – anterior pituitary
LH – anterior pituitary
estrogen – ovary (follicle)
progesterone – ovary (corpus luteum)
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Menstrual Cycle
1. Menstrual phase – loss of endometrium
layer=menses. Usual starting point, lasts
2 to 8 days (menses). FSH secretion
increases. Several ovarian follicles begin
to develop
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Menstrual Cycle
2. Follicular phase – FSH stimulates follicle
growth and estrogen secretion by the
follicle cells. LH secretion increases
slowly. FSH and estrogen promote ovum
growth and maturation. Estrogen
stimulates endometrium functional layer.
Regeneration phase ends with ovulation,
and sharp increase in LH
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Menstrual Cycle
3. Luteal Phase – influenced by LH, ruptured
follicle becomes corpus luteum and secretes
progesterone. Promotes endometrium growth
as progesterone increases, LH decreases. If
ovum not fertilized, progesterone starts to
decrease. Without progesterone, endometrium
cannot be maintained and sloughs off
(menstruation) FSH begins to increase (as
estrogen and progesterone decreases. Cycle
begins again.
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Menstrual Cycle
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Menstrual Cycle
Average cycle = 28 days
Amenorrhea = no periods
Menopause = between 45 to 55 yrs with
decreased estrogen and an increased risk
for osteoporosis
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