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HUMAN REPRODUCTIVE
SYSTEM
SL
TOPIC 6.6
6.6 Reproduction
• Draw and label diagrams of the adult male and female reproductive
systems.
• Outline the role of hormones in the menstrual cycle, including FSH
(follicle stimulating hormone), LH (luteinizing hormone), estrogen
and progesterone.
• Annotate a graph showing hormone levels in the menstrual cycle,
illustrating the relationship between changes in hormone levels and
ovulation, menstruation and thickening of the endometrium.
• List three roles of testosterone in males.
• Outline the process of in vitro fertilization (IVF).
• Discuss the ethical issues associated with IVF.
FEMALE
REPRODUCTIVE
SYSTEM
What are the organs of female reproductive
system?
Ovaries: produce egg cells and estrogen
and progesterone
Oviduct: transfer egg cell from ovaries to the
uterus. Fertilization takes place in oviduct.
Uterus: Embryo develops in the uterus.
Cervix: entrance of uterus. It holds the fetus
in the uterus during pregnancy.
Vagina: entrance for sperm and exit for the
fetus.
MALE
REPRODUCTIVE
SYSTEM
What are the organs of male
reproductive system?
•
•
•
•
Testes: to produce sperm and testosterone.
Epididimis: sperms structures are completed here.
Sperm duct: storage of sperms
Glands (bulbourethral, prostate, seminal): to secrete
nutritional fluid and anti acid fluid.
• Penis: to deliver sperms to the females body. It has
eractile spongy tissue which blood fills during erection.
• Urethra: carries semen during ejaculation and urine
during urination.
HORMONAL
CONTROL OF
MALE
REPRODUCTIVE
SYSTEM
ROLES OF HORMONES
• FSH: stimulates testes to produce sperm
• LH: stimulates testes to produce testosterone
• Testosterone:
a. stimulates testes cells (leydig cells) for sperm
production (meiosis)
b. provides secondary sexual characteristics
c. stimulates hypothalamus for the regulation of FSH and
LH secretion and for reproductive behaviors (libido).
d. initiates prenatal development of male genitelia
MENSTRUAL CYCLE
Monthly cycle of ovulation and menstruation
in female. (28 days)
It includes hormonal changes and structural
changes in the uterus and ovaries.
There are two cycles in the menstrual cycle.
1- Ovarian cycle:
2- Uterus cycle.
Figure 27.6_3
OVARIAN CYCLE
0
10
5
Days
14 15
20
25
28
Ovarian cycle
Growing
follicle
Mature
follicle
Ovulation
Pre-ovulatory phase
Estrogen secreted
by growing follicle
Corpus Degenerating
corpus
luteum
luteum
Post-ovulatory phase
Progesterone and
estrogen secreted by
remnant of follicle
Figure 27.6_4
0
5
10
Days
14 15
20
25
28
Peak causes
LH surge
Ovarian
hormones
in blood
Estrogen
Progesterone
Low levels of
estrogen trigger
menstruation
Progesterone and
estrogen promote
thickening of
endometrium
Figure 27.6_5
UTERUS CYCLE
Menstrual cycle
Endometrium
0
5
Menstruation
10
14 15
Days
20
25
28
FOLLICLE PHASE (10-12 DAYS)
New cycle starts with a menstrual period.
1- FSH is secreted by the pituitary gland and
stimulates development of a follicle (immature egg
cell( in the ovary.
2- Developing follicle secretes estrogen which
stimulates;
a. uterus to increase thickness of the
endometrium.
b. pituitary gland ( reduces secretion of
FSH, negative feedback control)
3- Estrogen level increases and leads to LH
secretion.
OVULATION PHASE
• LH stimulates mature follicle and egg cell
is released into oviduct.
• LH also convert follicle to corpus luteum
(yellow body) which secretes
progesterone.
CORPUS LUTEUM PHASE
1- Follicle cells secrete progesterone.
2- Progesterone;
-stimulates endometrium to increase thickness
(prepares it self for the implantation of embryo)
-stimulate pituitary gland to inhibit secretion of FSH,
and LH.
3- Low level of FSH and LH degenerate corpus luteum, so
progesterone level decreases.
4- New cycle starts with menstrual period which
endometrium tissue breaks down and is lost through the
vagina.
3.
IN VITRO FERTILIZATION
• In vitro fertilization (IVF) is the most common assisted
reproductive technology. Fertilization occurs in a culture dish and an
early embryo is implanted in the uterus.
Figure 27.18
Implantation
Zygote
Collected
egg
In vitro fertilization
Collected
sperm
8-cell
embryo
Figure 27.18_1
Sexual activity can transmit disease
• Sexually transmitted diseases (STDs)
caused by bacteria can often be cured.
• Chlamydia
– is the most common bacterial STD,
– often produces no symptoms, and
– can lead to pelvic inflammatory disease and
infertility.
© 2012 Pearson Education, Inc.
Sexual activity can transmit disease
• Viral diseases
– such as genital herpes and HIV,
– can only be controlled.
• The best way to avoid the spread of STDs is
abstinence.
• Latex condoms provide the best protection
against disease transmission for “safer sex.”
© 2012 Pearson Education, Inc.
Table 27.7