http://www.youtube.com/watch?v=WGJsrGmWeKE&feature=related
Male Reproductive Hormones
1.
androsterone
2.
testosterone
(Urinary
bladder)
Seminal vesicle
(Rectum)
(Pubic bone)
Erectile
tissue of
penis
Vas deferens
Ejaculatory duct
Prostate gland
Urethra
Bulbourethral gland
Vas deferens
Epididymis
Glans penis
Testis
Scrotum
Prepuce
Seminal
vesicle
(behind
bladder)
(Urinary
bladder)
Prostate gland
Urethra
Scrotum
Glans penis
Bulbourethral
gland
Erectile tissue
of penis
Vas deferens
Epididymis
Testis
Male Reproductive Hormones
 both hormones are released from testes
Testes Cells
1. Leydig interstitial cells synthesize hormones
(between seminiferous tubules)
2. Sertoli cells synthesize sperm within
seminiferous tubules
Testosterone Role
 stimulates spermatogenesis (production of mature
sperm cells) – life time process
 develops male characteristics at puberty
Gonadotropic Hormones

gonadotropic hormones regulate gonad
development (male and female)

produced in the anterior pituitary; released upon
hypothalamus signal
1.
follicle stimulating hormone (FSH)
2.
luteinizing hormone (LH)
Male Gonad Development
1. Hypothalamus secretes gonadotropinreleasing hormone (GnRH)
2. Anterior pituitary gland releases FSH & LH
3. FSH stimulates Sertoli cells to form mature
sperm
4. LH stimulates Leydig cells to secrete
testosterone
Male Gonad Development
Role of testosterone:
1. promotes Sertoli cell activity - increases sperm cell
production
2. negative feedback on hypothalamus - inhibits the
hypothalamus by decreasing the secretion of FSH
and LH from the anterior pituitary gland
To Much Testosterone
 Stronger sex drive
 may lead to risky behaviours
 More impulsive and more
aggressive
 Mood changes
 irritability and depression
Stimuli from other
areas in the brain
Hypothalamus
GnRH from the
hypothalamus regulates FSH and LH
release from the
anterior pituitary.
If testosterone
levels get too
high
Anterior
pituitary
Negative
feedback
FSH acts on the
Sertoli cells of the
seminiferous
tubules, promoting
spermatogenesis.
LH stimulates the
Leydig cells to make
testosterone, which
in turn stimulates
sperm production.
Leydig cells
make
testosterone
Primary and
secondary sex
characteristics
Sertoli cells
Figure 46.14
Spermatogenesis
Testis
Female Reproductive System
1.
estrogen
2.
progesterone
Female Reproductive System
 both produced in the ovaries
Ovaries
Oviduct
Follicles
Uterus
Uterine wall
Endometrium
Corpus luteum
Cervix
Vagina
Female Reproductive System
 comparatively more complicated than male
reproductive system
 Each ovary contains about 400,000 follicles at puberty
 Only about 400 eggs will mature and go through
ovulation throughout a woman’s life
 Monthly cycle until menopause (~12 x 50 yrs) = 400450 cycles
 female hormones responsible for oogenesis
(development of mature egg cells) and ovulation
Ovary Follicle Cells
1. primary oocyte fertilized by sperm
2. granulosa cells provide nutrients for primary
oocyte
Female Reproductive System
Female Gonad Development

GnRH, FSH and LH involved
1.
Hypothalamus secretes gonadotropin-releasing
hormone (GnRH)
2.
Anterior pituitary gland releases FSH & LH
3.
FSH matures follicle
4.
LH causes ovulation and causes corpus luteum
maturation
Menstrual/Ovarian Cycle
Menstrual Cycle
menstruation (flow phase)
1.



Shedding of the endometrium
Occurs only if there is no ovum fertilization
estrogen and progesterone levels low
follicular phase
2.



Development of follicles
estrogen secretion by granulosa cells
Estrogen signals the endometrium to thicken
Menstrual Cycle
3. ovulation




ovum leaves ovary
granulosa cells
become corpus
luteum
corpus luteum begins
to secrete
progesterone
estrogen levels start
to decrease
b
Ovary
Uterus
Endometrium
(a)
From ovulation to implantation
Endometrium
Inner cell mass
Cavity
Blastocyst
(b)
Implantation of blastocyst
Trophoblast
Menstrual Cycle
4. luteal stage
 corpus luteum secretes progesterone & small amount of
estrogen
 progesterone encourages endometrium development for
embryo
 If no fertilization occurs = no embryo


corpus luteum degenerates after about 10 days and produces a
scar (corpus albicans)
Concentrations of estrogen and progesterone decrease
 Causing weak uterine contractions (marking the beginning
of the flow phase)
 http://www.youtube.com/watch?v=WGJsrGmWeK
E&feature=related
Can a female get pregnant before she
has had her first period?
 YES!
 By the time she has reached
puberty  400,000 follicles (no
Corpus Luteum)
 Hypothalamus GnRH
 AP  FSH, LH
 FSH  induces
development of follicles
 Ovulation occurs before
menstruation!
What regulates the events of the
menstrual/ovarian cycle?
 Varying levels of LH and
FSH
 determined by varying levels
of estrogen and
progesterone
 Many different positive and
negative feedback
mechanisms involved
1. Follicular Phase

Low level of estrogen
inhibits production of LH
and FSH (keeping their
levels low)

Inhibits AP to prevent
ovulation
2
3
1
2. Ovulation

High estrogen stimulates
LH and FSH production
(more effect on LH than
FSH)

Stimulates AP to cause
ovulation
3. Luteal Phase

High levels of
progesterone and
estrogen inhibits LH and
FSH production

Inhibit AP and
Hypothalamus
2
1
3
Menopause
 ovaries lose responsiveness to FSH and LH
 usually occurs between ages 46 and 54
 most other mammals do not undergo menopause
 thought to allow human females to take care of
grandchildren rather than continue to reproduce
Man-opause?
 Andropause  male menopause
 Decreased levels of testosterone
 Sex drive decreased
 Increase in memory loss
 Breast enlargement
 Body composition = more fat, less muscle

More fat = more testosterone is converted to estrogen
In class work
 Lab Exercise 8.5.1 (Hormone Levels During the
Menstrual Cycle)
Homework
 Section 8.5 – Page 399 #1—5,7-13