2. REPRODUCTIVE SYSTEM
MALE REPRODUCTIVE SYSTEM
STRUCTURE
Testes
-
(testis :singular)
Scrotum
Seminiferous tubules
Leydig cells
Rete testis
-
Epididymis
-
Vas deferens
-
Urethra
-
Bladder sphincter
Seminal vesicles
-
Prostate gland
-
Bulbourethral gland
-
Penis
-
FUNCTION
Produce sperm cells
Deliver them to female reproductive
tract
Site of hormone production
Serves as cooling unit
Site of sperm production
Produce testosterone
Path where sperm from seminiferous
tubules travel to epididymis
Temporary storage site for immature
sperm
Site of maturation
Gain ability to swim
Pass through the live sperm from storage
site into urethra
Tube that conduct semen and urine at
different time
Constrict when semen is ejaculated
Secrete nutritive fluids rich in fructose
and prostaglandin
Secrete milky and alkaline fluid that
neutralize acidic environment of vagina.
Secrete mucus when men sexually
excited
Mucus cleanses urethra from urine
Copulatory organ
Delivers sperm into female reproductive
tract
Spermatogenesis
P1
P2
P3
P4
P5
P6
P7
P8
Process of sperm production
Sperm form in the seminiferous tubules
Spermatogonium remain at the basement membrane of seminiferous tubules (as stem cells)
At puberty, FSH secreted
Caused stem cell to be pushed forward tubule lumen
Enlarged into primary spermatocyte
Primary spermatocyte undergoes Meiosis I
Form two haploid secondary spermatocytes
Secondary spermatocytes undergoes meiosis II
Form 4 haploid spermatids
IKMAL_NIK/2013
3. Prophase
Spermiogenesis – the final stage of spermatogenesis
-
Spermatids mature and become motile spermatozoa
Stages of Spermiogenesis
-
Golgi phase
Cap phase
Acrosomal phase
Maturation phase
Spermatids undergo
Spermiogenesis to become
spermatozoa
Once the spermatozoa is completely
matured, it will become sperm
After Spermiogenesis, spermatids will develop flagella
Therefore, there will be 4 mature sperm cells
Head contain DNA
Sperm:
Acrosome – has enzymes that help
sperm to penetrate ovum
Midpiece – has mitochondria
(provide energy)
IKMAL_NIK/2013
4. Spermatogoniumprimary spermatocytesecondary spermatocytespermatidsspermatozoasperm
Involvement of Hypothalamus and pituitary gland in endocrine regulation of male
Hypothalamus – secrete GnRH (gonadotropin releasing hormone)
GnRH stimulate anterior pituitary gland to secrete FSH and LH
LH stimulate Leydig cell to produce testosterone
Testosterone – stimulating the formation and development of the sperm
FSH stimulate Sertoli cell to produce protein that concentrate testosterone
What happen when there are numerous sperms?
Sertoli cell release inhibin, which will stimulate hypothalamus and pituitary gland to cut the release
of GnRH and FSH
What happen when there is excessive testosterone?
-
Hypothalamus reduce secretion of GnRH
Anterior pituitary gland reduce production of LH and FSH
So testosterone will be less secreted by interstitial cells
Role of secretions
Secretions
GnRH
-
FSH
-
LH
-
testosterone
-
Inhibin
-
Function
Stimulate anterior pituitary gland to
produce LH and FSH
Stimulate Sertoli cell to produce protein
that concentrate testosterone
Caused stem cell to be pushed to tubule
lumen and enlarged into primary
spermatocyte
Stimulate Leydig cell to produce
testosterone
Produce male primary sex characteristics
Stimulate development of secondary
male characteristics
Act on hypothalamus to cut secretion of
GnRH
Give effect to secretion of FSH and LH
IKMAL_NIK/2013
5. Female Reproductive Cycle
during first day of menstrual bleeding,
hypothalamus is stimulated to release GnRH
to anterior pituitary gland.
Anterior pituitary gland stimulated to
release FSH and LH.
FSH and LH will stimulate follicle to grow
The growing follicle will stimulates
granulose cell to produce estrogen. Estrogen
level in blood rises. The increasing level of
estrogen will promote the growth of
endometrium layer.
Anterior pituitary gland detects high level
of estrogen. Causing outpouring of LH.
Causing outpouring of LH.
High
level
of
LH
will
cause
ovulation(release of secondary oocyte). End
of follicular phase
The released secondary oocyte left the
granulosa cells in the ovary. This will form the
corpus luteum, which secretes progesterone
and some estrogen.
Progesterone will maintain the endometrium
layer.
IKMAL_NIK/2013
6. Continue:
Two conditions:
1. If pregnancy occur, corpus luteum will maintain to secrete progesterone and estrogen to
maintain endometrium layer.
Hypothalamus will be inhibited from releasing GnRH to pituitary gland. So less secretion FSH
from pituitary gland. No development of other follicles.
Blastocyst formed after implantation. Blastocyst able to secrete hCG. The function of the hCG
is to stimulate the corpus luteum to release large amount of progesterone and estrogen to
maintain the endometrium layer from being sloughed off.
After placenta formed, it take over the function of secreting hCG. (before this, hCG secreted
by blastocyst).
2. If no pregnancy occur, corpus luteum will degenerate. No secretion of progesterone and
estrogen. Endometrium layer will slough off.
IKMAL_NIK/2013