1. The Male Reproductive System o Seminiferous Tubules
 Sertolli Cells
External Genital Organs Stimulated by Follicle-
o Penis: the anatomically male copulatory organ. Stimulating Hormone
o Scrotum:It holds and protects the testes. It (FSH)
also contains numerous nerves and blood o For
vessels. Spermatogenesis
Internal Genital Organs Testosterone Secretion
o Epidydimis: a whitish mass of tightly coiled -Testosterone: produced mostly in the
tubes cupped against the testicles testes
 acts as a maturation and storage place -small amounts of testosterone: produced
for sperm before they pass into the vas from steroids secreted by the outer layer of the
deferens adrenal glands (adrenal cortex)
o Vas Deferens:long, muscular tube that travels
from the epididymis into the pelvic cavity Chemical signals for testosterone Secretion:
 transports mature sperm to the urethra
in preparation for ejaculation. -from the Pituitary Gland
o Testes:“male gonads”; the organs that produce
-Hypothalamus (tells the testes how much
sperm cells
testosterone to produce)
 produces hormones, including
testosterone, which stimulates the controls hormone production in
production of sperm cells and facilitates the pituitary gland by means of gonadotropin-
male maturation releasing hormone (GnRH) tells the pituitary
gland to make FSH and LH
Accessory Glands
Luteinizing hormone (LH): signals the
o Seminal Vesicle: provides sperm cells energy
testes to produce testosterone
and aids in their motility. 70% of the semen is
its secretion. ↑ testosterone = ↓ LH
o Prostate Gland: responsible for the
production of semen ↓ testosterone = ↑ LH
o BulbourethralGland: produces substances
related to nourishment of spermatozoa
Hermaphroditism: A condition in which both
*Testes has 2 compartments:
ovarian and testicular tissue is present in the body
o Interstitial Tissues
Pseudohermaphroditism: Involve individuals
 Leydig Cells
with either testes or ovaries, who have accessory
Stimulated by organs and external genitalia that are incompletely
Luteinizing hormone developed or that are inappropriate for their
(LH) chromosomal sex
Secretes Testosterone
o Maintain structure GONADAL AXIS
and function of the
male accessory sex -interactions between the hypothalamus, pituitary
organs gland, and the gonads that works together to
o Promote regulate development, reproduction, aging, and
development of other body processes
male secondary
Anterior pituitary gland: release FSH and LH
sex characteristics
(stimulated by hypothalamus: GnRH)

2. -stimulation of spermatogenesis }Causes release of LH & FSH
-stimulation of gonadal hormone secretion 4.LH & FSH travels to testicles
-maintenance of the structure of the gonads 5.LH stimulates Leydig cells – testosterone
Castration: will lead to an ↑ in secretion of the 6.FSH stimulates Sertolli cells – produce androgen
gonadotropic hormone (FSH & LH) binding globulin and inhibin
-gonads will then secrete products that exert a 7.↑levels of testosterone and inhibin
negative feedback effect of gonadotropin secretion
*results in ↓production of LH & FSH; production of
Negative Feedback Mechanism: testosterone &inhibin ↓
1.Inhibition of GnRH secretion from the
hypothalamus
PUBERTY
2.Inhibition of the pituitary’s response to a
given amount of GnRH -gonadotropin hormones = low until the beginning
of puberty
*testes and ovaries secrete inhibin, which is secreted
by the Steroli cells (polypeptide hormone). -rise in gonadotropin secretion= maturational
changes in the brain: result in ↑ GnRH secretion
*Inhibin: inhibits the secretion of FSH w/o affecting
LH secretion -Late puberty: pulsatile secretion of gonadotropins
-FSH and LH secretion ↑during periods of sleep and
↓during periods of wakefulness
-increased gonadotropin secretion during puberty
stimulates a rise in sex steroid secretion from gonads
1.Hypothalamus secretes GnRH
2.GnRH goes to anterior pituitary gland
3.GnRH binds with the receptors of pituitary gland

3. Secondary Sex Characteristics: physical Spermatogonia lose contact with the basement
manifestations of the hormonal changes during membrane, squeeze through the tight junctions of
puberty the blood-testis barrier and differentiate into
PRIMARY SPERMATOCYTES (diploid -46
chromosomes)
Each primary spermatocyte replicate its DNA-
MEIOSIS I begins. Meiotic spindle pulls one
chromosome of each pair to an opposite pole of
dividing cell forming SECONDARY
SPERMATOCYTES (23 chromosomes:haploid)
-each chromosome within a secondary
spermatocyte is made up of two chromatids still
attached by a centromere
MEIOSIS II:The chromosomes line up in single file
along the metaphase plate, two chromatids of each
chromosome separate resulting to four haploid
cells, Spermatids
As spermatogenic cell proliferate, they fail to
complete cytoplasmic separation creating
CYTOPLASMIC BRIDGES (communication among
cells)
SPERMIOGENESIS
Final stage of spermatogenesis
Each spermatid becomes a single SPERM CELL
HORMONAL factors (spermatogenesis)
Testosterone
-Secreted by Leydig Cells (interstitium of testis)
-Essential for growth and division of the testicular
germinal cells (first stage in forming sperm)
Luteinizing hormone
-secreted by anterior pituitary gland
-stimulate Leydig cells to secrete testosterone
FSH
-secreted by anterior pituitary gland
Spermatogenesis is a process creates functional
sperm from an initially undifferentiated germ cell. -stimulate sertoli cells for the conversion of
spermatids to sperm
Primordial germ cells migrate into the testes and
Estrogen
become immature germ cell, SPERMATOGONIA
-formed from testosterone by sertoli cells

4. -essential for spermiogenesis i. Coloration of the skin
develops less consistently
Growth hormone than in the female
-metabolic functions of testes EXCITEMENT IN MALE:
o Penis becomes partially erect
-early division of spermatogonia (if absent, cause o Erection may be partially lost and regained
infertility) repeatedly during an extended excitement
phase
SPERM o Testicles: become drawn upward toward the
perineum
 300 million sperm complete the process of
o Scrotum: tense and thicken during the erection
spermatogenesis
process
 60 micrometers (to reach and penetrate
the secondary oocyte) B. Plateau Phase
o Period of sexual excitement prior to orgasm
 PARTS: o Increase in circulation and heart rate
1. Head : 4-5 micrometers PLATEAU PHASE IN MALE
*nucleus – 23 highly condensed acrosome o Male urethral sphincter contracts
o To prevent urine from mixing with semen
*acrosome – covers the ant. 2/3 of the o Guard against retrograde ejaculation (semen is
nucleus redirected to the urinary bladder)
- caplike vesicle filled with enzymes that o start to secrete seminal fluid or pre-ejaculatory
help a sperm to penetrate a second oocyte to bring fluid
about fertilization o Testicles rise closer to the body
2. Tail C. Orgasmic Phase
o Conclusion of the plateau phase
*neck – constricted region behind the head o Experienced by both males and females
(contains centrioles) o Accompanied by quick cycles of muscle
contraction in the lower pelvic muscles
*middle piece-contains mitochondria
o Heart rate is increased even further
(energy for locomotion of sperm to site of
fertilization and for sperm metabolism) ORGASMIC PHASE IN MALE
*principal piece- longest portion o Usually associated with ejaculation
o Each ejection – associated with a wave of
*end piece-terminal,tapering portion of the tail
sexual pleasure
o Produce the greatest quantity of semen
o Each contraction – associated with a
THE HUMAN RESPONSE diminishing volume of semen and a milder
wave of pleasure
A. Excitation Phase: (arousal phase)
o Occurs at the result of any erotic D. Resolution Phase
physical or mental stimulation (kissing, o Allows the muscles to relax, blood pressure to
foreplay, etc.) drop, and the body to slow down
o Preparation for sexual intercourse o Refractory Period: May or may not be
o ↑ Heart rate, breathing rate, and rise in experienced
blood pressure o Further stimulation may cause a return to the
o Myotonia: Increase in muscle tone plateau stage – allows the possibility of
(voluntarily and involuntarily) multiple orgasms
o Vasocongestion (“sex flush”)

5. ERECTION
SEMEN —Erection
o ejaculated at the same time of orgasm
o came from: sperm and seminal plasma —Erection – an increase in length and width of the
o rapid decline of volume and sperm count with penis achieved as a result of blood flow into the
repeated ejaculation erectile tissues
 average volume= 2.5 to 3.5 ml
 100 million sperms per ml of semen —Erectile Tissues
o sperm count under 20 million = sterile
o speed: 3mm per minute ◦Corpora Cavernosa (2)
SEMEN COMPOSITION: ◦Corpus Spongiosum
Seminal Vesicles (60%) –Urethra runs through it
fructose: main energy Achievedby parasympathetic nerve-induced
Phosphorylcholine vasodilation of arterioles that allows blood flow
Ergothioneine into the corpora cavernosa.
Ascorbic Acid
Flavins Nitric Oxide: neurotransmitter
Prostaglandin: stimulate muscle
Erectile tissues become engorged with blood
contractions in female
and veins are restricted thus comes erection
Prostate gland (20%)
—Controlled by two portions of the central
Spermine: counteracts the vaginal fluid
Citric acid nervous system
Cholesterol and Phospholipid ◦Hypothalamus
Zinc
Acid Phosphate ◦Sacral portion of spinal cord
Bulbourethral Gland —Conscious sexual thoughts originate in the
Alkaline Mucus based cerebral cortex via hypothalamus thus increasing
the parasympathetic nerve activity to promote the
Lubrication prior to ejaculation
erection. (Vasodilation)
“precum”: provide sexual activity with a
natural lubricant EMISSION AND EJACULATION
Buffers: Phosphate&Bicarbonate
—Emission- movement of semen into the urethra
SEMEN PATHWAY
—Ejaculation-forcible expulsion of semen from
urethra outside the penis
◦Stimulated by sympathetic nerves,
causing peristaltic contractions of the
Vas Ejacula tubular system, the seminal vesicles,
Epidyd Urethr
Testes Defere tory
imis
ns Duct
a prostate, and muscles at the base of the
penis
MALE FERTILITY

6. —Each ejaculation is 1.5 -5.0 ml.
—Bulk of Semen is fluid from seminal vesicles and
prostate
—For people who can’t control their own
hormones a suggestion of a Vasectomy is on order
—Vasectomy- to tie or block the vas deferens
which restrict sperm from entering urethra
—Sperm accumulates in crypts, phagocytosed and
destroyed by immune system.
—Condoms
—-only effective 97 % of the time
—-Aids in preventing STDs
Diseases
—Gonorrhea (Tulo)
-caused by bacterium
NeisseriaGonorrhoeae
-Sexually transmitted (Oral, vaginal, anal)
-symptoms are burning sensation and
penile discharge (hence Tulo)
—Herpes (Can be Oral or Genital)
-Viral infection caused by the Herpes
Simplex Virus