Download CHAPTER 36: ANIMAL REPRODUCTION Diploid

CHAPTER 36: ANIMAL REPRODUCTION
Diploid 46 Haploid 23
Gametos o gonads: 23+23= 46
Gonads: organ where reproductive cells are formed (in males: testes) (in females: ovaries)
Hormones:
 GnRH: gonadotropin releasing hormone- hypothalamus: puberty. Stimulates to LH (stimulates anterior
pituitary to produce LH and FSH)
 LH: leuteinizing hormone: stimulates interstitial cells to produce testosterone
 FSH: follicle stimulating hormone: stimulates Sertoli cells and spermatogonia to begin spermatogenesis.
Secondary sexual characteristics that develop during puberty:
Hypothalamus: GnRH: stimulates pituitary: LH y FSH: production of gametes (sperm or egg): production of
hormones (testosterone and estrogen)
MEN
WOMEN
Penis and testes enlarge
Pubic, underarm and facial hair appears
Larynx enlarges (deepening voice)
Muscular development increases
Enlarged breasts
Pubic and underarm hair
Begin menstruating
COPULATION
Blood pressure increases: erection
Blood flow to vagina, labia and clitoris
Movements stimulate touch receptors on the penis,
Female orgasm (possible) stimulation of penis.
triggering ejaculation
Contraction of vagina
Male orgasm: causes ejaculation and feelings of pleasure Increase cardiac frequency
CREATION OF SEXUAL CELLS
Spermatogenesis: spermatogonia: meiosis: primary
Oogenesis: oogonia: primary oocyte stops at prophase I
spermatocyte: secondary spermatocyte: 4 spermatids
(3rd moth of fetus): meiosis (puberty): secondary oocyte
and 3 polar body
The human male reproductive tract
Testis (male
gonad):
produces sperm
and testosterone
• Seminiferous
tubules (inside):
produce sperm
• Interstitial cells:
produce
testosterone
• Spermatogonia:
diploid cell from
which sperm
arise:
• Sertoli cells:
regulate
spermatogenesis
and nourish
developing sperm
Epididymis
and vas
deferens
(ducts):
• store
sperm;
conduct
sperm
from testes
to penis
Urethra
(duct):
• conducts
semen
from vas
deferens
and urine
from
urinary
bladder to
the tip of
the penis
Penis:
•deposits
sperm in
female
reproducti
ve tract
Seminal
vesicles
(glands)
•secrete
fluid into
semen
Prostate
gland:
Bulboureth
ral glands:
• secretes
fluids into
semen
•secrete
fluid into
semen
Accessory Structures
 Scrotum: sac that contains the testes: maintains temperature of spermatozoids
Spermatogenesis: process by which sperm cells form spermatogonium experience a series of developmental
events that leads to the production of haploid sperm
 Spermatozoa: mature sperm
o Head: haploid nucleus
 Acrosome: contains enzymes that dissolve protective
layers around the egg enabling its entrance
o Midpiece: mitochondria/energy
o Tail: flagellum: movement

Sperm production regulated by negative feedback: sertoli cells secrete hormone: inhibin: inhibits GnRH,
LH and FSH production
 Semen: sperm mixed with fluid secretions from seminal vesicle, prostate gland, bulbourethral glands:
o FUNCTIONS:
 Transport spermatozoids
 provides energy that powers swimming
 neutralizes vagina´s pH
 Ejaculation: muscles encircling the epididymis, vas deferens and urethra contract forcing semen out of
the penis and into vagina
 Developmental options: mitosis-spermatogenesis
The female reproductive tract
Ovary
(gonad):
•produces eggs,
estrogen and
progesterone
Fibria
Uterine tube:
Uterus:
Cervix:
Vagina:
•(opening of
uterine tube):
bears cilia that
sweep egg into
oviduct
•conducts egg
to uterus; site
of fertilization
•muscular
chamber
where fetus
develops
•closes off
lower end of
uterus. Ring of
connective
tissue that
holds
developing
baby in uterus
•receptacle for
semen; birth
canal
Semen: pH básico
Vagina: pH ácido
 Polar body: discarded set of chromosomes
 Zygote: fertilized egg
 Clitoris: derived from the same embryological tissue as the tip of the penis, becomes engorged with
blood (in front of the vagina)
 Corpus luteum: formed by follicle cells that enlarge and become glandular. It secretes estrogen and
progesterone. No fertilization = breaks down
 Endometrium: inner lining of the uterus that is richly supplied with blood vessels
 Placenta: transfers oxygen, carbon dioxide, nutrients and wastes between fetus and mother
 Menstruation: flow of tissue and blood that results from the breakdown of endometrial blood vessels
FERTILIZATION



sperm and egg nuclei unite (haploid nuclei of sperm and egg fuse:
diploid nucleus)
Corona radiate (follicle cells) and zona pellucida (inner jellylike layer)
form a barrier between the sperm and the egg
Sperm enters, triggers 2 changes:
o Release chemicals into the zona pellucida reinforcing it and
preventing further sperm from entering
o Egg undergoes its second meiotic division
Contraceptives
Prevent ovulation: suppress LH,
continuous supply of estrogen and
progesterone.
•Birth control pill: synthetic hormones.
Daily
•Contraceptive patch: synthetic
hormones. weekly
•Injections: synthetic hormones 3
months
•Nuva Ring: around cervix. Impregnated
estrogen and progesterone. 1 month
Barrier methods (preventing sperm and
egg from meeting)
•Abstinence: 100% efectivo
•Condom (male and female)
•Today sponge: impregnated with
spermicide (in vagina)
•Diaphragm/ cervical cap: cérvix.
reusable
•Rhytm: measure body temperature.
Estimate time of ovulation.
•Spermicide: kill spermatozoids
Gongorrhea
Syphilis
Chlamydia
Bacteria
Neisseria
gonorrcheae
Bacteria:
Treponema
pallidum
Bacteria
Clamydia
trachomatis
HIV virus
Males:
inflammation
of the
urethra,
discharge of
pus from the
penis
Begins with
sore at the
site of
infection
Inflammation
of the
urethra (m),
urethra and
cervix (f)
Acquired
immune
deficiency
syndrome
Can lead to
infertility
blocking
uterine
tubes.
Spread
damaging
organs (skin,
kidneys,
heart, brain)
Infect and
block uterine
tubes:
sterility
Genital
herpes
AIDS
Herpes 1 and
Herpes 2
(virus)
Genital
warts
Human
papilloma
virus
Prevent Implatation
•IUD (intrauterine device): plastic device
with hormones or copper in uterus
through cervix
•Morning after pill: 2; abortiva
•Sterilization (permanent): interrupt
paths
•Vasectomy: vas deferens
•Tubal ligation: uterine tube
Trichomoni
asis
Trichomonas
vaginalis
(protist)
Crab lice
Parasite
(arachnid):
Pthirus pubic
Human
papilloma
virus
Human
papilloma
virus
Genital warts
Painful
blisters on
the genitals
and
surrounding
skin
Attacks the
immune
system, leaving
the victim
vulnerable to
infections (can
be fatal)
Growths or
bumps that
appear on
the external
genitalia,
Warts are
risk factor for
cervical
cancer
(women)
Discharge
caused by
inflammation
in response
to the
parasite
Severe
itching,
Irritating,
spread
infectious
diseases
Sometimes
warts in the
throat
Cervical cancer
(and cancer of
the vulva,
vagina, penis,
anus,
oropharynx)
Copulation: behavior by which the male deposits sperm directly into the reproductive tract of the female
Menstrual Cycle
Day 1
• Increase of GnRH: release of LH and FSH
Day 28
Day 5
• No more estrogen and progesterone =
endometrium dies
• FSH develops follicles: secrete estrogen.
Day 24
Day 7
• No fertilization: corpus luteum dissolves.
• MORE ESTROGEN =
• Development of follicle and oocyte
• Growth of endometrium
• More GnRH
Day 21
Day 14
• Corpus luteum: estrogen and
progesterone: inhibit GnRH: less FSH and
LH
• Endometrium keeps developing
• Ovulation
• Remnants of follicle = corpus luteum
• LH:
• Resumption of meiosis I: formation of
secondary oocyte and first polar body