human reproduction. battle of the sexes!!! are males & females all that different?...
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Human Reproduction
Battle of the sexes!!!
Are males & females all that different?
Well…….…..YES and NO
Same embryonic tissues becomes male or female reproductive organs.
Male or Female???DNA determines baby’s gender
XX = FemaleXY = Male
All humans are female by defaultAt ~ 7 weeks the baby’s body may be “told” by DNA to become male
SRY gene located on the Y chromosome
Anatomy - similar
Testicles & Ovaries Glands responsible for the production of sex hormones and gametes
Start out inside body the Testicles “descend” before birth
Vas Deferens & OviductPassageway of gametes
Penis & ClitorisContain thousands of nerve ending to aid in sexual stimulation
Fetus begins with “starter parts” that could develop into either gender.
Same tissue – Same function
Physiology – VERY different!
MaleUncomplicatedProduce sperm
2-4 MILLION every day
FemaleVery Complicated!Born with ~ 400,000 eggs
Uses ~500
Ovulation1 egg “ripens” and is released once a month
Careful coordination of hormones & bodySupport life
Males
Produces male sex hormoneProduce 2-4 million sperm every day Outside body – why?Sperm like temps 1-2 cooler than body temp
Tube that carries sperm to the seminial vesicle and prostate
Temporary storage of spermDuring copulation, muscle contract to release sperm
Testes
Vas Deferens
Bladder
Epididymis
Prostate gland
Seminal vesicle
Urethra
Penis
Tube taking both urine and semen outside the bodyBulboureathral gland adds lubricant to aid travel of semen through the ureathra
Erected during copulation for insertion into vaginaDilation of arterioles causes the erectile tissue of penis become turgidSemen is squeezed from the penis to the top of vagina
Sperm
Semen contains300-500 million sperm – 5%Sperm food (fructose) – 30%Alkaline fluid (pH buffer) – 65%
Why so many sperm?
Why a pH buffer?
What is sperm?Then…
Used to think it was a tiny human inside each cellSpermists vs. Ovists
Now…Contains several partsHead
Contains chemicals to dissolve egg gooDad’s genetic information – one each of 44
autosomal chromosomes and 1 sex chromosomeMitochondria
EnergyContains mitochondrial DNA
from motherFlagellum
“tail” used for locomotion
Females
Vagina
Cervix
UterusOviduct
Ovary
For production of female gametes (ova/eggs)For production of female sex hormones
Carries the ovum forward by the beating action of the cilia on its inner surface and the contraction of muscles of oviduct
Allows for placenta to attachmentDuring embryo development it protects the embryo and provides a constant environment for the embryo to developDuring birth of baby it pushes the baby out by muscular contraction
Opening between the uterus and vagina
Birth canal
Menstrual Cycle
All about timing!!!Uterus must be ready when egg gets there in case it was fertilizedIf no fertilization, tear down lining of uterus and rebuild for next month
Estrogen Ovaries
Drop in levels causes shedding of uterine liningIncrease in levels causes uterine lining to thicken
Progesterone Corpus litheum (ruptured follicle)
Drop in levels causes shedding of uterine liningIncrease in levels causes uterine lining to thicken
LH (leuteinizing hormone) Pituitary gland & hypothalamus
Stimulates release of mature egg from ovary
FSH (follicle stimulating hormone) Pituitary gland
Acts on ovaries to mature the egg
HCG (Human Chorionic Gonadotropin) Corpus litheum (ruptured follicle)
Produced if fertilization occursStimulates continued secretion of progesterone
Hormones
Spermatogenesis
Oogenesis
Occurs in the testesProduces 4 hapoid
cellsProduces 4 viable
spermatozoaMotile – swim with
tailProduction begins at
pubertyProduction continues
for entire life
Occurs in the ovariesProduces 4 hapoid
cellsProduces 1 Ovum & 3
polar bodies Nonmotile – moved
by currentsAll eggs present at
birthEggs mature from puberty to
menopause
Birth ControlBirth Control Pills
Use hormones to “Trick” body into thinking it’s pregnant
No ovulation occursNo ovulation = no egg = no fertilization = no baby!No hormones taken for 7 days = menstruation
Barrier MethodMale and female condoms prevent sperm from entering the vaginaDiaphragm fitted over the cervix & along with use of spermacide to kill spermNo sperms= no fertilization= no baby!
Rhythm MethodPrevent copulation 7 days before and 7 days after ovulationUses basal temperature as guide
Surgical SterilizationCut and tie the vas deferens prevents sperm from leaving testesCut and tie the oviducts prevents egg from leaving ovary and sperm from finding egg
Birth Control
Sexual Reproduction in Humantestis
sperms
ovary
eggs (ova)
zygote
embryo
fetus
meiosis meiosis
fertilization