Páginas: 9 (2017 palabras) Publicado: 16 de agosto de 2010
Human Reproduction and Development
Human godans
* Primary sexual organs where genes are packaged into gametes
* Male - testes
* Female - ovaries
* Secrete sex hormones
* Regulate secondary sexual traits
Male reproductive system
Sperm cells are able to undergo meiosis (difference from other body cells); they mature in the epididymis. The penis is made up ofSPONGY tissue.

Semen = Sperm + Secretions
* Secretions from epididymis aid sperm maturation
* Seminal vesicle secretes fructose and prostaglandins
* Prostate-gland secretions buffer pH in the acidic vagina
* Bulbourethral gland secretes mucus
* Spermatogonium (2n) divides by mitosis to form primary spermatocyte (2n)
* Meiosis produces haploid spermatids* Spermatids mature to become sperm

Other Testicular Cells
* Sertoli cells
* Line the seminiferous tubules
* Nourish the developing sperm
* Leydig cells
* Lie between the seminiferous tubules
* Secrete testosterone

Male Hormonal Control
Sertoli Cells
Leydig Cells
Anterior Pituitary


Anterior Pituitary

FSHSertoli Cells
Leydig Cells

Formation and Development of Sperm

Female Reproductive Organs

* Ovary: Oocyte production and maturation, sex hormone production
* Oviduct: Ducts for conducting oocyte from ovary to uterus, fertilization normally occurs here
* Uterus: Chamber in which new individual develops
* Cervix: Secretion of mucus thatenhances sperm movement into uterus and (after fertilization) reduces embryo's risk of bacterial infection
* Vagina: Organ of sexual intercourse; birth canal
* Clitoris: Small organ responsive to sexual stimulation
* Labium Minor: One pair of inner skin folds of external genitals
* Labium Major: One of a pair of outermost fat-padded skin folds of external genitals
* Myometrium: Thickmuscle layers of uterus that stretch enormously during pregnancy
* Endometrium: Inner lining of uterus; site of implantation of blastocyst
Menstrual Cycle
* The fertile period for a human female occurs on a cyclic basis
* Menstrual cycle lasts about 28 days
* Follicular phase and luteal phase
Oocytes Arrested in Meiosis I
* Girl is born with primary oocytes already inovaries
* Each oocyte has entered meiosis I and stopped
* Meiosis resumes, one oocyte at a time, with the first menstrual cycle
Menarche to Menopause
* First menstruation, or menarche, usually occurs between ages 10-16
* Menstrual cycles continue until menopause, in a woman’s late 40s or early 50s
Ovarian Cycle
* Follicle grows and matures
* Ovulation occurs
* Corpusluteum forms
Female Hormonal Control


Anterior pituitary



follicle growth,
oocyte maturation

Rising estrogen stimulates surge in LH

Corpus luteum

Cycle Overview
* GnRH secretion affects LH and FSH secretion by pituitary
* LH and FSH affect follicle maturation
* Estrogen and progesteronefrom ovary affect uterus
* Sperm penetrates to egg cytoplasm
* Secondary oocyte undergoes meiosis II; forms mature egg
* Egg nucleus and sperm nucleus fuse to form diploid zygote
* A new individual is created
* Averages 38 weeks from fertilization
* Takes 2 weeks for blastocyst to form
* Weeks 3 to 8 - embryonic period
* Weeks 9 to birth- fetal period
Early Divisions
* Cleavage begins within 24 hours of fertilization
Day #1 Day #2 Day #3 Day#4 (morula)

Day 5 - Blastocyst Forms
* Cell secretions produce a fluid-filled cavity in center of ball of cells
* Layers of blastocyst
* Inner cell mass
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