BIO 181 - Human Anatomy and Physiology II: Reproductive System & Development
Chapter 27: The Reproductive System
Functions of the Male and Female Reproductive Systems
Male Reproductive System: Produces and delivers sperm.
Female Reproductive System: Produces ova (eggs), provides a site for fertilization, and supports the developing fetus.
Spermatogenesis and Oogenesis
Spermatogenesis: The process by which sperm cells are produced in the male.
Stages of Development:
Spermatogonia (diploid, 2N) - germ cells that divide by mitosis.
Primary Spermatocytes - undergo meiosis I to form two secondary spermatocytes (haploid, 1N).
Secondary Spermatocytes - undergo meiosis II to produce four spermatids (haploid, 1N).
Spermatids - differentiate into mature sperm via spermiogenesis.
Timing: Continuous process in males after puberty.
Chromosome Numbers: Beginning with diploid 2N spermatogonia and ending with haploid 1N spermatids.
Oogenesis: The production of ova (eggs) in the female.
Stages of Development:
Oogonia (diploid, 2N) - proliferate by mitosis; enter meiosis.
Primary Oocytes - arrested in prophase I until puberty.
Secondary Oocyte - completes meiosis I during the menstrual cycle and is ovulated.
Ovum (haploid, 1N) - completes meiosis II only upon fertilization.
Timing: Begins before birth, resumes at puberty, and ends at menopause.
Chromosome Numbers: Begins with diploid 2N oogonia and progresses to haploid 1N ovum.
Definitions and Examples
Gonads: Organs that produce gametes.
Example: Testes (male), Ovaries (female).
Gametes: Reproductive cells (sperm for males, eggs for females).
Zygote: The fertilized egg that results from the fusion of sperm and egg, restoring the diploid state (2N).
Gametogenesis and Fertilization
Gametogenesis: The overall process of forming gametes.
Fertilization: The integration of sperm and egg, leading to zygote formation.
Structures of the Male Reproductive System
Components and functions to be identified: Testes, Epididymis, Vas deferens, Seminal vesicles, Prostate gland, Bulbourethral glands, Penis.
Pathway of Sperm upon Ejaculation
Sperm is produced in the testis.
Moves to the epididymis for maturation.
Travels through the vas deferens.
Mixes with seminal fluid in the seminal vesicles and prostate gland.
Passes through the urethra during ejaculation.
Semen Production
Components of Semen:
Seminal fluid (produced by seminal vesicles).
Prostatic fluid (produced by prostate gland).
Bulbourethral fluid (produced by bulbourethral glands).
Functions: Provides nourishment for sperm, creates an optimal environment for sperm survival.
Amount of Semen: Typically around 3-5 mL per ejaculation.
Hormonal Control of Male Reproductive System
GnRH (Gonadotropin-Releasing Hormone): Released from the hypothalamus; stimulates the pituitary gland.
FSH (Follicle-Stimulating Hormone): Stimulates spermatogenesis in the Sertoli cells of the testes.
LH (Luteinizing Hormone): Stimulates Leydig cells to produce testosterone.
Testosterone: Key androgen responsible for secondary male characteristics and spermatogenesis.
Inhibin: Produced by Sertoli cells; inhibits FSH secretion to regulate sperm production.
Female Reproductive System Structures
Key structures to be identified: Ovaries, Fallopian tubes, Uterus, Cervix, Vagina.
Detailed descriptions of functions of structures.
Ovarian Follicle and Related Structures
Ovarian Follicle: Structure housing the developing oocyte.
Graafian Follicle: Mature follicle ready to release an egg.
Antrum: Fluid-filled cavity within the mature follicle.
Corona Radiata: Layer of cells surrounding the oocyte.
Zona Pellucida: Glycoprotein layer surrounding the egg, crucial for sperm binding.
Corpus Luteum: Structure formed from the follicle post-ovulation; produces progesterone.
Corpus Albicans: Degenerated corpus luteum if fertilization does not occur.
Ovarian and Uterine Cycles
Ovarian Cycle Stages:
Follicular Phase: Growth of follicles, influenced by FSH.
Luteal Phase: Corpus luteum formation and progesterone secretion following ovulation.
Uterine Cycle Phases:
Menstrual Phase: Shedding of the endometrial lining.
Proliferative Phase: Rebuilding of the endometrium influenced by estrogen.
Secretory Phase: Further thickening of the endometrium due to progesterone from the corpus luteum.
Events in Ovarian and Uterine Cycles
Follicular vs. Luteal Phases:
Follicular Phase involves oocyte maturation; Luteal Phase involves corpus luteum activity.
Proliferative vs. Secretory Phases:
Proliferative Phase is the rebuilding of endometrium; Secretory Phase is preparation for potential implantation.
Chapter 28: Pregnancy and Human Development
Stages of the Human Sexual Response
Identify and describe the 4 stages: excitement, plateau, orgasm, resolution.
Key Terms and Definitions
Conceptus: The product of conception at various stages of development.
Pregnancy: The period of development from fertilization until birth.
Gestation Period: Duration of pregnancy, typically around 40 weeks in humans.
Capacitation, Fertilization, and Implantation
Capacitation: Process sperm undergo to gain the ability to fertilize the egg.
Fertilization: Union of sperm and egg; typically occurs in the fallopian tubes.
Implantation: Attachment of the blastocyst to the uterine lining.
Stages of Embryonic Development
Zygote: Fertilized egg.
2/4/8/16 Cell Stages: Successive divisions of the zygote as it undergoes cleavage.
Morula: Solid ball of cells (around 16 cells).
Blastula/Blastocyst: Hollow structure formed from morula; contains inner cell mass.
Gastrula: Stage where germ layers form (ectoderm, mesoderm, endoderm).
Relationship Between Key Structures
Placenta: Organ that develops for nutrient and gas exchange between mother and fetus.
Umbilical Cord: Connects fetus to the placenta.
Chorionic Villi: Projections from the placenta that provide surface area for exchange.
Amnion, Chorion, Allantois, Yolk Sac: Extra-embryonic membranes involved in protection, nourishment, and waste removal.
Functions of the Placenta
Facilitates the exchange of materials (oxygen, nutrients, waste) between maternal and fetal blood but maintains separate circulatory systems.
Hormonal Functions and Associated Glands
Prolactin: Stimulates milk production in the mammary glands.
Oxytocin: Stimulates contractions during labor and milk ejection during breastfeeding.
hCG: Maintains corpus luteum in early pregnancy and is the basis for pregnancy tests.
Primary Germ Layers and Their Organs
Ectoderm: Develops into skin, nervous system.
Mesoderm: Forms muscles, bones, and circulatory system.
Endoderm: Becomes internal organs like the gastrointestinal tract.
Embryo vs. Fetus
An embryo is the developing human from fertilization to 8 weeks; a fetus is from 8 weeks to birth.
Induction of Labor
Hormonal changes leading to labor onset, including increased levels of oxytocin.
Stages of Labor
First Stage: Dilation of the cervix.
Second Stage: Delivery of the baby.
Third Stage: Delivery of the placenta.
Positive Feedback Mechanism of Milk Production/Lactation
Oxytocin release leads to milk ejection; mechanical stimulation of the nipple during breastfeeding enhances prolactin for milk production.