Advanced Human Embryology, Development &
Genetics Master Review: Fertilization,
Capacitation, Amphimixis, Cleavage, Blastocyst &
Implantation, Gastrulation & Germ Layer
Differentiation (Ectoderm, Mesoderm, Endoderm),
Placentation & Extraembryonic Membranes,
Trimester Development, Organogenesis, Endocrine
Placenta (hCG, hPL, Progesterone), Parturition &
Labor Stages, Multiple Births, Postnatal Growth &
Puberty, Senescence & Geriatrics, Mendelian &
Polygenic Inheritance, Genetic Recombination,
Mutation, Sex-Linked Traits, Chromosomal
Abnormalities, and Human Genome Principles
Exam Questions Verifed and Provided with A+
Graded Rationales Latest Updated 2026
Development
Gradual modification of anatomical structures & physiological characteristics from fertilization
to maturity
Inheritance
Transfer of genetic material from generation to generation
Differentiation
- Creation of different types of cells required in development
- Occurs through selective changes in genetic activity
--> As development proceeds, some genes are turned off, others are turned on
- Involves changes in genetic activity of some cells but not others
Fertilization (Conception)
When development begins
,Embryonic Development
- Occurs during first two months after fertilization
- Embryology: the study of these events
Fetal Development
- Begins at start of 9th week
- Continues until birth
Prenatal Development
Embryonic & fetal development stages
Postnatal Development
- Commences at birth
- Continues to maturity (the state of full development or completed growth
Genetics
The study of mechanisms responsible for inheritance
Fertilization
- Fusion of two haploid gametes each containing 23 chromosomes
- Produces zygote containing 46 chromosomes
- Occurs in uterine tube within a day after ovulation
--> Secondary oocyte travels a few centimeters
--> Spermatozoa must cover distance between vagina & ampulla
Spermatozoon
- Delivers paternal chromosomes to fertilization site
- Travels relatively large distance
- Small, efficient, & highly streamlined
Gamete
, Provides:
- Cellular organelles
- Inclusions
- Nourishment
- Genetic programming necessary to support development of embryo for a week
Capacitation
Changes of spermatozoa while in female
- Must occur before spermatozoa can fertilize secondary oocyte
--> Contract with secretions can fertilize secondary oocyte
--> Exposure to conditions in female reproductive tract
Hyaluronidase
- Enzyme breaks down bonds between adjacent follicle cells
- Allows spermatozoa to reach oocyte
Acrosin
- A proteolytic enzyme
- Required to reach oocyte
Acrosomes
- Release hyaluronidase & across
- Penetrate corona radiata, zona pellucida, toward oocyte surface
Oocyte Activation
- Contact and fusion of cell membranes of sperm and oocyte
- Follows fertilization
- Oocyte completes meiosis II, becomes mature ovum
Polyspermy
Genetics Master Review: Fertilization,
Capacitation, Amphimixis, Cleavage, Blastocyst &
Implantation, Gastrulation & Germ Layer
Differentiation (Ectoderm, Mesoderm, Endoderm),
Placentation & Extraembryonic Membranes,
Trimester Development, Organogenesis, Endocrine
Placenta (hCG, hPL, Progesterone), Parturition &
Labor Stages, Multiple Births, Postnatal Growth &
Puberty, Senescence & Geriatrics, Mendelian &
Polygenic Inheritance, Genetic Recombination,
Mutation, Sex-Linked Traits, Chromosomal
Abnormalities, and Human Genome Principles
Exam Questions Verifed and Provided with A+
Graded Rationales Latest Updated 2026
Development
Gradual modification of anatomical structures & physiological characteristics from fertilization
to maturity
Inheritance
Transfer of genetic material from generation to generation
Differentiation
- Creation of different types of cells required in development
- Occurs through selective changes in genetic activity
--> As development proceeds, some genes are turned off, others are turned on
- Involves changes in genetic activity of some cells but not others
Fertilization (Conception)
When development begins
,Embryonic Development
- Occurs during first two months after fertilization
- Embryology: the study of these events
Fetal Development
- Begins at start of 9th week
- Continues until birth
Prenatal Development
Embryonic & fetal development stages
Postnatal Development
- Commences at birth
- Continues to maturity (the state of full development or completed growth
Genetics
The study of mechanisms responsible for inheritance
Fertilization
- Fusion of two haploid gametes each containing 23 chromosomes
- Produces zygote containing 46 chromosomes
- Occurs in uterine tube within a day after ovulation
--> Secondary oocyte travels a few centimeters
--> Spermatozoa must cover distance between vagina & ampulla
Spermatozoon
- Delivers paternal chromosomes to fertilization site
- Travels relatively large distance
- Small, efficient, & highly streamlined
Gamete
, Provides:
- Cellular organelles
- Inclusions
- Nourishment
- Genetic programming necessary to support development of embryo for a week
Capacitation
Changes of spermatozoa while in female
- Must occur before spermatozoa can fertilize secondary oocyte
--> Contract with secretions can fertilize secondary oocyte
--> Exposure to conditions in female reproductive tract
Hyaluronidase
- Enzyme breaks down bonds between adjacent follicle cells
- Allows spermatozoa to reach oocyte
Acrosin
- A proteolytic enzyme
- Required to reach oocyte
Acrosomes
- Release hyaluronidase & across
- Penetrate corona radiata, zona pellucida, toward oocyte surface
Oocyte Activation
- Contact and fusion of cell membranes of sperm and oocyte
- Follows fertilization
- Oocyte completes meiosis II, becomes mature ovum
Polyspermy
