Trilaminar Germ Disk Embryo Formation and Gastrulation week 3 is a period of rapid development of the conceptus coinciding with the first missed menstrual period. By days 15-16, the embryo is 1.5 mm long, and one clearly sees the primitive streak, Hensen’s node, and the notochordal process- All morphologic indications characteristic of gastrulation. The latter […]
Explore MoreWeek 2 is about the implantation process and blastocyst differentiation. Note that all cells produced from the initial fertilization event are defined as the “conceptus” and will include cells with both embryonic and extraembryonic features. In the conceptus, this is a period of blastocyst “hatching” rapid blastocyst differentiation into extraembryonic and embryonic tissues and proliferation. […]
Explore MoreThe first week of human development begins with fertilization of the egg by sperm forming the first cell, the zygote. Cell division leads to a ball of cells, the morula. Further cell division and the formation of a cavity in the ball of cells forms the blastocyst. Initially, there is a halving of chromosomal content in the gametes […]
Explore MoreImplantation is the stage in embryonic development in which the blastocyst hatches as the embryo, and adheres to the wall of the uterus. Once this adhesion is successful, the female is considered to be pregnant and the embryo will receive oxygen and nutrients from the mother in order to grow. We can learn this lesson […]
Explore MoreFertilization is the union of male(sperm) and female(oocyte) gametes to form a zygote and marks the beginning of the pregnancy. Embryonic life begins with fertilization. Fertilization process require 24 hours. During this lesson we need to discuss about Ovulation Getting the spermatozoa ready Key steps of fertilization The formation of the zygote Abnormal Fertilization Ovulation […]
Explore MoreA cell cycle is a series of events that takes place in a cell as it grows and divides. A cell spends most of its time in what is called interphase, and during this time it grows, replicates its chromosomes, and prepares for cell division. The cell then leaves interphase, undergoes mitosis, and completes its […]
Explore MoreThe sequence of events that result in the contraction of an individual muscle fibre begins with a signal—the neurotransmitter, ACh—from the motor neuron innervating that fibre. The local membrane of the fibre will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, […]
Explore MoreThe ability of eukaryotic cells to adopt a variety of shapes, organize many compartments in the interior, interact mechanically with the environment and carry out coordinated movement depends on cytoskeleton. The cytoskeleton is a network of fibers forming the “infrastructure” of eukaryotic cells, prokaryotic cells, and archaeans. In eukaryotic cells, these fibers consist of a complex mesh of protein filaments […]
Explore MoreGametogenesis is the production of gametes from haploid precursor cells. In animals and higher plants, two morphologically distinct types of gametes are produced (male and female) via distinct differentiation programs. Animals produce a tissue that is dedicated to forming gametes, called the germ line. Now we are going to learn about the, The Germ Line Sexual […]
Explore MoreEmbryology is the branch of biology that studies the prenatal development of gametes, fertilization, and development of embryos and foetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology. Embryology can be mainly studied under two main divisions. They are EMBRYOGENESIS and ORGANOGENESIS. Embryogenesis is the process of initiation and […]
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