critical terminology for lab 2 listed in the lab 2 excercise pamphlet Flashcards
Zygote:
a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.
Cleavage:
cell division, especially of a fertilized egg cell.
Morula:
a solid ball of cells resulting from division of a fertilized ovum, and from which a blastula is formed.
Blastula
is a hollow sphere of cells, referred to as blastomeres, surrounding an inner fluid-filled cavity called the blastocoele formed during an early stage of embryonic development in animals.
Blastocoel:
the fluid-filled cavity of a blastula.
Blastomeres:
is a type of cell produced by cleavage (cell division) of the zygote after fertilization and is an essential part of blastula formation.
Blastoderm:
the layer of embryonic tissue that forms prior to the development of the embryonic axis.
the outer layer of cells that forms the wall of a blastula.
Holoblastic:
(of an ovum) having cleavage planes that divide the egg into separate blastomeres. It is a complete cleavage. Holoblastic eggs have less yolk than meroblastic
Meroblastic:
is incomplete or partial cleavage meaning it does not penetrate the egg completely. Has a high content of yolk.
Vegetal pole:
In developmental biology, an embryo is divided into two hemispheres: the animal pole and the vegetal pole within a blastula. he vegetal pole contains large yolky cells that divide very slowly, in contrast with the animal pole above it.
animal pole:
The animal pole consists of small cells that divide rapidly, in contrast with the vegetal pole below it. In some cases, the animal pole is thought to differentiate into the later embryo itself, forming the three primary germ layers and participating in gastrulation.
Gastrulation:
is a phase early in the embryonic development of most animals, during which the single-layered blastula is reorganized into a “three-layered” structure known as the gastrula. These three germ layers are known as the ectoderm, mesoderm, and endoderm.
Gastrula:
an embryo at the stage following the blastula, when it is a hollow cup-shaped structure having three layers of cells.
Blastopore:
the opening of the central cavity of an embryo in the early stage of development.
Protostomate:
Any of a major group of animals defined by its embryonic development, in which the first opening in the embryo becomes the mouth.
deuterostomate:
in deuterostomes, the first opening (the blastopore) becomes the anus, while in protostomes, it becomes the mouth.
ectoderm:
the outermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the epidermis and nerve tissue.
endoderm:
the innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures.
Mesoderm
the middle layer of an embryo in early development, between the endoderm and ectoderm. Gives rise to connective tissue, cartilage and bone.
Differentiation:
The normal process by which a less specialized cell develops or matures to become more distinct in form and function.
Neurulation:
refers to the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube. The embryo at this stage is termed the neurula.
Neurula:
an embryo in the stage of development in which part of the ectoderm is differentiated into neural tissue and in which the neural tube, which develops into the brain and spinal cord, is formed.
Neural Plate:
The neural plate is a key developmental structure that serves as the basis for the nervous system. Neurulation includes the transformation of the neural plate into the neural tube. The embryo at this stage woul dbe called a neurula. The neural plate is made up of ectoderm.
Neural groove:
The neural groove is a shallow median groove of the neural plate between the neural folds of an embryo.
Neural fold
the lateral longitudinal fold on each side of the neural plate that by folding over and fusing with the opposite fold gives rise to the neural tube
Neural Tube:
The neural tube is the embryonic structure that ultimately forms the brain and spinal cord. It is formed in a process called neurulation, in primary and secondary neurulation processes.
Neurocoel:
a cavity in the embryonic brain and spinal cord that develops into the ventricles and central canal respectively
Neural crest:
Neural crest cells are a temporary group of cells unique to vertebrates that arise from the embryonic ectoderm cell layer, and in turn give rise to a diverse cell lineage and are migratory. They give rise to peripheral nervous system, ectomesenchyme, visceral skeleton, cranial muscles, teeth and others.
Notochord:
a cartilaginous skeletal rod supporting the body in all embryonic and some adult chordate animals.
Coelom:
A coelom is a fluid-filled body cavity that is completely lined by tissue created from the mesoderm
Gastrocoel (archenteron)
The invagination of the blastomere produces the archentron which will become the digestive system. The opening into the archentron is the blastopore, which will become the anus. The cavity of the archentron is called the gastrocoel.
epidermis:
skin layer over the dermis derived from ectoderm
Epimere:
mesoderm becomes organized into three regions, epimere, mesomere and hypomere. Epimere The somites constitute most of the dorsal mesoderm and have three regions: dermatome, sclerotome and myotome.
Mesomere:
gives rise to the kidney tubules, excretory organs, and reproductive ducts.
Myocoel:
a cavity in the centre of an early myotome.
hypomere
lateral-plate mesoderm is confined to the trunk and is divided into somatic mesoderm (parietal peritoneum) and splanchnic mesoderm (visceral peritoneum, mesenteries, heart and associated structures, lymphatic system, gonads and visceral muscles)
stomodeum:
The embryonic invagination of surface ectoderm that contributes to the mouth.
Proctodeum:
the embryonic invagination of surface ectoderm that contributes to the hindgut, usually giving rise to the cloaca.
forebrain:
the anterior part of the brain, including the cerebral hemispheres, the thalamus, and the hypothalamus.
midbrain:
a small central part of the brainstem, developing from the middle of the primitive or embryonic brain. Important for motor movements and auditory and visual.
Hindbrain
the lower part of the brainstem, comprising the cerebellum, pons, and medulla oblongata.
spinal cord:
the cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system.
somite:
each of a number of body segments containing the same internal structures,
nephrotome:
segmental forerunner of the nephron in the urinary structure of the early embryo.
foregut:
anterior embryonic gut that gives rise to the pharynx, esophagus, stomach, and anterior intestine.
midgut
the middle part of the alimentary canal, including (in vertebrates) the small intestine.
hindgut
Posterior embryonic gut that gives rise nto the posterior intestines.
Ectodermal Placodes
Ectodermal placodes are focal thickenings of the cranial ectoderm that generate many different components of the sensory systems of the head.
