Topic 2C Flashcards
Ectoderm
outermost layer; gives rise to the epidermis & organs that make up the nervous system (brain, nerves, spinal cord)
Mesoderm
middle layer; develops into the circulatory system (blood cells, vessels, heart); various connective tissues (bone, muscle, tendons, dermal layer) of animal body & kidney.
Endoderm
forms the epithelial lining of the whole of the digestive tube (except part of the mouth and pharynx) and the end part of the rectum; also forms the lining cells of all the glands that open into the digestive tube; also forms internal organs like the stomach, colon, liver, pancreas, urinary bladder, epithelial parts of the trachea, the lungs, pharynx, thyroid, parathyroid, and intestines.
neural crest
a 2-strip tissue that runs lengthwise above the neural tube; develops into the peripheral nervous system.
Neural plate
thin strip of cells that are the 1st sign of the nervous system
Neural tube →
central nervous system
Neurulation
sequence of stages from neural plate → neural tube → neural crest
Morphogens
molecules that can cause nearby cells to follow a particular developmental pathway by expressing pathway-specific genes. The cell only becomes committed to a specific lineage s/p determination
Determination
commitment to a specific cellular lineage
Paracrine
acts on cells in the local area
Endocrine
involves secreted hormones that travel through the bloodstream to a distant target tissue
Autocrine
acts on the same cell that secreted the signal in the 1st place
Juxtacrine
acts through direct stimulation of the adjacent cells
Direct signaling
occurs by transferring signaling molecules across gap junctions b/t neighboring cells
Induction
one group of cells changing the behavior of an adjacent group of cells
Cell migration
central process in the development & maintenance of multicellular organisms
Pluripotent stem cells
the embryonic cells that develop from totipotent stem cells are precursors to the fundamental tissue layers of the embryo. It has the potential to differentiate into any human tissue but cannot support the full development of an organism; doesn’t do cells in the placental structures; the 3 germ layers
Totipotent stem cells
the 1st embryonic cells that arise from the division of the zygote. They have the potential to differentiate into any of the cells needed to enable an organism to grow and develop.
Multipotent stem cells
pluripotent cells that become slightly more specialized. It has the potential to differentiate into different types of cells within a given cell lineage or a small number of lineages, such as a red blood cell or white blood cell.
Acetylation of histone proteins
DECREASES positive charge on lysine residues and weakens interaction of DNA with histone
• Results in open DNA = easier transcription
Methylation of genes
often results in SILENCING of gene expression
Senescence
process by which cells stop proliferating in response to environmental stressors and are cleared away by immune cells (allows for shaping of tissues) à Loss of cell’s power of division and growth (as you age ya know)
