Ch5: Hyperplasias and Neoplasms Flashcards
fertilized ovum
all the cells of the body derived from one cell
through embryonic development, starting with stem cells, successive cell division continues to more and more specialized (differentiated) cells. main function is to divide and produce daughter cells- they pass thru several intermediate stages of differentiation until mature.
differentiation
maturation from a nonspecific cell type to a specialized cell
*the more differentiated a cell type becomes, the more its capacity to proliferate decreases
pluripotent
can differentiate into many different types of adult cells
labile cells
skin, GI tract, bone
continuously dividing and can regenerate
thus most abnormal growths occur in tissues
hyperplasia
undergo excessive growth
neoplasia
new growth
stable cells
liver, kidney
normally divide only in response to injury
permanent cells
cardiac muscle, neurons
do not normally undergo division once they mature
germ cells
normally confined to gonads
somatic cells
4 major categories:
1: epithelial cells
2: CT cells
3: muscle cells
4: nervous tissue cells
epithelial cells
form the skin, lining of spaces, and various glands.
*usually labile cells-continuously replacing
Surface lining cells:
1: stratified squamous
2: transitional
3: columnar
stratified squamous epithelium
forms a tough protective barrier
Keratinized: comprises the outer layer of skin
Nonkeratinized: lines the mouth, pharynx, larynx, esophagus and anus
transitional epithelium
also multilayered but lacks surface layer of keratin and intercellular bridges.
confined to urinary tract, renal pelvis, ureter, bladder and urethra
columnar epithelium
usually composed of 1 layer of tall cells-often mucus secreting
forms mucous membranes lining the nose, trachea, bronchi, stomach, small intestine, colon and many ducts leading from glands
CT cells
*labile cells
mostly derived from mesoderm
recognized by lack of closeness with other cells and by the substances they produce
*can be stimulated to divide more rapidly-stable cells
1: fibroblasts: collagen
2: chondrocytes: cartilage
3: osteocytes: bone
4: endothelial cells: blood vessels
muscle cells
derived from mesoderm close approximation together elongated fiber like structure abundant contractile cytoplasm heart muscles can't be replaced, skeletal have very little capacity but smooth muscle cells, esp small blood vessels can reproduce
nervous tissue cells
derived from ectoderm
includes neurons and supporting cells
neurons- long processes (axons) carry electrical impulses
neurons limited capacity for replacement but supporting cells can
glial cells
supporting nervous tissue cells in the brain and spinal cord
schwann cells
supporting nervous tissue cells in peripheral nerves
hyperplasia and hypertrophy
exaggerated responses to a growth stimulus
increase in volume in the tissue
increased cell proliferating resulting in increased tissue mass
labile cells respond by increasing in number (hyperplasia)
stable cells increase in size (hypertrophy)
physiologic hypertrophy
occurs in response to physiologic demands
pregnancy, growing muscle, puberty
pathologic hypertrophy
increase in size of tissue bc of abnormal condition
thyroid, HTN
neoplasia
new growth
proliferation of cells that are independent of normal growth control mechanisms
autonomous growth- cells grow in the absence of a growth promoting stimulus
metaplasia
replacement of one tissue type by another
most commonly change from columnar epithelium to stratified squamous
