Chapter 3: Tissues and Skin Flashcards
what is a tissue
layers or groups of similar cells
what are the four main types of tissue
epithelial tissue, connective tissue, muscle tissue, and nervous tissue
what is a tight junction
a tight junction is like seams on clothing. no spaces, the cell membranes are fused
what is a desmosome
acts like a buttoned shirt, allowing small holes for solutes to pass. it is found on the epidermis
what is the purpose of a gap junction
allows for cytoplasmic exchange, allowing contents of one cell to go t another
what is the purpose of a hemidesmosome
it anchors the cell to something extracellular (protein fibers, etc)
where is epithelial tissue found
it is always found on the surface
which tissues are dependent on diffusion
epithelial tissues because they lack blood vessels
what are characteristics only epithelial tissues have
tightly packed single (simple) or multiple (stratified) layer(s) of cells, cells are squamous(like a laptop), cuboidal, or columnar. they cover organs, line body cavities, form protective barriers, attach to the basement membrane, reproduce rapidly, and lack blood vessels
which tissues may never touch?
connective tissue
what is a collagenous (collagen) fibers?
bundles of thick, flexible fibers. collagen is found in bundles and tears if there is too much resistance
what is elastic fibers
are stretchy fibers, but go back to normal after being stretched
what are characteristics of a muscle tissue
not all require neural input, capable of contraction (gets shorter not longer), many proteins filaments in the cytoplasm, muscle cells = muscle fibers
is a fiber and filament the same thing
no, a whole muscle is a fiber, and within the cell are filaments
what are the differences between the proteins in connective tissue and the proteins in muscle tissue?
in connective tissue the proteins are outside the cell membrane in the matrix, and in the muscle tissue the proteins are inside the cell
what is exteroception
the ability to feel things at the surface
why is vitamin d production important
vitamin D absorbs calcium