Tissue (W3 CH5.1) Flashcards
Definition of Tissue
a group of similar cells and cell products that arise from the same region of the embryo and work together to preform a specific structural or physiological role in an organ
four primary tissues
epithelial
connective
nervous
muscular
What is a matrix composed of?
fibrous proteins and a clear gel known as ground substance, tissue fluid, extracellular fluid, interstitial fluid, or tissue gel.
primary germ layers
ectoderm, mesoderm, and endoderm; three layers of an early embryo from which all later tissues and organs arise
ectoderm
outer layer that gives rise to epidermis and nervous system
endoderm
- innermost layer of primary germ layer
- gives rise to mucous membrane of digestive and respiratory tracts and to digestive glands
mesoderm
- between endoderm and ectoderm
- loosely organized cells
- turns into gelatinous tissues called mesenchyme
mesenchyme
- formed from mesoderm
- composed of wispy collagen
- gives rise to cardiac muscle, bone, and blood
histological sections
issues preparations mounted on microscope slides
tissue specimen are preserved in a
fixative (a chemical such as formalin that prevents decay)
sectioning a tissue consists of
reducing a 3-d structure to a series of 2-D slices into various levels or planes of section
tissue cut on long axis is
longitudinal section (I.s.)
a cut perpendicular to the long axis of the body or an organ
Cross section
oblique section
a section cut on a slant between a longitudinal and cross section
how are liquid tissues such as blood and soft tissues such as spinal cord shown
they are prepared as smears (tissue is rubbed or spread across the slide rather than sliced)
