Introduction Flashcards
What are cells?
functional units of living organisms
differentiate to perform special functions
What are tissues?
cells with similar morphology and/or function
What are organs?
anatomically discreet collections of tissues that perform certain functions (liver,kidney)
What is parenchyma?
cells that make up the functional elements of an organ
What is stroma?
structural framework of an organ, background tissue
Tissues and organs are organized into
larger systems - may be discreet entities (CNS) or diffuse aggregates (immune system)
What are the five basic tissue types?
blood, connective tissue, epithelium, muscle, and nervous tissue
What is blood?
fluid tissue, contained within vessels of circulatory system
What is connective tissue?
surrounds and supports other tissue
What is epithelium?
covers body surfaces, lines cavities, and forms glands
What is muscle?
contains specialized contractile cells responsible for movement
What is nervous tissue?
contains modified cells responsible for intercellular communication
Tissue preparation
unfixed tissues autolyze/denature
prevent this with fixation in formalin (preserve tissue)
place tissue in cassette
embed in liquid parafin or plastic resin
microtome/grind
mount on slide
remove paraffin
rehdyrate with alcohol and xylene
place coverslip over
What is an H&E stain?
hematoxylin - blue basic dye, stains acids (nuclei) = basophilic (purple/blue)
most common
What is an eosin stain?
red-pink, acidic dye, stains bases (proteins) = eosinophilic (red-pink)
What are the special stains?
gram (bacteria) GMS, and silver stain (fungi)
What is another name for the cell membrane? Function?
plasmalemma - functions as semi-permeable membrane
What is a common feature of a cell membrane?
phospholipid bilayer (amphoteric and amphipathic) composed of hydrophilic heads and hydrophobic tails
What does the hydrophilic portion of cell membranes contain?
charged N groups and charged phosphate groups
present on both inside and outside of membrane
What does the hydrophobic portion of cell mebranes contain?
two long chain FA’s covalently linked to glycerol
What creates the tri-laminar appearance on the cell membrane EM?
2 electron dense layers (hydrophilic)
1 electron lucent layer (hydrophobic)
What is the fluid mosaic model?
fluidity of the membrane increases when temperature increases and decreases with saturation of fatty acids
What helps regulate fluidity and stabilizes membranes?
cholesterol
increase cholesterol stiffens membrane and decrease fluidity
What is the ratio of cholesterol and phospholipids in the cell membrane?
1:1
