Lecture 1: Background & History Flashcards
Define histology
The study of tissue science, microscopic anatomy of cells
Name the four major tissue groups
Epithelial
Connective tissue
Muscle tissue
Nervous tissu
name the types of epithelium
simple columnar
simple cuboidal
stratified squamous
transitional
marie francois Xavier birchat
father of modern histology
perceived that different organs have different tissues, described 21 such tissues without the use of a microscope
Rudolf carl virchow
pioneer of pathology
applied cell theory to discern pathological processes
since new cells come from old ones, it can give insight to pathological processes
Matthias schleiden
the cell is the essential unit of life
cells arise by budding from the nucleus
= free cell formation theory
theodore schwann
by comparing animal and plant cells, was able to identify 5 classes of tissues
schleiden and schwann
credited with discovery that all organisms are composed of cells
albert koliker
wrote 1st textbook on histology
wrote model textbook for embryology
by applying schwann’s theory to embryonic development
Zacharias janssen
uncle and nephew
created first compound microscope with 30x mag.
Robert hooke
coined term ‘cell’
Anthony leeuwenhoek
was a janitor
made over 247 microscopes with 100x mag.
sent 26 to royal society
refraction of light
light waves traveling through a medium will bend and travel at a fixed velocity specific to each type of medium
refractive index
angle at which light strikes/enters a medium
what is the result when light waves strike a medium at perpendicular?
waves will continue without bending
velocity will change
how to calculate RI
refractive index =
light velocity/velocity of light in medium
RI of air
1
refractive power
a measure of how much a lens bends light waves
unit measure of refraction
diopter
1d = 1 meter///focal length
the point at which all parallel light waves will pass after traveling through a lens
focal point
distance from center of lens to focal point
focal length
what type of lens will exhibit a focal point?
convex lens
characteristics of a real image
inverted
larger than actual object
can be projected on a screen
when is a real image formed?
when an object is outside the focal point
how is the greatest magnification of a real image obtained?
lens has a short focal length
object is as close as possible to focal point
characteristics of a virtual image
not inverted
cannot be projected on screen
can be magnified
what is significant about the light rays radiated from the object of a virtual image?
rays cannot be brought to focus
the ability of an instrument to distinguish two small points as separate entities
resolution
how can we accomplish resolution?
the diameter of diffraction lines around the two points must be reduced, if the lines cross it is impossible to distinguish between the two points
relate refraction and resolution
the smaller d is
the greater detail in picture
how can we improve resolution
use higher RI
use shorter wavelengths
compare the theoretical and actual resolution power of the TEM
theoretical = 0.01A actual = 5 - 10 A
