INTRODUCTION TO HISTOLOGY

Question 1

study of tissues and its organization in organs

tissue biology and functions

This subject involves all aspects of tissue biology, with the focus on how cells’ structure and arrangement optimize functions specific to each organ.

Answer 1

Histology

Question 2

Tissues - has 2 interacting components:

Answer 2

cells
extracellular matrix

Question 3

consists of many kinds of macromolecules, most of which form complex structures, such as collagen fibrils.

supports the cell and contains the fluid transporting nutrient to the cells, and carrying away their wastes and secretory products.

During development, cells and their associated matrix become functionally specialized and give rise to fundamental types of tissues with characteristic structural features.

organs are formed by an orderly combination of these tissues, and their precise arrangement allows the functioning of each organism as w whole.

Answer 3

Extracellular matrix

Question 4

Methods of studying Histology:

Answer 4

Microscopy
Molecular methods

Question 5

Tissue Preparation Steps:

Answer 5

Fixation
Dehydration
Clearing
Infiltration
Embedding
Trimming
Sectioning
Staining
Mounting
Labeling

Question 6

• in order to study tissues under a microscope, they must be preserved (fixation)

most important step in the preparation of tissue specimens for histopathologic techniques.

Consists of a chemical or physical method of killing the tissue and inactivating its enzymatic actions and yet retaining its characteristic peculiarities of shape, structure, and morphologic features.

the prosecutor selects the appropriate sample and slices a thin representative section of the specimen to be submitted for processing.

Answer 6

Fixation

Question 7

after fixation of 24 hrs, the tissue is transferred into ascending grades of ethanol or isopropyl alcohol to remove excess intracellular and extracellular water.

starts with a 70% alcohol serially increasing concentration to the absolute concentration of 100% pure alcohol in order to be miscible with the next chemical step, which is clearing.

Answer 7

Dehydration

Question 8

involves removal of the dehydrating agent and its replacement with a hydrocarbon chemical (xylene, toluene, benzene) which is miscible with alcohol and embedding medium such as paraffin wax.

Answer 8

Clearing

Question 9

hydrocarbon chemical s

Answer 9

(xylene, toluene, benzene)

Question 10

process by which tissue is permeated with an embedding medium usually liquid paraffin, at its given melting point temperature of 56-58 degrees centigrade.

Answer 10

Wax Impregnation / Infiltration

Question 11

paraffin block is sliced into micro-thin sections (4-6 microns) using a __.

Answer 11

microtome

Question 12

a basic natural dye that stains the nucleus in shades of blue to blue-violet to black (hence ‘basophilic’)

Answer 12

Hematoxylin

Question 13

stain is an acid dye that has an affinity for staining the cytoplasm in shades of pink to orange to red (hence’eosinophilic’)

Answer 13

Eosin

Question 14

thorough examination of the small structural details comprising each biologic saple is facilitated by observing the specimen under microscope.

is the starting point of any discussion related to microscopic anatomy.

Answer 14

microscopy

Question 15

2 TYPES OF MICROSCOPy

Answer 15

Light Microscopy
Electron Microscopy

Question 16

Light Microscopes

Answer 16

Bright-field microscopy
Fluorescence microscopy
Phase-contrast microscopy
Confocal microscopy
Polarizing microscopy

Question 17

Electron microscopy:

Answer 17

Transmission Electron Microscopy
Scanning Electron Microscopy

Question 18

____ most commonly used by students.
Source of illumination is ___

image appears dark against a bright contrast/background.

Answer 18

Bright-Field microscope, tungsten light

Question 19

used in observing live and unstained samples.

utlizes an ___ located underneath the condenser.

specimen appears brightly lit against a dark background.

___ causative agent of syphilis can be identified using this.

Answer 19

Dark-Field microscope, opaque disk, Treponema pallidum,

Question 20

microscope preferred if the specimen is transluscent and colorless.

Light source is a ___

more detailed parts of living cell can be observed with high resolution

Answer 20

Phase-Contrast microscope , tungsten halogen lamp

Question 21

achieves high resolution and sharp focus by using a small point of high-intensity light, often from a laser, and a plate with a pinhole aperture in front of the image detecto

Answer 21

Confocal microscopy

Question 22

Allows the recognition of stained or unstained structures made of highly organized subunits.

Answer 22

Polarizing microscope

Question 23

• The ability to rotate the direction of vibration of polarized light a feature of crystalline substances or substances containing highly oriented molecules, such as cellulose, collagen microtubules, and actin filaments

Answer 23

Birefringence

Question 24

based on the interaction of tissue components with beams of electrons. 1000-fold increase in resolution

Answer 24

Electron microscope

Question 25

is an imaging system that permits resolution around 3 nm.
This high resolution allows isolated particles magnified as much as 400.000 times to be viewed in detail.

Answer 25

The transmission electron microscope (TEM)

Question 26

is a method of localizing newly synthesized macromolecules in cells or fissue sections.

adioactively labeled metabolites, provided to the living cells are incorporated into specific macromolecules , and emit weak radiation that is restricted to those regions where the molecules are located.

Answer 26

Audioradiobiography

Question 27

radioactive precursor of DNA

Answer 27

tritium-labeled thymidine