Tissue or web

Study of tissues of the body

It involves all aspects of tissue biology with focus on how cells structure and arrangement optimize functions specific to each organ

Two interacting components of tissues

It produce ecm

Smallest living parts of the body and Basic structural and function units

Animal cells are

Bacteria are

Connective tissues non cellular portion is known as the

It holds water and giving the physical scaffolding for the cells

Form part of a selective barrier to the external environment

Supports the cells and contains fluid transporting nutrients to the cells carying away wastes

In human the main components of extracellular matrix are

Father of modern histology and descriptive anatomy

First did the study of tissus and used the term tissue in an anatomic sense

Discovered different weaves and textures in the body and named then layers of tissues

Preperation of tissues for study

It is the most crucial step for the preperation of tissues it preserved the samples structure and prevent decomposition

Examples of fixative or liquid fixing agent

Remove water from the sample to prepare it for emedding

Replace alcohol with a substance that is transparent to allow light to pass through

Remove a substantial amount of fat from the tissue which otherwise presents a barrier to wax infiltration

The ethanol is gradually replaced with xylene

Completely displace the clearing agent.

Provide support and orientation for sectioning

Hardening of infiltration tissue with paraffin

Produce thin sections for microscopy

The hardened block with tissue and surrounding embedding medium is trimmed and placed for sectioning in a microtome

Secure the sections onto a microscope slide

Enhance contrast and reveal specific structures. Dyes stain material more or less selectively, often behaving like acid or basic compounds

Structures stained purple

Structures stained pink

Major types of light microscopy

Used in a wide variety of laboratory application as the standard microscope

Increasing contrast without staining by producing a bright image on darker background

Uses refraction and interference caused by structures in the specimen to create high-contrast, high-resolution images without staining

Uses interference patterns to enhance contrast between different features of a specimen to produce high-contrast images

Uses flourescent stains to produce an image

Uses laser to scan multiple z-planes successively

Uses scanning technique, fluorochromes, and long-wavelength light to penetrate into deep thick specimens

Major types of electron microscopy

Uses electron beams that pass through a specimen to visualize small images

Uses electron beams to visualize surfaces

Interpretations of structures in tissue selections

Minor shrinkage of cells or tissue produced by the fixative or by ethanol that needed for paraffin embedding

Create artificial spaces between cells and other tissue

May confuse with linear structures in the tissue

From the stain which may confused with cellular structures such as cytoplasmic granules

Types of tissue sections