Lecture 1 - Microanatomy (Histology) and Embryology Flashcards Preview

First Semester: Microscopic Anatomy > Lecture 1 - Microanatomy (Histology) and Embryology > Flashcards

Flashcards in Lecture 1 - Microanatomy (Histology) and Embryology Deck (38):
1

Anatomy definition

The science which deals with structures of healthy body of animals and humans. The structure is revealed by naked eye observation and it is based on dissection`

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Gross Anatomy definition

encompasses all those structures accessible by dissection and direct inspection

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Microanatomy - histology definition

study of the tissues of the body and how cells and tissue integrate to form organs.

involves all aspects of tissue biology with emphasis on cell structure and function, including functions specific to each organ

4

Embryology definition

the science which deals with ontogenetic development i.e. with development of a new individual (development of embryo and fetus).

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Three branches of histology

Cytology
General histology
Special histology

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Cytology

deals with the structure and function of the cell

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General histology

deals with the structure of tissue

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Special histology

deals with microscopic structure of organs (also called organology)

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Histological slides are cut about how big?

4-8 micrometers

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Two interacting components that make up tissues

Cells
Extracellular matrix

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Extracellular matrix

Anything next to and between cells

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Light microscopy

Light beam is transmitted through a tissue

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Light microscopy includes (6)

-Conventional bright field microscopy
-Fluorescence
-Phase-contrast
-Differential interference
-Confocal
-Polarizing

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Most common light microscopy

Bright field microscopy

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Bright field microscopy

requires staining, suchas cytochemical demonstration of mitochondria in sperm

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Two types of microscopes

Phase contrast microscopy

Fluorescence microscopy

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Phase contrast microscopy basis

-Based on principle that light changes speed when passing through structures with different refractive indices.

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Phase contrast microscopy use

Allows observation of living non-stained structures

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Fluorescence microscopy basis

Based on affinity of fluorescent compounds for specific cell components

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Advantages of LM (4)

-Relatively inexpensive
-Provides rapid diagnosis
-Allows observation of living specimens
-Resolving power of LM id 0.2 micrometers

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Disadvantages of LM (4)

-2-D image
-Resolving power is limited by the wavelength of light
-Requires maintenance
-Requires expertise for proper diagnosis (quality analysis and quality control)

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Stereomicroscope

-Also called dissecting microscope
-Uses whole mount

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Advantages of dissecting scopes (4)

-Relatively inexpensive
-Practical/versatile
-Can provide 3D image
-Can be used in microsurgery and with other types of specimens

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Disadvantages of dissecting scopes (2)

-Low resolving power
-Needs to be maintained

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Transmission Electron Microscopy

Very thin slides
Can go inside cells

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Scanning electron microscopy

Just scans the surfaces
Useful for structures that live on surfaces such as parasites

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Transmission electron microscopy is based on

the interaction of electrons and tissue components

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What causes the 1,000 fold increase in resolution with TEM?

The wavelength in the electron beam is shorter

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Advantages of TEM (2)

-Great resolving power (0.16-0.18 nanometers)
-Very useful for rapid diagnosis of viruses and other microscopic organisms

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Disadvantages of TEM (4)

-2D
-Black and white
-Can't be used in living object
-Very expensive

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3 conditions objects must meet to be observed under LM or TEM

-Must be fresh and well-preserved in order to retain structure and molecular composition
-Must be thin enough to allow light transmission
-Must have enough contrast to observe details

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7 steps for tissue processing for observation in a microscope

1. Take it out
2. Fixation (12-24 hours)
3. Dehydrate using alcohol
4. Clearing
5. Embed in paraffin wax
6. Cut using microtome
7. Stain to create contrast

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What do we use for fixation?

10% buffered formalin to penetrate tissue

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What do we use for clearing?

Xylene

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How thick do we cut slides?

1-7 micrometers

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What is the most common stain used in routine staining?

Hematoxylin – eosin

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Example of special staining?

silver stain use to demonstrate elastin.

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What are histochemical methods of staining used for?

used to demonstrate chemical constituients DNA, RNA, lipids, glycogen, carbohydrates and elements such as Ca, Fe etc.