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Flashcards in 510-1 Deck (37):

What is Histology?

The study of (normal/healthy) tissue


How many different types of cells are there in the human body?



What is a tissue?

2 or more different types of cells working together


Name the 4 primary tissues.

1.) Epithelial
2.) Muscular
3.) Connective
4.) Neural


What is an organ?

Two or more tissue types working together (with a distinct border).


What is histotechnology?

The process of preparing a tissue for microscopy.


What are the 7 steps of histotechnology?

1.) Grossing and Fixation
2.) Processing
3.) Embedding
4.) Sectioning
5.) Staining
6.) Coverslipping
7.) Diagnosis


What is grossing and fixation?

Grossing- the process of cutting a tissue sample to size and marking the margin/orientation with ink

Fixation- placing the specimen in a fixative (formaldehyde) to change the structure of the proteins and prevent bacterial decay
* don't want to leave formaldehyde on the specimen for too long because it will break down into formic acid and damage the tissue


What is processing?

Processing- placing the specimen in a series of solutions to draw water out of the sample and eventually replace the water with parafin wax (alcohol, xylene, limonene)


What is embedding?

Embedding- the specimen is placed in a mold and liquid paraffin wax (crude oil) is poured over it. Once dry the mold is removed.


What is sectioning?

Sectioning- the wax block is cut into very small sections (less than 1/2 the diameter of a cell) with an instrument called a microtome. The ribbon is transferred to a water bath to remove the wrinkles.


What is staining?

Staining- wax is first removed from the specimen through a series of solvents because most stains are water soluble. The specimen is then stained for cellular contract (usually with hematoxylin and eosin).


What is hematoxylin and eosin (H&E)?

The standard stain. Hematoxylin stains the cell nucleus blue. Eosin stains the cell cytoplasm, connective tissue, and erythrocytes orange/red.


What is coverslipping?

Coverslipping- a coverslip is glues to the slide for preservation and protection.


What is a diagnosis?

Diagnosis- a pathologist examines the slide and determines whether the tissue is healthy or abnormal.


What is pathology?

The study of (abnormal) tissue.


Name the 3 types of microscopy.

1.) Light microscopy
2.) Transmission electron microscopy
3.) Scanning electron microscopy


What is light microscopy?

Visible light is focused onto a glass lens and resolution is limited due to the wavelength of light (blurry).


What is transmission electron microscopy?

High energy electrons are focused through a specimen using strong magnets. A 2D image is created.


What is scanning electron microscopy?

High energy electrons are focused onto the surface of a specimen by strong magnets and the reflected electrons are detected. A 3D image is formed.


What is a coronal and sagital section?

Coronal- slice through the side of the body
Sagital- slice through the midline of the body


What is ground substance?

Substance between cells that is not water or fibrous proteins. It can be liquid (plasma), rubbery (cartilage), stony (bone), or elastic (tendon).


What is simple epithelium?

One layer of cells.


What is stratified epithelium?

2 or more layers of cells


What is pseudostratified epithelium?

One layer of cells that look like more than one layer


What are the 4 epithelial cell shapes?

Squamous, cuboidal, columnar, transitional


What are 3 epithelial modifications?

Cilia, microvilli, keratinization


What are the 4 types of connective tissue?

1.) Embryonic connective tissue
2.) Connective tissue proper (loose, dense, reticular, elastic)
3.) Specialized connective tissue (hematopoietic, adipose)
3.) Supportive connective tissue (cartilage, bone)


What are the two main functions of muscles?

1.) movement of bones
2.) movement of substance through hollow organs


What are the 3 types of muscle tissue?

Cardiac, skeletal, smooth


What are the two components of neural tissue?

Neurons and glial cells


What is differentiation?

When an unspecialized cell becomes specialized (ex. ectoderm to skin)


What is metaplasia?

When tissue changes from one type to another. Can be normal (ossification of cartilage) or abnormal (the trachea of smokers change from simple ciliated to stratified non-ciliated)


What is hyperplasia?

Abnormal growth of number of cells non-tumerous (ex. prostate enlargement due to the increase in the number of prostate cells)


What is Hypertrophy?

Growth of cells (ex. growth of muscled from exercise)


What is Neoplasia?

Abnormal growth of tissue that forms a tumor. Can be benign (not life threatening) or malignant (life threatening)


What is connective tissue?

Cells suspended in abundant extracellular matrix (the volume of ECM is greater than the volume of cells)