Epithelial Tissue Flashcards
Histology Definition
the study of tissues; aim to understand microanatomy of cells, organs and tissues
Preparation of tissue
- Removal of tissue via biopsy/autopsy
- Fixation of tissue - preservation of cells in fixatives (fomalin-formaldehyde)
- Embedding - set in paraffin block
- Slice and mounting tissue on a slide
- Staining and viewing; paraffin is melted then stained
Haemotoxylin and Eosin (H&E)
nuclei are stained purple (haematoxylin) other structures are pink (eosin)
Types of primary tissue
epithelial, connective, muscle, nervous
Epithelial tissue
Covers and protects - forms boundaries Covering and lining epithelium (skin, lining of cavities) Glandular epithelium (glands) Avascular Innervated Ability to regenerate
Cell Layers
single, stratified, pseudostratified
single cell layer
only one layer of cells
stratified layer
multiple layers
Pseudostratified
looks like multiple layers; only has one
Cell shapes
squamous, cuboidal, columnar, transitional
Squamous cells
thin and flat
Cuboidal
square, nucleus sits in the middle
Columnar
tall, oval nuclei towards the bottom
Transitional
can change shape; found in urinary system
Simple squamous epithelium: function
diffusion, filtration, some secretion
Simple squamous epithelium: locations
alveoli, serous membranes and pleura, pericardium and peritoneum
Simple cuboidal epithelium: function
(may have microvilli, cilia)
Absorption, secretion, movement
Simple cuboidal epithelium: locations
kidney tubules, terminal bronchioles
Simple columnar epithelium: function
(some have cilia)
absorption, secretion, movement
Simple columnar epithelium: locations
intestines, stomach, fallopian tubes
Transitional epithelium
(sometimes resembles stratified sqaumous/cuboidal depending on state)
Accommodates changes in fluid volume in organs
Stratified squamous
Basal cells are cuboidal - become progressively flatter towards the surface
> keratinized
> non-keratinized
Stratified squamous: functions
protection against abrasions and loss of water
Stratified squamous: locations
Keratinized: soles of the feet, palms, skin
Non-keratinized: mouth, oesophagus, anus, vagina
Stratified columnar: functions
absorption, secretion, protection
Stratified columnar: locations
ducts of the mammory glands, larynx, part of the male urethra
Pseudostratified columnar: functions
secretion, movement
Pseudostratified columnar: locations
pharynx, trachea, male’s sperm carrying duct
Non-existent cell types
simple transitional, pseudostratified squamous, pseudostratified cuboidal, pseudostratified transitional
