TISSUES o Stratified epithelium - more than one layer of cells
but only the basal layer attaches the deepest layer
to the basement membrane; deepest cells are
A group of cells with similar structure and function,
cuboidal or columnar
plus the extracellular substance surrounding them.
o Pseudostratified columnar epithelium - one layer
Histology - the study of tissues of cells with all the cells attached to the basement
membrane
Types of Tissues o Transitional epithelium – stratified cells that
1. Epithelial – a covering or lining tissue appear cuboidal when not stretched and squamous
2. Connective – a diverse primary tissue type that when stretched
makes up part of every organ in the body
3. Muscle – a tissue that contracts or shortens, making Functional Characteristics
movement possible Cell Layers and Cell Shapes
4. Nervous – responsible for coordinating and Simple Squamous
controlling body activities o lungs – gas exchange/diffusion
o kidneys – filtration
Epithelial tissue - covers and protects surfaces, both
Simple Cuboidal
outside and inside the body
o carry out active transport, facilitated diffusion,
Epithelial Tissue Characteristics secretion, absorption
o Mostly composed of cells Simple Columnar
o Covers body surfaces o secretion of mucus, enzymes, absorption
o Has an exposed surface Pseudostratified Columnar
o Attaches at the basal surface o secrete mucus
o Specialized cell connections and matrix Stratified Squamous
attachments o protection, reduce water loss
o Avascular Transitional
o Capable of regeneration o protection, enables organ to contract or expand
o urinary bladder – enlarge when filled with urine
Functions of Epithelial Tissues
✓ Protects underlying structures Location of Epithelium
✓ Acts as a barrier Simple Squamous
✓ Permits passage of substances − air sacs of lungs
✓ Secreting substances − blood vessels
✓ Absorption of substances − kidneys
Classification of Epithelial Tissue − surface layers of membranes
Acc. to Layers Simple Cuboidal
o simple – single-layered − kidney tubules
o stratified – multi-layered − glandular organs
o pseudostratified – single-layered but appears to be − terminal bronchioles
stratified − ovaries
o transitional – stratified; can be greatly stretched Simple Columnar
Acc. to Shapes − glands, ducts
o squamous – flattened or scalelike − bronchioles
o cuboidal – cube-like − gallbladder
o columnar – tall and thin − auditory tube
− digestive tract
Structure − uterus
o Simple epithelium - single layer of cells with each − uterine tubes
cell extending from the basement membrane to the Pseudostratified
free surface − nasal cavity
o Simple Cuboidal epithelium – single layer of − nasal sinuses
cube-shaped cells that have microvilli or cilia − auditory tubes
o Simple Columnar epithelium – single layer of tall − pharynx
narrow cells that have cilia or microvilli
− trachea
− bronchi
labd
but only the basal layer attaches the deepest layer
to the basement membrane; deepest cells are
A group of cells with similar structure and function,
cuboidal or columnar
plus the extracellular substance surrounding them.
o Pseudostratified columnar epithelium - one layer
Histology - the study of tissues of cells with all the cells attached to the basement
membrane
Types of Tissues o Transitional epithelium – stratified cells that
1. Epithelial – a covering or lining tissue appear cuboidal when not stretched and squamous
2. Connective – a diverse primary tissue type that when stretched
makes up part of every organ in the body
3. Muscle – a tissue that contracts or shortens, making Functional Characteristics
movement possible Cell Layers and Cell Shapes
4. Nervous – responsible for coordinating and Simple Squamous
controlling body activities o lungs – gas exchange/diffusion
o kidneys – filtration
Epithelial tissue - covers and protects surfaces, both
Simple Cuboidal
outside and inside the body
o carry out active transport, facilitated diffusion,
Epithelial Tissue Characteristics secretion, absorption
o Mostly composed of cells Simple Columnar
o Covers body surfaces o secretion of mucus, enzymes, absorption
o Has an exposed surface Pseudostratified Columnar
o Attaches at the basal surface o secrete mucus
o Specialized cell connections and matrix Stratified Squamous
attachments o protection, reduce water loss
o Avascular Transitional
o Capable of regeneration o protection, enables organ to contract or expand
o urinary bladder – enlarge when filled with urine
Functions of Epithelial Tissues
✓ Protects underlying structures Location of Epithelium
✓ Acts as a barrier Simple Squamous
✓ Permits passage of substances − air sacs of lungs
✓ Secreting substances − blood vessels
✓ Absorption of substances − kidneys
Classification of Epithelial Tissue − surface layers of membranes
Acc. to Layers Simple Cuboidal
o simple – single-layered − kidney tubules
o stratified – multi-layered − glandular organs
o pseudostratified – single-layered but appears to be − terminal bronchioles
stratified − ovaries
o transitional – stratified; can be greatly stretched Simple Columnar
Acc. to Shapes − glands, ducts
o squamous – flattened or scalelike − bronchioles
o cuboidal – cube-like − gallbladder
o columnar – tall and thin − auditory tube
− digestive tract
Structure − uterus
o Simple epithelium - single layer of cells with each − uterine tubes
cell extending from the basement membrane to the Pseudostratified
free surface − nasal cavity
o Simple Cuboidal epithelium – single layer of − nasal sinuses
cube-shaped cells that have microvilli or cilia − auditory tubes
o Simple Columnar epithelium – single layer of tall − pharynx
narrow cells that have cilia or microvilli
− trachea
− bronchi
labd
