Tissues Flashcards
What are the four types of tissues in the human body?
Epithelial, Connective, Muscle, Nervous
What are 3 places that epithelial tissue is found?
- Covering body surfaces
- Lining body cavities
- Forming glands
Epithelial cells rest on a….
basement membrane /basal lamina
What are the 3 major functions of epithelial cells
- Covering and lining (protection)
- absorption
- Secretion
How do epithelial cells receive their nutrition?
All epithelial are avascular (no capillaries).
They are dependent on proximity to loose connective tissue for their nutrient and oxygen supplies and by-product removal
What always lies on the interface between epithelial cells and connective tissue?
a basal lamina
What are 3 chief characteristics of epithelial cells ?
- Form a sheet of closely associated cells held together by junctional complexes with very little intercellular space
- Ability to shed and renew
- Made up by polarized epithelial cells that have specific functions depending on the location in the body
What are the 8 types of epithelial tissue?
- Simple squamous
- Stratified squamous
- Simple cuboidal
- Stratified cuboidal
- Simple columnar
- Stratified columnar
- Pseudostratified columnar
- Transitional
What kind of places are simple squamous epithelia found in? what are some examples?
places where there is a very rapid passage
of chemicals
ex:
1. Endothelium of lymphatic vessels
2. Alveoli of lungs
3. Lining of capillaries
4. Some parts of kidney glomerulus and tubules
What functions can simple squamous epithelium perform?
some simple secretion (such as lubricating substances), and some filtering
Simple squamous epithelium lining blood vessels is called ?
endothelium
The simple squamous epithelium that covers body cavities is called?
mesothelium
What are 2 key differences between simple squamous epithelium and simple cuboidal epithelium?
- thicker (cube shaped) and more protective
- a more complex cytoplasm, and perform more complex functions in terms of secretion and absorption
- still allow passage of chemicals
What are two examples of where simple cuboidal epithelium is found?
The secretory part of most glands (like the thyroid for example)
Most tubules of the kidney
What is the morphology of simple columnar epithelium?
A single layer of tall cells. The nucleus tends to be elongated and localized near the basement membrane
Have microvilli and/or cilia
What tasks are simple columnar epithelium active in?
Secretion and absorption
Where are simple columnar epithelium found? (2 examples)
- Bronchioles (ciliated)
2. Small intestine (microvilli)
What is the distinguishing morphology of pseudostratified columnar epithelium? (2 things)
- Cells are tall and thin, but vary in height – all touch the basement membrane, but not all make it to the apical surface
- The nucleus may be found at different points/levels
Can pseudostratified columnar epithelium have cilia?
Yes
Where is an example of pseudostratified columnar epithelium?
Trachea
What types of cells tend to be intermixed with pseudostratified columnar epithelium?
Mucous secreting goblet cells
How is stratified epithelial tissue named?
based on the type of cell found at the surface
What is the most common type of stratified epithelium?
stratified squamous epithelium
- lower layers may be cuboidal or columnar
what is the main useful feature of stratified epithelium?
protection and durability