Section 3 Flashcards
Section 3, Module 1
What are the 4 basic types of tissue in the human body that are the building blocks for every organ?
Epithelial tissue, connective tissue, nervous tissue and muscular tissue
What are the two types of epithelium, and describe them briefly?
- Covering epithelium: Cells that cover the external and internal surfaces
- Glandular epithelium: cells that produce and secrete product, such as hormones
True or false:
Epithelium is composed of closely apposed cells.
True:
Epithelium is composed of closely apposed (side by side) cells with very little or no intervening cellular substance.
Explain how epithelial cells are joined together.
Adjacent epithelial cells are joined by specialized junctions. (tight junctions, adhering junctions, desmosomes, and gap junctions)
What are the four different types of junctions that adjacent epithelial cells are joined by?
Tight junctions, adhering junctions, desmosomes, and gap junctions
(just know the names, they’re discussed more in PHGY 170)
Describe the polarity of an epithelial cell.
An epithelial cell has an exposed (apical) surface that faces the exterior of the boy or internal space, and a basal surface where it is attached to the underlying tissue.
How are epithelial cells separated from the underlying tissue?
Epithelial cells rest on and are attached to the basal lamina (basement membrane) which separates it from the underlying tissue.
How do epithelial tissues receive nutrients?
Epithelial cells have no direct blood supply. The epithelial cells receive nutrients from the blood vessels in the underlying tissue.
Are epithelial cells renewed?
Yes, epithelial cells are renewed continuously.
List and describe the functions of epithelium.
- Support and protect (it covers and lines external and internal surfaces of the body protecting the underlying tissue from injury, pathogens, and dehydration. E.g, skin)
- Permeability (it allows substances to be absorbed into the body. E.g, epithelium lining the digestive system absorbs nutrients from the food)
- Sensation (some contain specialized cells that are able to detect sensory stimuli. E.g skin senses touch, tongue senses taste)
- Secretion (some are specialized to secrete specific substances. E.g, skin secretes lubricating oil, enzymes and hormones are secreted by digestive system)
Name some of the functions of epithelial tissue.
- cover and line surfaces
- protection (skin)
- permeability (absorption in the digestive system)
- sensation (skin)
- contractility/secretion (of glandular cells)
Identify the difference between simple and stratified epithelia.
Simple is only one cell layer thick, whereas stratified is two or more.
What is squamous epithelia shape?
Flat (thin), wide, and somewhat irregular in shape
What is cuboidal epithelia shape?
About the same size on all sides; the nucleus is usually centrally located
What is columnar epithelia shape?
Taller than they are wide; nucleus is oval and located in the basal region of the cell
How are epithelial tissues named? (First name + last name)
a) cell organization + cell shape
b) cell shape + cell organization
a) cell organization + cell shape
E.g, simple squamous
E.g, stratified columnar
What is simple squamous epithelium and what are some examples of where it is found?
It is a simple squamous epithelium that consists of a single layer of flattened cells.
It can be found lining blood vessels.
Why is it useful that blood vessels are lined with simple squamous epithelium?
Blood vessels transport materials to and from cells, and for energy efficiency it should have a thin barrier allowing for rapid exchange
The single layer of flattened cells provides a thin barrier between vessels and tissues, allowing material to travel a short distance between the two.
What is simple cuboidal epithelium and what are some examples of where it is found?
Consists of a single layer of cube cells.
For example, can be found lining some glands.
What is simple columnar epithelium and what are some examples of where it is found?
Consists of a single layer of column shaped cells.
It can be found lining the gastrointestinal tract.
Why is it useful that the gastrointestinal tract is lined with simple columnar epithelium?
The single layer cells allows for rapid secretion or absorption of material.
What is stratified squamous epithelium and what are some examples of where it is found?
It has multiple layers of flat shaped cells.
The basal cells may be more cuboidal in shape, but the apical (superficial) cells display a squamous flattened shape.
For example, it makes up the most superficial layer of skin as multiple thin layers of small cells. This allows the skin to protect deeper structures from abrasion and damage.
What is stratified cuboidal epithelium and what are some examples of where it is found?
Contains multiple layers of cube shaped cells.
Can be located in ducts of some glands. Functions of these cells include secretion, protection, and strengthening the walls of ducts of glands.
What is stratified columnar epithelium and what are some examples of where it is found?
Contains multiple layers of column shaped cells.
It is relatively rare in the human body, but they can be found in the male urethra. The function of these cells include protection and secretion.