A&P1 - LP#5 Flashcards
Tissue level of Organization & Epithelial Tissue
There are FOUR types of tissues
- Epithelial Tissue
- Connective Tissue
- Muscular Tissue
- Nervous Tissue
This type of tissue covers body surfaces, and lines hollow organs, body cavities and ducts; they also form glands
Allows the body to interact with both its internal and external environment
Epithelial Tissue
This type of tissue protects and supports the body and its organs. Various types bind organs together, stores energy reserves as fat, and helps provide the body with immunity to disease-causing organisms.
Connective Tissue
This type of tissue is composed of cells specialized for contraction and generation of force. Also generates heat that warms the body.
Muscular Tissue
This type of tissue detects changes in a variety of conditions inside and outside the body and responds by generating electrical signals called nerve action potentials that activate muscular contractions and glandular secretions.
Nervous Tissue
There are THREE types of Embryonic Tissue
- Endoderm
- Mesoderm
- Ectoderm
This type of embryonic tissue ultimately becomes the epithelial lining of the GI tract, respiratory tract and several other organs
Endoderm
This type of embryonic tissue gives rise to muscles, bones, and other connective tissues and the peritoneum
Mesoderm
This type of embryonic tissue comes the epidermis of the skin and the nervous system.
Ectoderm
There are FIVE types of cell junctions:
- Tight Junctions
- Adherens Junctions
- Desmosomes
- Hemidesmosoems
- Gap Junctions
This type of cell junction fuses together outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells.
Tight Junctions
This type of cell junction belts adjacent cells to one another with cadherins that enter into the intercellular space and connect.
Adherens Junctions
This type of cell junction attaches adjacent cells to one another with cadherins but the intermediate filaments are the supporting structure inside the cytosol that they attach to.
Desmosomes
This type of cell junction has integrin that anchors cells to the basement membranes
Hemidesmosomes
This type of cell junction has membrane proteins called connexins that form tiny fluid filled tunnels call connexsons. It allows the cells in a tissue to communicate with one another. In a developing embryo, some of the chemical and electrical signals that regulate growth and cell differentiation travel via these. It enables nerve or muscle impulses to spread rapidly among cells.
Gap Junctions
There are THREE major functions of Epithelial Tissue
- Selective barriers that limit or aid in transfer of substances into or out of cell.
- Secretory surfaces that release products produced by the cells onto their free surface (apical surface)
- Protective services that resist the abrasive influences of the environment
There are various surfaces to Epithelial tissue. They are…
- Apical (free) surface - faces the body surfaces
- Lateral surfaces - faces an adjacent cell
- Basal Surface - Opposite of apical, connects to the basement membrane.
Epithelium is classified according to TWO characteristics
- Arrangement of cells into layers
2. Shape of cells
There are THREE types of cells based on arrangement into layers:
- Simple Epithelium
- Stratified Epithelium
- Pseudostratified Epithelium
A single layer of cells that functions in diffusion, osmosis, filtration, secretion, or absorption.
Simple Epithelium
Two or more layers of cells used for protection from wear and tear.
Stratified Epithelium
Appears to have multiple layers of cells because the cell nuclei lie at different levels and not all cells reach the apical surface BUT it’s actually just a simple epithelium because all cells rest on the basement membrane. Those not reaching the apical surface may contain cilia - helps move particles along the epithelial tissue.
Pseudostratified Epithelium
Type cells classified by cell SHAPE:
- Squamous Cells
- Cuboidal Cells
- Columnar Cells
- Transitional Cells
This type of cell is thin and flat allowing for rapid passage of substances through them.
Squamous Cells