ch 4 the tissue lvl Flashcards
tissue
is a group of cells
- common embryonic cells
- function together to carry out specialized activities
what are the 4 types of tissue
1) Epithelial
2) connective
3) Muscular
4) Nervous
epithelial tissue
- covers the body surfaces
- lines hollow organs, body cavities, duct
- forms glands
connective tissue
- protects, supports, and binds organs
- stores energy as fat, provides immunity
muscular tissue
- generates physical force to make body structures move
- generates body heat
nervous tissue
- detect changes in the body and responds by generating nerve impulses
3 major functions of epithelial tissue
1) selective barrier
2) secretory surfaces
3) protective surfaces
Selective barrier
regulates the movement of materials in and out of the body
secretory surfaces
that releases products onto the free surfaces
Apical (free) surface (a general feature of Epithelial Cells)
Faces the body surface, body cavity, lumen, or duct
Lateral surfaces (a general feature of Epithelial Cells)
Faces adjacent cells
Basal surface (a general feature of Epithelial Cells)
adhere to extracellular materials (basement membrane)
Basement membrane (a general feature of Epithelial Cells)
- Thin extracellular layer
- point of attachment and support for overlying epithelial tissue
Epithelial Tissues
- Have a nerve supply
- Avascular
- Blood vessels in the connective tissue bring in nutrients and eliminate waste
- High rate of cell division for renew and repair
Epithelium
Covering and lining epithelium
- Outer covering of skin and some internal organs
Glandular epithelium
- Secreting portion of glands
Covering and Lining Epithelium is normally classified according to what
- Arrangement of cells into layers
- Shapes of cells
Arrangement of epithelial cells in layers
1) simple epithelium
2) Pseudostratified epithelium
3) Stratified epithelium
Stratified epithelium
- two or more layers of cells
- protection
Pseudostratified epithelium
- Appear to have multiple layers
- nuclei at different levels
Simple epithelium
- Single layer of cells
- function in diffusion, osmosis, filtration, secretion, or absorption
Cells vary in shape depending on their function like ?
1) squamous
2) cuboidal
squamous
Thin cells, arranged like floor tiles
cuboidal
- Function in secretion or absorption
- shaped like cubes
what are the shapes of the epithelial cells
1) Columnar
2) Transitional
Columnar
- like columns
- May have cilia or microvilli
- secretion and absorption
transitional
- Cells change shape, transition from flat to cuboidal
Ex: urinary bladder
Simple squamous epithelium
- Single layer of flattened cells
- Found at sites for filtration or diffusion
Covering and Lining Epithelium - Endothelium
- simple squamous that lines the heart, blood vessels, and lymphatic vessels
Stratified Squamous Epithelium
cells that are flat in the apical layer
- New cells are pushed up toward apical layer
- As cells move further from the blood supply they dehydrate, harden, and die
Keratinized form contain the fibrous protein keratin
- Found in superficial layers of the skin
Nonkeratinized form does not contain keratin
- Found in mouth and esophagus
Glandular Epithelium: Endocrine Glands
- Secretions, called hormones, diffuse directly into the bloodstream
Glandular Epithelium: Exocrine Glands
Secrete products into ducts that empty onto the surfaces of epithelium
Connective Tissue
Most abundant tissues in the body
Numerous functions
- Binds tissues together
- Supports tissue
- Protects and insulates organs
- transport
- Energy reserves and immune responses
