Tissues Flashcards
What are the 4 types of tissues?
- Epithelial
- Connective
- Muscle
- Nervous
What is the function of epithelial tissue?
- to cover a body surface or to line a body cavity or tube
- form glands (group of cells that secrete products)
- protection, absorption, secretion, diffusion, filtration, excretion, sensory reception
What are the characteristics of epithelial tissue? (6)
- tight fitting cells with no spaces
- cells are held together by specialized junctions
- cells exhibit polarity (apical surface is free, basal surface is attached by basement membrane to underlying tissue)
- supported by connective tissue
- avascular
- high regeneration capacity
What are the 2 types of layers of cells in epithelial tissue?
- simple: single layer of cells
2. stratified: many layers of cells
What are the 3 shapes of cells in epithelial tissue?
- squamous: flat cell, disc shaped nucleus
- cuboidal: box-like cell, spherical nucleus
- columnar: rectangular cell, elongated nucleus at the base
Where are simple squamous cells found and what are they used for?
- found where a thin cell is needed for diffusion (lungs), filtration (kidneys), a smooth frictionless surface (chambers of heart)
Where are stratified squamous cells found and what are they used for?
- found where protection from wear and tear is needed (ex: skin, mouth, esophagus)
Where are simple cuboidal cells found and what are they used for?
- used for absorption and secretion (ex: kidney tubules and glands)
Where are simple columnar cells found and what are they used for?
- used for absorption and secretion (ex: digestive tract and glands)
Explain “Pseudostratified Columnar” cells, where they are found, and one specific feature about them
- appears to be many layers but is one
- is found in the respiratory tract for secretion
- presence of cilia and goblet cells that form the mucociliary system
Explain “Transitional Epithelium” tissue and where its found
- many layers become few when tissue is stretched
- found in urinary bladder wall
What are the 2 types of glands?
exocrine and endocrine
Define endocrine glands
- ductless
- secretes products into interstitial fluid that are distributed by blood stream (ex: thyroid gland)
Define exocrine glands
- with ducts that connect to exterior
- secrete products onto external surfaces (ex: sweat glands or goblet cells)
What are the functions of connective tissue? (4)
- binds and supports: tendons, ligaments, bone, cartilage, adipose, areolar
- protects: bone, cartilage, adipose
- insulates: adipose
- transports: blood
What are some characteristics of connective tissue?
- vascularization varies
- not cellular (few cells)
- non-living extracellular space called matrix dominates and is responsible for properties
- diverse properties (fluid, gel or solid) due to variation in composition of fibers and ground substance
- 3 structural elements: GS, extracellular fibers, cells
What are the2 types of connective tissue matrix secreting cells?
- blast: a young cell secreting matrix
- cyte: a mature cell secreting matrix
List and define the 3 types of extracellular fibers
- collagen: found singly or in bundles, tough, providing tensile strength
- reticular: single collagen fibers that are cross-linked forming a delicate net or mesh
- elastic: allow for stretch and recoil
What is the function of areolar tissue?
- soft padding
- fluid transport medium that allows immune cells to move under skin
- reservoir for water and fat
- provides nutrient support for epithelial tissue
What is the function of adipose tissue?
- food reserve that acts as a soft packing material
- cushioning
- insulating
- vascularized
Describe and explain dense regular tissue
- handles tensions in one direction
- consists of parallel bundles of collagen fibers
- poorly vascularized
- ROPE-LIKE
- location: all tendons and ligaments
Describe and explain dense irregular tissue
- sheet-like
- function: forms sheets that handle tensions in many directions
- structure: collagen bundles are irregularly arranged
- located under skin
Describe and explain Hyaline Cartilage
- firm but rubbery
- function: shock absorption
- gs is gel
- avascular and lacks nerve fibers
Describe and explain bone
- rigid and hard support
- function: resists compression
- structure: matrix is solid composed of calcium and phosphate salts deposited on collagen fibers
