Tissues Review Flashcards
What is the definition of tissues?
·Groups of cells with similar structure and function
Four primary types of tissues
·Epithelium
·Connective
·Nervous
·Muscle
Where are epithelial tissues found?
·Body coverings
·Body linings
·Glandular tissues
Functions of epithelial tissue
·Protection
·Absorption
·Filtration
·Secretion
Epithelium characteristics
·Cells fit closely together
·Tissue layer always has one free surface
·The lower surface is bound by a basement membrane
·Avascular (no blood supply)
·Regenerates easily if well nourished
Number of cell layers (classification of epithelium)
·Simple- one layer
·Stratified- more than one layer
Shape of cells (classification of epithelium)
·Squamous- flattened
·Cuboidal- cube shaped
·Columnar- column like
Simple squamous
·Single layer of flat cells
·Usually forms membranes
·Lines body cavities
·Lines lungs and capillaries
Simple cuboidal
·Single layer of cube like cells
·Common in glands and their ducts
·Forms walls of kidney tubules
·Covers the ovaries
Simple columnar
·Single layer of tall cells
·Often includes goblet cells, which produces mucus
·Lines digestive tract
Pseudostratified Columnar
·Single layer, but some cells are shorter than others
·Often looks double layered
·Sometimes ciliated, such as in the respiratory tract
·May function in absorption or secretion
Stratified squamous
·Cells at the free edge are flattened
·Found as a protective covering where friction is common
·Locations: skin, mouth, esophagus
Stratified cuboidal
·Two layers of cuboidal cells
Stratified columnar
·Surface cells are columnar, cells underneath vary in size and shape
Stratified cuboidal/columnar
·Rare in human body
·Found mainly in ducts of large glands
Transitional epithelium
·Shape of cells depends upon the amount of stretching
·Lines organs of the urinary system
What is a gland?
·One or more cells that secretes a particular products
·Two major types
Endocrine gland
·Ductless
·Secretions are hormones
Exocrine gland
·Empty through ducts to the epithelial surface
·Includes sweat and oil glands
Connective tissue
·Found everywhere in the body
·Most abundant and widely distributed
Connective tissue functions
·Binds body tissues together
·Supports the body
·Provides protection
CT characteristics
·Variations in blood supply: some have poor blood supply/are avascular, some are well vascularized
·Extracellular matrix: non-living material that surrounds living cells
Bone CT
·Bone cells in lacunae (cavities)
·Hard matrix of calcium salts
·Large numbers of collagen fibers
·Protect and support the body
Hyaline cartilage
·Most common cartilage
·Abundant collagen fibers
·Rubbery matrix
·Entire fetal skeleton is hyaline cartilage
Elastic cartilage
·Provides elasticity
·Supports the external ear and surrounds larynx (voicebox)
Fibrocartilage
·Highly compressible
·Forms cushion-like discs between vertebrae
Dense CT
·Main matrix element is collagen fibers
·Cells are fibroblasts
·Tendon: attach muscle to bone
·Ligaments: attach bone to bone
Areolar CT
·Most widely distributed CT
·Soft, pliable tissue
·Contains all fiber types
·Can soak up excess fluid
Reticular CT
·Delicate network of interwoven fibers
·Forms stroma (internal supporting network) of lymphoid organs
·Lymph nodes, spleen, bone marrow
Blood
·Blood cells surrounded by fluid matrix
·Fibers are visible during clotting
·Functions as the transport vehicle for materials
Muscle tissue
·Function is to produce movement
·Three types: skeletal, cardiac, smooth
Skeletal muscle
·Can be controlled voluntarily
·Cells attach to CT
·Cells are striated
·Cells have more than one nucleus
Cardiac muscle
·Found only in the heart
·Function is to pump blood- involuntary
·Cells attached to other cardiac muscle cells at intercalated discs
·Cells are striated
·One nucleus per cell
Smooth muscle
·Involuntary muscle
·Surrounds hollow organs
·Attached to other smooth muscle cells
·No visible striations
·One nucleus per cell
Nervous tissue
·Neurons and nerve support cells
·Function is to send impulses to other areas of the body
·Irritability, conductivity
