1.3. Types of Tissues Flashcards
Histology
Study of tissue
Tissue
Cells with similar structure and function
Types of Tissues
Epithelial Tissue
Connective Tissue
Muscle
Nervous
Epithelial Tissue
Covering or lining tissue
Special Epithelial Tissue Characteristics
- Composed of cells
- Covers the surface
- Has an exposed surface
- Attached to basal surface
- Specialized cell connections and matrix attachments
- Avascular (absence of blood vessels)
- Capable or regeneration
- Exogrine and Endocrine glands
Functions of Epithelial Tissue
- Protects the underlying surface
- Acts as a barrier
- Permits passage of substances (gas exchange)
- Secreting substances (sweat and mucous glands)
- Absorption of substances (digest food, intestine)
2 Basis of Epithelial Tissues’ Classification
NUMBER OF PRESENT CELL LAYERS
Simple Epithelium - single
Stratified Epithelium - 2 or more
SHAPE OF THE CELL
Squamous - flat and scalelike
Cuboidal - cube shaped, as wide as they are tall
Columnar - taller than they are wide
Simple Epithelium
Single cell layer (basement membrane to free surface)
Simple Squamous Epithelium
- Single layer of flat, hexagonal cells
- Diffusion, filtration, secretion, protection
- Blood & lymphatic vessels, heart, alveoli kidney tubules, lining of body cavities’ serous membrane
Simple Cuboidal Epithelium
- Single layer of cube shaped cells
- Secretion & absorption of kidney tubules, movement of particles in mucus out of bronchioles
- Endocrine glands, kidney tubules, brain, bronchioles, ovaries
Simple Columbar Epithelium
- Single layer of tall, narrow cells, have cilia & microvili (layers are at same levels)
- Movement of particles out of bronchioles, movement of oocytes through uterine tubes, secretion of glands, absorption by cells of intestine
- Glands & ducts, bronchioles, auditory tubes, uterus, uterine tubes, ventricles
Pseudostartified Columbar Epithelium
- Falsely stratified, one cell layer with all cells attached to basement membrane
- Ciliated cells
- Presence of Goblet Cells
- Cells are at different levels and appear stratified
- Synthesize and secrete mucus into free surface
- Nasal cavity, nasal sinuses, auditory tubes, pharynx, trachea, bronchi
Stratified Epithelium
- More than one cell layer
- Basal layer attaches deepest layer to basement membrane
Stratified Squamous Epithelium
- Cuboidal cells in basal layer & flattened toward surface
- Protects against abrasion, forms barrier against infection, reduce loss of water from body
- Keratinized and Non-Keratinized
Keratinized
- Cytoplasm is replaced by Keratin (protein)
- Outer layer of skin
- Makes skin waterproof
- Show presence of nucleated dead cells
Non- Keratinized
- Surface cells retain nucleus and cytoplasm
- Where oldest cells are found
- Nucleated cells are alive
- Superficial open to internal surface, mouth, larynx, esophagus, anus, vagina, inferior urethra, corneas
Transitional Epithelium
- Cuboidal when organ or tube is not stretched
- Squamous when organ or tube is stretched
- Accommodates fluctuations in volume of fluid, protects against caustic urine effects
- Stretches numbe rof layers are lessened so cells cna easily pass through
- Urinary bladder, ureters, superior urethra
Cilia
- Move materials over top of cells
- Allows movement of substances
Microvili
Increase surface area
Cell Connections
- Hold one cell to another
- Hold one cell to basement membrane
- Binds cells together
- Help form permeability barrier
- Provide me hanism for intercellular communication
Cell Connectors
DEMOSOMES - bind cells together
HEMIDESMOSOMES - between cell and cell membrane
TIGHT JUNCTIONS - forms barrier and anchors cells to each other (intestine linings)
ADHESION BELTS - prevent passage of materials between epithelial cells (below tight junctions)
GAP JUNCTIONS - allow small molecules & ions to pass from one epithelial cell to adjacent
Glands
Secretory organ that secrete substances
Gland Classification According to Modes of Secretion
MEROCRINE - release secretory products by exocytosis
APOCRINE - release of secretory products as oinched off fragements of gland cells
HOLOCRINE - involves shedding of entire cells
Types of Glands
EXOCRINE - with ducts (transport secreted material to free surface) lined with epithelium
ENDOCRINE - ductless gland, secrete products into bloodstream
Unicellular Gland
Single cell
Simple Gland
Multicellular, single unbranched duct
Types of Simple Glands
Simple Tubular
Simple Branched Tubular
Simple Acinar
Simple Branched Acinar
Simple Tubular
Glands forming straight tube with no branching of secretiry portion
Simple Branched Tubular
Gland with several tubular secretory portions branching from single duct
Simple Acinar
Glands with single sac like secretory gland
Simple Branched Acinar
Glands with several acinar secretiry portions branching from single duct
Compound Glands
Multicellular, several ducts
Types of Compound Glands
Compound Tubular
Compound Acinar
Compound Tubuloacinar
Compound Tubular
Glands with multiple ducts, with narrow tubular secretory portion
Compound Acinar
Glands with multiple ducts, with several sac lik secretory portion
Compount Tubuloacinar
Glands with multiple ducts, several tubular and acinar secretory portion
Shapes of Secretory Regions
TUBULAR - shaped as tubules
ACINAR or ALVEOLAR - shaped in savlike structures
Connective Tissue
- Make up part of every organ
- Enclose and separate tissues
- Connect tissue to one another
- Support and move parts
- Store compounds
- Cushion and insulate
- Transport
- Protect
Connective Tissue Cells
- Produce extracellular matrix
OSTEOBLAST - bone-forming cells
OSTEOCYTES - bone cells
OSTEOCLAST - bone destroying cells
FIBROBLAST - form fibrous ct
FIBROCYTES - maintain fibrous ct
CHONDROBLAST - form cartilage and chondrocytes
WBC or LEUKOCYTES - liquid type of ct
MACROPHAGES - capable of phagocytizing (neutrophil) foreign substances
MAST CELLS - nonmotile cells that release chemicals
Extracellular Matrix
COMPONENTS
- Protein Fibers (collagen, reticular, elastic)
- Ground Substance
- Fluid
MATRIX STRUCTURE
- Responsible for functional characteristics of ct
Matrix Protein Fibers
COLLAGEN FIBERS - microscopic ropes, flexible but resist stretching
RETICULAR FIBERS - short, colagen fibers; form supporting network
ELASTIC FIBERS - Have ability to return to original shape, give elastic quality
Matrix Ground Substance
- Trap large quantities of water between polysaccharides
- Return to original shape
PROTEOGLYCANS - consist protein core attached to polysaccharides
