Lecture 3 - Histology Flashcards
Cell characteristics
-Cells form organisms/tissues/organs
-Cell division occurs to replicate
Cell functions
-Cover surfaces
-Storage of nutrients/energy
-Creates connections
-Protects body
-Communication
-Reproduction
Four types of tissues
-Nervous
-Muscle - cardiac, smooth, skeletal
-Epithelial - lining of organs, skin
-Connective - bone, tendon, padding, fat
Epithelial tissue characteristics
-High con. of cells
-Polarity - apical/basal surface
-Basement membrane attachment
-Avascular (blood vessels in underlying connective tissue)
-High regeneration capacity
Epithelial tissue purpose
-Lining
-Barrier/protection
-Selective permeability
-Secretion
Intercellular junctions
-Tight junctions - small pieces of tissue holding cells together
-Gap junctions - create tunnels from cell to cell to allow substance travel
-Anchoring junctions - holding cells together.
Epithelia classification
Simple - 1 layer
Stratified - more than 1 layer
–
Pseudostratified - 1
stretched layer
Cuboidial - 1 layer, cube
Columnar - 1 layer, column
Simple squamous epithelium
-Function: diffusion/filtration
-Location: alveoli, blood vessel lining, serous membrane
Simple cuboidal epithelium
-Function: absorption/secretion
-Location: Kidney tubules, glands
Simple columnar epithelium
-Function: absoption/secretion/movement(if ciliated)
-Location: Gut lining (non ciliated), uterine tube lining (ciliated)
Pseudostratified columnar epithelium
-Function: protection/movement (if ciliated)
-Location: respiratory tract lining.
Stratified squamous epithelium
-Function: protection
-Location: skin epidermis, lining of mouth (pharynx, esophagus, throat, anus, vagina)
Transitional epithelium
-Function: distention/relaxation of urinary structures
-Location: Ureter/bladder/urethra lining
Glandular epithelium
-Exocrine glands: secrete products onto epithelial surface
-Endocrine glands: ductless, cells secrete into interstitial fluid + bloodstream, forms endocrine system
Exocrine gland secretion forms
-Merocrine - secretion droplets
-Apocrine - pinched off portion
-Holocrine - mature cell dies, top explodes
Connective tissue
-Structure: sparse cells in extracellular matrix
-Functions: protection (physical and immune), support (framing, binding), storage, blood transport
Connective tissue types
Mesenchyme -> connective tissue proper, supporting connective tissue, fluid connective tissue
Loose connective tissue proper types
Areolar, adipose, reticular
Dense connective tissue proper types
Regular, irregular, elastic
Areolar tissue
-Structure: fibers, fibroblasts, ground substance
-Function: protects organs, binds epithelia to deeper tissues (loosely)
-Location: subcutaneous tissue, skin
Adipose tissue
-Structure: fat in loose extracellular matrix
-Function: energy storage, protects, cushions, insulates
-Location: Surrounds organs, subcutaneous tissue
Reticular tissue
-Structure: WBC, fibroblasts, reticular fibers, ground substance
-Function: supportive framework
-Location: Lymph nodes, spleen, bone marrow
Dense regular connective tissue
-Structure: dense, parallel collagen fibers, fibroblasts, ground substance
-Function: Resists stress in one direction
-Location: tendons, ligaments
Dense irregular connective tissue
-Structure: randomly arranged collagen fibers, fibroblasts, ground substance
-Function: Resists stress in al directions
-Location: Dermis, organ capsules
