Tissues And Irgans Flashcards
Tissue definition
A collection of cells that are adapted to perform a specific function
Organ Definition
2 or more tissues combined to create a structural unit that has a particular function that are a sum of its parts
3 Cells That don’t form part of tissues
Ova
SPermatozoa
Blood corpuscles
Epithelial Tissues
Form continuous layers that cover surfaces and line cavities of the body
Mesothelium
The tissue that lines closed cavities like:
-Peritoneal
-Pleural
-Periocardial
Epithelium also lines heart, blood and lymphatic vessels as endothelium
Endothelium = specialised form of epithelium
Epithelial CLassified by shape of cells and their arrangement in tissues
Classified morphologically (by shape and structure)
Epithelial functions
-Protection
-SSecretion
-Absorption
-Reproduction
-Sensation
-Lubrication
-Excretion
Simple Squamous Epitheelium
Lines heart, blood vessels, pleural and peritoneal cavities
Exchange of substances, secreting lubricants
Simple Cuboidal Epithelium
Ducts of exocrine glands, kidney tubules, parenchyma of glands
Lining , secretory activities or absorption
Simple columnar epithelium
Line GI Tract and large excretory ducts of glands
Secretion of enzymes, mucus and absorption of nutrients and fluids
Pseudostratified columnar epithelium
Lining and protein secretion
Also for sensory reception
Can be ciliiated
Upper respiratory system
Nasal cavity and ear
Stratified squamous epithelium
Protects underlying tissues form external environment
Epidermis covers exterior of body and some interior surfaces of body cavities.
(Non keratinised, mouth, oesophagus,vagina)
(Keratinised, epidermis of skin)
Stratified
Arranged in layers
Pseudostratified
Closely packed cells which look like they are arranged in layers but are actually all attactched to a basement membrane.
Squamous
flat scale shaped cells
Cuboidal
cell shaped like a cube
Same width as height
Columnar
Tall narrow somewhat cylindrical/prismatic cells
Regeneration
Epithelial cells have a capacity for regeneration
Metaplasia
Have capacity to change from one type of epithelium to another
Neoplasia
Tumour = Neoplasm
Carcinoma = Tumours that form in the epithelium
Glandular epithelial tumours = adenoma(benign) adenocarcinoma(malignant)
Transitional
The cells can be stretched and change shape, allows organs to expand/change shape.
Stratified cuboidal epithelium
Absorption and secretion
(Sweatgland ducts)
Stratified columnar epithelium
Conjunctiva of eye
Large secretory ducts
Part of male urethra
Secretes tears and other fluids, absorbs excess materials produced elsewhere or protection
Transitional epithelium (urothelium)
Lines bladder and ureters
Allows for stretching of organs and chemically protects tissues underneath
Epithelial call adherence systems
Lateral surface
Basal surface
Lateral surface
Tall Animals Don’t Greet Children
Tight junctions
Adhesion junctions / adhesion belt
Desmosomes
Gap junctions
Cell adhesion molecules
Tight junctions
Top of lateral surface
Don’t let big molecules into tissue
Can clap open and closed to let small molecules through (paracelluar transport)
Adhesion junctions
Joins actin bundles in 2 cells together
1/3 way down from top of lateral surface
Made of actin filaments
Tissue stabilising faster and another transport barrier
Desmosomes
Joins intermediate filament bundles in one cell to an.other
Halfway down
strongest type of cell to cell adhesion
Provides mechanical strength
Made intracellularly of cytokeratin fibres and E-Cadherins
Gap junctions
Close to base of cell
Allows quick Communication between cells.
Lets small molecules move from one cell to another
Distributed throughout cardiac muscle and smooth muscle
Basal surface
Hemi-desmosomes
Focal adhesions
Integrins
Hemi-desmosomes
Anchors intermediate filaments to basal Lamina
Focal adhesions
Anchors actin filaments in cell to the basal Lamina
Mucosal membrane
The most inner lining of some organs and body cavities
Where mucosal membranes found?
Gi tract, respiratory system, urinary tract
Mucus function
Prevents Pathogen / dirt entry
Prevents tissue dehydration
Lubrication
G1 tract lining
Epithelial cells lining lumen attach to basement membrane
Lamina propria = connective tissue
Muscularis mucosae smooth muscle
Mucosa =3layers
Epithelia
Lamina propria
Muscularis mucosa
Mucosa function
Stop pathogen entry
More contents and expel waste
Absorb contents in lumen
Bladder
Urotheciam= transitional epithelium of bladder
