Introduction to Histology and Epithelium Flashcards
Define Tissue
Group of similar cells working together to carry out a common function + the extracelluar matrix surrounding them
Cytosol
Intracellular fluid
Simple vs Complex tissue
Simple contains all the same cell type, Complex contains several different cell types
Parenchyma vs Stroma
Parenchyma is working tissue, Stroma is supporting tissue which also supplies nutrition (via blood vessels or ducts)
Define Organ
Several tissues grouped into a morphologically recognisable structure, performing a set of functions.
List 4 types of tissue and briefly describe their function
Connective (protects and supports), Epithelial (covers and lines body surfaces), Muscle (cells contract to generate force), Nervous (generate electrical signals in response to environment)
Extracellular Matrix (ECM)
the material between cells
How are cells joined to one another or other structures? List the types:
Cell juntions: GAP, Tight, Adherens, Desmosome, Focal adhesions, Hemidesmosomes
GAP junctions: function, component, example
Metabolic and electric coupling
Connexins
e.g. cardiac tissue
TIght junctions: function, component, cytoskeleton, example
Barrier, selective permeability and cells polarity;
Claudings;
Actin;
e.g. epidermis
Adherens junctions: function, component, cytoskeleton, example
Tissue integrity, contractility, motility;
Cadherins;
Actin;
e.g. morphogenesis
Desmosomes: functions, components, cytoskeleton, example
Strong adhesions and resist mechanical strength;
Desmosomal cadherins;
IF;
e.g. epidermis (keratins)
Focal adhesions: function, component, cytoskeleton, example
Cell anchorage, mechanical and biochemical signalling;
Integrins,
Actin,
e.g. cell migration
Hemidesmosomes: function, component, cytoskeleton, example
Cell anchorage;
Integrins;
IF;
e.g. Dermal-epidermal junction
5 stages of tissue processing for histology
Fixation, embedding, sectioning, staining, mounting
What is the role of fixation?
preserves tissue, prevents degridation, kills bacteria, enhances tissue staining
Methods of tissue fixation:
Freezing (dry ice or liquid nitrogen), Chemical fixation (inactivated enzymes and hardens tissue, often aldehyde based chemical used)
What is the role of embedding?
Provides support for tissue when sectioning