The tissue level of organisation Flashcards
(40 cards)
What is a tissue?
Group of cells similar in function and structure
What are the four primary tissue types?
- Epithelial
- Connective
- Muscle
- Nervous
What does histology study?
The microscopic study of tissues and organs through sectioning, staining, and examining those sections under a microscope
What is the most commonly used stain in histology?
Haematoxylin and Eosin (H&E) staining
What does Haematoxylin stain?
Acidic structures (nucleic acids)
What does Eosin stain?
Basic structures (proteins/cytoplasm)
What are the characteristics of epithelium?
- Cells have polarity
- Closely packed cells and special contacts
- Supported by connective tissue reticular lamina
- Avascular, but innervated
- High rate of regeneration
What are the two forms of epithelium?
- Covering and lining epithelium
- Glandular epithelium
What is the difference between endocrine and exocrine glands?
- Endocrine: secrete directly into blood supply (e.g., hormones)
- Exocrine: secrete via a duct (e.g., liver secreting bile)
What is a cutaneous membrane?
Skin (dry)
What are mucous membranes?
Moist membranes that line body cavities that open to the exterior of the body
What are serous membranes?
Moist membranes in a closed ventral body cavity
What is simple epithelium?
Single layer of cells that functions in diffusion, osmosis, filtration, secretion, or absorption
What characterizes pseudostratified epithelium?
Appears to have multiple layers because cell nuclei lie at different levels, but is actually a simple epithelium
What is stratified epithelium?
Consists of two or more layers of cells that protect underlying tissues
What are squamous cells?
Thin/flat cells that allow for rapid passage of substances
What are cuboidal cells?
Cells as tall as they are wide, shaped like cubes or hexagons
What are columnar cells?
Cells taller than they are wide, specialized for secretion and absorption
What are the major functions of connective tissue?
- Binding and support
- Protection
- Insulation
- Transportation (blood)
What is the extracellular matrix (ECM)?
Nonliving substance that separates cells in connective tissue
What are the structural elements of connective tissue?
- Ground Substance
- Fibres
- Cells
What are the types of fibres found in connective tissue?
- Collagen fibres
- Elastic fibres
- Reticular fibres
What is the function of fibroblasts?
Immature form of connective tissue cells that are mitotically active and secretory
What is the function of adipocytes?
Fat cells that store energy
