cytology connective tissues Flashcards
(86 cards)
What are the functions of the connective tissues?
- Provide a structural matrix, that supports and connects tissues and cells, forming body organs
- Interstitial fluid allows the exchange of nutrients and waste between cells and the blood supply
What is the major components of the connective tissue?
- Extracellular matrix
which insludes protein fibres, Ground substances, Water
What do the differences in the composisiton of cells, fibers and ground substances create?
They create a structural and functional variability across the connective tissue types
Where do connective tissues originate from?
- Embryonic mesenchymne
What is the structure of mesenchymal cells?
- They are undiferentiated cells with a large nuclei and spindle-shaped cytoplasmic extensions
Name types of connective tissues
- Soft connective tissues proper
-specialsied types( bone, cartilage)
What are the most common cells in connective tissue proper?
Fibroblasts
What are the roles of fibroblasts?
- Proudcing and maintaning ECM components including:
-collagen
-elastin - Ground substances
-The ECM compoents are synthesisied and secreted by fibroblasts and then further modified outside the cell to form the matrix
Name the 2 cell states of fibroblasts
- Active fibroblasts
- Quiescent fibroblasts(fibrocytes)
Explain the strutcure of fibroblats in an Active fibroblast state
- Larger with abundant cytoplasm and irregular branches
-Contain a lot of RER and well developed Golgi Apparatus - Nucleus is large,eurochromatic, with a prominent nucleolus
Explain the structure of Quiescent fibroblasts
- Smaller, spindle-shaped with fewer cytoplasmic processes
- Less RER darker heterochromatic nucleus
What are adipcoytes also known as?
Fat cells
What are adipocytes dervived from?
Mesenchymne
Where are adipocytes found?
Connective tissues of verious organs
What are the functions of Adipocytes?
- Energy storage: They store lipds for metabolic use
- Cushioning + insulation:Protect and insulate skin and internal organs
What is the functions of Macrophages
-Specialize in phagocytosis
-Secrete growth factors critical for tissue repair and regeneration
-Play a role in antigen processing and presentation for lymphocyte activation.
-Abundant at sites of inflammation and involved in tissue repair.
What are the characteristics of Macrophages: Nucleus, surface and Cellular structure
Nucleus:
- Oval or kidney shaped
Surface:
- Irregular with pleats and protrusions, aiding pinocytotic and phagocytic activity
Cellular Structure:
- Contains well developed Golgi Apparatus and
many lysosomes
Where do Macrophages orgiinate from?
Originate from monocytes circulating in the blood.
Monocytes migrate into tissues, where they differentiate into macrophages.
Where do Monocytes form?
-Monocytes form in the yolk sac during early embryonic development and become part of the mononuclear phagocyte system
What do macrophages do in response to inflammation?
- Increase in size and protein synthesis
- Recruit additional monocytes from bone marrow
What is the structure of Mast cells?
- Oval or irregularly shaped
- Contains Basophillic secretory granules which change the colour of basic dyes from blue to purple/red due to sulfated GAGs
What is the function of Mast cells?
They release bioactive substances invloved in:
-Local inflammatory responses
- Innate immunity
-Tissue repair
Name some examples of the molecules released from Mast cells?
-Histamine
-Chemotactic factors
-Cytokines
Where are Mast cells found near and where are they located
-Found near small blood vessels in skin and mesenteries
-Located in tissues lining the digestive and respiratory tracts
