Histology 3 (Connective Tissues) Flashcards
What cells are connective tissues derived from?
Cells in the mesoderm layer of the developing embryo
What is the cellular component of connective tissues?
Fibroblasts
Adipocytes
What are the extracellular components of connective tissues?
Visible fibres and invisible ground substances
Give examples of visible fibres
Collagen
Elastic
Reticulin
Give examples of ground substance (Hydrophilic Jelly)
Proteoglycans
Glycosaminoglycans (GAGS)
Laminin
Fibronectin (Invisible Fibres)
Where are connective tissue cells mainly derived from?
Relatively undifferentiated pluripotential mesenchymal cells
What cells can mesenchymal cells give rise to?
Mast cells
Fibroblasts
Chondroblasts
Osteoblasts
Adipocytes
What are mast cells?
A type of white blood cell that is found in connective tissues all through the body, especially under the skin, near blood vessels and lymph vessels, in nerves, and in the lungs and intestines.
What are fibroblasts?
Fibroblasts are the most common cell type represented in connective tissue. These cells produce a diverse group of products including collagen type I, III, and IV, proteoglycans, fibronectin, laminins, glycosaminoglycans, metalloproteinases, and even prostaglandins
What are chondroblasts?
Cells that play an important role in the formation of cartilage (AKA chondrogenesis).
They are located in the perichondrium, which is a layer of connective tissue that surrounds developing bone and also helps protect cartilage.
What are osteoblasts?
Osteoblasts are cuboidal cells that are located along the bone surface comprising 4–6% of the total resident bone cells and are largely known for their bone forming function
What are white adipocytes?
Rounded cells that store excess energy in the form of fatty molecules, mainly triglycerides
What are brown adipocytes?
Special type of body fat that is turned on (activated) when you get cold.
Brown fat produces heat to help maintain your body temperature in cold conditions
Thermogenesis
Which adipocytes contain more mitochondria?
Brown
Give examples of connective tissues that arise from the haematopoetic stem cell line?
Monocytes
Macrophages
Lymphocytes
Mast cells
Blood cells
What is the haematopoetic stem cell line?
Give rise to all blood cell types including myeloid and lymphoid lineages
Why does ground substance appear as white spaces on histological slides?
Doesn’t stain with haematoxylin and eosin
Give 3 ways connective tissues can be divided into?
Fibrous
Hard
Fatty
What is fibrous tissue divided into?
Loose
Dense
Depending on arrangement of collagen fibres within them
What are examples of hard connective tissue?
Cartilage
Bone
What are the two types of fatty connective tissue?
White
Brown
What is the principle extracellular fibre?
Collagen
What is collagen secreted by?
Fibroblasts
What is tropocollagen?
A triple helix of peptides
How are the fibres of collagen assembled?
Extracellularly
How many types of collagen are there?
More than 20
Where is Type 1 collagen prevalent in?
Skin and bones
Where is Type 2 collagen prevalent?
Cartilage
Where is Type 3 collagen prevalent?
Liver, bone marrow and spleen
What is Type 3 collagen also known as?
Reticulin
What does Type 3 collagen do?
Provides a scaffold for the liver, bone marrow and spleen
Where is Type 4 collagen found?
Basement membrane of epithelia
Where is Type 5 collagen prevalent?
Placenta
What do collagen fibres look like histologically?
Extracellular
Stained pink with H&E