Connective Tissue (2) Flashcards
What part of the ECM is this?
Ground substance
What is A and B?
A) connective tissue
B) ground substance
Where is ground substance located?
surrounds the fibres and cells of the CT
What 2 proteins are linked to carbohydrate molecules in the ground substance?
proteoglycans (PGs)
glycosaminoglycans (GAGs)
How are PGs and GAGs linked to in ground substance?
carbohydrate molecules
What are the 2 categories of cells found in connective tissue?
fixed cells
transient cells
What are the cells classed as fixed cells
- fibroblasts
- macrophages
- adipocytes
- mast cells
- undifferentiated cells
What is meant by fixed cells?
Fixed cells (or resident cells) - resident population of cells that develop and remain within connective tissue.
What is the role of fibroblast cells?
synthesise the extracellular matrix and collagen
What is an example of transient cells?
white blood cells
neutrophils, eosinophils, basophils, lymphocytes, and monocytes, plasma cells, macrophages, myofibroblasts, melanocytes
What is meant by transient cells in connective tissue?
Transient cells are leukocytes (white blood cells) that circulate in the bloodstream and migrate into connective tissue at sites of an immune response.
What cell is shown in this diagram?
white blood cell
What is A and B in the connective tissue?
fibroblasts
connective tissu
What is this an image of?
WBC penetrating a blood vessel
What are the arrows in these images pointing to in connective tissue?
Fibroblasts
Where are fibroblasts located in CT?
loose CT
What do fibroblasts secrete?
collagen, reticular and elastin fibres
What do fibroblasts synthesise?
collagen, elastin fibres and ground substance
What is the structure/shape of fibroblasts?
Nucleus ovoid, often flattened, one small nucleolus
Long, thin cytoplasmic processes which blend with matrix
When are fibroblasts especially active?
during repair at a wound site
What is A and B in this image?
A) mast cell
B) granules
What is the shape of mast cells?
ovoid connective tissue cell with spherical nucleus
Do mast cells contain granules?
YES
many granules in cytoplasm that secrete histamine
What is the role of herapin?
anti-coagulant
decrease clotting
Where are mast cells found?
Found especially in skin and mucous membranes – immune response, allergy anaphylaxis!
What causes mast cells to release histamine?
Exposure to antigen leads to reaction and release of histamine-containing granules
What is a macrophage?
phagocytic and lysosomal
What is a plasma cell?
produce and secrete antibodies (B cells)
What is a lymphocyte?
smallest of the CT cells 6-8mm, immune response)
B and T cells, secondary immune response
What is a Melanocyte?
Pigment cells
provide pigmentation and thus photoprotection from ultraviolet radiation.
What is the mesenchyme?
embryonic (mucous) CT
What type of connective tissue is shown?
mesenchyme
What makes up the mesenchyme?
Undifferentiated stellate cells, reticular fibres and large amounts of ground substance
What are stellate cells?
Stellate cells are quiescent fibroblasts that normally reside in sinusoidal walls within the subendothelial space of Disse. Stellate cells are activated by inflammatory mediators to commence collagen synthesis. Simultaneously, there occurs activation of tissue metalloproteinases that degrade collagen.
What replaces mesenchyme develop into in adults?
directly replaced by loose CT
Does the mesenchyme give rise to all the CT?
YES
Usually gives rise to all CT
What is the role of the mucous CT?
mesenchyme with very large amounts of ground substance present in umbilical cord
What is A and B?
mesenchyme
Identify the tissue shown below
adipose
Identify the tissue shown below
dense regular CT
Identify the cells indicated at A and state their function
Fibroblast, synthesise collagen and ground substances
Identify the type of fibres shown at B
collagen fibres
Name one location in the body where this type of tissue is found
tendons & ligaments
