Connective Tissue Flashcards
What is connective tissue made up from?
Cells
Extracellular matrix
What are the three different fibre types found in the Extracellular matrix of connective tissue?
Reticular, elastic, collagen.
List some of the properties of mesenchymal connective tissue.
In this tissue cells have a tapering appearance. There is abundant ground substance, and cells are similar but are able to differentiate giving rise to new cell types.
What cell types can mesenchymal cells differentiate into?
Chondroblasts, lipoblasts, fibroblasts, osteoblasts, myoblasts.
Where is mucous connective tissue found?
Mucous connective tissue is found in the umbilical cord. Gelatin like ground substance surrounds spindle shaped mesenchymal cells. It contains blood capillaries bearing blood cells.
Describe the structure of a peptidoglycan monomer
This contains a core protein which has approximately 100 GAG glycosaminoglycan units joined. Hyaluronic acid molecules have these attached.
Beside Hyaluronic acid molecules and peptidoglycan monomers, what other substance is found in ground substance of connective tissue?
Collagen fibrils.
Why does ground substance in connective tissue remain hydrated?
GAG molecules have a negative charge and they therefore Stacy water molecules.
What are the four different types of collagen?
1 - forms fibrils and bundles (tendons organs skin dermis)
2 - fibrils don’t form bundles (hyaline/elastic cartilage)
3- recticulin (fibres around nerve/muscle cells)
4 - basement membrane
Describe the structure of type 1 collagen.
It is made up of staggered collagen molecules which is what gives the banding pattern. Each molecule is made up from a triple helical arrangement of a chains. Gly-X-Y is the amino acid pattern. Where X and Y are small.
How do fibroblasts secrete collagen to be formed into bundles?
Fibroblasts secrete pro collagen which is assembles into collagen fibrils. These then form aggregates which form bundles in the same direction.
Describe the structure of a lymph node.
Lymph nodes have a mesh of reticular fibres with lymphocytes densely packed in the spaces inbetween.
What is the name for a fibre made up primarily of elastin but then enfolded and surrounded by fibrillin?
Elastic fibre.
What is Marfans syndrome? Why can it be fatal?
It is a disorder of the elastic tissue caused by abnormal expression of the fibrillin gene. It can lead to aortic rupture.
Name the three layers of a small elastic artery
Tunica intima - endothelium
Tunica media - elastic lamellae
Tunica adventitia - collagen (loose connective tissue)
State the differences in collagen and fibroblasts between loose and dense irregular connective tissue.
In loose irregular, there is less collagen an abundant fibroblasts. In dense irregular, there is abundant collagen and fewer fibroblasts.
What type of connective tissue is the dermis and what are some of its properties?
It is dense irregular connective tissue. Collagen bundles go in different directions which prevents tearing, and elastic fibres allow the skin to stretch.
Connective tissue has protective properties with organs and glands. Where can it be found?
Loose or dense irregular connective tissue forms capsules around organs and glands, and is also responsible for splitting glands into lobules.
What type of connective tissue is found in tendons?
Dense regular. Collagen bundles lie in the same direction as the tensile force, and flattened fibroblasts lie between these bundles.
What is a myotendious junction?
It is the point where tendon collagen fibres join skeletal muscle fibres.
What is the difference between a tendon and a ligament?
Tendons connect muscle to bone whilst ligaments connect bone to bone.
How is collagen arranged in ligaments?
Collagen is packed in a parallel arrangement and is arranged into fascicles which are separated by loose connective tissue.
What are fibroblasts responsible for and therefore what can be said about their cell ultrastructure?
Fibroblasts lay down collagen and ground substance. They therefore need abundant RER. These cells are very important for healing.
When do macrophages move into connective tissue?
During inflammation. They are phagocytic and breakdown foreign material and organisms.
What is a mast cell?
Mast cells are found near blood vessels in connective tissue. They contain granules which are released during trauma.
What three substances do mast cell granules contain?
Heparin - anticoagulant
Histidine - increases blood vessel permeability
Substances to attract eosinophils and neutrophils.
Why do adipocytes show as empty white circles under micro graphs?
The fat is washed away during the preparation process.
Give three functions of adipose tissue.
Fuel reserve, thermal insulation, shock absorption.
What is connective tissue?
Connective tissue is the tissue which connects other types of tissue such as muscle, nerve, epithelial and offers structural but also metabolic and physiological support.
