12. Connective And Adipose Tissue Flashcards
What is connective tissue made up of?
Connective tissue cells
Extracellular proteins/glycoproteins
‘Gels’
What are the main cells in connective tissue?
Fibroblasts
Chondrocytes
Osteocytes/osteoblasts/osteoclasts
Stem cells/bone marrow/blood/adipocytes
What are the main products of connective tissue?
Fibres
Ground substance
Wax and gel-like materials
What are the 3 main components of connective tissue?
Cells
Fibres
Ground substance
What fibres re present in connective tissue?
Collagen
Elastin
Reticular fibres
What are the functions of connective tissue?
Binding and supporting Protecting Insulating Storing reserve fuel and cells Transport Separation of tissues
What is another term for loose connective tissue?
Areolar tissue
Give 2 examples of loose connective tissue
Submucosa of colon
Superficial layer of dermis in skin
What is the structure of loose connective tissue?
Fibroblasts, macrophages WBC, mast cells, adipocytes
2 main fibres - collagen, elastin
Ground substance - proteoglycan
What are the functions of loose connective tissue?
Hold vessels that supply fluids
Permits cell migration
Involved in inflammation pathways
Packaging around organs
Where is loose connective tissue distributed?
Under epithelial cell layers
Around glands
Surrounding capillaries
Nerves and sinusoids
What are fibroblasts?
Synthesise and secrete fibres that lie in ground substance
Important in wound healing process
What are myofibroblasts?
Modified fibroblasts
Contain actin and myosin
Responsible for wound contraction
What are macrophages?
Phagocytic, degrade foreign organisms and cell debris
Antigen presenting cells
Move into loose connective tissue when local inflammation
What are mast cells?
Contains abundant granules
- histamine increases blood vessel wall permeability
- heparin is anticoagulant
- cytokines attract eosinophils and neutrophils
What are white adipocytes?
Single,large lipid droplet with nucleus, cytoplasm nd organelles squeezed to one side of cell
Unilocular
What is the function of white adipocytes?
Padding and shock absorber
Insulation
Energy reserve
What are brown adipocytes?
Multiple small lipid droplets with nucleus, cytoplasm and organelles squeezed to centre of cell
Mainly in neonates
Lots of mitochondria
What is the function of brown adipocytes?
Insulation and energy reserve
How is heat generated using brown adipocytes?
Oxidative phosphorylation uncoupled
Lipid breakdown accelerated
How is heat generated using white adipocytes?
After shivering reflex
Lipid breakdown slow
What is the feature of collagen type 1?
Fibrils aggregate into fibres and fibre bundles
90% of all collagen
What is the feature of type 2 collagen?
Fibrils do not form fibres
Present in hyaline and elastic cartilage
What is type 3 collagen also called?
Reticulin
What is the function of reticulin?
Provides supporting framework/sponge
Absent in areolar tissue
What is the function of elastin?
Allows tissues to recoil after stretch or distension
What is ground substance?
Viscous, clear substance with slippery feel
Composed of proteoglycans
What are proteoglycans?
Large macromolecules with core protein which glycosaminoglycans (GAGs) covalently bind
What is dense connective tissue?
Fibrous or collagenous tissue
Contains fibroblasts
What are the 2 types of dense connective tissue?
Irregular
Regular
Describe irregular dense connective tissue and give an example
Fibres running in different directions to resist stresses
Collagen 1 fibres in all directions
E.g. superficial layer of dermis in skin to prevent tearing
Describe regular dense connective tissue and give and example
Fibres running in parallel to each other
Collagen 1 fibres in parallel
Resist stress in one direction
E.g. in tendons that connect muscles to bones
What are myotendinuous junctions and what is their purpose?
Skeletal muscle fibres connecting with tendon collagen bundles at junctions provide physiological strength
What are tendons?
Connect muscle to bone
Very strong
Forces transmitted along collagen bundles
What are ligaments?
Similar to tendons Connect bone to bone Parallel collagen fibres Undulate Wrapped in loose connective tissue (fascicles)
What are the 3 types of fascia?
Superficial
Deep
Visceral or parietal
What is fascia?
Made up of fibrous connective tissue
Flexible
Contains closely packed bundles of collagen fibres
What are elastin fibres?
Elastin main component of elastic fibres, surrounded by microfibrils
In most connective tissue
Why is vitamin C important in collagen production?
Required for intracellular production of procollagen
Without, collagen formation disputed
What do smooth muscle cells produce?
Elastin, collagen, matrix
What is Marfan’s syndrome?
Autosomal dominant
Expression of fibrillin 1 gene affected
Elastic tissue abnormal
What are the signs of Marfan’s?
Abnormally tall
Arachnodactyly
Joint dislocation
Aortic rupture
What is osteogenesis imperfecta?
Brittle bone disease Mutated collagen fibres do not knit together or not enough produced Weakened bones Short stature Blue sclera Hypermobility
