Connective tissue (proper) Flashcards
What is connective tissue made up of (3 components)?
- Cells
- Fibres
- Ground substance (e.g. proteoglycans)
What is the extracellular matrix made up of?
Ground substance and fibres
Structure/function of CT (6 things)
- Binding & supporting
- Protecting
- Insulating
- Storing reserve fuel and cells
- Transporting substances within the body (blood & interstitium)
- Separation of tissues
Loose CT key points (4 things)
- Contains multiple cell types
- Fibroblast, macrophages, WBC, mast cells, adipocytes
- Contains collagenous and elastic fibres
- Gel-like ground substance (e.g. hyaluronic acid)
Functions of loose CT/areolar tissue (6 things)
- Holds vessels that supply fluids
- Permits cell migration
- Involved in inflammation pathways
- Acts as packaging around organs
- Generally holds everything in place
- Cushions & stabilises organs
Fibroblasts key points (5 things)
- Synthesise & secrete fibres that lie within ground substance
- Very important in wound healing process
- Primarily responsible for scar tissue formation
- Myofibroblasts contain actin and myosin
- Responsible for wound contraction when tissue loss occurred
What are macrophages?
Professional APCs- they move into loose CT
Mast cells key points (5 things)
- Histamine (increases blood vessel wall permeability)
- Heparin (anticoagulant)
- Cytokines (signalling)
- Absent from CNS to avoid damaging effects of oedema
- Become coated with IgE, which specifically bind allergens (rapidly releases granules after cross link binding)
Unilocular adipocytes key points (5 things)
- White adipocytes
- Single large lipid droplets
- Cytoplasm and all organelles squeezed to one side of cell
- Padding and shock absorber
- Insulation and energy reserve
Multilocular adipocytes key points (6 things)
- Brown adipocytes
- Very few in adults
- Multiple small lipid droplets
- Cytoplasm and organelles all squeezed to centre of cell
- Provides insulation and energy reserve
- Increased no. mitochondria
Type I collagen (3 things)
- Most widely distributed
- Fibrils aggregate into fibres and fibre bundles
- Tendons, capsules of organs, skin dermis
Type II collagen (2 things)
- Fibrils don’t form fibres
- Hyaline and elastic cartilage
Type III collagen (3 things)
- Fibrils form fibres
- Around muscle & nerve cells, lymphatic tissues, lymphatic organs, tendons
- Called reticulin
Type IV collagen (2 things)
- Unique form present in basement membrane
- Considered of epithelial tissue
What is absent in areolar tissue?
Reticulin
Loose CT location (4 things)
- Beneath epithelia
- Associated with epithelium of glands
- Around small blood vessels
- Can swell then return to original size
What is ground substance (5 things)?
- Viscous clear substance with slippery feel (lots of water)
- Composed of proteoglycans
- Large macromolecules to which GAGs are covalently bound
- GAGs attract water to form a hydrated gel
- A unique GAG is hyaluronic acid (in cartilage)
Proteoglycan structure (4 things)
- Hyaluronate is key
- GAGs attached to core proteins
- In turn these are attached to the hyaluronate
- The sugar moieties attract water but make ground substance sticky and slippery too
The myotendinous junction key points (3 things)
- Skeletal muscle fibres connecting with tendon collagen bundles here provides tremendous physiological strength
- Collagen interacts with collagen fibres coating the muscle fibres
- Cross-links between these fibres results in mechanical strength
Tendon anatomy (3 things)
- Very strong
- Forces can be transmitted along collagen bundles as they can glide over each other
- Mainly made of water
Irregular dense CT (4 things)
- Contains fibroblasts
- Collagen I fibres in all directions
- Resists stress in all directions
- Deep layer of dermis and submucosa of intestine
Regular dense CT (4 things)
- Contains fibroblasts
- Collagen I fibres in parallel
- Resist stress in only one direction
- Tendons, ligaments, aponeuroses
Ligaments key points (4 things)
- Connect bone to bone
- Parallel collagen fibres
- Not straight but undulate
- Wrapped in loose CT (fascicles)
3 types of fascia (name based on anatomical position)
- Superficial
- Deep
- Visceral/parietal
Fascia key points (3 things)
- Fibrous CT containing closely packed bundles of collagen fibres
- Flexible and can resist unidirectional tension forces
- Straightens out wavy pattern of fibres
Collagen fibril production (3 things)
- Vitamin C needed for intracellular production of procollagen where it hydroxylates proline & lysine
- Lack of disrupts collagen formation
- Poor wound healing and impaired bone formation
Scurvy symptoms (6 things)
- Gum disease and tooth loss
- Bruising of skin and hair loss
- Bleeding
- Poor wound healing
- Weakness and fatigue
- Impaired bone development in young
Marfan’s syndrome key points (4 things)
- Autosomal dominant disorder
- Expression of fibrillin 1 gene affected so elastic tissue abnormal
- Abnormally tall, arachnodactyly, frequent joint dislocation, risk of catastrophic aortic rupture
- Wingspan greater than height
Locations where elastin fibres have an important role (4 things)
- Dermis
- Artery walls
- Lungs
- Sites bearing elastic cartilage
What is osteogenesis imperfecta (3 things)?
- “Brittle bone disease”
- Mild to severe
- Mutated collagen fibres that don’t knit together, not enough produced or both
Symptoms of osteogenesis imperfecta (6 things)
- Weakened bones
- Short stature (depends on type)
- Presence of blue sclera
- Hearing loss
- Hypermobility & flat/arched feet
- Poor teeth development
Mucoid CT key points (5 things)
- Immature fibroblasts
- Thin collagen fibres
- Jelly-like ground substance (hyaluronic acid)
- Umibilical cord
- Vitreous humour of eye
