2.2 Connective Tissue Flashcards
What are the 4 tissue types?
Nerve, Muscle, Epithelial and Connective tissue
What are the characteristics of connective tissue?
Extracellular matrix containing specialised cells
What are the functions of connective tissue?
Connects - cells to form tissues, tissues to form organs.
Protects - adipose cushion for organs
Transports - nutrients to epithelial cells
Defence - lymph contains immune cells
Storage- triglyceride storage in adipose
Wound healing- macrophages and fibroblasts
What is connective tissue made up of?
- Fibres
- Cells
- Ground substance
What fibre types are present in CT and how do they differ?
- Collagen - type 1, high tensile strength
- Elastin - fibrillin, allows recoil
- Reticular - type 3 collagen, supporting framework
What is the composition of ground substance?
Made of proteoglycans, which consist of a core protein and covalently bound glycosaminoglycans (GAGs) which are long chained polysaccharides. They attract water, giving it a high water content. Resists compression.
Hyaluronic acid = GAG in cartilage.
What are some of the fixed cells present in CT?
Melanocytes Macrophages Mast cells Fibroblasts Adipocytes
What are some wandering cells in CT?
Plasma cells, white blood cells, macrophages
Why are fibroblasts so important?
They secrete fibres and ground substance. E.g pro collagen
What is in the mast cell granules?
Heparin (anticoagulant) and Histamine
What are the 3 types of loose CT?
- Areolar
- Reticular
- Adipose
What are the characteristics of loose CT?
Allows free movement with minimal resistance.
How does areolar, reticular and adipose loose CT differ?
- Areolar lies beneath all epithelia.
- Reticular is dominated by reticular fibres and forms framework around organs and lymph nodes.
- Adipose has little extracellular space, filled with adipocytes which cushion organs.
What are the 3 types of dense CT?
Regular, Irregular and Elastic
Explain the structure and function of regular dense CT.
Parallel collagen fibres with mainly fibroblasts and little ground substance.
High tensile strength in one direction.
Where is regular dense CT found and why?
Tendons, ligaments and muscle apaneurosis because resists stress in one direction.
How does irrregular dense CT differ from regular?
random deposition of collagen fibres allow it to resist stress in multiple directions.
Where is irregular dense CT found?
Dermis of the skin
What is elastic CT and where is it found?
Type of dense CT where elastic fibres dominate over collagen fibres.
Present between spinal vertebrae.
What is fascia and what is it’s function?
Sheets of dense connective tissue which support and compartmentalise.
How does loose CT differ structurally from dense CT?
loose CT contains many different cell types, whereas dense CT is mainly fibroblasts.
loose CT contains sparse collagen fibres, dense contains lots of collagen fibres
loose CT has abundant ground substance, more viscous.
Where is loose CT located?
beneath epithelia (areolar) with important role in diffusion, around small blood vessels and the superficial layer of the dermis.
Aside from the dermis, where is dense irregular CT located?
submucosa of the small intestine
What is the structure of the collagen fibres?
Triple helix of 3 alpha chains
What is the disease caused by abnormal type 1 collagen?
osteogenesis imperfecta
What is Marfan’s syndrome?
expression of fibrillin gene is abnormal, leading to abnormal elastic fibres.
Abnormally tall with frequent joint dislocation.
Autosomal dominant.
What type of collagen are reticular fibres made from?
Type 3
What is the primary component of elastic fibres?
Elastin
Where are elastic fibres particularly important?
Dermis, Artery walls, lungs and sites with elastic cartilage
What is required for collagen pro collagen production?
Vitamin C
