ToB 9 Connective Tissues Flashcards
Define ‘connective tissue’:
Tissue which links together muscle, nerve and epithelial tissues, providing structural support, and metabolic and physiological support.
Name the 6 functions of connective tissue:
1) Provide substance and form to the body and organs
2) Provide a medium for diffusion of nutrients and wastes
3) Attach muscle-to-bone, and bone-to-bone
4) Provide a cushion between tissues and organs
5) Defend against infection
6) Aid in injury and repair
Name the 6 main types of connective tissue:
1) Loose connective tissue
2) Dense connective tissue
3) Cartilage
4) Bone
5) Blood
6) Lymph system
What are the 4 basic types of tissue in the human body?
1) Epithelial
2) Muscular
3) Nervous
4) Connective
What tissue is the tissue is the most abundant, widely distributed, and varied type?
Connective tissue
What are the 2 general components of connective tissue?
1) Cells
2) Extracellular matrix
What are the 2 general components of the extracellular matrix within connective tissue?
1) Ground substance
2) Fibres
What 3 types of fibres may be found in connective tissue?
1) Collagen
2) Reticular
3) Elastic
What type of fibres are found in the lung connective tissue?
Elastic fibres
What type of fibres are found in the lymph node connective tissue?
Reticular fibres
What type of connective tissue is present in the umbilical cord?
Mucous connective tissue
The dermis is an example of what kind of connective tissue?
Dense irregular connective tissue
Tendons are examples of what kind of connective tissue?
Dense regular connective tissue
What are the 3 main classes of connective tissue?
1) Embryonic connective tissue
2) Connective tissue proper
3) Specialised connective tissue
What are the 2 types of embryonic connective tissue?
1) Mesenchyme
2) Mucous connective tissue
Give an example of mucous connective tissue:
Umbilical cord
What are the different types of connective tissue proper?
Loose/areolar connective tissue
Dense connective tissue (Regular or irregular)
Name the 6 types of specialised connective tissue:
1) Adipose tissue
2) Blood
3) Cartilage
4) Bone
5) Lymphatic tissue
6) Haemopoetic tissue
Lymphatic tissue would come under what main class of connective tissue?
Specialised connective tissue
Loose/areolar connective tissue would come under which main class of connective tissue?
Connective tissue proper
What type of embryonic connective tissue is pluripotent?
Mesenchyme cells
Define pluripotent:
Cells which can give rise to many different cell types
What type of cells form the mesenchyme?
Mostly mesodermal cells, but also some ectodermal cells.
Maturation and proliferation of mesenchyme cells give rise to what?
- Various connective tissues
- Serous membranes
- Vascular system
- Urogenital system
- Muscle
What cell type forms cartilage?
Chondroblasts
What is the main function of chondroblasts?
Formation of cartilage
What cell type forms adipose cells?
Lipoblasts
What is the main function of lipoblasts?
Formation of adipose cells
What cell type forms supporting tissues such as ligaments/tendons?
Fibroblasts
What is the main function of fibroblasts?
Formation of supporting tissues such as ligaments/tendons
What cell type forms bone?
Osteoblasts
What is the main function of osteoblasts?
Formation of bone
What cell type forms skeletal muscle cells?
Myoblasts
What is the main function of myoblasts?
Formation of skeletal muscle cells
Why is it important for mesenchymal cells to persist in the adult?
To produce new connective tissue when required for healing
What is the general constitution of mucous connective tissue?
- Mostly specialised ground substance
- Few mesenchymal cells
- Few fibres
What is the main constituent of cartilage ground substance?
Proteoglycans, made up of core proteins each with approx. 100 glycosaminoglycan (GAG) units joined. These core proteins are linked onto hyaluronic acid, to form a hyaluronate proteoglycan aggregate.
Why does cartilage ground substance form a hydrated gel?
The glycosaminoglycans give the ground substance a high density of negative charge, attracting water
What is meant by ‘GAG’?
Glycosaminoglycan
What is formed when GAG units attach to a hyaluronic acid molecule?
Hyaluronate proteoglycan aggregate
Describe cartilage extracellular matrix:
Hyaluronate proteoglycan aggregates form an interwoven network with collagen fibrils
What are the 3 main properties of GAGs, and why?
1) Highly negative charge
2) Inflexible
3) Strongly hydrophilic
Allows attraction of water to form gel-like substance, and makes the connective tissue good at resisting compressive forces.
What proportion of our whole-body protein content is collagen?
Between 1/4 to 1/3
What is gelatin?
Collagen which has been hydrolysed irreversibly, and is used in the food industry
What is the most common type of collagen?
Type I
Describe Type I collagen:
Collagen fibrils aggregate into fibres and fibre bundles.
Give 3 examples of where you can find collagen Type I:
1) Tendons
2) Capsules of organs
3) Skin dermis
Which types of collagen form fibres?
Types I and III
Describe Type II collagen:
Collagen fibrils do not form fibres
Where is Type II collagen found?
Hyaline cartilage
Elastic cartilage
What type of collagen is present in hyaline cartilage?
Type II
What type of collagen is present in tendons?
Type I
Describe Type III collagen:
Collagen fibres form fibres called Reticulin.
What is an alternative name for Type III collagen?
Reticulin
What is an alternative name for Reticulin?
Type III collagen
What type of collagen is found in the basal lamina of a basement membrane?
Type IV
Where is type IV collagen found?
In the basal lamina of the basement membrane ONLY
Define and explain the appearance of a type I collagen fibril after staining:
It has repeating periodic banding every 68nm, which is produced because each collagen fibril is composed of staggered collagen molecules. Adjacent molecules have a small gap between them, where heavy metal stains, therefore ‘gap’ zones produce the dark staining bands.
What is the length and width of a type I collagen molecule?
300nm long, 1.5nm wide