Connective Tissue Flashcards
What are the 4 basic types of tissue?
Epithelial
Muscle
Nerve
Connective
What e=are some examples of specialised connective tissue?
Adipose Lymphatic Blood Haemopoietic Cartilage Bone
What are the functions of connective tissue?
- Connects cells to form tissues, connects tissues to form organs and connects organs to form the body. Some tissues provide support as well as connecting (cartilage and bone)
- Transportation - provide a medium for diffusion of nutrients and wastes
- Protection - provide a cushion between tissues and organs and
provides insulation (adipose tissue) - Storage (adipose tissue)
- Defence against infection (blood, lymph, fixed and wandering cells)
- Wound healing (macrophages, fibroblasts, myofibroblasts)
What is CT proper?
General connective tissue - loose and dense
What components does CT proper comprise?
Cells
Fibres
Ground substance
What types of fibres are found in connective tissue and what are their properties?
Collagen – Flexible with high tensile strength
Reticular (also collagen) – Provide a supporting framework/sponge
Elastin – Allows tissues to recoil after stretch or distension (elasticity is the ability to recoil to original size)
What is ground substance?
Ground substance is a viscous, clear substance with a slippery feel. It has a high water content. Composed of proteoglycans
What is a proteoglycan?
A proteoglycan is a large macromolecule consisting of a core protein to which glycosaminoglycans are covalently bound
What is a glysaminoglycan?
Glycosaminoglycans (GAGs) are long-chained polysaccharides. GAGs attract water to form a hydrated gel that permits rapid diffusion but also resists compression.
What is hyaluronic acid?
A unique GAG is hyaluronic acid that is
bound to proteoglycans by a link protein to form giant hydrophilic macromolecules. It is present in the ground substance of cartilage.
The swelling pressure or turgor that occurs in cartilage ground
substance allows it to resist compression without inhibiting flexibility
What is the extracellular matrix?
A term used to describe a complex extracellular structural network that consists of ground substance and fibres
Ground substance made of starch and proteins
GAGS on proteoglycans
Fibres support ground substance
What are the differences in loose and dense connective tissue in terms of cells, fibres and ground substance?
Loose – Many cells – Sparse collagen fibres – Abundant ground substance – Viscous, gel-like consistency – Important role in transport (by diffusion)
Dense
– Few cells, nearly all fibroblasts
– Many collagen fibres
– Little ground substance
Where is loose connective tissue found and why?
Located beneath epithelia (to facilitate diffusion)
Associated with epithelium of glands
Located around small blood vessels
All of the above are sites where pathogens, such as bacteria that have breached an epithelial surface, can be challenged and destroyed by the cells of the immune system. During these reactions, loose connective tissue can undergo considerable swelling
What are the 2 types of dense connective tissue?
Regular and irregular
Describe dense regular connective tissue and where it is found
– Collagen fibres are arranged in parallel bundles and are densely packed. Between the bundles are fibroblasts
– Designed to withstand stress in a single direction
– Seen in tendons, ligaments and aponeuroses
Describe dense irregular connective tissue and where it is found
- Collagen fibres are arranged in bundles orientated in various directions. Between the bundles are fibroblasts
– Designed to withstand stress in multiple directions
– Examples are submucosa of intestine and deep layers of dermis
What are tendons?
A cord of strong fibrous collagen tissue which connects muscle to bone