Tissue Structure Flashcards
What is a tissue
Collection of similar cells that are grouped together in an organised manner to fulfil a particular function
What are tissues made of
Extracellukar matrix made up proteins
They form strong fibres in bone but are more flexible in skin to allow it to stretch
Two types of bone tissue
Compact (cortisol) which is dense and forms a hollow cylinder
Cancellous bone
Osteoblasts
Form bone
Secrete collagen and organise the mineralisation
Osteoclasts
Disassemble bone in order to remodel it into an optimal shape
Skeletal muscle
Myofibres are long thin multinucleated cells that are specialised to suit their contractile function
Packed together in a highly aligned manner
Lots of mitochondrial
Tendons
Network of collagen that runs through the muscle and surrounds the
High tensile strength that join muscle to bone
Musculoskeletal system
Flexors and extensors work in antagonistic pairs
Blood vessels ( capillaries)
Dissolved nutrients and oxygen can diffuse out of the blood into the tissue
Continuous exchange of fluid between the inside of the capillaries and the surrounding tissue cells
Skin repair
Blood fills the area= clot
Mesh of fibrin fibres formed from circulating fibrinogen
Inflammation
Fibrin clot provided temporary protection and supports migration of fibroblasts
Healed skin can have a scarred appearance (fibrosis)
Bone repair
Blood from damaged vessels clots and forms fibrin scaffold that supports migration of stem cells and new osteoblasts into the repair site
New blood vessel develop and the temporary fibrin scaffold is replaced with collagen
Gradually the fibrin scaffold is completely replaced with bone Extracellukar matrix and becomes mineralised
New Bone ecm eventually remodels to become a strong supporting bone
Muscle repair
Fibrin scaffold forms and becomes populated with capillaries and fibroblasts
Stem cells in the muscle tissue multiply and produce new myoblasts that can fuse with damaged myofibres to repair them or can merge to form new myofibres
New and repaired myofibres become fully integrated and the temporary fibrin scaffold is replaced by collagen and other ECM molecules
Tendon repair
Fibrin scaffold supports in growth of tiny capillaries and fibroblasts
Fibrin gradually replaced with collagen
Eventually after a long time due to poor blood supply, collagen is remodelled to become strong and aligned
In some cases fibrosis can cause adhesions to form
Nerve repair
Injury cuts axon, distal part disintegrates
Debris is cleared away by macrophages and Schwann cells
Schwann cells form a pathway that can guide axon re growth
Eventually this process can result in growth to the target and restoration of function
