The Machine That Repairs Itself Flashcards
Skin layers
- Epidermis
- Dermis (nerves and connective tissues)
- Subcutaneous layer (looser as you go down. Fat)
Structures of the musculoskeletal system
Muscles Bones Ligaments Tendons Cartilage
What is the difference between muscle cells and connective tissue cells?
Muscle cells are tightly packed together. Connective tissue cells are not tightly packed and float in a matrix.
How do muscles to contract
Myosin (thick filaments) grab onto and wrap around thin filaments (actin) causing them to shorten
Muscle cell fibre> microfibril> myofilament
What two substances are vital for muscles to contract
ATP to provide the head with energy
Calcium to allow myosin to bind with actin
Collagen
Connective tissues are characterised by having specialised cells in a matrix
These cells secrete substances to make the matrix
The matrix makes the tissues resilient and strong
Collagen important in bones, cartilage, loose connective tissue and fibrous connective tissue
Chondrocytes
Make the matrix in cartilage
Chondro= cartilage
Cell that secrete the matrix in loose connective tissue
Fibroblasts
Cell that secrete the matrix in ligament connective tissue
Fibroblasts
Cell that secrete the matrix in tendon connective tissue
Fibroblasts
Cell that secrete the matrix in cartilage connective tissue
Chondrocytes
Cell that secrete the matrix in bone connective tissue
Osteoblasts and osteoblasts
Bone tissue
Protection
Produce blood cells (marrow)
Made of collagen and calcium salts
Compact bone and spongy bone (usually has both to keep bone hard but light)
Will remodel to take most strain on parts most used. If you don’t use it you lose it
Cells that make and maintain the bone matrix
Osteoblasts:
Builds bone. Stimulated by weight on bones and oestrogen (weight bearing exercise = good to prevent Holly spongy bone)
Osteoclasts:
Consumes bone. Stimulated by lack of use and low plasma calcium levels
Bones with insufficient calcium salts in them are soft. Bones with insufficient collagen are brittle.
Bone development
Begin as cartilage at birth
Slowly bone laid down from middle outward
Bands of cartilage line the top and bottom= growth plate
End of puberty and growth plate sealed and only lubricating cartilage remains
Cartilage three types
Hyaline:
-areas with great movement. Lubricates. Glossy appearance.
Fibrocartilage:
-tougher and fibrous. Areas where cushioning is needed. In between knee and vertebra
Elastic:
-areas where more flexibility is needed, epiglottis and outer ear.
Tendons
Muscle to bone
Have protective outer sheath
Their elasticity reduces energy required for movement
Tendinitis= inflammation from reparative movement. More common now due to office work
Types of joint
Synovial: freely movable (have synovial fluid filled space)
Fibrous: not freely movable (skull)
Ligamentous (or cartilaginous) slightly movable
Phases of healing (inflammatory response)
Inflammatory phase:
-starts immediately and lasts a few days
Repair/proliferation phase:
-starts after a few days, lasts for a few weeks. Only starts if inflammatory phases has cleaned up the area. May stay in the phase and produce scar tissue
Maturation/ remodelling phase:
-starts after a few weeks, may last a couple of years.
Skin healing
Healing by first intention:
- small, superficial wound to the epidermis. Rapid cell proliferation to fill the gaps
Healing by second intention:
- deeper wound, reaches dermis. Fibroblasts produce granulation tissue so the epidermis has cells to build on. Will most likely leave a fibrous scar.
Bone healing
Inflammatory response leads to increased bleeding and potential clot formation
Clot must be removed
Granulation tissue starts to form, this is only fibrous connective tissue atm so is not strong
Area is ossified (calcium salts laid down) weeks later making it hard
Weeks later it is remodelled to become normal bone
