The Machine That Repairs Itself

Question 1

Skin layers

Answer 1

1. Epidermis
2. Dermis (nerves and connective tissues)
3. Subcutaneous layer (looser as you go down. Fat)

Question 2

Structures of the musculoskeletal system

Answer 2

Muscles
Bones
Ligaments 
Tendons 
Cartilage

Question 3

What is the difference between muscle cells and connective tissue cells?

Answer 3

Muscle cells are tightly packed together. Connective tissue cells are not tightly packed and float in a matrix.

Question 4

How do muscles to contract

Answer 4

Myosin (thick filaments) grab onto and wrap around thin filaments (actin) causing them to shorten

Muscle cell fibre> microfibril> myofilament

Question 5

What two substances are vital for muscles to contract

Answer 5

ATP to provide the head with energy

Calcium to allow myosin to bind with actin

Question 6

Collagen

Answer 6

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

Question 7

Chondrocytes

Answer 7

Make the matrix in cartilage

Chondro= cartilage

Question 8

Cell that secrete the matrix in loose connective tissue

Answer 8

Fibroblasts

Question 9

Cell that secrete the matrix in ligament connective tissue

Answer 9

Fibroblasts

Question 10

Cell that secrete the matrix in tendon connective tissue

Answer 10

Fibroblasts

Question 11

Cell that secrete the matrix in cartilage connective tissue

Answer 11

Chondrocytes

Question 12

Cell that secrete the matrix in bone connective tissue

Answer 12

Osteoblasts and osteoblasts

Question 13

Bone tissue

Answer 13

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

Question 14

Cells that make and maintain the bone matrix

Answer 14

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.

Question 15

Bone development

Answer 15

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

Question 16

Cartilage three types

Answer 16

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.

Question 17

Tendons

Answer 17

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

Question 18

Types of joint

Answer 18

Synovial: freely movable (have synovial fluid filled space)
Fibrous: not freely movable (skull)
Ligamentous (or cartilaginous) slightly movable

Question 19

Phases of healing (inflammatory response)

Answer 19

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.

Question 20

Skin healing

Answer 20

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.

Question 21

Bone healing

Answer 21

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