Biology

I. Types of bones

a) long bones

E.g.: femur, tibia, fibula, humerus, radius, ulna

b) flat bones

E.g.:  scapula                                                    bones of the skull

II. Structure of bones

• cartilage
  • at the end of long bones
• compact bone:
  • concentric rings (lamellae)
  • with central canals
• spongy bone
  • numerous cavities
  • trabeculae – can be rearranged
  • red bone marrow
• medullary cavity
  • yellow bone marrow
• periosteum
  • covers the surface
  • rich in blood vessels and nerves

Bone marrow:

• red bone marrow:

Produces blood cells

• yellow bone marrow:
• mostly adipose tissue

Can convert into each other.

III. Bone connections:

 Joints / articulations – where bones meet

 a) fixed

sutures:
between cranial bones
fontanels: allow slight movement during birth

fusion :
sacrum, pelvis

cartilaginous joint:
cartilaginous discs between vertebrae
between ribs and sternum
slightly movable

 b) movable

synovial joints:
joints of the ankle, elbow, shoulder, knee

IV. Disorders:

• dislocation: (=ficam) bones are separated, displaced at a joint

• sprain: (=rándulás) stretching or tearing ligaments

• arthritis: joint inflammation, autoimmune reaction

• Osteoporosis:

extreme bone loss -> easily broken
peak density at 35
smoking, heavy drinking, lack of exercise
prevention: plenty of Ca2+, regular exercise