Anatomy- the human skeleton Flashcards
what are the functions of the human skeleton?
-support
-protect
-locomotion
-mineral reserve
-haematopoiesis
what is bone made of?
functional units called osteons (haversian system)
what is the composition of osteons?
30% organic -type 1 collagen
70% inorganic - calcium and phosphate salt
what are osteoblasts
lay down new bone
what are osteoclasts
break down old bone
what is rickets?
caused by a vid D deficiency, vit d is requited for calcium absorption, bones become overly flexible as they lack mineral content
what is osteogenesis imperfecta?
it is a genetic disorder which affects collagen production, bones become brittle and fracture easily
what are long bones?
-longer than wide
-long shaft
-bones of the limbs eg femur
what are short bones?
-wider than their length
-similar to long bones
-bones of wrist and ankle
what are flat bones?
-thin and flat, usually curved
-eg the skull, sternum, scapula
what are irregular bones?
-dont fit in the other categories
-vertebrae, sacrum, facial bones
what are sesamoid bones?
-small round bones embedded in tendons
-protect tendon and increase movement
what is the function of the type I collagen
allows bending to occur, provides strength
what is the function of the inorganic structure
makes bone sturdy and gives compressive strength
how is collagen laid out?
collagen fibres run in opposite direction so bone can withstand force from opposite directions
what is the function of the long tube like diaphysis?
-strong but has some flexibility
-mostly compact bone
what is the function of the two epiphyses?
-articular surfaces for joints
-mostly spongy bone but compact on surface
what is the function of epiphyseal growth plate?
-seperates diaphysis and epiphyses
-site of growth
-once growth complete, plate ossifies -> epiphyseal line
what is the function of periosteum?
-covers outer surface of the bone
-site of attatchment for tendons
what is the function of endosteum?
lines internal surfaces of cavities with bones
how do bones grow?
bone can only be laid onto a surface, they can’t divide. in order to grow bones need to have the growth plate made up of cartilage as they can grow by apositional growth and interstitial growth. eg cartilage is able to grow from the middle out
what is apositional growth?
the increase in the diameter of bones by addition of bony tissue at the surfaces of bones.
what is interstitial growth?
the process that adds or removes solid mass at locations inside a solid material.
how many bones does the normal body have generally ?
206
how many bones do newborns have?
270
how are bones connected?
joints
what are fibrous joints?
don’t allow movement, found between bones of scull (sutures)
what are cartilaginous joints?
have a layer of cartilage between the two connecting bones
what are synovial joints?
have a gap between two bone surfaces. allow a much greater range of movement (eg numerous )
what is the axial skeleton?
- skull (22)
-vertebral column (33)
-ribs (12 pairs)
-sternum
what is the appendicular skeleton?
-pectoral girdle
-bones of the arms/hands
what is the lower limb?
-pelvic girdle
-bones of the legs/ feet