SHEDDING MY SKELETON
PROBLEM STATEMENT

Amy asked her mother, “Mum, what happened
to the crayfish?”
Her mother replied, “When a crayfish is
growing, it needs to shed its skeleton.”
Then Amy asked, “Mummy, when will I shed my
skeleton?”
CONTENT

Bones
 Bone
Cells
 Characteristics
& Functions
 Formation
Of Bones
 Types Of Bones
 Spongy
& Compact Bones
 Composition
Of Bones
 Functions Of Bones
BONE CELLS

Osteoblasts
 They
are commonly bone-forming cells.
 They secrete osteoid which form bone matrix.

Osteocyte.
A

mature osteoblasts surrounded by bone matrix.
Osteoclasts.
 Resorption
of bones.
FORMATION OF BONES

Bone Development & Growth

Skeletal Growth begins 6 weeks after fertilisation
 At


this time, all skeletal elements are made up of cartilage
Bone formation: Osteogenesis
Ossification
During development, cartilage & connective tissue is
replaced by bone
 Process of replacing other tissues with bone

 Calcification,
ossification.
deposition of calcium salts, occurs during
FORMATION OF BONES

Intramembranous Ossification
Bone develops within sheets or membranes of
connective tissue
 Begins when osteoblasts differentiate within
embryonic/fetal connective/fibrous tissue

 Osteoblasts
differentiate from connective tissue stem cells
after the organic components of the matrix, secreted by the
stem cells becomes calcified.

Blood Vessels begin to grow into the area to meet
osteoblasts’ demands for oxygen and a reliable supply
of nutrients.
 Over
time, blood vessels become trapped within the
developing bone.
FORMATION OF BONES

Endochondral Bones
 Bone
replaces existing cartilage
 Most of the bones of the skeleton are formed
through this ossification of existing hyaline
cartilage.
4 TYPES OF BONE

Long Bones

Irregular Bones
http://www.crnasomeday.com/anatpages/types.htm

Short Bones

Flat Bones
OTHERS

Sesamoid / Round Bones

Sutural / Wormian bones
COMPOSITION OF BONES
Bone or Osseous Tissue, is a supporting
connective tissue & it contains specialised cells &
a matrix of extracellular protein fibers & ground
substance
 Distinctive solid, stony character of bone results
from the deposition of calcium salts within the
matrix.

2/3 of weight of the bone comes from Calcium
Phosphate
 1/3 of weight is dominated by collagen fibers with
osteocytes & other cell types.

COMPOSITION OF BONES
Hyaline cartilage
 Epiphysis
 Cancellous bone
 Epiphyseal plate
 Diaphysis
 Compact bone
 Periosteum
 Medullary cavity

FUNCTION OF BONES

Major functions

Support


Protection



Protect the internal organs
Assisting in movement


The softer tissues and provides points of attachment for most
skeletal muscles.
Skeletal muscles are attached to bones, therefore when the
associated muscles contract they cause bones to move
Storage of minerals
Production of blood cell.

blood cells are produced by the marrow located in some bones
CONCLUSION

Amy, don’t be stupid, we can’t shed our
skeleton.
CREDITS
http://people.eku.edu/ritchisong/bone_growth.
jpg
 http://www.shoppingtrolley.net/lesson1-bonetypes.shtml
 http://www.bbc.co.uk/schools/gcsebitesize/pe
/anatomy/bonecompositionrev2.shtml
 Essentials Of Anatomy & Physiology, Martini
Bartholomew, Third Edition
