1. A LESSON FOR PARENTS By Matt Cortale, Casey Dillon, Ian Doyle
Bone growth

2. What is the Function of Bone?
Support, Movement & Protection!
gives shape to head, etc.
supports body’s weight
protects lungs, etc.
bones and muscles interact
when limbs or body parts move

3. Bone Growth In The Fetus

4. Intramembranous Bones In The Fetus
The flat bones of the skull are INTRAMEMBRANOUS BONES.
During their development, unspecialized connective tissue appears at the sites of future bones.
Dense blood vessels form and supply the connective tissue with blood.
Eventually, through a process called intramembranous ossification, this connective tissue forms flat bone.

5. Endochondral Bones In The Fetus
Most bones of the skeleton are ENDOCHONDRAL BONES.
They develop from masses of hyaline cartilage shaped like future bony structures.
These cartilaginous models grow rapidly for a time and then begin to change extensively.
Eventually, through a process called endochondral ossification, this hyaline cartilage forms endochondral bones.

6. Endochondral Bone Development
Major Stages (a-d fetal), (e child), (f adult)

7. Fetal Stage
In the region known as the primary ossification center, bony tissue begins to replace hyaline cartilage.
The epiphyses remain cartilaginous and continue to grow into secondary ossification centers.

8. Child Stage
Here, in the child stage of long bone, we see the formation of the epiphyseal plates or disks.
These plates lie between the primary and secondary ossification centers of the long bone.
Long bone continues to lengthen while the epiphyseal plates are active.
However, once the epiphyseal plates ossify, lengthening is no longer possible at that end of the bone.

9. Adult Stage
A developing bone thickens as compact bone just beneath the periosteum or outer layer of bone.
The bone in the central regions of the epiphysis and diaphysis remains spongy, and hyaline cartilage on the end of epiphyses persists throughout life.

10. What Do Bones Need to Grow?
Vitamin A supports bone development
Vitamin C strengthens bone
Vitamin D supports bone structure
Bones, like muscles, need physical stress to break down and cause the bone to regenerate healthier cells

11. Vitamins Vitamin A Vitamin C Vitamin D
Necessary for osteoblast and osteoclast
Deficiency may retard bone development
Vitamin C
Required for collagen synthesis
Deficiency results in slender, fragile bones
Vitamin D
Necessary for calcium absorption

12. Hormones Growth Hormone Stimulates division of cartilage cells
Pituitary dwarfism- bones fail to develop normally and child is very short. This is due to lack of growth hormone.
Pituitary gigantism- excess growth hormone is released, height may exceed 8 ft.
Acromegaly- In adults, excess growth hormone causes enlarged hands, feet, and jaw.

13. Hormones (cont’d) Sex Hormones
In males testosterone, in females estrogen
Cause long bones to grow considerably.
Become abundant at puberty
Estrogen typically has a stronger effect on epiphyseal plates which is why females reach their maximum growth earlier than males.

14. Hormones (cont’d) Thyroid Hormone
Stimulates replacement of cartilage with bone tissue
Increases cellular metabolism
Stimulates osteoblast activity

15. Male vs Female Growth
Females tend to hit puberty earlier than boys. This is why girls are usually taller than boys in elementary school. Girls usually stop growing at the age of 17.
Males develop longer and hit puberty at an older age. This is why men tend to be taller than women in adulthood. Men usually stop growing by the age of 18 but can grow up to the age of 25.
As our body ages, both sexes decrease in heighth after about age thirty.

16. Life-Span Bone Growth Puberty age 12 Puberty age 10 Age 30 Age 30
Male Skeletor Female Skeletor

17. Thank you for watching this presentation!