BONE PRESENTATION PART 3

Jim

Matt

TylerDR. T

Importance of Bone• Bones are not static, which means they are constantly

changing shape and composition to meet the body’s needs. The role of bones extends beyond the function of simply giving your body its shape

• Support• Protection• Movement

• Blood Cell Production• Mineral Storage

Support• Bones provide support and structure• Without bones the human body would essentially be

nothing more than shapeless blob of tissue

Protection• According to Minnesota State’s Emuseum – bones play

an important role in the protection of the vital organs throughout the body

• Skull and backbone (vertebrae) – protect the central nervous system

• Ribs – protect chest – organs as lungs and heart

Movement• Not all of our muscles need to be attached to bones in

order to move (because we have muscles in our digestive and cardiovascular system that helps these systems function)

• The muscles that we use for voluntary movement all require bones to work properly

• Muscles are attached to bones by bands of tissue called tendons. Bones are necessary because the muscles need something to attach to in order to contract and cause motion

Blood Cell Production• According to the University of Michigan Comprehensive

Cancer Center – bones also are important as a center for the production of blood cells

• Inside the bone – filled with a jelly-like material called bone marrow

• Bone marrow – contain red blood cells (needed to transport oxygen throughout the body)

What Else?

1.White blood cells (needed for the immune system)2.Adipocytes (fat cells)3.Fibroblasts (needed to make connective tissue)

Mineral Storage• Much of the body’s calcium is stored in bones• When the body needs more calcium, bone tissue can be

broken down to increase the blood’s supply• Excess calcium can also be stored in bone tissue for later

use

Impact of Aging on BoneChanges

• People lose bone mass or density as they age, especially women after menopause. The bones lose calcium and other minerals

• Vertebrae also lose some of their mineral content, making each bone thinner. The spinal column becomes curved and compressed

• The foot arches become less pronounced, contributing to a slight loss of height

Impact of Aging on BoneChanges

• The long bones of the arms and legs are more brittle because of mineral loss, but they do not change length. This makes the arms and legs look longer when compared with the shortened trunk

•  Joints become stiffer and less flexible• Minerals may deposit in and around some joints

(calcification). Most common in the shoulder

Effects of Those Changes• Bones become more brittle and may break more easily• Breakdown of the joints may lead to inflammation, pain,

stiffness, and deformity• These changes range from minor stiffness to

severe arthritis

Common Problems• Osteoporosis is a common problem, especially for older

women. Bones break more easily. Compression fractures of the vertebrae can cause pain and reduce mobility

• The risk of injury increases because gait changes, instability, and loss of balance may lead to falls

Increasing/Decreasing Bone• The cells involved in increasing and decreasing bone:

• osteoblasts • osteocytes • osteoclasts

Osteoblasts• Osteoblasts are the bone-forming cells. They create a

protein mixture known as an osteoid, which mineralizes and becomes bone. They also produce enzymes that help to mineralize the bone and matrix proteins.

Osteocytes• Osteocytes are primarily inactive osteoblasts. They

maintain bone tissue. It is thought that osteocytes are the cells that control the osteoblast and osteoclasts and tell them when to form or resorb bone.

Osteoclasts• Osteoclasts are the bone-resorption cells, aka they break

down the bone. They play a vital role in calcium homeostasis

Remodeling• The continuing process of bone synthesis and destruction

is referred to as bone remodeling• Helps to maintain structure and normal calcium levels in

the body• During childhood, bone formation outpaces bone

resorption which allows the skeleton to grow• After skeletal maturity is reached the two processes

approximately balance and maintain the skeleton, assuming no disease is present.

Remodeling• Controlled by the stress put on the skeletal system• Under-stressed bone will cause resorption rates to

outpace formation, thus creating thinner and weaker bones (examples)

• The opposite can be seen with bones that are suddenly put under higher levels of stress (examples)