The Skeletal System

Overview

Allows MovementSupportProtectionRed Blood Cell ProductionMineral Storage

Overview

A newborn baby has 305 bones in it’s body, and it continues to develop to the age of 25

At that age the bones fuse together to obtain maximum strength.

OverviewThe average adult skeleton has 206

bones

The largest bones are in the thigh (Femur) and in the upper arm (Humerus).

The smallest bones are the 3 tiny bones in you middle inner ear

Overview

All bones are living organs, which contain living materials (cells), and non- living (mineral) materials

Divisions of the Skeleton

The skeleton is divided into 2 parts:1. The Axial Skeleton2. The Appendicular Skeleton

Divisions of the Skeleton

The Axial Skeleton refers to all bones that are grouped along the midline (middle) of the body.

These include: the skull, spinal column & chest.

Divisions of the Skeleton

The Appendicular Skeleton refers to appendages that are attached to the axial skeleton.

These include: the pelvic girdle, arms & legs (126 bones)

Functions

Body MovementFramework (support)ProtectionMineral StorageProduction of Red Blood Cells

Functions

Movement:Bones work together with skeletal muscles to help produce movement

Muscles, which are usually arranged in pairs, are attached to the skeleton, when one contracts…the other relaxes, etc…

Functions

Muscles move the bones, bones meet (articulate) at the joints, and the whole body then becomes mobile

FunctionsFramework (Support):

Bones provide support for tendons and ligaments and the framework for body shape

Tendons= cords of thick, strong fibres that connect muscle to bone

Ligaments= cords of thick, strong fibres that connect bone to bone

FunctionsProtection:

Bones such as the cranium, ribs and sternum provide vital protection for internal organs such as the brain, heart and lungs

FunctionsMineral Storage:

Bones are a site for storage and the release of minerals.

Foods that contain more calcium and phosphorus than the body are stored in the bones in the form of collagen.

Collagen = A strong, flexible material produced by bone cells. Forms the main part of connective tissue such as tendons and ligaments

Mineral Storage

Functions

Red Blood Cell Production:Bones are responsible for the production of new blood cells.The spaces between the spongy bone are filled with red bone marrowHaemoglobin is a protein inside RBCs that transports Oxygen around the body

FunctionsRed Bone Marrow is

bone tissue that makes Red Blood Cells and some White Blood Cells

Production decreases as you age, after peaking during puberty.

What’s in a Bone? Periosteum

Is a tough membrane.Contains blood vessels that enter the bone at many points nourishing the cells inside.Contains the cells for growth and repair.

What’s in a Bone?

Compact bone lies beneath the periosteum and as the name suggests it is hard and dense.

Compact bone covers the spongy bone at either end of long bone.

What’s in a Bone?

Compact bone is at it’s thickest at the shaft of the bone.Compact bone gives strength, whilst spongy bone acts as a shock absorber

What’s in a Bone?Yellow Bone Marrow

fills the shaft of the long bone and is used as a fat storage site (long term energy).

It is mostly made of fat cells