Skeletal System
Physiology and Anatomy
Callum van Aswegen
Skeletal System Assignment
The skeletal system is made up of the bones, cartilage and joints in our bodies. The skeleton
acts as a protection to the vital organs as well as giving the body structure and giving the
body support.
Axial skeleton- provides the aim area of support and protection for our body. The bones
that make up the axial skeleton are: the cranium (skull) the thorax (rib cage) and the
vertebral column (spine)
Appendicular skeleton- this part of the skeleton consists of the bones of the limbs. The
bones that consist of the appendicular skeleton are the femur, fibula, and tibula which are
in the legs. The humerus, radius and ulna which is in the arms as well as the girdles that join
to the axis skeleton
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The skeletal system has 206 bones.
80 bones form our axial skeleton
126 form our appendicular skeleton
This is a labelled skeleton of the human
Appendicular skeleton:
Upper limb bones: 60 bones form the upper limbs and each upper limb is made up of 1
humerus, 1 radius, 1 ulna, 8 carpals 5 metacarpals, and 14 phalanges.
Lower limb bones: 60 bones form the lower limbs. Each lower limb bone is made up of 1
femur, 1 tibia, 1 fibula, 1 patella, 7 tarsals, 5 metatarsals and 14 phalanges.
Skeletal System
Physiology and Anatomy
Callum van Aswegen
Bones of the lower limbs are designed to take the weight of the body, locomotion and
maintain the upright posture. Due to this being the case they need to have a high degree
of strength and stability.
Shoulder girdle- this consists of 4 bones, 2 clavicles and 2 scapula. These bones connect the
limbs of the upper body to the thorax.
Pelvic girdle- this is made up of 3 bones. The ilium, ischium and pubis, these bones have the
tendency to fuse together when one ages and becomes mature. It is then known as the
innominate bone. The main structure and purpose of the pelvic girdle is to provide a solid
base to take the weight of the upper body. As well as providing attachment for the upper
body muscles of our lower back and legs. It also protects the digestive system and
reproductive organs.
Support- the skeleton gives our
body shape; it provides the
supporting framework for the
soft tissues of the body. This
prevents the body and from all
humans collapsing in a heap on
the floor.
Protection: the bones of the skeleton surround and protect vital tissues and organs in the
body.
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The skull protects the brain
The thorax protects the heart and lungs
The vertebral column protects the spinal cord
The pelvis protects the abdominal and reproductive organs
The skeletal system moves by a co-ordinated action of the muscles on the bones. Tendons
attach muscles to bones and this allows and provides leverage. When muscles pull on a
bone they act as levers and movement occurs at the joint.
Skeletal System
Physiology and Anatomy
Callum van Aswegen
In our skeletal system our bones are not completely solid as this would make our structure
incredibly heavy and hard to move. We have blood vessels that feed through the centre of
the bones and is stored in the middle known as the bone marrow. Bones that are long
continuously produce red and white blood cells. This is a crucial process because in our body
red blood cells die every minute so it is very important that our bones are in good condition
to keep processing and making these red and white blood cells.
Definition of bone marrow- Fat or blood forming tissue found within bone cavities.
The bones of the skeleton are classified according to their shape and size and can be divided
into certain categories. Long bones are found in the limbs, these acts like levers such as the
femur in the thigh and the humerus in the upper arm. They have shafts known as the
diaphysis and two expanded ends known as the epiphysis.
Definitions of:
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Diaphysis- “the shaft of a long bone”
Epiphysis-“the rounded end of a long bone”
Short bones are small, light, strong, cube shaped bones. An example of this bone is the
carpals of our wrist and the tarsals of our feet.
Flat bones are thin, flattened and slightly curved. These bones have large surface areas,
examples of this type of bone is the pelvis, scapulae and cranium.
Sesamoid bones are found in tendons, example in the patella.
Irregular bones have a complex shape and cannot be put into any category. Example[le is
the hip bone and the vertebrae.
Term
Anterior
Posterior
Medial
Lateral
Proximal
Distal
Superior
Inferior
What it means
To the front or in the front
To the rear or behind
Towards the mid line
Away from the mid line
Near to the root or origin
Away from the root or origin
Above
Below
“Exercise increases the strength of bones. They adapt to
stress imposed during exercise by laying down more
calcium”
Skeletal System
Physiology and Anatomy
Callum van Aswegen
Definitions of words used in the formation and purpose of the Skeletal
System
Extension- “straightening a limb to increase the angle at the joint e.g. straightening your
arm and returning to the starting position of a bicep curl”
Abduction- “moving a limb away from the mid line of the body e.g. lifting your arms from
the sides of your body”
Adduction- “two moving a limb towards the midline of the body e.g. lowering your arms
back to your sides”
Circumduction- “moving a limb a full 360 degrees circle e.g. circling your shoulder”
Rotation- “turning about the vertical axis of your body, inwards and outwards such as the
shoulder and hip”
Pronation- “the inward rotation of the forearm so that the palm of the hand is facing
backwards and downwards e.g. wrist joint during a table tennis forehand topspin shot”
Supination- “the outward rotation of the forearm so that the palm of the hand is facing
forwards and upwards e.g. wrist joint during a table tennis backhand topspin shot”
Inversion- “moving the foot and ankle inwards”
Eversion- “moving the foot and ankle outwards”
Hypertension-extension- “this involves movement beyond the normal anatomical position
in a direction opposite to flexion. This occurs at the spine when a cricketer arches his/her
back when bowling”
Tendons attach muscle to bone
Ligaments attach bone to bone
Bones are not static. They become stronger and denser
as a result of the demand one puts on them. This can be through physical activities such as sport, or
everyday life such as work. Physical activities can increase the mineral content of our bones.
The types of exercise that help build strong bones are strength training and weight bearing exercises
that work against gravity. Good examples of these sports are tennis, netball, basketball, aerobics,
dancing walking and running. Bones are strengthened as a result of stress put on them. The quantity
of calcium and collagen increases and reduces the risk of osteoporosis.