provide internal
core structure for the attachment of muscles.
Protection of human organs
Keeps body shape
2) joints - place in your
body Where two bones are connected
Three types of joints in your body:
I) fibrous joints
join bones where
no movement is allowed
An example will be the bones of your cranium (the skull).
Ii) cartilaginous joints
allows slight, restricted movement
for example the discs between the vertebrae of the spine
Iii) synovial joints
Allow
free movement in one or more directions to the joints of the pelvic and pectoral girdles.
These joints facilitate movements like standing, sitting, walking and running.
Ii) cartilaginous joints
allows slight, restricted movement
for example the discs between the vertebrae of the spine
Iii) synovial joints
Allow
free movement in one or more directions to the joints of the pelvic and pectoral girdles.
These joints facilitate movements like standing, sitting, walking and running.
Iii) synovial joints
Allow
free movement in one or more directions to the joints of the pelvic and pectoral girdles.
These joints facilitate movements like standing, sitting, walking and running.
3) ligaments – connect bone and bone.
Hold bone in place so that they work in a coordinated manner.
4) tendons - connect muscles to bone.
Attachment to the skeletal muscles move your bones
Facilitate the various positions of the body related to movement and balance.
5) antagonistic muscles
Antagonistic = ‘opposite’
Antagonistic movement of muscles
at least
two sets of muscles
one set
contracts and the other
relaxes
Contraction = stimulated muscle – becomes shorter and thicker
Relaxation = muscle relaxes
Example: biceps and triceps
The
biceps is an example of a
flexor muscle (muscle whose contraction shortens a body part)
Whereas the
triceps is an example of an
extensor muscle (muscle whose contraction extends or stretches a body part).
Note that voluntary muscles are normally connected to at least two bones.
In the case of the biceps the two bones involved are the
scapula and the
humerus
When the biceps muscle contracts only one of the bones moves ( in this case the
radius). The point of attachment to the movable bone is called the
point of insertion and the biceps is attached to this point by a single tendon. So when the biceps
contracts the forearm is lifted or bent, decreasing the angle between the forearm and humerus. and flexing your arm, Thus the biceps is a
flexor muscle
The biceps muscle gets its name from having two tendons attached to the scapula.
The resistance. of these two tendons prevents the contractile force of thebiceps from moving the scapula and therefore
there is no movement of the bone..
The point of attachment of a muscle to the immovable bone is called the
point of origin.
When the arm is bent the biceps cannot contract as it is already in a contracted
state as muscles can only cause movement by
pulling as they contract not by pushing when they relax.
Therefore the straightening of the arm is brought about by the contraction of
the
triceps muscle which is an
extensor muscle as it increases the angle between forearm and humerus
The triceps has three points of origin, two on the humerus and one on the
scapula, and a single point of insertion on the ulna.
Title
Video illustrating the mechanics of the antagonism within the biceps and
triceps.
