Download Unit 12 - Support, Movement and Locomotion

Topic 12 – Support, Movement & Locomotion
12.1 – Bones, 12.2 – Joints, 12.3 – Antagonistic muscles
SUFEATIN SURHAN  BIOLOGY MSPSBS  2010
SYLLABUS CHECKLIST
Candidates should be able to:
a) identify and describe, from diagrams, photographs and real specimens, the main bones of the forelimb
(humerus, radius, ulna and scapula) of a mammal;
b) describe the type of movement permitted by the ball and socket joint and the hinge joint of the
forelimb;
c) describe the action of the antagonistic muscles at the hinge joint.
SUPPORT, MOVEMENT & LOCOMOTION
 SUPPORT: refers to the skeleton and its role in
holding the body structure and giving it shape.
 MOVEMENT: refers to the change in the position of
one part of the body in relation to another part.
 LOCOMOTION: refers to the movement of the entire
body from one place to another.
FUNCTIONS OF SKELETON
1. To provide support and give and maintain the body
shape.
2. To allow movements at the joints through the
contraction of muscle attached to the bones
3. To provide protection to delicate organs.
Example:
Ribcage protects the lungs, liver, heart,
and major blood vessels.
Cranium (skull) protects the brain, inner
and middle ear and nasal organs.
Vertebral column (backbone) protects
the spinal cord.
4. Production of red blood cells and white blood cells
in the bone marrow.
 The mammalian skeleton can be divided into:
1. AXIAL SKELETON which consists of the skull
(cranium and face bones), vertebral column,
ribs and the sternum.
2. APPENDICULAR SKELETON which consists of:
(a) LIMBS: forelimbs and hindlimbs.
(b) GIRDLES: Shoulder (Pectoral) girdle and Hip
(Pelvic) girdle.
 Bones and cartilages are both made up of non-living
mineral substances such as Calcium Phosphate and
Calcium Carbonate.
 Bones are tougher and inelastic compared to
cartilages as it contains more mineral salts.
 Cartilages contain collagen and are found in the
pinna, the end of the nose and at the ends of bones
where a joint is located. It allows bones to move
smoothly over one another.
They help to reduce
fritction at the joint and acts as a shock absorber.
 The bone marrow is found in the centre of the bone
and has a good supply of blood.
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STRUCTURE OF FORELIMB (FOREARM)
 The forearm is made up of 4 main bones: Scapula,
Humerus, Radius and Ulna.
 There are joints in between these bones:
(a) Between the Scapula and Humerus (at the
shoulder) is the Ball and socket joint.
(b) Between the Humerus and the Ulna (at the
elbow) is the Hinge joint.
 Movement of the forelimbs is brought about by a
pair of skeletal muscles: biceps and triceps, which
act antagonistically to each other.
 Since biceps are responsible for the bending or
flexing of the forearm it is also known as flexor
muscle.
 As triceps are responsible for the straightening of
the forearm, it is known as extensor muscle.
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Skeletal Muscles, Tendons and Ligaments
 Muscles that move the body are called skeletal
-
scapula and 1 point of attachment to the radius.
muscles which are voluntary muscles.
 Muscles are attached to a bone at both ends through
the tendons.
 Tendons are tough inelastic fibres. Their toughness
is particularly important where they pass over a
bony structure.
 Biceps and triceps have different number of tendons
Biceps have 2 points of attachment to the
-
Triceps have 2 points of attachment to the
scapula, 1 point of attachment to the humerus
and 1 pint of attachment to the ulna.
 Ligaments hold bones together at a joint and
prevent the dislocation of the bone at joints. They
consist of tough fibrous and elastic tissues.
for attachment to their respective bones:
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Joints
 Joints are formed when two or more bones
articulate.
 They can be classified as movable (synovial joints)
and immovable joints.
 Synovial joints contain synovial fluid in between the
bones.
1. Ball and Socket Joint.
Consist of a ball-like head of one bone fitting into
the socket-like structure of another bone.
Allows movement in all planes (360o rotation) –
backward, forward and sideways.
Found at the shoulders and hips.
 Synovial membrane lining the capsular ligament
secretes synovial fluid and holds the synovial fluid in
place.
 The synovial fluid lubricates the joint and helps to
reduce friction at the joint.
2. Hinge joint
Allow movement in one plane only (180o rotation).
Example is the bending and straightening of the
arms and knees.
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