2.1 (b) - Role of Muscles, Ligaments & Tendons In

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• To label the bones, the skeletal muscle and tendons in a diagram of the arm;

• To explain how movement is brought about in a limb;

• To state the function of cartilage & synovial fluid at joints.

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• Movement is caused by the contraction of skeletal muscles which interact with the bones.

• Muscle cells contract in response to stimulation which carried by nerve impulses.

• Muscles are attached to bones by tendons near a joint.

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• Tendons consist of very strong inelastic, non-stretchable collagen fibres & appear as glistening silver-grey strands between the muscles & bones

• Function : to ensure that the force produced by the contraction of muscles is transmitted to the part of the body to be move.

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• A joint is formed where 2 or more bones come together held together at a joint by ligaments.

• Ligaments are tough & strong connective tissues, elastic & allow the movement of bones at a joint. Also important in preventing dislocation.

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TYPE OF JOINT

CHARACTERISTIC EXAMPLE FUNCTION

Immovable/ fixed(suture)

Bones held together by fibrous connective tissue. No movement between bones.

•Skull•Pelvic girdle

•Protects delicate tissues of brain & sense organs•Protect urogenital organs; support body

Partially movable

Cartilage bridges the joints. Movement is restricted.

•Vertebral column.

•Some degree of flexibility•Cartilage is a shock absorber, cushions joint & reduces friction

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TYPE OF JOINT

CHARACTERISTIC EXAMPLE FUNCTION

Movable/sinovial(i) Hinge

(ii) Ball-and-socket

•Ends of articulating bones are covered with cartilage. Joint enclosed by joint capsule. It is lined with a thin synovial membrane which secretes synovial fluid.

•Knee, elbow, finger joints

•Shoulder, hip joint

•Movement in one plane

•Movement in all planes and some rotational movement

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TENDON LIGAMENT

similarities

made up of collagen fibreshold two types of tissues together

differences

Bone & muscle Bone & bone

No elastin tissues Elastin tissues present

Inelastic Elastic

COMPARISON BETWEEN TENDON & LIGAMENT

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MUSCLES

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• Action on muscles in bringing about movement

• Some muscles work together to bring about movement while other muscles work in opposition to one another

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Antagonistic Muscles• Muscles which work in opposition. Eg : biceps and triceps

• Muscles can contract and relax • Muscles can pull on the bones but cannot push

• Muscles which straighten limbs are called extensors

• Muscles which bend limbs are called flexors

• Extensor work antagonistically with flexor.

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ANTAGONISTIC MUSCLES

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• All muscles have 2 primary proteins – Actin – MyosiN

• Actin and myosin are found in sarcomeres, the functional units of muscle contradiction

• Sacromeres consist of thick filaments (actin) which interact to bring about muscle contraction.

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• The source of energy for contradiction of muscles is ATP, which is produced in adjacent mitochondria in the muscles

• Movement of the body involves the coordination of opposing muscles which are attached to the bones across the joints

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• At the joint, the bones are allowed to move, in relation to each other, y the elastic ligaments.

• The Synovial membrane secretes synovial fluid which serves as a lubricant to minimize the friction between two bones

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• The articulating surfaces of the bones are covered by flexible cartilage.

• Cartilage protects the joint and allows smooth movements.

• It also absorb shock when pressure is placed on the joint, for example when walking.

• W/out synovial fluid and cartilage, the bones will rub together.

• It can lead pain and swelling of joints

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