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Locomotion and Movement - Joints

Grade 11CBSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Joints are essential for all types of movements involving the bony parts of the body. In these movements, joints act as a fulcrum for the force generated by the muscles.

Fibrous Joints: These do not allow any movement. For example, the flat skull bones which fuse end-to-end with the help of dense fibrous connective tissues in the form of sutures to form the cranium.

Cartilaginous Joints: The bones involved are joined together with the help of cartilages. This joint permits limited movement, such as between the adjacent vertebrae in the vertebral column.

Synovial Joints: Characterized by the presence of a fluid-filled synovial cavity between the articulating surfaces of the two bones. This arrangement allows considerable movement and assists in locomotion.

Ball and Socket Joint: Found between the humerus and pectoral girdle, and between the femur and acetabulum of the pelvic girdle (BallSocketBall \in Socket).

Hinge Joint: Allows movement primarily in one plane, such as the knee joint and elbow joint.

Pivot Joint: Found between the first cervical vertebra, the Atlas, and the second, the Axis (AtlasAxisAtlas-Axis).

Gliding Joint: Found between the carpals of the wrist.

Saddle Joint: Found between the carpal and metacarpal of the thumb.

Gout: Inflammation of joints due to the accumulation of uric acid (C5H4N4O3C_5H_4N_4O_3) crystals.

Osteoarthritis: Degeneration of joint cartilage and the underlying bone, often associated with the depletion of Ca2+Ca^{2+} and aging.

📐Formulae

Force×Lever Arm=Torque (Movement at Joint fulcrum)\text{Force} \times \text{Lever Arm} = \text{Torque (Movement at Joint fulcrum)}

C5H4N4O3 (Uric Acid accumulation in Gout)C_5H_4N_4O_3 \text{ (Uric Acid accumulation in Gout)}

Ca10(PO4)6(OH)2 (Hydroxyapatite in bone matrix)Ca_{10}(PO_4)_6(OH)_2 \text{ (Hydroxyapatite in bone matrix)}

💡Examples

Problem 1:

Identify the type of synovial joint present between the Atlas and Axis vertebrae that allows the 'no' movement of the head.

Solution:

Pivot Joint

Explanation:

The Pivot joint (TrochoidTrochoid joint) consists of a bony pivot-like process that rotates within a ring formed by another bone and a ligament. In the case of the Atlas (C1C_1) and Axis (C2C_2), the odontoid process of the axis fits into the atlas, allowing rotational movement.

Problem 2:

A patient suffers from inflammation of joints and tests positive for high levels of C5H4N4O3C_5H_4N_4O_3 in the blood. Name the condition.

Solution:

Gout (Gouty Arthritis)

Explanation:

Gout is a metabolic disorder characterized by hyperuricemia, where excess uric acid (C5H4N4O3C_5H_4N_4O_3) precipitates as monosodium urate crystals in the synovial fluid, leading to acute inflammation.

Problem 3:

Contrast the movement allowed by the joint in the cranium vs the joint in the pubic symphysis.

Solution:

Cranium: Zero movement; Pubic symphysis: Limited movement.

Explanation:

The cranium uses fibrous joints (sutures) which are synarthrosessynarthroses (immovable). The pubic symphysis is a cartilaginous joint (symphysis) which is an amphiarthrosisamphiarthrosis, allowing limited movement especially during childbirth.

Joints - Revision Notes & Key Diagrams | CBSE Class 11 Biology