: - Define the physiology of Contraction and movement of joint .
Muscle Contraction
•Muscle contraction is the activation of tension generating sites within muscle cell. In physiology muscle contraction des not necessarily mean muscle shortening because muscle tension can be produced without change in muscle tength such a when holding a heavy book or dumbbell at the same position. The termination of muscle contraction is followed by muscle relaxation, which ua return of the muscle fibers to their low tension generating state
:- Muscle Contraction
→ Muscle contraction can be described based on two variables - length and tensions. A muscle contraction is described as isometric if muscle tension changes but the muscle length remains the same. In contrail a muscle contraction is isofonic if muscle tension remains the same throughout the contraction. If the muscle length shortens the contraction is concentric. If the muscle length lengthens the centrachion is eccentric In natural movement that underline locomotor activity, muscle contraction are multifaceted as
Joint
- they are able to produce change in hongth and tersion in a time varying manres. Therefore neither Length nes tenina is likely remain the same in muscles that contract during Lecometer activity; In vertebrates skeletal musck antractors as they
require syraptic copul from meter neurons. A single motos newson is able to innervate multiple muscle likent therebly. causing the fibers to contract at the same time. Once innervatet the protein filament within each ckeletal muscle fiber skik part each to produce a contraction which is explained by the sliding filament theory they contraction proceed can be described as a tartch summation or betanus, depending on the frequency of action potential. In skeletal muscher mucche tomon is at its greated when the muscle is stretched to an intermediate length as described by the length tension relations
Unlike skeletal muscle, the contraction of smuth and cardic muscle are myogenic < meaing that they are initiated by the sweeth or both muscle cell themselves instead of being stimulated by an outsiche event such as nerve stimulatives although thy can be necklated by stimuls from the autonomic nesvout system. The mechanisms of contraction in these muscle tissures are similar to those in skeletal musche haves.
:- Tendens
→ Tendens allach many skeletal muscks across joints allowing muscle contraction to move the bones across the yount Muscles generally work in paix to produce movement when one muscle flexes fox centraids) the other reloxer, a process know as antagonism Ligaments and tenders of the aun and Leg
Ball and socket joint
Hinge joint
Plane joint
Skeletal muscle
There are three types of joints: immovable paully movable and synovial inmoralle joings like these connecting the cranial benes have exlges that tightly interlock partly merable, joint allow some degree of flexibility and weally have Cartilage between the hopes example Vertebrae joint permit the greatest degree of flexibility and have the end of bener covered with a connective tissue filled with sgreviable flux example hip. Special
the outer surface of the synovial joints centains ligaments that strengthen goinds and hotel banes in pecition. the inner surface the synovial members has celle producing groval fluid that lubricales the joint and prevent the lowe cartilage cap: on the born from rubbing together. Some goinh also have tendent & connective tissue linking murcles to beness Bursat are small saps filled with synovial think that acture friction in the joint.
