11.2 Muscles and Movement
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Transcript of 11.2 Muscles and Movement
11.2 Muscles and Movement
The joints in our body provide mobility and hold the body together. Most joints include the following:
• Bones• Ligaments• Muscles• Tendons• Nerves
Interesting Note:Arthrology is the study of joints and Rheumatology is the branch of medicine devoted to joint diseases/conditions
Their Function in Movement
1. Bones – they contain several different tissues and are therefore considered organs– They provide a hard framework to support the
body– They allow protection of vulnerable softer tissue
and organs– They acts as levers so movement can occur– They form blood cells in their bone marrow– They allow the storage of minerals (esp. Calcium
and Phosphorus)
Bones involved in Movement
Human adults have 206 bones
2. Muscles – for movement to occur muscles must be attached to bones and this attachment is provided by the tendons– Muscles provide the
force necessary for movement by shortening the length of their fibers (this is why muscles must exist as antagonistic pairs )
Ex: hamstring contracts to bend knee and quadriceps contracts to straighten knee
• 3. Tendons – cords of dense connective tissue
4. Ligaments – tough band-like structures that serve to strengthen the joint by connecting bone to bone; ligaments have many different types of sensory nerve endings that constantly monitor the joint to ensure no hyperextension
KNEE JOINT
Human Elbow JointDraw fully labeled joint on board
Elbow Parts and their FunctionJoint Part Function
Cartilage Reduces friction and absorbs compression
Synovial fluid Lubricates to reduce friction and provides nutrients to the cells of the cartilage
Joint capsule Surrounds the joint, encloses the synovial cavity, and unites the connecting bones
Tendons Attach muscle to bone
Ligaments Connect bone to bone
Biceps muscle Contracts to bring about flexion (bending) of arm
Triceps muscle Contracts to cause extension (straightening) of arm
Humerus Upper arm bone; Acts as a lever that allows anchorage of the muscles to the elbow
Radius Lower, top arm bone; acts as a lever for biceps
Ulna Lower, bottom arm bone; acts as a lever for triceps
Hinge Joints• The elbow and the
knee are both hinge joints since they permit an opening/closing type of movement
• Both are also one directional
• Both also are called synovial joints because they have a synovial cavity
Ball and Socket Joints
• Examples include the hip joint and shoulder joint• Permits movement in several directions
Ball and Socket vs. Hinge JointsHip Joint Knee Joint
Freely movable Freely movableAngular motions in many directions and rotational movements
Angular motion in one direction
Motions possible are flexion, extension, abduction, adduction, circumduction, and rotation
Motions possible are flexion and extension
Ball-like structure fits into a cup-like depression
Convex surface fits into a concave surface
Definitions of Movement
• Flexion – decrease in angle between connecting bones
• Extension – increase in angle between connecting bone
• Abduction – movement of bone away from body midline
• Adduction – movement of bone toward midline• Circumduction – distal or far end of a limb moves in
a circle• Rotation – a bone revolves around it own axis