Levers in human body
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The document discusses levers in the human body. It defines levers as rigid bars that rotate around a fulcrum or axis. There are three classes of levers - first class has the fulcrum between the effort and resistance arms, second class has the resistance arm between the effort and fulcrum, and third class has the effort arm between the fulcrum and resistance. Examples of each class in the human body include the head lifting muscles using the atlas joint as a first class lever, the Achilles tendon acting as a second class lever, and the bicep muscle bending the elbow as a third class lever. Levers in the body allow for increased power, distance, speed, and precision of
![Regents Biology 2015/2016
[ Levers in human
body ]
Mohamed M.Elsaied
2016/2017
Supervised by :- Dr. Abouzeid A.Thabet
Allied Medical Science
Biomechanics](https://image.slidesharecdn.com/leversinhumanbody-170608101751/85/Levers-in-human-body-1-320.jpg)
Levers in human body
- 1. Regents Biology 2015/2016 [ Levers in human body ] Mohamed M.Elsaied 2016/2017 Supervised by :- Dr. Abouzeid A.Thabet Allied Medical Science Biomechanics
- 2. Introduction Mohamed M.Elsaied 2016/2017 When person is moving his leg - arms - any part of his body He depend on his Skelton system (muscle forces) by contraction or extension muscles. In fact the bone in moving work as A lever Levers cannot be changed, but they can be utilized more efficiently .
- 3. levers Mohamed M.Elsaied 2016/2017 Definition of levers A rigid bar that turns about an axis of rotation or a fulcrum . Parts of a lever - Fulcrum Axis of rotation of the lever . - Effort Arm The part of the lever that the effort force . - Resistance Arm The part of the lever that applies the resistance force .
- 4. Classification of levers Mohamed M.Elsaied 2016/2017 First Class Lever A first-class lever is a lever in which the fulcrum (Axis) is located between the input effort (Force) and the output load (Resistance). Second Class Lever Resistance (load) is located between the effort arm and the fulcrum . Third Class Lever The effort force is located between the fulcrum and the resistance .
- 5. The 3 Classes of Levers Mohamed M.Elsaied 2016/2017 | Resistance Arm | | Force Arm | A F R | Force Arm | | Resistance Arm | A R| Resistance Arm | F A R | Force Arm | F • FAR 1st • ARF 2nd • AFR 3rd
- 6. 1 st class of lever in human body Mohamed M.Elsaied 2016/2017 The joint between the skull and the atlas vertebrae of the spine the spine is the fulcrum across which muscles lift the head .
- 7. Mohamed M.Elsaied 2016/2017 The joint between the hummers and radius – ulna .
- 8. 2 nd class of lever in human body Mohamed M.Elsaied 2016/2017 The Achilles tendon, pushing or pulling across the heel of the foot .
- 10. 3 rd class of lever in human body Mohamed M.Elsaied 2016/2017 The elbow joint: when lifting a book, the elbow joint is the fulcrum across which the biceps muscle performs the work.
- 12. Benefit from lever ? Mohamed M.Elsaied 2016/2017 Increase power Increase distance Increase speed Transfer power from one place to another precision in work safety Avoid risks