1. B.1: Muscles & Movement

2. Joints Joints = articulation or arthrosis
Joints allow the movement of our body and hold it together.
Joints include bones, ligaments, muscles, tendons, and nerves.

3. Types of Joints

4. B.1.1 – The role of bones in human movement
Bones are organs made up of different types of tissues.
Functions:
Hard “framework” for body support
Protection of organs and soft tissue
Form blood cells in bone marrow
Store minerals, especially Calcium and Phosphorus
Act as levers for movement

5. B.1.1 – The role of muscles in human movement
Muscles provide the force necessary for movement.
This happens by shortening their cells (muscle fibers) when the nerve signals.
They must exist as antagonistic pairs, so that the body part can return to normal after one muscle contracts.

6. B.1.1 – The role of tendons in human movement
Tendons attach muscles to bones – this is essential for movement.
Tendons are cords of dense connective tissue.
By acting as levers, bones magnify the force provided by muscles.

7. B.1.1 – The role of ligaments in human movement
Ligaments are tough, band-like structures that strengthen and stabilize the joint.
Ligaments connect bone to bone.

8. B.1.1 – The role of nerves in human movement
Nerves send the signal to muscles of when to contract.
Special nerves in ligaments allow proprioception (your body’s ability to sense it’s own position & movement).
This helps prevent over-extension of the joint.

9. B.1.2 – Hinge Joint: Human Elbow Joint
B.1.2 – label a diagram of the human elbow joint, including:
cartilage,
synovial fluid,
joint capsule,
named bones (radius, ulna ,humerus)
antagonistic muscles (biceps and triceps).

10. Pictures

11. Quick Video: http://www.youtube.com/watch?v=o2DpznoBqNY

12. Joint Part
Function
Humerus
Acts as a lever that allows the origin of the elbow muscles.
Radius
Acts as a lever where the biceps muscle inserts.
Ulna
Acts as a lever where the triceps muscle inserts.
Biceps muscle
Contracts to cause flexion (bending) of the arm.
Triceps muscle
Contracts to cause extension (straightening) of the arm.
Tendons
Attach muscle to bone.
Ligaments
Connect bone to bone.
Cartilage
Reduces friction & absorbs compression
Synovial fluid
Lubricates to reduce friction and provide nutrients to the cells of the cartilage.
Joint capsule
Surrounds the joint, encloses the synovial cavity, and unites the connecting bones.

13. B.1.4 – Hinge Joint: Knee
The knee is a freely movable (diarthrotic) joint

14. B.1.4 – Ball and socket joint: Hip
The hip joint is also diarthrotic, but has many different types of movement possibilities.

15. Hip vs. Knee Joints Hip Joint Knee Joint Freely movable
Ball-like structure of femur fits into a cup-like depression in hip (the acetabulum)
Convex surface fits into a concave surface.
Movements = flexion, extension, abduction, adduction, circumduction and rotation.
Movements = flexion & extension in one direction

19. Muscle Contraction – “sliding filament hypothesis”

20. Process of Contraction
1. Nerve signal (action potential) travels to the end of a motor neuron (nerve that controls a muscle). End portion is called a synaptic end-bulb.
Motor Neuron
Synaptic end bulb
Membrane
Inside of muscle cell
Point of connection = neuromuscular junction

22. 2. Synaptic vesicles within neuron dump Acetylcholine (ACh) into synapse (gap between the neuron and muscle) ACh diffuses across to muscle and lands on ACh receptor proteins.
Membrane
AcetylCholine
ACh receptor proteins

23. 3. ACh receptors start a new action potential (A. P
3. ACh receptors start a new action potential (A.P.) that spreads out across the sarcolemma. They will continue to send out A.P. until the Ach is broken down.

24. 4. A.P. spreads out across the sarcolemma and deep within muscle fiber via transverse tubules
5. As the action potential passes by sarcoplasmic reticulum (SR) the SR release Ca +2 which diffuse to the thin (actin) filaments.

25. 6. Thin filaments are made of actin (to which myosin heads can attach).
Ca +2 binds to actin , making it change shape so that it can accept myosin heads

26. 7. Myosin heads (with an attached ADP + P) binds to actin, forming a cross-bridge. This triggers the heads to bend, pulling on the thin filaments towards the H Zone using energy of the now released ADP + P to shorten the sarcomere.

27. 8. ATP will attach to myosin causing it to release the actin
8. ATP will attach to myosin causing it to release the actin. Thus, the cross-bridges are broken.
The crossbridges will reattach further down on actin and keep pulling as long as there is Ca+2 and ATP is available.

28. 9. Once the action potential stops, SR pump Ca+2 back in (using ATP).
Muscle contraction ends.

32. Muscle fibers
Stages: fully relaxed, slightly contracted, moderately contracted, fully contracted