Option B – Muscles Movement and Fitness

Option B – Muscles Movement and Fitness

B1 - Muscles and movementB.1.1 State the roles of bones, ligaments, muscles, tendons and nerves in human movement.

Bones provide the structure onto which soft tissue is built, as well as provide a system of levers that allow for movement through muscular contraction.

http://jagpower.blogspot.com/2011/10/bones-provide-structure-onto-which-soft.html

Ligaments hold bones together

http://www.aclsolutions.com/images/Seif_knee%20anatomy02.jpg

Muscles do the work….They pull against bones to provide movement.

http://www.human-body-facts.com/images/human-body-muscle-diagram.jpg

Tendons join muscles to bones.

httphttp://www.ehrenchiropractic.com/nervous_sys.jpg://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/8956.jpg

Nerves signal muscles to contract.

B.1.2 Label a diagram of the human elbow joint, including cartilage, synovial fluid, joint capsule, named bones and antagonistic muscles (biceps and triceps).

Outline the functions of the structures in the human elbow joint named.

Bending the elbow diagram - put the numbers in the right places!1. Ulna2. Radius3. Contracted biceps brachii muscle4. Relaxed triceps muscle5. Humerus

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Straightening the elbow diagram - put the numbers in the right places!1. Radius2. Relaxed biceps brachii muscle3. Humerus4. Contracted triceps muscle5. Tendon6. Ulna

http://campaigns2.axappphealthcare.co.uk/medical-encyclopaedia/bending-the-elbow

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Match the description on the right with the part on the left : • Holds the bones

together.

• Provides a very smooth surface to reduce friction.

• Acts as a lubricant.

• Secretes and holds in synovial fluid

B.1.4 Compare the movements of the hip joint and the knee joint.

Knee: hinge joint - considerable movement in one plane - constrains movement from other two planes

• flexion (bends)• extension (straightens)

Hip: ball and socket joint - movement in three planes

• protraction /retraction: forward and backwards • abduction/adduction: sideways in and out • rotation: circular movement

B.1.4 Compare the movements of the hip joint and the knee joint.

B.1.5 Describe the structure of striated muscle fibres, including the myofibrils with light and dark bands, mitochondria, the sarcoplasmic

reticulum, nuclei and the sarcolemma.

Structure of muscle fibers:

Each muscle is made up of bundles of muscle fibres. Each fibre is then made up of even smaller structures, called myofibrils.

The myofibrils are sarcomeres attached end to end, which contain light and dark bands, causing the myofibril to appear striped.

In between the myofibrils, there are mitochondria to provide the energy for muscle contraction. The sarcoplasmic reticulum surrounds each myofibril

B.1.5 Describe the structure of striated muscle fibres, including the myofibrils with light and dark bands, mitochondria, the sarcoplasmic reticulum, nuclei and the sarcolemma.

B.1.6 Draw and label a diagram to show the structure of a sarcomere, including Z lines, actin filaments, myosin

filaments with heads, and the resultant light and dark bands.

B.1.7 Explain how skeletal muscle contracts, including the release of calcium ions from the sarcoplasmic reticulum, the formation of cross-bridges, the sliding of actin and myosin

filaments, and the use of ATP to break cross-bridges and re-set myosin heads.

A nerve impulse is sent and reaches the neuromuscular junction causing a neurotransmitter to be released into the synapse.

This triggers the depolarisation of the sarcolemma, which is the plasma membrane on the muscle fibre. As a result, calcium ionsare released from the sarcoplasmic reticulum and this exposes binding sites for myosin to form cross bridges with thin actin filaments. The actin is pulled to the midline.

ATP is then hydrolysed at the myosin head, causing it to detach from the actin binding site , then reattach further along the filament. The entire cycle repeats.

How a muscle contraction is signalled - Animation - YouTubewww.youtube.com/watch?v=CepeYFvqmk4

B.1.8 Analyse electron micrographs to find the state of contraction of muscle fibres.

If electron micrographs of a relaxed and contracted myofibril are compared it can be seen that: 1. Each sarcomere gets shorter (Z-Z) when the muscle contracts, so the whole muscle gets shorter. 2. But the dark band, which represents the thick filament, does not change in length.

This shows that the filaments don’t contract themselves, but instead they slide past each other.

http://click4biology.info/c4b/11/hum11.2.htm#8