6-3 Skeletal muscles

Question 1

What are tendons?

Answer 1

• Non elastic tissue which connects muscles to bones

Question 2

What are ligaments?

Answer 2

• Elastic tissue that joins bones together and determines the amount of movement possible at a joint.

Question 3

What are joints?

Answer 3

• The area where two bones are attached for the purpose of permitting body parts to move, they are made of fibrous connective tissue and cartilage.

Question 4

What are antagonistic muscle pairs?

Answer 4

• Pairs of muscles which pull in opposite directions, as one muscle contracts, the other relaxes.
• Flexors and extensors are antagonistic pair such as triceps and biceps.

Question 5

Describe the structure of skeletal muscles?

Answer 5

• Skeletal muscles are under voluntary control.
• Attached to bones by tendons and ligaments.
• Muscle cells are grouped together to make larger, stronger structures.
• Protein fibres called myofibrils run through these groups of cells increasing their strength.
• Myofibrils are made from thick and thin filaments which overlap in places to give a banded appearance.
• Within these the thick filaments are made of myosin and the thin filaments are made of actin.
• Two actin molecules are twisted together to make the filament.
• The myosin has heads which can attach to specific binding sites on the actin when the muscle is contracting.

Question 6

What is phosphocreatine?

Answer 6

• Phosphocreatine is a molecule that can be used to supply the phosphate for ADP phosphorylation to ATP.

Question 7

What are slow twitch fibres?

Answer 7

• STF are specialised for slow contractions and are adapted to long period of exercise such as marathon running therefore, they do not fatigue quickly.
• They are adapted to aerobic exercise by having a large store of myoglobin, a rich supply of blood vessels and numerous mitochondria.

Question 8

What are fast twitch fibres?

Answer 8

• FTF on the other hand are adapted for rapid release of energy during intense exercise such as sprinting.
• As a result they are adapted by having thick and numerous myosin filaments, a high concentration of glycogen, a high concentration of enzymes needed for anaerobic respiration, and a store of phosphocreatine.