Muscles And Contraction

Question 1

Epimysium

Answer 1

Connective fascia and collagen that covers the entire muscle separating it from surrounding tissue

Question 2

Perimysium

Answer 2

Surrounds bundles of muscle fibres, contains blood vessels and nerves to supply fascicles

Question 3

Emdomysium

Answer 3

Surrounds muscle fibre, contains capillaries and nerve fibres

Question 4

Muscle Structure

Answer 4

Muscle, Fascicles, Muscle Fibres, myofibrils, myofilaments, sarcomeres

Question 5

Sarcolemma

Answer 5

Cell membrane of muscle cell

Question 6

Transverse Tubules

Answer 6

Carry muscle action potentials into the cell, terminal cisternae are attached which store calcium

Question 7

Sarcoplasmic Recticulum

Answer 7

Surrounds each myofibril helping the transmission of action potential

Question 8

Myosin

Answer 8

Contractile protein that binds to actin

Question 9

Tropomyosin and troponin

Answer 9

Regulatory proteins that block the actin binding site from myosin

Question 10

Structural Proteins

Answer 10

Provide alignment, elasticity and extensibility e.g. Titin, myomesin, nebulin and dystrophin

Question 11

Titin

Answer 11

Anchors myosin to m line and z disc, stretches 4 times resting length, important in eccentric contractions

Question 12

Sliding Filament Mechanism

Answer 12

Myosin cross bridges pull on actin causing it to slide towards M line causing the sarcomere to shorten the muscle fibre to shorten and the muscle contract

Question 13

Skeletal Muscle Contraction

Answer 13

Ach released into synaptic cleft
Na channels open causing AP to be passed on
AP spreads over sarcolemma down t tubules
AP reaches triad
Terminal Cisternae release Ca into sarcoplasm and binds with troponin
Troponin tropomyosin compels moves revealing binding site on actin
Contraction cycle begins

Question 14

Contraction Cycle

Answer 14

Active site is exposed as Ca binds to troponin causing the complex to move
Cross bridge is formed as myosin heads move using ATP and bind to actin
Pivoting of myosin head occurs as it pulls actin towards M line releasing ADP + P
Cross bridge detaches as myosin head binds to ATP

Question 15

Muscle Relaxation

Answer 15

AchE breaks down Ach in synaptic cleft
AP in muscle ceases
Ca channels close and detached from troponin is AT into terminal cisternae so Ca concentration falls in muscle cell
Complex recovers binding site on actin
Muscle relaxes

Question 16

Creatine Phosphate

Answer 16

ATP + creatine = creatine phosphate
Breaks down quickly
Lasts up to 15 secs

Question 17

Anaerobic respiration

Answer 17

ATP produced in glycolysis
Pyruvic acid produced
Turns to lactic acid
Causes muscle fatigue

Question 18

Aerobic Respiration

Answer 18

Pyruvic acid enters mitochondria 
Generates ATP H2O + heat
Fatty acids and Amino Acids can also be used
90% of ATP production
Lasts 10 mins +