Skeletal Muscle

Get Started. It's Free
or sign up with your email address
Rocket clouds
Skeletal Muscle by Mind Map: Skeletal Muscle

1. Muscle Fibre

1.1. Sarcolemma

1.1.1. T- tubules - Rapid AP transmission

1.2. Sarcoplasmic Reticulum

1.2.1. Termina Cisternae - SR Ca ATPase - Ca2+ into SR

1.3. Sarcoplasm

2. Motor Unit

2.1. Muscle fibres + Somatic motor neurone

2.2. All -or- Nothing contraction

2.3. Graded Response - Change No./Type activated units

2.3.1. Fine motor e.g Eye - 3 to 5 fibres

2.3.2. Gross Motor e.g large muscle - 2000 fibres

3. Myofibril

3.1. Repeating sarcomere units

3.1.1. Z- Lines - myosin + actin

3.2. Shorten in contraction

3.2.1. Isotonic - contract + shortens --> move load

3.2.2. Contaction - Myosin heads form cross bridges with actin. --> ATP

3.2.2.1. Tension ∝ No. Cross bridges

3.2.3. Isometric - Contact + NO shortening --> load NOT moved

4. Meat Tenderness

4.1. Aerobic metabolism stops but ATP is produced.

4.2. Cross bridges broken = Tender

4.2.1. Storage - Hung - Actin and Myosin bond broken by proteolytic enzymes.

4.3. 8 - 15hrs = Glycogen deminished = rigor mortis + tough meat

5. Glycogen + pH

5.1. Anarobic metabolism = Lactate and H+ --> Dec. pH

5.2. Dec pH = reduced bacterial growth.

5.3. Stress - mixing/ long transport distances = High pH = Inc. chance of meet going bad.

6. Classification of Muscle fibres

6.1. Type 1 - Slow twitch - Oxidative - Red muscle

6.1.1. Slow sustained movements

6.1.2. Increased myoglobin, mitochondria and blood vessels

6.1.3. Energy = oxidative phosphorylation - aerobic

6.2. Type 11A - Fast twitch : Oxidative-Glycolytic - Red muscle

6.3. Type 11B - Fast twitch: Glycolytic - White muscle

6.3.1. Fast & high power output

6.3.2. Increase No. Myofilaments

6.3.3. Anaerobic Glycolysis - Fatigue easily

7. Contraction and ATP

7.1. Na - K ATPase restores Na+ and K+.

7.2. Myosin ATPase (Contraction) and Calcium Pumps

7.3. ATP + creatine --> ADP +phosphocreatine CREATINE KINASE

7.4. Glycolysis - Very fast, Anaerobic or Aerobic

7.4.1. Glucose + 2 NAD(+) + 2ADP + 2P --> Pyruvate + 2NADH + 2H(+) + 2ATP + 2h20

7.4.2. NAD+ replenished in oxidative phosphorylation.

7.4.3. Anaerobic

7.4.3.1. Pyruvate + NADH + H+ --> Lactate + NAD+

7.4.3.2. Lactic acidosis - due to acidic metabollic waste.

8. Contol of contraction

8.1. 1. Neuromuscular Junction

8.1.1. Somatic motor neurone --> Acetylcholine - Bind --> nicotinic cholinergenic receptor.

8.1.1.1. Influx of Na+ = End plate potential

8.2. 2. Excitation-Contraction coupling

8.2.1. AP --> sarcolemma - t tubules = Ca2+ realease - SR

8.2.1.1. Ca2+ -->troponin = free actin binding site - Cross bridges

8.2.2. Timing - 1 Relax/Contract Cycle = Twitch

8.2.2.1. Twitch --> 2nd AP = latent period ( - biochemical processes)

9. Factors affecting contraction force.

9.1. Length - Tension

9.1.1. Optimum overlap - Z lines not too close/ far apart before contraction.

9.2. Summation

9.2.1. Close stimuli - Relax failure = summation - Tetanus (Prolonged Contraction)