The Muscular System

1. The Muscular System By Jacob Barabas and Gavin Fernandes

2. Striated Muscle • The general category that includes cardiac muscles and skeletal muscles • Striated- Muscle where contractile fibrils are parallel • Result of sarcomeres

3. 3 types of muscles • Smooth muscles (also the visceral muscles) -help move things, help with other systems • Cardiac muscles- heart • Skeletal Muscle- what we tend to consider muscles

4. Smooth muscle • Involuntary muscle • Cannot be controlled consciously • Examples of where it can be found: • Walls of stomach • Uterus • Bladder • Prostate • Intestines • Arteries and veins • Eye • Each cell has one nucleus, and is not striated (striped)

5. Smooth muscles (cont.) • Move things around the body • Food getting moved through the stomach • Pushing blood through arteries • Regulate air flow in lungs • Sperm flow in reproductive tract • Shrinking pupil • Control things so you don’t have to • Types • Visceral- All cells working together • Multi-unit= Cells work independently

6. Cardiac Muscles • Involuntary contracting muscles in the heart • Rhythmic Contractions pump blood out aorta • Autorhythmic- regulates itself • Arrangement gives the heart strength • Cardiac Muscles are striated • Striated- Muscle in which the contractile fibrils are in parallel rows

7. Cardiac Muscles (cont) • Cells are shaped like Xs or Ys • Connected by intercalated disks • Made by finger-like projections from cells • These bond together and form a strong connection between the cells • These let the heart withstand high blood pressure and a lifetime of hard work • Good for sending electromagnetic signals • Lets the heart cells beat as a unit

8. Skeletal Muscles • Voluntary muscles • Any conscious movement in the body • Striated • These are the muscles that we use to move • Biceps- Two points of origin • Triceps-Three points of origin • Hamstrings- Four points of origin • Tendons connect muscle to bone • When tightened, these muscles cause movement • To bend your arm, your bicep contracts • To extend your arm, your tricep contracts

9. Skeletal Muscles (cont) • Usually connected to two bones across a joint • Always connect in at least one place • Very strong muscles • Composed of myocytes • Move by shortening their length, pulling tendons, pulling bones closer to each other (one bone is pulled to another, stationary bone).

10. Skeletal muscles (cont) Type 1: Fibres : Resistant to fatigue, Type 2: A Fibres : Resistant to fatigue, uncommon Type 2B Fibres: Such fibres are found in large numbers in the muscles of the arms

11. Skeletal Muscles (cont) • The place on the stationary bone that is connected to the muscle via tendons is called the origin • On the moving bone-insertions • The belly is the part of the muscle that contracts

12. Skeletal muscle contracting • Muscles come in pairs (i.e. quadriceps and hamstrings) • One to flex, one to extend • Muscles arranged in fibers • Combined by muscle cells • Composed of units called myofibrils • Composed of myosin and actin • Protein filaments-long chains of proteins

13. Skeletal muscle contracting (cont) • Sarcomere • Functional unit of a muscle • Part that contracts • Cyclic interactions allow actin filaments and myosin filaments to interact allowing muscle contraction

14. How skeletal muscles get their names • Location • Rectus abdominis- in the abdominal region • Tibialis anterior- connects to the tibia • Origin and insertion- what it connects to • Sternocleidomastoid- connects to the sternum and clavical • Number of origins • 2 origins=bicep • 3 origins=tricep • 4 origins=quadricep • Function • Supinator supinates • Shape • Deltoids are shaped like triangles (deltas)

15. Muscle metabolism • Aerobic respiration- produces 36 ATP • Anaerobic- produces but 2 ATP • To keep muscles working • Myoglobin- red pigment • Has oxygen in it in case of a lack • Creatine phosphate turns ADP back into ATP • Glycogen- composed of many glucoses, can be broken up • Fatigue- many waste materials (ADP and lactic acid)

17. In Conclusion The muscular system is a very important system in the body. It allows your body to move and is the fundamental basis of movements like running, jumping, etc. The muscular system is complex, and is responsible for the beating of one’s heart and for countless other things, like moving food through the digestive system and non-conscious movements.

18. Thank you for listening…….. THE END