Chapter 10 p278 Chapter 11 p 312

Is this what you guys want to look like?

…or you girls?

…this is a little more realistic…

…and this is more like what we have to learn!!

What is the difference between a typical animal cell and a MUSCLE CELL? Why are muscle cells called MUSCLE FIBERS? What do you think a MYOFIBER is?

Muscle fiber: Cytoplasm: SARCOPLASM Cell membrane: SARCOLEMMA ER: SARCOPLASMIC RETICULUM Nucleus A muscle cell is a MUSCLE FIBER !!

One MUSCLE FIBER is wrapped in connective tissue called ENDOMYSIUM A bunch of muscle fibers are wrapped in connective tissue called PERIMYSIUM and the whole thing is called a FASCICLE. All the fascicles are wrapped in connective tissue called the EPIMYSIUM Epimysium forms the tendon

Muscle fiber or one muscle cell

Let’s COLOR… Page 142A…….numbers only… Right now…….

Remember, one muscle cell/muscle fiber is made of a thousand or more myofibrils … and each of them is made of thousands of myofilaments !!

One Muscle fiber One-thousand myofibrils Thousands of myofilaments Thin – actin Thick -- myosin is made of each of which contains

UH OH.. more new terms: Sarcomere – basic contractile unit of a myofibril; thin myofilaments –made of proteins called actin, tropomyosin, and troponin; thick myofilaments – made entirely of myosin; T tubules – inward extensions of sarcolemma at a right angle to the long axis of the cell; Z disk or Z line – separates one sarcomere from the next and also serves as an anchor for the myofibrils;

Let’s color!!!! Page 142A….numbers Right now…..

Neuromuscular junction Impulse travels down the AXON of the motor nerve to the terminal end plate. There, the NEUROTRANSMITTER Acetylcholine (Ach) is released to cross the SYNAPSE and stimulate the sarcolemma of the muscle cell:

Are you absolutely, positively, guaranteed, for sure that you know what each of these things are????????? terminal end plate calcium Ach sarcolemma T tubules SR sarcoplasm sarcomere troponin tropomyosin ATP

Terminal end plate of neuron Calcium is required to trigger the release of Ach Ach diffuses rapidly across synapse Ach receptors initiate an impulse that travels along the sarcolemma, along T tubules to the SR Ca is released from SR into the sarcoplasm where it binds to troponin molecules in the thin myofilaments Tropomyosin molecules in those thin filaments shift, exposing actin’s active sites Energized myosin cross bridges bind to actin and pull the thin myofilament toward the center of the sarcomere This continues several times a second as long as there is ATP available As the thin filaments slide past the thick filaments, the entire muscle shortens Sliding filament theory

Relaxation Immediately after the Calcium is released into the sarcoplasm, it is pumped back into the SR. The Ca is stripped off the troponin molecules…troponin without Calcium allows the tropomyosin to block the active sites on actin. The contraction is over.

Disuse atrophy: prolonged inactivity results in decreased muscle mass; Hypertrophy: exercise results in increased muscle mass; Strength training: exercise increasing resistance, isometric exercises, and weight lifting results in increased numbers of myofilaments (protein strands) Endurance training: (aerobic training) increases a muscle’s ability to sustain moderate exercise over a long period—results in increase vascular presence which increases supply of oxygen and glucose; Muscle fibers must continually resynthesize ATP– energy is also supplied by the breakdown of creatine phosphate which is present in small amounts in muscle fibers.

Lactic acid accumulates in muscle tissue and causes a burning sensation. Some of it is carried back to the liver where it is converted back into glucose…this takes time…time to work the soreness out.

1. 3 types of muscle fibers—slow, fast, intermediate 2. Myography13. myalgia 3. Twitch14. contusion 4. Treppe15. poliomyelitis 5. Tetanus16. Duchene Muscular Dystrophy 6. Muscle tone17. Myasthenia Gravis 7. Graded strength principle 18. Hernia 8. Isotonic contractions19. Origin/Insertion 9. Isometric contrctions20. Prime mover/agonist 10. Cramps21. Antagonist 11. Convulsions22. Synergist 12. Fibrillation23. fixator muscle ASSIGNMENT: one minute verbal report or description of one of these:

TEST Wednesday, January 28

Naming muscles Location -- brachialis in arm; gluteus in buttocks Function – flexor carpi radialis Shape -- deltoid (triangular) Direction of fibers – rectus (straight) abdominus Number of heads – biceps brachii, triceps brachii Points of attachment – sternocleidomastoid Size of muscle – gluteus maximus, gluteus medius, and gluteus minimus Table on page in your textbook LEARN THESE!!