Compendium Review Chapter 12 (Cont'd)

IV. Whole Muscle Contraction, Cont'd.
V. Muscular Disorders
VI. Homeostasis

IV. Whole Muscle Contraction, Cont'd.
2. Fermentation: Produces 2 ATP from the breakdown of glucose to lactate anaerobically.
- Most likely to begin with glycogen.
- Hormones signal muscle cells to break down glycogen, making glucose available.
- Fast-acting, but results in buildup of lactate, which produces short-term muscle aches and fatigue upon exercising.
- Oxygen-debt: Continuous intake of oxygen. Required to complete the metabolism of lactate and bring cells back to their original energy state.
- Lactate is brought to liver, and 20% is broken down into carbon dioxide and water.
- ATP is gained, and then it reconverts 80% of lactate to glucose and glycogen.
3. Cellular Respiration:
- Myoglobin: molecule that combines with ans stores oxygen.
- Makes use of glucose from the breakdown of glycogen stored in muscle, blood, and fatty acids. (Mader 237)
(Insert Muscle Contraction Requires Energy picture / Frolich PowerPoint Slide 11)
D. Fast-Twitch and Slow-Twitch Muscle Fibers
1d. All muscle fibers metabolize both aerobically and anaerobically.
2d. Fast-Twitch fibers: Usually rely on creatine phophate pathway and fermentation, which are anaerobic (no oxygen required).
- Designed for strength because their motor units have many fibers.
- Provide explosions of energy.
- Light in color / fewer mitochondria, little or not myoglobin, and fewer blood vessels than Slow-Twitch fibers.
- Maximum tension is greater.
- Vulnerable to accumulation of lactate.
(Insert Fast-Twitch Muscle Fibers picture / www.muscleandstrength.com / http://www.muscleandstrength.com/articles/muscle-and-muscle-fibers.html)
3d. Slow-Twitch Muscle Fibers: Prefer Cellular Respiration (aerobic).
- Steadier tug, more endurance.
- Tire only when fuel supply is gone.
- Many mitochondria, dark in color, because of myoglobin (Respiratory pigment found in muscles.)
- Surrounded by thick capillary beds, draw more blood and oxygen.
- Low maximum tension.
- Highly resistant to fatigue.
- A high reserve of glycogen and fat, so mitochondria can keep a steady prolonged production of ATP as long as oxygen is available.
E. Delayed Onset Muscle Soreness:
- Due to tissue injury.
- Happens when muscles contract while lengthening. (Mader 239)
V. Muscular Disorders: Common VS Serious.
A. Common:
1a. Spasms: Sudden, involuntary muscular contractions usually accompanied by pain. (Smooth and Skeletal.)
2a. Convulsion: Multiple spasms.
3a. Cramps: Strong, painful spasms, usually due to strenuous activities.
4a. Facial Tics: Spasms controlled voluntarily, but with great effort. (ie, periodic eye blinking.)
5a. Tendinitis: Normal, smooth gliding motion of tendon is impaired, tendon is inflamed, and movement of joint becomes painful.
- Mostly caused by overuse.
(Insert Tendinitis picture / www.ktvu.com / http://www.ktvu.com/encyclopedia/6867816/detail.html)
6a. Bursitis: An inflammation of the bursa, which provides a smooth, slippery surface where muscles and tendons glide over bones.
- Results from repetitive movement or from prolonged and excessive pressure.
B. Muscular Diseases: More serious, requiring medical care.
1b. Myalgia: Achy muscles.
- Most common cause is either overuse or overstretching.
2b. Fibromyalgia: Chronic condition.
- Symptoms: achy pain, tenderness, and stiffness of muscles.
3b. Muscular Dystrophy: A group of disorders characterized by a progressive degeneration and weakening of muscles.
- As muscle fibers die, fat and connective tissue take their place.
- Duchenne Muscular Dystrophy: Most common.
- Inherited through flawed gene carried by mother.
- Caused by protein dystrophin.
(Insert Muscular Dystrophy Stem Cells in Mice picture / www.dogflu.ca / http://www.dogflu.ca/health/news?from=630)
(Insert Muscular Dystrophy in Human picture / www.dinf.ne.jp / http://www.dinf.ne.jp/doc/english/global/david/dwe002/dwe00212.htm)
4b. Myasthenia Gravis: Autoimmune disease characterized by weakness in muscles of eyelids, face, neck and extremities.
5b. Amyotrophic Lateral Sclerosis: (Lou Gehrig's disease).
- Gradual loss of ability to walk, talk, chew, and swallow.
- Mental abilities and sensations are not affected. (Mader 240)
VI. Homeostasis
A. Both the muscular and skeletal systems contribute to homeostasis.
B. Both Systems Produce Movement.
- Body movements allow us to respond to certain types of changes in environment: (ie moving into shade when you are hot.)
- Other movements, like the skeletal muscles allowing the jaw and tongue to move, are necessary for supplying body's cells with nutrients.
C. Both Systems Protect Body Parts.
- Skeletal protects soft internal organs.
- Muscular pads bones, offering protection for abdominal organs.
D. Both Store and Release Calcium:
- Calcium is essential for muscle contraction and nerve conduction.
- Necessary for regulation of cellular metabolism.
- Skeleton is a reservoir for storing calcium.
E. Blood Cells are Produced in Bones:
- Red bone marrow is the site of blood cell production. They also carry oxygen in blood.
- White blood cells originate in red bone marrow, and are necessary to defend your body.
- Bones contain yellow and red bone marrow. Fat is stored in yellow.
(Insert Bone Marrow picture / www.drstandley.com / http://www.drstandley.com/bodysystems_skeletal.shtml)
F. Muscles Help Maintain Body Temperature:
1f. When you are cold, smooth muscles in blood vessels that supply your skin constrict, reducing amount of blood that is close to surface of body. Conserves heat.
2f. Skeletal muscle contraction requires ATP, and using ATP generates heat.