1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system What are the characteristics of muscles? What are the functions of the muscular system? What are common disorders of the muscular system? How are muscular disorders treated? How does the muscular system relate to the body’s support and movement? 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Contractibility Excitability Extensibility Elasticity All muscles, whether they are skeletal, smooth, or cardiac have four common characteristics. 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Contractibility A quality possessed by no other body tissue. When a muscle shortens or contracts, it reduces the distance between the part of its contents, or the space it surrounds. The contraction of the skeletal muscles that connect a pair of bones brings the attachment points closer together, thus causing the bone to move. When cardiac muscles contract, they reduce the area in the heart chambers, pumping blood from the heart into the blood vessels. Likewise, smooth muscles surround blood vessels and the intestines, causing the diameter of these tubes to decrease upon contraction. 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Contractibility Myoneural stimulation + contraction of muscle proteins = movement and heat Movement of muscles occurs as a result of two major events. Myoneural stimulation and contraction of muscle proteins. Skeletal muscles must be stimulated by nerve impulses to contract. A motor neuron (nerve cell) stimulates all of the skeletal muscles within a motor unit. A motor unit is a motor neuron plus all the muscle fibers it stimulates. The junction between the motor neuron’s fiber (axon), which transmits the impulse, and the muscle cells’s sarcolemma (muscle cell membrane) is the neuromuscular junction. The gap between the axon and the muscle cell is known as the synaptic cleft. 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Contractibility Neurotransmitter at site of muscle stimulus. The sodium-potassium pump of the membrane of a muscle cell. The purpose of this slide is to illustrate the complexity of the process of movement. When the nerve impulses reach the end of the axon, the chemical neurotransmitter acetylcholine is released. When this happens, acetylcholine diffuses across the synaptic cleft and attaches to the receptors on the sarcolemma. The sarcolemma then becomes temporiarily permeable to sodium ions which go rushing into the muscle cell. This gives the muscle cell excessive positive ions which upset and change the electrical condition of the sarcolemma. This electrical upset causes an action potential (an electric current). Skeletal muscle contraction begins with the actiion potential which travels along the muscle fiber length. The basic source of energy is from glucose and the energy derived is stored in the form of ATP and phosphocreatinine. The latter serves as a trigger mechanism by allowing energy transfer to the protein molecules, actin and myosin, within the muscle fibers. Once begun, the action potential travels over the entire surface of the sarcolemma, conducting the electric impulse from one end of the cell to the other. This results in the contraction of the muscle cell. The movement of lelctrical current along the sarcolemma causes calcium ions to be released from storage areas inside the muscle cell. When calcium ions attach to the action myofilaments (contractile elements of the skeletal muscle), the sliding of the myofilaments is triggered and the whole cell shortens. The sliding of the myofilaments is energized by ATP. The events that return the cell to a resting phase include the diffusion of potassium and sodium ions back to their initial positions outside the cell. When the action potential ends, calcium ions are reabsorbed into their storage areas and the muscle cell relaxes and returns to its original length. The amazing part is that this entire activity takes place in just a few thousanths of a second. 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Excitability- Responds to stimuli Characteristic of both muscle and nervous cells (neurons). It is the ability to respond to certain stimuli by producing electric signals called action potentials (impulses) 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Extensibility- Stretching The ability to be stretched. When we bend our forearm, the muscles on the back of it are extended or stretched. 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Elasticity- Return to Original length when relaxed Muscles also exhibit elasticity (the ability to return to original length when relaxing) 1.05 Understand the functions and disorders of the muscular system

Characteristics of Muscles Contractibility Excitability Extensibility Elasticity These four characteristics, collectively, produce a veritable mechanical device capable of complex, intricate movements. 1.05 Understand the functions and disorders of the muscular system

Muscle Tone Muscle tone – always slightly contracted and ready to pull. Atrophy: a- ________ -trophy ________ Hypertrophy: hyper- _______ -trophy ________ To function, muscles should always be slightly contracted and ready to pull. This is known as muscle tone. Muscle tone can be achieved through proper nutrition and regular exercise. Atrophy – if we fail to exercise, our muscles become weak and flaccid. They may shrink from dissue. Hypertrophy – if we overexercise, muscles will become enlarged. In hypertrophy, the size of the muscle fiber (cell) enlarges. 1.05 Understand the functions and disorders of the muscular system

Muscle Injuries & Disorders Mrs. Smith's Muscular System notes Pg. 394 - 398 Muscle Injuries & Disorders Atrophy: The deterioration of muscle. CAUSE Occurs in muscles that are not used, as when a limb is in a cast. Muscle decreases in size & strength PG. 396

1.05 Understand the functions and disorders of the muscular system Muscle Tone John just got a cast off his leg. His calf muscle on the affected leg is 1” smaller in diameter than his other calf muscle. What happened? How do you explain this to him? Atrophy – non use causes to shrink 1.05 Understand the functions and disorders of the muscular system

Muscle Tone Exercise & Training What are the advantages of exercise? Are there any disadvantages of exercise? Maintain muscle tone Could injure if not properly warmed up. Could become fatigued. 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Muscle Fatigue Discuss muscle fatigue: What causes muscle fatigue? Accumulation of lactic acid in the muscle. How does the body correct muscle fatigue? Getting oxygen back to the muscle cell. Oxygen debt is the amount of oxygen needed to refill the muscle. Discuss aerobic and anaerobic exercise. Give examples of each. During vigorous exercise, the blood is unable to transport enough oxygen for the complete oxidation of glucose in the muscles. This causes the the muscles to contract anaerobically (without oxygen). Lactic acid normally leaves the muscle, passing into the blood stream: but if vigorous exercise continues, the lactic acid level in the b lood rises sharply. In such cases, lactic acid accumulates within the muscle and impedes the contraction which causes fatigue and cramps. After exercise, a person must stop, rest, and take in enough oxygen to change the lactic acid back to glucose and other substances to be used by the muscle cells. Respirations increase to get oxygen back to the muscles. 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Types of exercise http://www.livestrong.com/article/255055-what-is-the-difference-between-aerobic-anaerobic-exercise/ Aerobic With oxygen or requiring oxygen Anaerobic Without oxygen 1.05 Understand the functions and disorders of the muscular system

Functions of the Muscular System What are the functions of the muscular system? Over 650 different muscles in the body. For any of these muscles to produce movement in any part of the body, it must be able to exert ist force upon a movable object. Muscles must be attached to bones for leverage in order to have something to pull against. They only pull….never push. 1.05 Understand the functions and disorders of the muscular system

Mrs. Smith's Muscular System notes 3 Functions of Muscles Pg. 394 - 398 Movement All body movements are the result of muscle contraction and relaxation. Muscles move organs and tissues within your body. Bones must be moved by muscles or they could not function.

Movement: Skeletal Muscle Receptors in muscles provide the brain with information about body position and movement. The brain controls the contraction of skeletal muscle. 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Movement Origin – Part of the skeletal muscle that is attached to a fixed structure or bone It moves least during a contraction. 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Insertion The other end of a muscle, attached to a movable part Moves the most during a muscle contraction. Belly – central body of a muscle 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Arranged in pairs Prime mover Produces movement in a single direction Antagonist Produces movement in the opposite direction The muscles of the body are arranged in antagonist pairs 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Synergists Help to steady a movement or stabilize joint activity 1.05 Understand the functions and disorders of the muscular system

Movement: Smooth Muscle Digestive System The nervous system regulates the speed at which food moves through the digestive tract. 1.05 Understand the functions and disorders of the muscular system

Movement: Cardiac Muscle Circulatory System Heartbeat The nervous system and hormones regulate the speed at which the heart beats. 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Posture How does the muscular system effect posture? 1.05 Understand the functions and disorders of the muscular system

Mrs. Smith's Muscular System notes Pg. 394 - 398 Maintenance of Posture Bones support your body, but your skeleton cannot balance upright by itself. To keep your body upright (against the pull of gravity), muscles must continually contract, pulling against your bones.

1.05 Understand the functions and disorders of the muscular system Body Heat Muscles produce heat, to keep us warm. We maintain our body temperature at 98.6 Muscle gets energy from ATP. ATP is released to produce heat when muscle is stimulated. 1.05 Understand the functions and disorders of the muscular system

Mrs. Smith's Muscular System notes Pg. 394 - 398 3. Production of Body Heat The constant muscle contractions throughout your body produce a large amount of heat. This heat helps maintain your body’s normal temperature. Avg. Body Temp. 98.6°

1.05 Understand the functions and disorders of the muscular system

Mrs. Smith's Muscular System notes Pg. 394 - 398 How does the body maintain its temp. in colder environments? How does the body maintain its temp. in warmer environments? SHIVERING SWEATING PG. 398

Disease or disorder of the Muscle Myopathy Disease or disorder of the Muscle 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Fibromyalgia Collection of symptoms Chronic muscle pain lasting 3+ months Fatigue, headache, numbness Joint pain Treatment directed at pain relief Exercise regularly, massage therapy Chiropractic procedures, relaxation Techniques, strengthening exercise 1.05 Understand the functions and disorders of the muscular system

Mrs. Smith's Muscular System notes Hernia An organ/tissue that pokes through an area of weak muscle. CAUSE: Straining to lift heavy objects. TREATMENT : Surgery *Intervertebral disc bulges out pressing on nerve. Pg. 394 - 398 *Intestine pushes through abdm. Wall

Mrs. Smith's Muscular System notes Pg. 394 - 398 Cramp: Intense & prolonged muscle contraction causing pain. CAUSE: overworked TREATMENT: massaging, stretching, K ↑. Strain: Muscle stretched or torn CAUSE: overworked, sudden force or pull. TREATMENT: R.I.C.E. PREVENTION: warm-up, stretch PG. 398

Mrs. Smith's Muscular System notes Pg. 394 - 398 Tendonitis Inflammation of the tendon. CAUSE overuse, injury, aging SIGNS Joint pain & Swelling TREATMENT Rest PG. 398

Mrs. Smith's Muscular System notes Bruise Pg. 394 - 398 An area of discolored skin that appears after an injury causes the blood vessels beneath the skin to rupture and leak. CAUSE: forceful blow to the area. TREATMENT: Ice to reduce swelling. PG. 398

1.05 Understand the functions and disorders of the muscular system Myasthenia Gravis Cause unknown but believed to be due to defect in the immune system Symptoms progressive muscle weakness and paralysis Prognosis could be fatal in extreme cases (respiratory paralysis) 1.05 Understand the functions and disorders of the muscular system

1.05 Understand the functions and disorders of the muscular system Tetanus Cause infectious disease- continuous spasm of involuntary muscles Toxin –clostridium tetani Enter body through puncture wound Can be prevented by a tetanus anti toxoid vaccine 1.05 Understand the functions and disorders of the muscular system

Mrs. Smith's Muscular System notes Pg. 394 - 398 Muscular Dystrophy - An hereditary disease that slowly destroys muscle tissue. - Gradually lose muscle control; may become unable to move. ►NO CURE w/ early detection, it can be delayed through exercise programs. Muscle Spasm - Occurs when a single muscle involuntarily contracts. ☺THE END☺ PG. 398

1.05 Understand the functions and disorders of the muscular system What are the characteristics of muscles? What are the functions of the muscular system? What are common disorders of the muscular system? How are muscular disorders treated? How does the muscular system relate to the body’s support and movement? 1.05 Understand the functions and disorders of the muscular system