1. 1.05 Understand the functions and disorders of the muscular system

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. Muscle Injuries & Disorders
Mrs. Smith's Muscular System notes Pg
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

13. 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

14. 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

15. 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

16. 1.05 Understand the functions and disorders of the muscular system
Types of exercise
Aerobic
With oxygen or requiring oxygen
Anaerobic
Without oxygen
1.05 Understand the functions and disorders of the muscular system

17. 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

18. Mrs. Smith's Muscular System notes
3 Functions of Muscles Pg
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.

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. Mrs. Smith's Muscular System notesPg
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.

28. 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

29. Mrs. Smith's Muscular System notesPg
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°

30. 1.05 Understand the functions and disorders of the muscular system

31. Mrs. Smith's Muscular System notesPg
How does the body maintain its temp. in colder environments?
How does the body maintain its temp. in warmer environments?
SHIVERING
SWEATING
PG. 398

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

33. 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

34. 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
*Intestine pushes through abdm. Wall

35. Mrs. Smith's Muscular System notesPg
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

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

37. Mrs. Smith's Muscular System notes
Bruise Pg
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

38. 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

39. 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

40. Mrs. Smith's Muscular System notesPg
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

41. 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