1. The Muscular System

2. Functions of Muscle Tissue
Movement Facilitation
Thermogenesis
Postural Support
Regulation of Organ Volume
Pumps Blood (HEART)

3. Characteristics of Muscle Tissue
Contractility
ability to become short and thick while producing movement

4. Characteristics of Muscle Tissue
Extensibility
The ability of muscle tissue to be elongated or stretched
Smooth muscle

5. Characteristics of Muscle Tissue
Elasticity
ability to return to its normal resting length
Skeletal from being shorter—smooth—from extended

6. Characteristic of Muscle tissue
Excitability (irritability)
ability to receive and respond to a stimulus

7. Cardiac Muscle Forms heart wall (Myocardium) striated involuntary
Fibers quadrangular & branching
centrally located nucleus
sarcolemmas connected by intercalated discs
gap junctions

8. Smooth (Visceral) Muscle
walls of hollow internal surfaces such as:
blood vessels - stomach
urinary bladder - intestines
non striated
involuntary
can be stretched to great lengths
allows for tremendous size variability

9. Skeletal Muscle
attached to bones
striated
voluntary
Multinucleated

10. Characteristics of Skeletal Muscle
Muscle origin: where muscle begins--tendon attaches to immovable bone (proximal)
Muscle insertion: where muscle ends--tendon attaches to moveable bone (distal)
Belly (gaster): fleshy portion of muscle between tendons

11. Key terms Sarcolemma - muscle cell membrane
Sarcoplasm = muscle cell cytoplasm

12. Key terms Myofilaments --contain contractile elements of muscle fiber
Sarcomere: one section of contractile filaments

13. Actin Thin Myofilaments 2 regulatory proteins
Tropomyosin- follows contour of filament
Troponin = protein on tropomyosin
Receptor site for Ca+

14. Myosin
Thick Myofilaments
globular head
Aka cross bridges

15. SLIDING FILAMNET THEORY OF MUSCLE CONTRACTION
SEE HANDOUT

16. Muscle--Nerve Interaction
Motor Neuron = nerve cell that excites muscle fiber
Motor Unit = motor neuron & all the muscle fibers it can effect

17. Neuromuscular Junction
Neuromuscular Junction = place between nerve & muscle fiber
Motor End Plate - location on muscle fiber next to the nerve

18. Acetylcholine
Acetylcholine (Ach) = neurotransmitter released to begin muscle contraction (action potential)
acetylcholine Receptors—on motor end plate-makes membrane more permeable to Na+

19. Roles of Skeletal Muscles Agonist--Antagonist
Agonist (Prime Mover)
Main muscle
Antagonist
opposite movement

20. Roles of Skeletal Muscles Synergist
Synergist—assists agonist
provides additional force

21. Roles of Skeletal Muscles Fixator
Fixator (Stabilizer)
stabilizes a body segment
prime mover can act more effectively

22. SKELETAL MUSCLE ORGANIZATION
Muscle fibers: elongated muscle cells
Endomysium: membrane around muscle fibers
Perimysium: membrane around fascicles
Epimysium: membrane around entire muscle (fascia)

23. The end

25. Intramuscular Injections
injections that penetrate the skin and subcutaneous tissue
used for prompt absorption
used when large doses are necessary
Preferred Sites:
Gluteus Medius Muscle
Vastus Lateralis Muscle
Deltoid Muscle

26. Muscle Diseases and Disorders

27. Abnormal Contractions
an unintended muscular contraction not stimulated by normal mechanisms
may be caused by dehydration, electrolyte imbalances or neurological disorders and abnormalities

28. Myalgia (Fibromyalgia)
painful disorders of muscles, tendons, and surrounding soft tissue
Chronic condition
Treat symptoms no cure

29. Muscular Dystrophies muscle destroying diseases
degeneration of individual muscle fibers
progressive atrophy of skeletal muscles
Usually due to a genetic defect

30. Myasthenia Gravis (MG)
a weakness of skeletal muscle
at neuromuscular junction
an auto-immune disorder caused by antibodies that disable the Ach receptors at the motor end plate

31. Shinsplints strengthen tibialis anterior muscle
pain in the lower leg which may be caused by:
tendonitis of the tibialis anterior muscle
inflammation of the periosteum
stress fracture of the tibia
exaggerated enlargement of muscles within the epimysium
pulling away of the periosteum from the underlying bone
Treatment:
RICE
strengthen tibialis anterior muscle