1. FASCIA, MUSCLES, TENDONS

2. Skeletal Muscle Structure
Origin:
Proximal attachment
Insertion:
Distal attachment
Tendons:
Peritendineum
Aponeurosis

3. Skeletal Muscle Hierarchy
Myofilament:
Thick filaments
Myosin
Thin filaments
Actin
Myofibril:
Bundle of myofilaments
Segmentally arranged into sarcomeres

4. Skeletal Muscle Hierarchy
Myofiber
Made up of many myofibrils
Multinucleated in skeletal muscles
= muscle cell
Fascicle
Bundle of myofibers
Muscle
Composed of several to several hundred fascicles

5. Connective Tissues Endomysium: Perimysium: Surrounds a myofiber
Surrounds a fascicle

6. Connective Tissues Epimysium:
Covers entire muscle
Blends in with deep fascia
Connective tissue supports provide physical support and a pathway for nerves and vessels.

8. Myofilaments Actin myofilaments (F-actin): Myosin filaments:
Polymers of G-actin
Tropomyosin
Troponin
Myosin filaments:
ATPase

9. Sarcomeres Z-line (Z-actin): I bands: Composed of Z-actin
Marks ends of Z-actin
I bands:
Part of a sarcomere composed entirely of actin

10. Sarcomeres A band: H band:
Part of a sarcomere composed of both actin and myosin
H band:
Part of a sarcomere composed entirely of myosin

11. Sliding Filament Theory
During a contraction:
I band and H band shorten
A band remains the same length
Sliding occurs when ATPase heads of myosin attach to actin via troponin and swivel.

14. Myofiber Sarcoplasmic reticulum: T-tubules:
Equivalent to endoplasmic reticulum of most cells.
T-tubules:
Tubular extensions of the muscle fiber membrane that extend down into the cytoplasm (saracoplasm).
Conduct action potential from cell membrane surface to interior.

15. Myofiber
Cisternae:
Saccular extensions of the sarcoplasmic reticulum that release calcium ions in response to action potential.
Calcium ions trigger sliding of myosin and actin filaments, resulting in a contraction.

17. Myofiber Type The myofiber type (red or white) depends on innervation.
All myofibers in a motor unit are of the same type.

18. Dark (red) Fibers Fatigue resistant Contract slowly (slow twitch)
Rely on oxidative phosphorylation
Have a large number of mitochondria
Have a high concentration of myoglobin
Have a low concentration of ATPase

19. Light (white) Fibers Fatigue easily Contract rapidly (fast twitch)
Rely on glycolysis
Have a small number of mitochondria
Have a low concentration of myoglobin
Have a high concentration of ATPase

20. Neuromuscular Junctions
Components:
Presynaptic membrane:
Terminal end of motor neuron.
Synaptic cleft
Postsynaptic membrane:
Sarcolemma (cell membrane of myofiber)

21. Motor Unit
Consists of a motor neuron and all the myofibers it innervates
Units for fine control have fewer fibers
Units for gross control have many fibers

23. Muscle Classification
Fiber arrangement
Shape
Origin and insertion
Function

24. Fiber Arrangement Straight: Fusiform: Unipennate: Bipennate:
Example: rectus abdominis
Fusiform:
Example: biceps brachii
Unipennate:
Example: palmar interosseous muscles
Bipennate:
Example: dorsal interosseous muscles
Multipennate:
Example: deltoid muscle

26. Muscle Shape
Deltoid
Trapezius

27. Muscle Origin/Insertion
Coracobrachialis
Sternocleidomastoid

28. Muscle Function
Pronater teres
Extensor digitorum

29. Contraction Definition: Types of contraction:
A contraction is a muscle’s response to a stimulus.
Types of contraction:
Isotonic (the length of the muscle changes)
Concentric (length decreases)
Eccentric (length increases)
Isometric (the length of the muscle stays the same)

30. Types of Action Agonist (prime mover): Antagonist: Synergist:
A muscle that primarily carries out the desired action.
Antagonist:
A muscle that opposes the agonist.
Synergist:
A muscle that eliminates the unwanted action of the agonist.

31. Types of Action Fixator:
A muscle that stabilizes the origin of another muscle.
Note: a single muscle can be all the above at one time or another.

32. Insufficiency
Refers to the inability of a multijoint muscle to maximally contract simultaneously over all joints crossed.
Active:
Refers to the agonist
Passive:
Refers to the antagonist

33. Smooth Muscle Synonyms: Found in: Visceral Involuntary
Walls of visceral tubes (intestines, etc.)
Associated with hair follicles
Around glandular structures
In walls of blood vessels

34. Smooth Muscle Characteristics
Bundles of sheets of individual cells.
Not striated (smooth).
Cells are primarily elongated and tapered.
Mononucleated.

35. Smooth Muscle Characteristics
Nuclei are centrally located in each cell.
Does not conduct action potential.
Cells connected by gap junctions.
Not under voluntary control.

37. Cardiac Muscle Tissue Found only in walls of heart. Characteristics:
Striated (sarcomeres)
Mononucleated cells:
May branch
Intercalated discs:
Sites of transfer of stimulus between adjacent cells.