1. The Muscular System 5
Lesson 5.1: Muscle Tissue Categories and Functions Lesson 5.2: Skeletal Muscle Actions Lesson 5.3: The Major Skeletal Muscles Lesson 5.4: Common Injuries and Disorders of Muscles

2. Muscle Tissue Categories and Functions
Chapter 5: The Muscular System
Lesson 5.1
Muscle Tissue Categories and Functions

3. Muscle Tissue Categories Functions skeletal smooth cardiac
behavioral properties
tension and types of skeletal muscle contractions

4. Muscle Tissue Categories
skeletal
voluntary
striated
smooth
involuntary
no striations
cardiac
intercalated disks

5. Muscle Tissue Categories

6. Skeletal Muscle Organization
Sarcolemma and endomysium surrounds the muscle fiber
Perimysium bundles groups of muscle fibers to make up a fascicle
Epimysium encloses several fascicles to make up a muscle
Aponeurosis connects muscle to other tissues

7. Skeletal Muscle Organization

8. Behavioral Properties of Muscle
extensibility–stretch
elasticity–snap back
irritability–respond
contractility–shorten

9. Muscle Tissue Functions
tension and types of skeletal muscle contraction
agonist–moves bone
antagonist–opposes the movement of the agonist

10. Concentric Contraction
agonist contracts, antagonist relaxes

11. Eccentric Contraction
agonist contracts while lengthening, antagonist relaxes

12. Isometric Contraction
both agonist and antagonist contract

13. Skeletal Muscle Actions
Chapter 5: The Muscular System
Lesson 5.2
Skeletal Muscle Actions

14. Skeletal Muscle the motor unit skeletal fiber types
muscular strength, power, and endurance

15. The Motor Unit
group of muscle fibers under the control of one motor neuron
fibers, depending on size and function of muscle

16. Generating Action Potentials
Acetylcholine crosses the synaptic cleft at the neuromuscular junction (neurotransmitter)
Na+ rushes in, K+ rushes out->creates POSITIVE charge (Depolarization)
More Na+ enters- Action potential begins

17. Contraction of the Sarcomeres
Fed by glycogen (stored glucose)
Triggered by Ca++ release
Sarcomeres shorten by actin filaments (heads grabbing) sliding along myosin filaments
Number and frequency of action potentials determine speed and force of contraction!

18. Maximum Tension and Return to Relaxation
Action potential always causes entire motor unit muscle fibers to contract- then it must FULLY relax before a new stimulus can be applied
All-or-none law
Multiple motor units
must be stimulated to
produce maximum
tension
Sustained maximum
tension=tetanus

19. Skeletal Muscle Fiber Types
Type 1 - Slow-twitch contracts relatively slowly and is resistant to fatigue
Type IIa - These fast twitch muscle fibers are also known as intermediate fast-twitch fibers. Moderate fatigue
Type IIb - This fast twitch muscle fiber has the highest rate of contraction (rapid firing) of all the muscle fiber types, but it also has the highest rate of fatigue.
All muscle fibers in a motor unit are the same type, but not all motor units in a muscle are!

20. Skeletal Muscle Fiber Architecture
parallel fiber arrangements- large range of motion
Fusiform- biceps brachii
Bundled- rectus abdominus
Triangular- pectoralis major
pennate fiber arrangements-
Oblique attachment gives force,
Does not shorten as much
Unipennate- abductor pollux
Bipennate- rectus femoris
Multipennate-deltoid

21. Muscular Strength Rotary force that muscles can produce at a joint
the maximum weight you can lift is a measurement of muscular strength ONLY (no variable for speed)

22. Muscle Power
force x velocity (both force and speed contribute equally, so strength is not the determining factor)
how fast you can sprint is a measurement of muscle power

23. Muscle Endurance Muscle tension/time
Can be sustained or cyclical- varies based on activity
how far you can run is a measurement of muscle endurance
So is rowing
Handstands
Cycling

24. Fatigue Opposite of endurance Affected by:
Nature of work/exercise done
How often the muscle is used
Muscle fiber composition
Humidity/temperature of enviornment

25. The Major Skeletal Muscles
Chapter 5: The Muscular System
Lesson 5.3
The Major Skeletal Muscles

26. The Major Skeletal Muscles
directional motions
head and neck muscles
trunk muscles
upper limb muscles
lower limb muscles

27. Skeletal Muscle Attachments
Origin
fixed end of a muscle
Insertion
movable end of a muscle

28. Sagittal Plane Movements Anterior and Posterior
Flexion- forward (except knee)
Extension- back to normal position
Hyperextension- too far
Dorsiflexion- toes toward body
Plantar flexion- “gas pedal”- point toes

29. Frontal Plane Movements Medial and Lateral
Abduction- limb lateral
Adduction-limb medial
Inversion-foot medial
Eversion-foot lateral
radial deviation-
Hand lateral
at wrist
ulnar deviation-
Hand medial at wrist

30. Transverse Plane Movements Rotational
Medial rotation-toward midline
Lateral rotation- away from midline
Pronation- palm down
Supination- palm up

31. Multiplanar Movements Not in a single plane
Circumduction- make a circle
Opposition-
thumb to any of the other 4 fingers

32. Head and Neck Muscles All except orbicularis Oris and Platysma are paired

33. Trunk Muscles- Posture, stability and protection

34. Upper Limb Muscles- NOT all of them (just the major ones)

35. Lower Limb Muscles- (just the major ones)

36. Common Injuries and Disorders of Muscles
Chapter 5: The Muscular System
Lesson 5.4
Common Injuries and Disorders of Muscles

37. Muscle Injuries
Strain – overstretched muscle (less common in the more flexible, speed at time of injury is a factor as well)
grade I- mild: tightness 1 day
grade II- moderate: partial tear, temporary weakness and loss of function
grade III- severe: torn muscle, loss of function, internal bleeding, swelling.
EX: Hamstring strains most common, tend to reoccur, slow to heal (1/3 repeat within 1 year)

38. Muscle Injuries Contusion – bruised muscle from impact
myositis ossificans
When an already injured muscle is struck, forms calcium mass over 3-4 weeks. Reabsorbs after 6-7 weeks (usually)
Cramps – spasming muscle
Numerous causes: electrolyte imbalance, Ca, Mg, K deficiency, dehydration, idiopathic
Delayed onset muscle soreness – begins hours later, multiple, microscopic tears= pain, swelling and stiffness

39. Tendon Injuries Tendinitis –inflamed tendon
Tendinosis –degeneration of a tendon leading to rupture. No inflammation
Val Thoermer/Shutterstock.com

40. Joint / Stress Injuries
Rotational injury at shoulder
improper mechanics
Overuse of elbow- epicondylitis
Medial (little leaguer) tears
lateral tears (tennis elbow) tears
Shin splints- periosteum
Tibial tendons
Whiplash- abnormal motion
Cervical vertebrae,
muscle spasms
Attempt to protect spine

41. Muscle Disorders
Hernia - A hernia is the protrusion of an organ or the fascia of an organ through the muscular wall of the cavity that normally contains it.
Complications include strangulation
Repair with surgery
Various causes
Heavy lifting
Increased abdominal pressure
Present at birth 41

42. Muscle Disorders
Muscular dystrophy - a group of inherited, progressive disorders that involve muscle weakness and loss of muscle tissue, varies in severity. No cure.