1. Muscular System

2. Functions of Muscular System
Stabilizes Joints
Movement
Heat Production
Posture

3. Types of Muscle Skeletal Smooth Cardiac Striated Voluntary
Connect by tendons
Smooth
Nonstriated
Involuntary
double layered digestive track
Cardiac
Wrap around heart

4. Posture Good Posture Poor Posture Maintenance
body alignment that favors function with least work
Standing Position
Head and chest held high
Chin, abdomen, buttocks pulled in
Knees slightly bent
Feet firmly on ground 6 in. apart
Poor Posture
puts abnormal strain on ligaments and bones
Maintenance
Tonicity (muscle tone): muscles exert a pull against gravity

5. Tonicity Continual, partial contraction of a muscle Flaccid Spastic
Muscles with less tone than normal
Spastic
Muscles with more tone than normal

6. Change in Muscle Size Atrophy – decrease in muscle size
Bed Rest: lose 1% muscle strength/day
Hypertrophy – increase in muscle size

7. Muscles & Age Infancy & Childhood Aging
Muscle coordination and control allows developmental sequences to occur
Aging
Muscles degenerate with age

8. Characteristics of all Muscle
Excitability
Respond to stimuli
Contractility
Actively shorten to exert a pull
Tension that can be harnessed by CT
Extensibility
Continue to contract over range of resting lengths
Ex: smooth muscle can be stretched to several times its original length and still contract on stimulation
Elasticity
Return to original length after contraction

9. Types of Body Movement Origin-attachment to a immovable bone
Insertion- attachment to an movable bone
Muscles are always attached to at least 2 points
Movement is attained due to a muscle moving an attached bone

10. Muscle Attachment Does NOT move when muscle contracts Does move when

11. Classification of Muscle Group Actions
Agonist (Prime Mover)
Muscle most responsible for movement
Antagonist
Opposes prime mover
Provides precision and control during prime mover contraction
Relaxes when prime mover contracts
Synergist
Aid prime mover
Contract at same time as prime mover
Fixator
Joint stabilizer
Maintains posture/balance during prime mover contraction

12. Types of Musculo-Skeletal Movemen
Flexion
You will need to know the action or movement performed for each of the muscles we study. The first type of movement is called flexion. Note the lower leg is being flexed in this diagram. During flexion the angle of joint is decreased. As the knee is flexed, the angle between the lower leg and the thigh is decreased. Flexion of the upper arm is also illustrated in this diagram. Here the angle between the arm and the frontal plane is decreased.

13. Extension
Extension is the opposite of flexion. In extension the angle of a joint is increased. Extension of the lower leg causes an increased angle between the lower leg and the thigh.

14. Hyperextension
Flexion and extension also apply to the neck. When a joint is extended past the anatomical position the movement is called hyperextension.

15. Abduction, Adduction & Circumduction
Abduction refers to moving away from the median plane of the body. Adduction is the opposite movement to abduction. It is moving toward the medial plane. Circumduction refers to inscribing a circle while moving a limb.

16. Rotation
Rotation is turning a bone on its own axis. Moving the head back and forth to indicate “no” is an example of rotation. Note the difference between medial and lateral rotation. In lateral rotation the limb is rotated the lateral side of the body. Medial rotation rotates the limb toward the medial side of the body.

17. More Types of Movement……
Inversion- turn sole of foot medially
Eversion- turn sole of foot laterally
Pronation- palm facing down
Supination- palm facing up
Opposition- thumb touches tips of fingers on the same hand

18. The Skeletal Muscles There are about 650 muscles in the human body
The Skeletal Muscles There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this section we will only study a sample of the major muscles.
There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this unit will only study a sample of the major muscles.

19. Naming Muscles Location Function Shape Fiber direction
Number of heads/divisions
Points of attachment
Muscle size

20. Location Function Fiber Direction Shape Frontalis Frontal bone Femoris
Femur
Gluteus
Posterior of hip/thigh
Oculi
Eye
Oris
Mouth
Radialis
Radius
Ulnaris
Ulna
Brachialis
Arm
Abductor
Moves part away from body
Adductor
Moves part toward body
Depressor
Lowers a part
Extensor
Extends a part
Flexor
Flexes a part
Levator
Elevates a part
Rotator
Rotates a part
Fiber Direction
Shape
Oblique
Diagonal to midline
Rectus
Parallel to midline
Sphincter
Circling an opening
Transversus
Right angle to midline
Deltoid
Shaped like delta ∆
Orbicularis
Circular
Platy
Flattened; platelike
Quadratus
Square
Rhomboideus
Diamond-shaped
Trapezius
Trapezoidal

21. Muscle Fiber Arrangement
Parallel
Convergent
Pennate
Bipennate
Sphincter

22. Number of divisions Size Bicep Two heads Tricep Three heads Quadricep
Four heads
Size
Brevis
Short
Longus
Long
Magnus
Large
Maximus
Largest
Medius
Moderately sized
Minimus
Smaller

25. Raises eyebrows
Frowning
Mastication
Blinking
Laughing
Whistling, smiling
Puckering
Mastication
Flexes head

26. Moves head
Moves head
Flexes head

27. Superficial Back Muscles
Large, fan-shaped muscles provide force in a wide range of body positions
-EX: leaning back to straight vertical and all points in between.
Shrugging, pulling scapulas together and down
Rotator cuff
muscles
Stabilize shoulder joint, pull arm back
Shoulder movement
Pull the arm down,
Stabilize torso during many movements (EX: bench press)

28. Trunk Muscles - Thorax
Elevate ribs

29. Trunk Muscles Abdomen Flexes trunk Stabilizes Lower back Compresses

30. Upper Arm
Flexes
Upper arm
Extends forearm

31. Flexors

32. Extensors

33. Upper Leg Deep muscle Vastus intermedius Biceps femoris
Semimembranosus
Quadricep
Femoris
Semitendinosus

34. Lower Leg
Plantar flexion

35. Foot

36. Anal and Urogenital Muscles

37. Lever Systems 2nd Class 1st Class 3rd Class P = Force (push or pull)
Contracting Muscle
F = Fulcrum
Joint
L = Load
Weights, etc

38. -mysium=CT membrane
and tendon sheath
Myofilaments

40. H zone Z line Z line I band A band Sarcoplasm Space between actin
Muscle cell (fiber)
cytoplasm
H zone
Basic contractile unit of muscle fiber
Sarcoplasm
Z line
Z line
Muscle fiber
membrane
I band
A band
Bundle of microfilaments; almost fill sarcoplasm
Length of myosin heads (wide, dark stripes)
Length of actin (thin, light stripes)
Allows impulses to travel along sarcolemma deeper into muscle cell (fiber)
Network of tubules and sacs: pumps calcium ions in from sarcoplasm to store in sacs
Allows impulse traveling down T tubule to stimulate adjacent sacs

42. http://highered. mcgraw-hill

43. Myofilaments Attracted to actin and forms crossbridge
protein molecules
Holds tropomyosin in place
Covers active site on actin
Attracted to actin and forms crossbridge

44. Contraction
tropomyosin
troponin
Synaptic vesicle travels down motor neuron and binds to motor endplate
Acetylcholine released into synaptic cleft
Ach binds to receptor on sarcolemma
Impulse travels along sarcolemma and down t-tubules
Calcium released from sarcoplasmic reticulum
Calcium binds to troponin causing conformation change
tropomyosin shifts to expose active site on actin
myosin heads bind to actin
actin filaments are pulled past the myosin head; head unattaches and reattaches to a new site….repeat
Sliding Filament Theory - sliding of thin filaments toward center of each sarcomere shortens the myofibril and muscle fiber.

45. Excitation & Contraction
Impulse sent to muscle fiber
Muscle fiber creates movement
Synaptic cleft
Motor endplate
Neuromuscular junction
Synaptic vesicle
(neurotransmitter)

46. Motor Unit Smaller # fibers – more precise movement
Larger # fibers – more powerful contraction

47. All or NONE Quick jerk due to brief threshold stimulus
SR releasing Ca+2
All or NONE
Ca+2 bind to troponin;
Cross-bridging
Quick jerk due to brief threshold stimulus
One twitch – 1/10 sec
Rarely occur
Gradual, step-like increase in contraction strength
Series of twitch contractions 1 sec apart
Muscle contracts more forcefully after it has
contracted a few times, then when it first contracts
Warm-up before exercise
Smooth, sustained contractions
Coordinated contractions of different motor units
Multiple twitch waves add together to sustain
muscle tension for longer time
Very short periods of relaxation between peaks
of tension
Twitch waves fused into a single, sustained peak

48. Length-tension Relationship
Optimal length
Strongest max
contraction
possible
Overstretched
Muscle can’t develop tension due to filaments
too far apart
Sarcomere compressed
Muscle can’t develop tension

49. Energy Sources
ATP
Hydrolysis into ADP yields energy required for contraction
ATP binds to myosin head in order to pull actin
Fibers continually resynthesize ATP from breaking down creatine phosphate (requires glucose and oxygen)
Glucose & oxygen
Hemoglobin transfers O2 to muscle fiber
Fiber stores glucose as glycogen
At rest: Excess O2 in sarcoplasm is bound to myoglobin temporarily
Exercise: O2 concen. Decreases in muscle, so myoglobin resupplies muscle with O2

50. Respiration Aerobic Respiration Anaerobic Respiration Requires O2
Produces max amount of energy available from each glucose molecule
Anaerobic Respiration
Occurs when lack of O2
Forms lactic acid
During exercise
Muscles “burn”
O2 debt
Heavy breathing during exercise in order to process lactic acid

51. Muscle Fatigue Muscles loses ability to contract due to lack of ATP
Lactic acid build up
Cramp – muscle contracts spasmodically, but does not relax completely

52. Most body movements are a result of both types

53. Myopathies
Myalgia - muscle pain due to overstretching/tearing of muscle fibers
Fibromyalgia – widespread muscle and CT pain
Strain – caused by overexertion/trauma and can lead to muscle tear
Myositis - any muscle inflammation
Fibromyositis - tendon inflammation along with myositis
Cramps
Painful muscle spasms
Due to mild myositis, fibromyositis, irritation, iron, and water imbalance
Charley Horse
Intense muscle spasms
Last few seconds to few hours
Caused by injury or overuse
Dehydration
Low K+ or Ca+2
Nerve irritated
Treatment
Stop activity
Stretch and massage
Heat to relax muscle
Ice when spasm is over

54. Myopathies Contusion Poliomyelitis (Poilio) Muscular Dystrophy
Muscle bruise, local internal bleeding and inflammation
Crush injury: severe trauma to muscle, releasing fibers into bloodstream (life threatening)
Poliomyelitis (Poilio)
Viral infection of nerves controlling skeletal movement
Causes partial or full paralysis and death
Vaccine created in US in 1950s, but not everywhere
Muscular Dystrophy
Genetic disease caused by muscle atrophy
Some forms are fatal
Most common form is Duchenne Muscular Dystrophy (DMD)
Myasthenia Gravis
Autoimmune disease that attacks muscle cells at NM junction
Muscle weakness
Can become a crisis and affect all four limbs
Could die of respiratory failure

55. Myopathies Hernias “protrusion”
Reducible – can manipulate protruding organ back into abdominal cavity
Strangulated – blood flow to organ is stopped; obstruction, gangrene, pain. Vomiting, emergency surgery
Types
Inguinal – hernia extends into inguinal canal into scrotum or labia; affects more males
Femoral – affects more women below groin area due to pregnancy