THE MUSCULAR SYSTEM CHAPTER 8

1
THE MUSCULAR SYSTEM CHAPTER 8
2
FUNCTIONS OF THE SKELETAL SYSTEM?

• pull on bones to accomplish body movements
• provide muscle tone, maintain posture
• propel body fluids and food
• generate a heartbeat

3
FUNCTIONS OF THE SKELETAL SYSTEM?

• generate heat
• stabilize joints
• makes up about 40 of the bodys mass, over 600
  skeletal muscles

4
STRUCTURE OF A SKELETAL MUSCLE?

• Tendons connect muscles to bone

5
STRUCTURE OF A SKELETAL MUSCLE?

• composed of skeletal muscle tissue, nervous
  tissue, blood, CT

6
STRUCTURE OF A SKELETAL MUSCLE?

• fascia layers of CT that cover individual
  muscles hold them in place may form tendons,
  hooking up with a bones periosteum

7
STRUCTURE OF A SKELETAL MUSCLE?

• aponeuroses broad fibrous sheets of CT which
  attach to the coverings of adjacent muscles

8
STRUCTURE OF A SKELETAL MUSCLE?

• muscles are composed of bundles of fibers (muscle
  cells) fascicles
• fascicles are made of myofibrils

9

• myofibrils are made of thick thin filaments
• myosin thick filaments
• actin thin filaments
• arranged in an overlapping pattern the gives
  striated look

10
(No Transcript)
11

• Myofibrils slide over each other when muscles
  contract
• sliding filament theory of muscle contraction

12

• myofibrils consist of repeating units called
  sarcomeres the segment of myofibril that
  extends from one Z line to the next (Z lines are
  what the actin filaments attach to)
• striated muscles are created by I bands (the
  light part) and A bands (the dark part)

13

• neuromuscular junction is where a muscle fiber
  joins a motor neuron

14

• Muscle fiber
• ?
• Motor neuron
• ?
• brain or spinal cord

15

• the tips of the motor neuron contain
  neurotransmitters to communicate with the muscle
  fiber cause it to contract
• synaptic cleft the gap between the nerve
  endings the muscle cells

16
(No Transcript)
17

• motor unit a motor neuron all of the muscle
  fibers it controls

18
SKELETAL MUSCLE CONTRACTION?

• myosin has cross bridges which fit into binding
  sites on the actin filaments, pulling on them
  causing them to slide over the myosin

19
(No Transcript)
20
SKELETAL MUSCLE CONTRACTION?

• muscle contraction is initiated by a nerve
  impulse (action potential)
• requires acetylcholine, calcium ions, ATP
• acetylcholine is a neurotransmitter

21
SKELETAL MUSCLE CONTRACTION?

• 3 energy sources of ATP
• creatine phosphate allows immediate
  regeneration of ATP
• cellular respiration to break down glucose
• glycogen breaks down into glucose for cellular
  respiration

22
SKELETAL MUSCLE CONTRACTION?

• aerobic cell respiration takes place in the
  presence of oxygen makes 36 ATP per molecule of
  glucose

23
SKELETAL MUSCLE CONTRACTION?

• hemoglobin carries oxygen to the cells from the
  blood stream
• myoglobin temporarily stores oxygen in the muscles

24
SKELETAL MUSCLE CONTRACTION?

• during strenuous exercise, muscle cells must
  switch to anaerobic respiration which causes
  lactic acid to accumulate cause the burn

25
SKELETAL MUSCLE CONTRACTION?

• creates an oxygen debt the amount of oxygen it
  takes to revert the lactic acid into glucose
  restoring ATP creatine phosphate to their
  original levels
• anaerobic respiration makes only 2 ATP per
  molecule of glucose

26
SKELETAL MUSCLE CONTRACTION?

• muscle fatigue when muscles lose their ability
  to contract even when stimulated, usually due to
  lactic acid accumulation
• muscle cramps sustained involuntary muscle
  contraction

27
SKELETAL MUSCLE CONTRACTION?

• heat production via muscle contraction is
  significant for maintaining body temperature /
  homeostasis

28
MUSCULAR RESPONSES?

• threshold stimulus the minimal stimulus
  required to cause a muscle contraction

29
MUSCULAR RESPONSES?

• all-or-none response skeletal muscle fibers
  contract completely if they contract at all, not
  true for the whole muscle

30
MUSCULAR RESPONSES?

• twitch a single, brief, jerky contraction
• summation a rapid series of stimuli sums up
  the contractions
• tetanus sustained contraction with no relaxation

31
(No Transcript)
32
MUSCULAR RESPONSES?

• more muscle cells stimulated a stronger muscle
  contraction
• recruitment when more motor units are recruited
  to respond to increasing intensity of stimulation
• summation and recruitment together can produce a
  sustained contraction of increasing strength

33
MUSCULAR RESPONSES?

• isotonic muscle contractions muscles shorten,
  movement occurs
• isometric muscle contractions muscles stay the
  same length, no movement occurs ex. pushing
  against a wall

34
MUSCULAR RESPONSES?

• rigor mortis partial muscle contraction that
  happens after death

35

• A COMPARISON OF THE 3 MUSCLE TYPES
• location
• SKELETAL CARDIAC SMOOTH
• attached to heart walls of bones or
  skin visceral organs

36

• function
• SKELETAL CARDIAC SMOOTH
• movement, pumping blood peristalsis,
• posture vasoconstriction

37

• cell shape appearance
• SKELETAL CARDIAC SMOOTH
• multinucleate uninucleate uninucleate
• striated striated not striated
• cylindrical branched spindle-shaped

38

• contraction characteristics
• SKELETAL CARDIAC SMOOTH
• voluntary involuntary involuntary
• slow to fast slow very slow
• not rhythmic rhythmic some rhythmic

39

• skeletal muscle can contract rapidly with great
  force, but it tires easily must rest after
  short periods of activity
• smooth muscle contractions are slow and sustained

40

• cardiac muscle contractions are steady (set by a
  pacemaker), but they can be shifted into high
  gear the cells are connected by intercalated
  discs they react as a unit in an all-or-none
  manner

41
(No Transcript)
42
SKELETAL MUSCLE ACTIONS?

• movements depend on the type of joint the muscles
  are associated with the way the muscles are
  attached on either side of the joint
• remember muscles pull on bones which act as
  levers

43
SKELETAL MUSCLE ACTIONS?

• origin the end of a muscle attached to the bone
  that doesnt move
• insertion the end of the muscle attached to the
  bone that moves
• when muscles contract, the insertion is pulled
  toward the origin

44
SKELETAL MUSCLE ACTIONS?

• prime mover one muscle in a group that causes
  most of the movement
• synergist muscles that assist the prime mover
• antagonist causes movement opposite of the
  prime mover

45
SKELETAL MUSCLE ACTIONS?

• example the bicep is the prime mover of elbow
  flexion, its antagonist is the tricep the prime
  mover of elbow extension

46
MAJOR SKELETAL MUSCLES?

• naming skeletal muscles based on many sets of
  criteria
• direction of the fibers
• rectus straight, oblique slanted
• relative size of the muscle
• maximus largest, minimus smallest, longus
  long

47
MAJOR SKELETAL MUSCLES?

• location of the muscle
• named for the bone such as temporalis or
  frontalis
• number of origins or heads
• biceps 2, triceps 3, quadriceps 4

48

• location of the muscles origin insertion
• sternocleidomastoid sternum, clavicle, mastoid
  process
• shape of the muscle
• deltoid triangle
• action of the muscle
• flexor, extensor, adductor

49
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles of facial expression
• lie beneath the skin of the face scalp, used to
  communicate feelings through facial expression
• includes the frontalis, orbicularis oculi,
  orbicularis oris, zygomaticus, platysma

50
(No Transcript)
51
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles of mastication
• attach to the mandible, used for chewing
• includes the masseter temporalis

52
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the head
• found in the neck and upper back
• includes the sternocleidomastoid, sternohyoid

53
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the pectoral girdle
• most connect the scapula to nearby bones
• includes the trapezius, serratus anterior,
  pectoralis minor

54
(No Transcript)
55
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the arm
• these connect the humerus to various regions of
  the pectoral girdle, ribs, vertebral column
• includes the pectoralis major, teres major,
  latissimus dorsi, deltoid, infraspinatus

56
(No Transcript)
57
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the forearm
• these connect the radius ulna to the pectoral
  girdle or humerus
• includes the biceps brachii, brachialis,
  brachioradialis, triceps brachii, supinator

58
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the wrist, hand, fingers
• these muscles arise from the distal end of the
  humerus and from the radius ulna
• includes the flexor carpi radialis, flexor carpi
  ulnaris, palmaris longus, extensor carpi radialis
  longus, extensor carpi ulnaris, and extensor
  digitorum

59
(No Transcript)
60
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles of the abdominal wall
• these muscles connect the rib cage and vertebral
  column to the pelvic girdle
• includes the external oblique, internal oblique,
  transverses abdominis, and rectus abdominis

61
(No Transcript)
62
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles of the pelvic outlet
• these muscles form the floor of the pelvic cavity
  and fill the space within the pubic arch
• includes the bulbospongiosus and ischiocavernosus

63
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the thigh
• these muscles attach to the femur and to some
  part of the pelvic girdle
• includes the iliopsoas, gluteus maximus, gluteus
  medius, gluteus minimus, tensor fasciae latae,
  adductor longus, adductor magnus, and gracilis

64
(No Transcript)
65
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the leg
• these muscles connect the tibia or fibula to the
  femur or pelvic girdle
• includes the biceps femoris, semitendinosis,
  semimembranosus, sartorius, and the quadriceps
  femoris group rectus femoris, vastus lateralis,
  vastus medialis, vastus intermedius

66
(No Transcript)
67
SUPERFICIAL MUSCLES OF THE HUMAN BODY

• muscles that move the foot, ankle, toes
• these muscles attach the femur, tibia, and fibula
  to the bones of the foot
• includes the tibialis anterior, extensor
  digitorum longus, gastrocnemius, soleus, and
  peroneus longus

68
(No Transcript)
69
SUPERFICIAL MUSCLES OF THE HUMAN BODY
70
SUPERFICIAL MUSCLES OF THE HUMAN BODY