Muscles

1
Muscles

• function, actions and
• identification of
• major superficial muscles, some conditions and
  treatments

2
types of muscles

• Three structurally and functionally distinct
  types of muscle are found in vertebrates
• smooth muscle,
• skeletal muscle and
• cardiac muscle.

3
functions of skeletal muscles

• movement
• posture
• heat production
• shape
• facial expressions
• chewing, swallowing
• reflexes

4
naming skeletal muscles

• Skeletal muscles are named according to
  structural and/or functional characteristics.
• Location - temporalis (temporal bone) and
  tibialis anterior (front of tibia)
• Size - maximus (largest), minimus (smallest),
  longus (longest), brevis (shortest)
• Shape deltoid (triangular), trapezius
  (trapezoid), serratus (saw-like edge)

5
more on naming muscles

• Direction of fibers rectus (parrallel to
  midline), transverse (perpendicular to midline),
  oblique (diagonal to midline)
• Number of origins biceps (2), triceps (3),
  quadriceps (4)
• Origin and insertion sternocleidomastoid is
  named for the two places of origin as well as its
  insertion.
• Action what the muscle does when at work.

6
actions of skeletal muscles

• flexion-movement that decreases the angle _at_ a
  joint
• extension-movement that increases the angle _at_ a
  joint.

7
abd and add

• abduction-movement of an appendage away from the
  midline.
• adduction-movement of an appendage towards the
  midline.

8
rotation

• rotation -turning around the longitudinal axis _at_
  a joint. Can only occur at a pivot (radio-ulna /
  neck) or ball socket (shoulder / hip) joint.
• circumduction-Is a movement found _at_ ball socket
  (hip shoulder) and condyloid joints (wrist /
  ankle / knuckles).

9
supination - pronation

• supination -medial rotation of the forearm at the
  Radio Ulna joint, so the palms face up.
• pronation -Lateral rotation of forearm at the
  Radio Ulna joint, so the palms face down.

10
inversion - eversion

• inversion - twisting of the foot so that the sole
  faces inward.
• eversion - Twisting of the foot so that the sole
  faces outward.

11
dorsiflexion and plantar flexion

• dorsiflexion toe towards the knee using
  tibialis anterior
• plantar flexion point toes using gastrocnemius

12
shoulder girdle movements

• elevation - Upward movement of the shoulder
  girdle.
• depression - Downward movement of the shoulder
  girdle..Depression
• protraction and retraction are all movements
  associated with the shoulder girdle.

13
movements

• 1. Lateral rotation
• 2. medial rotation
• 3. Supination
• 4. Pronation
• 5. Eversion
• 6. Inversion
• 7. Adduction
• 8. Abduction

14
What do you know
about these muscles?

• Flexor carpi ulnaris
• Extensor carpi radialis
• Latissimis dorsi
• Transversus abdominis
• Rectus femoris
• Deltoid
• Trapezius
• Orbicularis oris, Orbicularis oculi
• Sternocleidomastoideus

15
skeletal muscle facts

• Skeletal muscle consists of very long tubular
  cells. The average length of skeletal muscle
  cells in humans is about 3 cm (sartorius muscle
  up to 30 cm, stapedius muscle only about 1 mm).
  Their diameters vary from 10 to 100 µm.
• Skeletal muscle fibres contain many peripherally
  placed nuclei.Up to several hundred rather small
  nuclei with 1 or 2 nucleoli are located just
  beneath the plasma membrane.

16
facts, continued

• Skeletal muscle fibres show in many preparations
  characteristic cross-striations. It is therefore
  also called striated muscle.
• Skeletal muscle is innervated by the somatic
  nervous system.
• Skeletal muscle makes up the voluntary muscle.

17
what students of anatomy learn about the skeletal
muscles

• over 600 named muscles in human
• makes up 40-50 of body weight
• the physiology of muscle action
• name, location, action, origin, insertion and
  often the nerve that serves the muscle

18
striatedmuscle tissue
19
the players

• myofibrils contract instantly if ATP and Ca2
  is added to them, meaning that it is these single
  myofibrils which are the force generators in
  muscle cells.

20
sarcomere

• Striated sarcomeres are separated by Z-discs.
  Two Z-discs bound a sarcomere in the direction of
  stretching. Thin filaments made of Actin are
  attached to each of these discs and extend
  towards each other inside the sarcomere. They do
  not overlap in the sarcomeres striated form. In
  this case there is a dark band visible between
  the Z-discs. This is made up of the thick Myosin
  filaments which overlap partially with the thin
  Actin filaments which extend into a light half of
  the I-Band region left and right of the dark
  A-band.

21
contraction shorten

• When Myofibrils contract the thin and thick
  filaments move past each other. Each sarcomere
  unit of the myofibrils shortens proportionally to
  the muscle contraction. Upon contraction, it is
  the light bands which shorten whereas the dark
  bands do not change in length. This is explained
  by the Actin filaments sliding into the dark
  region of Myosin filaments.

22
thick and thin

• Actin - the thin filaments
• Myosin - the thick filaments

23

24
structure of skeletal muscle
25
contraction
During contraction, actin fibers are pulled
inward a) pulling is by "hooks" on myosin
(myosin heads) b) hooks bend, using energy of
ATP c) each hook pulls, releases, pulls again
until muscle is contracted d) calcium (Ca2)
ions signal this to start -Ca2 into muscle
starts contraction -during relaxation, Ca2 is
transported out  
26
nerves and muscles
27
muscle ends

• origin-stationary end, the anchor
• insertion- moved end
• belly- the area in between

28
CAUTION

• NOTE These pictures are intended to provide a
  virtual tour of the lab models and specimens. 
  They are not intended to substitute for
  classroom/lab learning. They are simply
  supplemental material for you to use as reminders
  of what you should study or have already studied.

29
superficial muscles

• Muscles which occupy the layer closest to the
  surface of the skin are called superficial
  muscles. These are easily displayed on a person
  who has developed their physique for show or
  physical performance.

30
major muscles of face

• frontalis
• orbicularis oculi
• nasalis
• temporalis
• orbicularis oris
• zygomaticus major
• masseter
• mentalis
• levator labii superioris

31
(No Transcript)
32
Facial muscles around the mouth, directions of
muscle contraction

• A levator labii superioris
• B zygomaticus minor
• C zygomaticus major
• D risorius
• E depressor anguli oris
• F labii inferioris,
• G orbicularis oris

33
muscles of mastication

• temporalis
• medial and lateral pterygoids
• masseter

34
masseter

• masseter and directions of the lower jawbone
  movement

35
sternocleidomastoid

• sternocleidomastoid muscle is the main muscle
  on the side of the neck.

36
neck pain

• The trapezius muscle is the one that tenses up
  most often. When you see people reaching back to
  massage their shoulders, it is the trapezius
  muscle that they are trying to loosen.
• The other two muscles that have a tendency to
  tighten up are the sternocleidomastoid (often
  called the sterno-mastoid) and the scalene
  muscles.
• Keep it Moving! The neck is by far the most
  mobile portion of the spine. Its ROM is generally
  70 to 90 degrees.

37
bones of the neck, review

• The bones of the neck are called the cervical
  vertebrae.
• Every mammal on earth, even the giraffe, has 7
  of them. In humans, the cervical vertebrae are
  obviously a lot smaller than those of giraffes.
  They are also a lot smaller than the vertebrae of
  the other areas of the human spine.

38
neck pain?

• Our necks need to use their mobility in order
  to maintain it. They work best when they can
  consistently move into and out of their full
  range of motion in a gentle - that is, not a
  jarring - way.

39
non-used necks injuries

• We rotate our necks fully when we look over
  our shoulder and then back the car down the
  driveway. We extend our necks completely when we
  look up at the ceiling.
• The fact that we do not do these things often
  is one of the major reasons why our necks cause
  us problems. On occasion, when its essential for
  the neck to move to an extreme range of motion,
  it cant cope with the job. Thats when injuries
  occur.

40
muscles of the back
41
trapezius

• The trapezius covers a large section of the
  upper back. It conceals the upper part of the
  shoulder blade.

42
latissimus dorsi

• The latissimus dorsi occupy the middle back on
  either side.
• The gluteus maximus make up the back of the
  buttocks.

43
abdominal muscles

• 4 muscles of the abdominal area
• rectus abdominis
• external oblique
• internal oblique NS
• transversus abdominis NS

44
muscles of the arm
45
superficial muscles of the chest and front of the
arm.

• The shoulder muscles are called deltoids. These
  triangular muscles define the upper shoulders
• biceps brachii are easily recognizable large
  bumps on the upper inside of the arm
• The pectoralis muscles span the chest

46
superficial muscles of the posterior arm

• triceps brachii extends the arm,
  straightening the elbow

47
leg muscles
48
anterior muscles of the thigh

• Quads extensor of knee
• rectus femoris
• vastus lateralis
• vastus medius
• vastus intermedialis
• sartorius cross leg
• gracilis adducts leg

49
posterior muscles of the thigh

• The hamstring muscle group comprises three
  muscles
• biceps femoris
• semitendonosus
• semimembranosus
• The action of these muscles is to bend the
  knee and extend the hip.

50
adductors of the thigh

• adductor magnus, longus, brevis and the
  pectineus, make up the adductor group. 
• Groin pulls are a strain at the attachment of
  the adductors to the pubic bone.

51
major muscle of lower leg - anterior

• tibialis anterior flexes the foot pulls foot
  toward the knee

52
muscles of lower leg -posterior - calf muscles

• gastrocnemius is the calf muscle which are each
  divided into two hemispheres.
• soleus

53
soleus and Achilles tendon

• This picture illustrates the relationship
  between the superficial gastrocnemius muscle, the
  deeper soleus muscle and the large Achilles
  tendon which is visible attaching to the heel.

54
atrophy - hypertrophy

• no use
• average use
• increased use

55
muscle twitch

• cycle of contraction and relaxation
• latent phase

56
tetany

• Tetany-stimuli is so fast that muscle cannot
  relax - stays contracted
• (tetanus - bacterial toxin interferes with
  motor neuron function, uncontrolled stimulation)

57
chondromalacia (runner's knee)

• Wearing away and/or softening of the articular
  cartilage, tissue that covers and protects the
  underside of the patella, the bottom end of the
  femur, and top end of the tibia. It absorbs
  stress to the knee joint and allows the patella
  to track smoothly in its femoral groove.Causes
  Typically, excessive running Symptoms Pain
  around the patella (kneecap), usually occurring
  on the medial (inner) side and below (inferior
  aspect of the patella).

58
doctor and PT

• Recommended Treatment R.I.C.E. - Rest, Ice,
  Compression, Elevation. Reduce activity to
  promote healing. Avoid downhill runs especially.
  Strengthen surrounding muscles with a
  professionally recommended program. Apply Ice for
  10-15 minutes after each workout to reduce
  inflammation and pain. (If any skin irritation or
  adverse reaction occurs due to icing, see your
  medical doctor). A proper stretching (Quadriceps,
  Iliotibial Band) routine is highly recommended
  pre and post workouts. As with any orthopedic
  injury, a consultation with a sports medicine
  professional is recommended.

59
hamstring strain/tear

• occurs when excessive or repetitive stress
  causes tearing of the muscle fibers in the
  hamstring.Causes Tight hamstring muscles,
  muscle imbalance, sudden movement, and repetitive
  strain are all common types of hamstring
  injuries. Symptoms A sharp pain may be felt in
  the hamstring when a serious strain or tear
  occurs. This often happens during such action as
  an explosive move in basketball or a quick
  sprint. If you feel a deep ache in the hamstring
  area it may be a less severe strain or minor
  tear.

60
intramuscular injection

• intramuscular injection delivers medicine
  directly into the muscle
• deltoid
• gluteus medius

61
injections
62
muscular disorders

• Atrophy
• decrease in size of muscle fibers
• Disuse atrophy - bedridden individuals, casts
• Denervation atrophy - loss of nerves and muscle
  function
• Muscular Dystrophy - (Duchenne MD)
• Loss of muscle fibers
• Linked to young males (ages 3-5)
• Lacking certain protein thus allows too much
  Ca into cell this leads to cell death and
  replacement with scarring

63
muscular disorders

• Myasthenia gravis
• autoimmune disease
• antibodies bind to ACh receptors
• atrophy of muscle fibers
• drugs that keep levels of ACh high are used

64
what happens in rigor mortis?

• Ca pumps run out of ATP
• Ca cannot be removed
• continuous contraction
• eventually tissues break down

65
muscles of the face, review
66
(No Transcript)
67
(No Transcript)
68
references

• Link Publishing
• www.linkpublishing.com
• Texas Tech University
• www.biol.ttu.edu/Z2403/large20AP20pics
• humanback.htm
• PE World
• http//www.peworld.org/anatomy/muscles.htm
• Pro Tech Athletics
• www.pro-tecathletics.com/ kneeinjuries.htm
• Insite Fitness
• www.insitefitness.com.au/