A & P Ch 6 Musclular System Student PPT

© 2012 Pearson Education, Inc.

Muscular System – Ch 6http://www.youtube.com/watch?v=dmQSP8uUwL8

Dancing frog legs:

http://www.youtube.com/watch?v=dmQSP8uUwL8



http://community.ashworthcollege.edu/servlet/JiveServlet/showImage/2-46460-6900/body_builder_7sfw.gif


Overview of Muscle Tissues 1. Describe similarities and differences in the structure and function of the three types of muscle

tissue and indicate where they are found in the body. 2. State the 4 main functions of the muscular system and list the main parts of the muscular

system.3. Define and explain the role of the following: endomysium, perimysium, epimysium, tendon, and

aponeurosis. and label them on a diagram.Microscopic Anatomy of Skeletal Muscle 4. Describe the microscopic structure of skeletal muscle and explain the role of actin- and myosin-

containing myofilaments and label a sarcomere diagram.Skeletal Muscle Activity 5. Describe how an action potential is initiated in a muscle cell. (neuromuscular junction,

acetylcholine, Ca++…)6. Describe the events of muscle cell contraction (myosin heads binding to actin fibers & sliding

them past…). 8. Describe three ways in which ATP is regenerated during muscle activity. 9. Define oxygen debt and muscle fatigue and list possible causes of muscle fatigue. 10. Describe the effects of aerobic and resistance exercise on skeletal muscles and other body

organs. Muscle Movements, Types, and Names 11. Define origin, insertion, prime mover, antagonist, synergist, and fixator as they relate to

muscles. 12. Demonstrate or identify the different types of body movements. (flexion, extension,

hyperextension, rotation, abduction, adduction, supination, pronation, opposition)Gross Anatomy of Skeletal Muscles 14. Name and locate the major muscles of the human body (on a torso model, muscle chart, or

diagram) and state the action of each.

The Muscular System Ch 6 Goals


The Muscular System Muscles are responsible for all types of body movement

• Movement of• Skeleton• Facial expressions• Eyeball• Goosebumps• Iris to control amt of light into eye

• Heart beating• Substances through body


Characteristics of Muscles

•Skeletal and smooth muscle cells are elongated (muscle cell = muscle fiber)

•Contraction and shortening of muscles is due to the movement of microfilaments

•All muscles share some terminology

•Prefixes myo and mys refer to “muscle”

•Prefix sarco refers to “flesh”

• Composes almost 50% of body mass


3 Basic Muscle Types


Skeletal Muscle Characteristics• Most are attached by tendons to bones• Cells are multinucleate• Striated—have visible banding• Voluntary—subject to conscious control• Responds fastest to stimuli


Connective Tissue Wrappings of Skeletal Muscle• Cells are surrounded and bundled by connective tissue

• Endomysium—encloses a single muscle fiber (cell)• Perimysium—wraps around a fascicle (bundle) of muscle fibers• Epimysium—covers the entire skeletal muscle• Fascia—on the outside of the epimysium;

covers & separates muscles

Short video showing live human fascicles being stimulatedhttp://www.youtube.com/watch?v=1-dpnqNupns

http://www.youtube.com/watch?v=1-dpnqNupns



© 2012 Pearson Education, Inc. Figure 6.1

Blood vessel

Perimysium

Epimysium(wraps entiremuscle)

Musclefiber(cell)

Fascicle(wrapped byperimysium)

Endomysium(betweenfibers)

Tendon

Bone


Skeletal Muscle Attachments• Epimysium blends into a connective tissue attachment

• Tendons—cord-like structures • Mostly collagen fibers• Often cross a joint due to toughness and small size

• Aponeuroses—sheet-like structures• Attach muscles indirectly to bones, cartilages, or connective tissue coverings


Skeletal Muscle Attachments• Sites of muscle attachment

• Bones• Cartilages• Connective tissue coverings

• Some facial muscles attached from skull to skin – allow for facial expressions


Skeletal Muscle Functions

•Produce movement

•Maintain posture

•Stabilize joints

•Generate heat

Yea, I’m hot stuff.


Microscopic Anatomy of Skeletal Muscle•Sarcolemma—specialized plasma membrane

•Myofibrils—long organelles inside muscle cell

•Sarcoplasmic reticulum—specialized smooth endoplasmic reticulum

© 2012 Pearson Education, Inc. Figure 6.3a

Sarcolemma

Myofibril

Dark(A) band

Light(I) band

Nucleus

(a) Segment of a muscle fiber (cell)


Microscopic Anatomy of Skeletal Muscle• Myofibrils are aligned to give distinct bands

• I band = light band• Contains only thin filaments

• A band = dark band • Contains the entire length of the thick filaments


Microscopic Anatomy of Skeletal Muscle• Sarcomere—contractile unit of a muscle fiber (area b/t two Z discs)

• Organization of the sarcomere• Myofilaments

• Thick filaments = myosin filaments• Thin filaments = actin filaments


Microscopic Anatomy of Skeletal Muscle• Thick filaments = myosin filaments

• Composed of the protein myosin• Has ATPase enzymes• Myosin filaments have heads (extensions, or cross bridges)• Myosin and actin overlap somewhat

• Thin filaments = actin filaments• Composed of the protein actin• Anchored to the Z disc

© 2012 Pearson Education, Inc. Figure 6.3c

Z disc

Sarcomere

M lineZ disc

Thin (actin) filament

Thick (myosin) filament

(c) Sarcomere (segment of a myofibril)


Microscopic Anatomy of Skeletal Muscle• At rest, within the A band there is a zone that lacks actin filaments

• Called either the H zone or bare zone• Sarcoplasmic reticulum (SR)

• Stores and releases calcium• Surrounds the myofibril

© 2012 Pearson Education, Inc. Figure 6.3d

Thick filament Bare zone Thin filament

(d) Myofilament structure (within one sarcomere)


The Nerve Stimulus and Action Potential• Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract

• Motor unit—one motor neuron and all the skeletal muscle cells stimulated by that neuron

© 2012 Pearson Education, Inc. Figure 6.4a(a)

Spinal cord

Motor unit 1

Motor unit 2

Axon terminals at neuromuscular junctions

Nerve

Axon ofmotorneuron

Motor neuroncell bodies

Muscle Muscle fibers

© 2012 Pearson Education, Inc. Figure 6.4b

Axon terminals at neuromuscular junctions Muscle fibers

Branching axonto motor unit

(b)

•Neuromuscular junction

•Association site of axon terminal of the motor neuron and muscle

The Nerve Stimulus and Action Potential



The Nerve Stimulus and Action Potential•Synaptic cleft

•Gap between nerve and muscle

•Nerve and muscle do not make contact

•Area between nerve and muscle is filled with interstitial fluid

© 2012 Pearson Education, Inc. Figure 6.5, step 4

Action potential reaches axonterminal of motor neuron.

Calcium (Ca2+) channelsopen and Ca2+ enters the axon terminal.

Ca2+ entry causes somesynaptic vesicles to release theircontents (acetylcholine, a neurotransmitter) by exocytosis.

Acetylcholine diffuses acrossthe synaptic cleft and binds toreceptors in the sarcolemma.

Synaptic vesicle containing ACh

Axon terminal of motor neuron

Mitochondrion

Ca2+

Fusing synapticvesicleSarcoplasmof muscle fiber

Folds ofsarcolemma

Ca2+

AChreceptor

ACh

1

2

3

4

SarcolemmaSynapticcleft

Transmission of Nerve Impulse to Muscle


ACh binds and channels openthat allow simultaneous passageof Na+ into the muscle fiber and K+ out of the muscle fiber. MoreNa+ ions enter than K+ ions leaveand this produces a local changein the electrical conditions of themembrane (depolarization), whicheventually leads to an actionpotential.

5Ion channel insarcolemma opens;ions pass.

Na+ K+



ACh effects are ended by itsbreakdown in the synaptic cleft bythe enzyme acetylcholinesterase.

6

Ion channel closed;ions cannot pass.

Acetylcholinesterase

Na+

Degraded AChACh

K+



The Sliding Filament Theory of Muscle Contraction• Activation by nerve causes myosin heads (cross bridges) to attach to binding sites on the thin filament

• Myosin heads then bind to the next site of the thin filament and pull them toward the center of the sarcomere

• This continued action causes a sliding of the myosin along the actin

• The result is that the muscle is shortened (contracted)

© 2012 Pearson Education, Inc. Figure 6.7a–b

Myosin Actin

Z H

I

Z

A I

(a)

(b)

Z

I A I

Z



Muscle Response to Strong Stimuli

•Muscle force depends upon the number of fibers stimulated

•More fibers contracting results in greater muscle tension

•Muscles can continue to contract unless they run out of energy


Energy for Muscle Contraction

•Initially, muscles use stored ATP for energy

•ATP bonds are broken to release energy

•Only 4–6 seconds worth of ATP is stored by muscles

•After this initial time, other pathways must be utilized to produce ATP – there are 3 pathways to produce ATP



•Direct phosphorylation of ADP by creatine phosphate (CP)

•CP supplies are exhausted in less than 15 seconds

•About 1 ATP is created per CP molecule


Energy for Muscle Contraction• Anaerobic glycolysis and lactic acid formation

• Reaction that breaks down glucose without oxygen• Glucose is partially broken down to produce about 2 ATP

• This reaction is not as efficient, but is fast• Huge amounts of glucose are needed• Lactic acid produces muscle fatigue



•Aerobic respiration (with Oxygen)

•Glucose is broken down to CO2 & H2O, releasing energy (about 32 ATP)

•In mitochondria

•Slower reaction that requires continuous O2


Muscle Fatigue and Oxygen Deficit

•When a muscle is fatigued, it is unable to contract even with a stimulus

•Common cause for muscle fatigue is oxygen debt

•Oxygen must be “repaid” to tissue to remove oxygen deficit

•Oxygen is required to get rid of accumulated lactic acid

•Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less


Effect of Exercise on Muscles

•Exercise increases muscle size, strength, and endurance

•Aerobic (endurance) exercise (biking, jogging) results in stronger, more flexible muscles with greater resistance to fatigue

•Makes body metabolism more efficient

•Improves digestion, coordination

•Resistance (isometric) exercise (weight lifting) increases muscle size and strength


Five Golden Rules of Skeletal Muscle Activity

1. With a few exceptions, all skeletal muscles cross at least one joint.

2. Typically, the bulk of a skeletal muscle lies proximal to the joint crossed.

3. All skeletal muscles have at least two attachments: the origin and the insertion.

4. Skeletal muscles can only pull; they never push.

5. During contraction, a skeletal muscle insertion moves toward the origin.


Muscles and Body Movements

•Movement is attained due to a muscle moving an attached bone

•Muscles are attached to at least two points

•Origin

•Attachment to a moveable bone

•Insertion

•Attachment to an immovable bone


Tendon

Insertion

Brachialis

Origin

Musclecontracting


Types of Body Movements• Flexion

• Decreases the angle of the joint• Brings two bones closer together• Typical of bending hinge joints like knee and elbow or ball-and-socket joints like the hip

• Extension• Opposite of flexion• Increases angle between two bones• Typical of straightening the elbow or knee• Extension beyond 180° is hypertension

• Great video showing these:

http://www.youtube.com/watch?v=-GCgaoRdeaU






Types of Body Movements

•Rotation

•Movement of a bone around its longitudinal axis

•Common in ball-and-socket joints

•Example is when you move atlas around the dens of axis (shake your head “no”)



Types of Body Movements

•Abduction

•Movement of a limb away from the midline

•Adduction

•Opposite of abduction

•Movement of a limb toward the midline


Special Movements

•Supination

•Forearm rotates laterally so palm faces anteriorly

•Radius and ulna are parallel

•Pronation

•Forearm rotates medially so palm faces posteriorly

•Radius and ulna cross each other like an X

© 2012 Pearson Education, Inc. Figure 6.13g


Special Movements

•Opposition

•Move thumb to touch the tips of other fingers on the same hand

© 2012 Pearson Education, Inc. Figure 6.13h


Types of Muscles

•Prime mover—muscle with the major responsibility for a certain movement

•Antagonist—muscle that opposes or reverses a prime mover

•Synergist—muscle that aids a prime mover in a movement and helps prevent rotation

•Fixator—stabilizes the origin of a prime mover


Naming Skeletal Muscles

•By direction of muscle fibers

•Example: Rectus (straight)

•By relative size of the muscle

•Example: Maximus (largest)



•By location of the muscle

•Example: Temporalis (temporal bone)

•By number of origins

•Example: Triceps (three heads)



•By location of the muscle’s origin and insertion

•Example: Sterno (on the sternum)

•By shape of the muscle

•Example: Deltoid (triangular)

•By action of the muscle

•Example: Flexor and extensor (flexes or extends a bone)


Head and Neck Muscles

•Facial muscles•Frontalis—raises eyebrows•Orbicularis oculi—closes eyes, squints, blinks, winks

•Orbicularis oris—closes mouth and protrudes the lips

•Buccinator—flattens the cheek, chews•Zygomaticus—raises corners of the mouth

•Chewing muscles•Masseter—closes the jaw and elevates mandible

•Temporalis—synergist of the masseter, closes jaw


Head and Neck Muscles

•Neck muscles

•Platysma—pulls the corners of the mouth inferiorly

•Sternocleidomastoid—flexes the neck, rotates the head


Cranialaponeurosis

Orbicularisoris

Orbicularisoculi

Frontalis

Zygomaticus

Buccinator

Platysma

Temporalis

Occipitalis

Masseter

Sternocleidomastoid

Trapezius


Muscles of Trunk, Shoulder, Arm

•Anterior muscles

•Pectoralis major—adducts and flexes the humerus

•Intercostal muscles

•External intercostals—raise rib cage during inhalation

•Internal intercostals—depress the rib cage to move air out of the lungs when you exhale forcibly



•Muscles of the abdominal girdle

•Rectus abdominis—flexes vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing)

•External oblique—flex vertebral column; rotate trunk and bend it laterally

•Internal oblique—flex vertebral column; rotate trunk and bend it laterally

•Transversus abdominis—compresses abdominal contents



•Posterior muscles

•Trapezius—elevates, depresses, adducts, and stabilizes the scapula

•Latissimus dorsi—extends and adducts the humerus

•Erector spinae—back extension

•Quadratus lumborum—flexes the spine laterally

•Deltoid—arm abduction



•Muscles that arise from the shoulder girdle and cross the shoulder joint to insert into the humerus include:

•Pectoralis major

•Latissimus dorsi

•Deltoid

PLAY A&P Flix™: Movement at the glenohumeral joint: An overview.

PLAY A&P Flix™: Muscles that cross the glenohumeral joint.

PLAY A&P Flix™: Muscles of the pectoral girdle.

PLAYA&P Flix™: Muscles that act on the shoulder joint and humerus: An overview.


Muscles of the Upper Limb

•Biceps brachii—supinates forearm, flexes elbow

•Brachialis—elbow flexion

•Brachioradialis—weak muscle; elbow flexion

•Triceps brachii—elbow extension (antagonist to biceps brachii)

PLAY A&P Flix™: Movement at the elbow joint.

PLAY A&P Flix™: Muscles of the elbow joint.

PLAY A&P Flix™: The elbow joint and forearm: An overview.


Muscles of the Upper Limb

•Muscles of the forearm, which insert on the hand bones and cause their movement include:

•Flexor carpi—wrist flexion

•Flexor digitorum—finger flexion

•Extensor carpi—wrist extension

•Extensor digitorum—finger extension

PLAY A&P Flix™: Movements of the wrist and fingers (b).

PLAY A&P Flix™: Movements of the wrist and fingers (a).

PLAYA&P Flix™: Muscles that act on the wrist and fingers: An overview.


Muscles of the Lower Limb

•Muscles causing movement at the hip joint include:

•Gluteus maximus—hip extension

•Gluteus medius—hip abduction, steadies pelvis when walking

•Iliopsoas—hip flexion, keeps the upper body from falling backward when standing erect

•Adductor muscles—adduct the thighs

PLAY A&P Flix™: Movement at the hip joint: An overview.

PLAYA&P Flix™: Muscles that act on the hip joint and femur: An overview.


Gluteus medius

Gluteus maximus

Adductormagnus

Iliotibial tract

Biceps femoris

Semitendinosus

Semimembranosus

Gastrocnemius

(a)

Hamstring group


12th rib

Iliac crest

lliopsoas Psoas majorlliacus

Anterior superioriliac spine

Sartorius

Rectus femoris

Vastus lateralis

Vastus medialisQu

adri

cep

s

Patellarligament

(c)

Patella

Adductorgroup

5thlumbar vertebra

12ththoracic vertebra



•Muscles causing movement at the knee joint

•Hamstring group—thigh extension and knee flexion

•Biceps femoris

•Semimembranosus

•Semitendinosus


Gluteus medius

Gluteus maximus

Adductormagnus

Iliotibial tract

Biceps femoris

Semitendinosus

Semimembranosus

Gastrocnemius

(a)

Hamstring group



•Muscles causing movement at the knee joint

•Sartorius—flexes the thigh

•Quadriceps group—extends the knee

•Rectus femoris

•Vastus muscles (three)

PLAY A&P Flix™: Muscles that cross the knee joint: An overview.



•Muscles causing movement at ankle and foot

•Tibialis anterior—dorsiflexion, foot inversion

•Extensor digitorum longus—toe extension and dorsiflexion of the foot

•Fibularis muscles—plantar flexion, foot eversion

•Soleus—plantar flexion

PLAY A&P Flix™: Movements of the ankle and foot.

PLAY A&P Flix™: Posterior muscles that act on the ankle and foot.

PLAYA&P Flix™: Muscles that act on the ankle and foot: An overview.


Fibularis longus

Fibularis tertius

Tibialis anterior

Extensor digitorumlongus

Tibia

Soleus

(a)

Fibularis brevis


Gastrocnemius

Soleus

Calcaneal (Achilles)tendon

Medial malleolusLateralmalleolus

(b)


Facial• Temporalis

• Masseter

Shoulder

• Trapezius

• Deltoid

Arm• Triceps brachii• Biceps brachii

• Brachialis

Forearm• Brachioradialis• Flexor carpi radialis

Pelvis/thigh• lliopsoas

Thigh (Quadriceps)• Rectus femoris• Vastus lateralis• Vastus medialis

Leg• Fibularis longus

• Extensor digitorum longus

• Tibialis anterior

Facial• Frontalis

• Orbicularis oculi• Zygomaticus

• Orbicularis orisNeck• Platysma• SternocleidomastoidThorax• Pectoralis minor

• Pectoralis major

• Serratus anterior

• Intercostals

Abdomen

• Rectus abdominis

• External oblique• Internal oblique

• Transversus abdominis

Thigh

• Sartorius

• Adductor muscle

• Gracilis

Leg• Gastrocnemius

• Soleus


Arm• Triceps brachii

• Brachialis

Forearm• Brachioradialis• Extensor carpi radialis longus• Flexor carpi ulnaris

• Extensor carpi ulnaris• Extensor digitorum

lliotibial tract

Leg

• Gastrocnemius

• Soleus

• Fibularis longus

Calcaneal(Achilles)tendon

Neck• Occipitalis

• Sternocleidomastoid

• Trapezius

Shoulder/Back

• Deltoid

• Latissimus dorsi

Hip• Gluteus medius

• Gluteus maximus

Thigh• Adductor muscle• Hamstrings:

Biceps femoris

Semitendinosus

Semimembranosus

Documents

A & P Ch 6 Musclular System Student PPT