Actividades Fase I: Preparación y Planificación del Catastro de Clientes

Muscles of the Body

• Skeletal muscles

• Produce movements

• Blinking of eye, standing on tiptoe, swallowing food, etc.

• General principles of leverage

• Muscles act with or against each other • Criteria used in naming muscles

Arrangement of Fascicles in Muscles

• Skeletal muscles—consist of fascicles

• Fascicles—arranged in different patterns

• Fascicle arrangement—tells about action of a muscle Arrangement of Fascicles in Muscles

• Types of fascicle arrangement

• Parallel—fascicles run parallel to the long axis of the muscle • Strap-like—sternocleidomastoid

Arrangement of Fascicles in Muscles

• Types of fascicle arrangement

• Convergent

• Origin of the muscle is broad

• Fascicles converge toward the tendon of insertion • Example—pectoralis major

Arrangement of Fascicles in Muscles

• Types of fascicle arrangement

• Pennate

• Unipennate—fascicles insert into one side of the tendon • Bipennate—fascicles insert into the tendon from both sides • Multipennate—fascicles insert into one large tendon from all

sides

Arrangement of Fascicles in Muscles

• Circular

• Fascicles are arranged in concentric rings • Surround external body openings

• Sphincter—general name for a circular muscle • Examples

• Orbicularis oris and orbicularis oculi

Lever Systems: Bone-Muscle Relationships

• Movement of skeletal muscles involves leverage

• Lever—a rigid bar that moves • Fulcrum—a fixed point

• Effort—applied force • Load—resistance

Lever Systems: Bone-Muscle Relationships

• Bones—act as levers • Joints—act as fulcrums

• Muscle contraction—provides effort

• Applies force where muscle attaches to bone

• Load—bone, overlying tissue, and anything lifted

Lever Systems: Bone-Muscle Relationships

• Levers allow a given effort to

• Move a load farther

• Mechanical advantage

• Moves a large load over small distances

• Mechanical disadvantage

• Allows a load to be moved over a large distance Lever Systems: Bone-Muscle Relationships

• First-class lever

• Effort applied at one end • Load is at the opposite end

• Fulcrum is located between load and effort Lever Systems: Bone-Muscle Relationships

• Examples—seesaws, scissors, and lifting your head off your chest

Lever Systems: Bone-Muscle Relationships

• Second-class lever

• Effort applied at one end • Fulcrum is at the opposite end

• Load is between the effort and fulcrum

• Examples—wheelbarrow or standing on tiptoe • An uncommon type of lever in the body • Work at a mechanical advantage

Lever Systems: Bone-Muscle Relationships

• Third-class lever

• Effort is applied between the load and the fulcrum • Work speedily

• Always at a mechanical disadvantage

Lever Systems: Bone-Muscle Relationships

• Most skeletal muscles are third-class levers

• Example—biceps brachii • Fulcrum—the elbow joint

• Force—exerted on the proximal region of the radius • Load—the distal part of the forearm

Organization Scheme Based on Embryonic Development

• Embryonic origin • General function

• Muscles develop from mesoderm

• Myotomes • Somitomeres

•

The first seven myotomes of the head

• Splanchnic mesoderm

Development and Basic Organization of the Muscles Organization Scheme Based on Embryonic Development

• Muscles organized into four groups

• Musculature of the visceral organs • Pharyngeal arch muscles

• Axial muscles • Limb muscles

Organization Scheme Based on Embryonic Development

• Musculature of the visceral organs

• Includes smooth and cardiac muscle • Develops from splanchnic mesoderm

• Pharyngeal arch muscles

• Includes

• Skeletal muscles of the pharynx • Muscles of the head and neck

• Develop from the fourth to seventh somitomeres Pharyngeal Arch Muscles

Axial Muscles

• Lie anterior and posterior to the body axis • Muscles of the

• Thorax, abdomen, and pelvis

• Many muscles of the

• Neck and some of the head

• Function to move the trunk and maintain posture

Axial Muscles

• Develop from myotomes and some somitomeres

• Ventral regions of myotomes—muscles of the trunk and neck • Respiratory muscles

• Anterior abdominal wall muscles • Muscles of the pelvic floor

Axial Muscles Limb Muscles

• Limb muscles arise from lateral parts of nearby myotomes • Extensors

• Muscle mass dorsal to limb bones

• Flexors

• Muscle mass ventral to limb bones Limb Muscles

Muscle Actions and Interactions

• A muscle cannot reverse the movement it produces • Another muscle must undo the action

• Muscles with opposite actions lie on opposite sides of a joint

Muscle Actions and Interactions

• Prime mover (agonist)

• Has major responsibility for a certain movement

• Antagonist

• Opposes or reverses a movement

• Synergist—helps the prime mover • By adding extra force

• By reducing undesirable movements • Fixator

• A type of synergist that holds a bone firmly in place Muscle Compartments of the Limbs

• Dense fibrous connective tissue divides limb muscles into

compartments

• Muscles in opposing compartments are

• Agonist and antagonist pairs

• Each compartment is innervated by a single nerve

• The upper limb has anterior and posterior compartments

• Anterior arm compartment muscles • Flex the shoulder or arm

• Innervation is the musculocutaneous nerve • Anterior forearm compartment muscles

• Flex the wrist and digits

• Innervation is the median or ulnar nerve

Muscle Compartments of the Thigh

• Posterior compartment muscles

• Extend the hip and flex the knee

• Innervation is the tibial branch of the sciatic nerve

• Anterior compartment muscles

• Flex the hip and extend the knee • Innervation is the femoral nerve

• Medial compartment

• Adduct the thigh

• Innervation is the obturator nerve

Muscle Compartments of the Thigh and Leg Compartments of the Leg

• Posterior compartment muscles

• Contains digital and plantar flexors • Innervation is the tibial nerve

• Anterior compartment muscles

• Contains digital extensors and dorsiflexors • Innervation is the deep fibular nerve

• Lateral compartment muscles

• Plantar flex and evert the foot

• Innervation is the superficial fibular nerve Naming the Skeletal Muscles

• Location

• Example—the brachialis is located on the arm

• Shape

• Example—the deltoid is triangular

• Maximus, minimus, and longus indicate size • Example—gluteus maximus and gluteus minimus Naming the Skeletal Muscles

• Direction of fascicles and muscle fibers

• Name tells direction in which fibers run

• Example—rectus abdominis and transversus abdominis

• Location of attachments—name reveals point of origin and insertion

• Example—brachioradialis Naming the Skeletal Muscles

• Number of origins

• Two, three, or four origins

• Indicated by the words biceps, triceps, and quadriceps

• Action

• The action is part of the muscle’s name • Indicates type of muscle movement

• Flexor, extensor, adductor, or abductor

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In document PROYECTO DE REDUCCIÓN DE PÉRDIDAS DE AGUA EN TACNA, PERÚ (página 31-34)