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HUMAN ANATOMY LECTURE NINE MUSCLES

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Page 1: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

HUMAN ANATOMY

LECTURE NINE

MUSCLES

Page 2: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE FUNCTIONS

• Body movement • Posture• Respiration and heart beat• Production of body heat - maintains body temperature• Communication - speaking, writing, gesturing, facial

and body language• Constriction of organs and vessels - helps food move

through digestive tract and blood flow• Protects and supports soft tissues• Storage of nutrients

Page 3: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

PROPERTIES OF MUSCLE

• Contractility - ability of a muscle to shorten with force• Excitability - capacity of muscle to respond to a

stimulus• Extensibility - muscle can be stretched beyond its

normal resting length• Elasticity - ability of muscle to recoil to original resting

length after being stretched

Page 4: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

TYPES OF MUSCLE• Skeletal Muscle

- voluntary muscle- responsible for movement, respiration, posture, facial

expressions• Smooth Muscle

- involuntary- around organs, blood vessels, glands, skin- controlled by endocrine and autonomic nervous system

• Cardiac Muscle- autorhythmic- only found in heart- controlled by endocrine and autonomic nervous system

Page 5: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

SKELETAL MUSCLE

• Composed of muscle cells (fibres), connective tissue, blood vessels, nerves

• Fibres are long, cylindrical, multinucleated

• Smaller in diameter in small muscles and larger in larger muscles

• Striated appearance due to light and dark banding

Page 6: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

SKELETAL MUSCLE STRUCTURE• Epimysium (fascia) - sheath surrounding

entire muscle

- holds muscle together and separates

them into groups

- allows freedom of movement

- carries nerves, blood vessels, lymphatic

vessels

- continuous with connective tissue of

tendons and periosteum

• Muscle Fasciculi - muscle bundles

- composed of several muscle fibres

- surrounded by connective tissue layer

called perimysium

• Endomysium - connective tissue surrounding individual muscle fibres

Page 7: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

NERVE AND BLOOD SUPPLY

• Muscle cells are stimulated to contract by motor neuron axons at a neuromuscular junction (synapse)

• Axons are branched so that every muscle fibre is innervated

• Blood vessels and nerves enter the muscle together and follow the same branching pathway through the perimysium

• Within the endomysium arterioles branch into capillary beds surrounding each muscle fibre

Page 8: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

SKELETAL MUSCLE CELLS (FIBRES)• Sarcoplasm - cytoplasm containing

numerous myofibrils

• Myofibril - thread-like structure extending length of muscle fibre

- made up of proteins (actin and

myosin myofilaments)

• Sarcomeres - repeating arrangment of actin and myosin

- smallest section of muscle capable

of contracting

• Sarcolemma - cell membrane surrounding a muscle fibre (cell)

• Sarcoplasmic reticulum - similar to smooth ER

- forms tubular network around each

myofibril

Page 9: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

TRANSVERSE TUBULES

• Transverse tubules - narrow tubes continuous with sarcolemma extending into sarcoplasm at right angles to muscle fibre

- distributes signal (action potential) to contract through to interior of cell ensuring all cells contract simultaneously

• Terminal cisternae - thickening on either side of t-tubule

• Triad - terminal cisternae + t-tubule

Page 10: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature
Page 11: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

ACTIN (THIN) FILAMENTS• Two strands (F-actin) of pearl-like

proteins (G-actin) form a double helix extending the length of the muscle fibre

• Thin strand of nebulin holds the F-actin together

• G-actin contains the active site that binds the myosin during muscle contraction

• Tropomyosin winds through the F-actin and covers the active sites

• Troponin protein found at the ends of the tropomyosin forming the tropomyosin/troponin complex - binds Ca+2 and changes position during muscle contraction

Page 12: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MYOSIN (THICK) FILAMENTS

• Each ‘club’ consists of two heavy myosin molecules wound together to form a rod portion lying parallel with heads that extend laterally

• Myosin ‘heads’

- bind to active sites on the active sites on the actin molecules to form crossbridges

- attach to the ‘rod’ portion by a hinge that bends and straightens during contraction

Page 13: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

SARCOMERES

Repeating units of actin and myosin along the myofibril - smallest portion of muscle capable of contracting

• Z Line - network of protein fibres serving as attachment for actin

• I Band - actin filaments only (thin/light)

• A Band - length of myosin (thick/dark)

• H Zone - myosin only (lighter)

• M Line - myosin filaments are attached in center of H Zone

Alternating A and I Bands give muscle striated appearance

Page 14: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

SMOOTH & CARDIAC MUSCLESmooth Muscle• Not striated, made up of

separate distinct cells with an obvious nucleus – less actin and myosin

• Contract more slowly with no oxygen dept

• Two types:(i) Multinuceate - cells operate independently (ie: iris of eye, blood vessels, erectile muscles of hair(ii) Visceral - cells operate together (ie: surrounding digestive tract, reproductive and excretory organs)

Page 15: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Cardiac Muscle

• Long, branching cells

• Cells are striated but less organized than skeletal muscle

• All cells work together as a single unit - autorhythmic contraction

• Cells do not develop oxygen dept or fatigue

• Connected by intercalated discs

Page 16: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

GROSS MUSCLE ANATOMY

Most muscles extend from bone to bone and cross at least one joint• Tendons - attach muscle to bone

• Aponeuroses - broad, sheetlike tendon

Muscle terminology:• Origin/head - end of muscle attached to most stationary bone

• Insertion - end of muscle attached to bone with most movement

• Belly - largest area between origin and insertion

• Synergists - muscles that work together to cause a movement

- prime mover - plays major role in movement

- fixator - hold one bone in place while other bone is moved

• Agonist - muscle that causes an action when it contracts

• Antagonist - muscle working in opposition to agonist

Page 17: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE ATTACHMENT

Page 18: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE TYPES

Page 19: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE SHAPES

Page 20: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE NOMENCLATURE

Muscles are named according to:

• Location - pectoralis, gluteus, brachial

• Size - maximus, minimus, longus, brevis

• Shape - deltoid, quadratus, teres

• Orientation - rectus

• Origin and Insertion - sternocleidomastoid, brachioradialis

• Number of Heads - biceps, triceps

• Function - adductor, masseter

Page 21: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE MOVEMENT• Muscles, their tendons and bones act together as lever systems to move

parts of the body

• Muscle contractions are a pull or force by relative positions of the:

lever - bone

fulcrum - joint

weight or resistance - force of gravity due to weight of body parts or

weight of object being moved

Page 22: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

CLASSES OF LEVERS

Class I

• Fulcrum between force and weight

• See saw

• Head movement at the atlantooccipital joint

Class II

• Weight is between fulcrum and pull

• Wheelbarrow

• Standing on toes, metatarsophalangeal joint

Class III

• Pull located between fulcrum and weight

• Using a shovel

• Biceps brachii with elbow as fulcrum

Page 23: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

BODY MOVEMENTS

Page 24: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Flexion vs ExtensionFlexion - moves body part in anterior or ventral direction

Extension - moves body part in posterior or dorsal direction

Page 25: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Plantar Flexion vs DorsiflexionPlantar Flexion - movement of foot toward plantar surface

ie: standing on toes

Dorsiflexion - movement of foot toward shin

ie: walking on heel

Page 26: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Abduction vs AdductionAbduction - movement away from midline

Adduction - movement toward midline

Page 27: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Medial vs Lateral RotationMedial Rotation - anterior surface of limb rotates toward

body

Lateral Rotation - anterior surface of limb rotates away from body

Page 28: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Pronation vs SupinationPronation - rotation of forearm so palm is down

Supination - rotation of forearm so palm is up

Page 29: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Elevation vs DepressionElevation - movement in superior direction

Depression - movement in inferior direction

Page 30: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Protraction vs RetractionProtraction - gliding part horizontally forward

Retraction - gliding part horizontally backward

Page 31: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

CircumductionMovement in a cone/circular shape

Page 32: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Inversion vs EversionInversion - turning foot so plantar surface faces medially

Eversion - turning foot so plantar surface faces laterally

Page 33: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE ANATOMYANTERIOR VIEW

Page 34: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

MUSCLE ANATOMYPOSTERIOR VIEW

Page 35: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

HEAD MUSCLES

Divided into groups by function:

Facial ExpressionOrigin and insertion in the superficial

fascia

When muscles contract the skin moves

• Orbicularis oris - around mouth

• Obicularis oculi - opens and closes

eyelids

Page 36: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Mastication (chewing)

Involves elevation/depression of mandible and excursion to grind the teeth together

Act with muscles of hyoid in movement of mandible

Muscles of cheek and tongue aid mastication by pushing food under the teeth

• Temporalis - lifts mandible

• Masseseter - largest jaw muscle

Page 37: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Muscles of the Hyoid

Page 38: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Tongue MovementsImportant in speech - changes shape

Swallowing

- moves food around in mouth

- holds food in place during

grinding

- pushes food up to palate and back

toward pharynx

Intrinsic - entirely within the tongue, allow tongue to change shape

Extrinsic - insert in tongue, allow shape change and movement

• Glossals – tongue muscles (genioglossus, hyoglossus, palatoglossus, styloglossus)

Page 39: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Eye Muscles

6 eye muscles originate on surface of the orbit and control movement of eyeball

• Extra-ocular eye muscles

Page 40: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

NECK MUSCLESFlexion - muscles deep within neck

anterior margins of vertebral bodies

Extension - posterior neck muscles attached to occipital bone

Rotation and abduction - lateral and posterior muscle groups

• Sternocleidomastoid - from sternum to mastoid of skull, on either side of neck

• Trapezius - back of skull and upper vertebrae across to scapular spine

Page 41: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Posterior Deep Neck Muscles

Page 42: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Muscles of the Vertebral Column

Muscles that extend, laterally flex, and rotate the vertebral column - used to produce erect posture

Divided into deep and superficial groups

Deep - vertebrae to vertebrae

Superficial - vertebrae to ribs

Page 43: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

THORACIC MUSCLES

Involved in breathing

• External Intercostals - elevate ribs during inspiration

• Internal Intercostals - contract and depress ribs during exhalation

• Diaphragm - flattens during contraction

- separates thoracic and abdominal

cavities

Page 44: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

ABDOMINAL MUSCLES

Flex and rotate vertebral column, decrease volume of abdominal and thoracic cavities

Aid in forced expiration, vomiting, defecation, urination, childbirth

Crossing pattern of muscles adds strength to abdominal wall to support organs

• Rectus abdominus - inserts at xiphoid process down to pubic symphysis

• Internal and external abdominal obliques – flex and rotate abdomen

Page 45: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

PERINEAL MUSCLESPelvic Diaphragm - funnel shaped,

supports the pelvic viscera- pierced by anal canal, urethra,

vaginaPerineum - diamond shaped area

inferior to pelvic diaphragm- divided into urogenital triangle and anal triangle regions

• Bulbospongiosus - base of penis or sides of vagina

• Levator ani - tenses pelvic floor, elevates and retracts anus

• Sphincter ani externus - around anus• Sphincter urethrae - around urethral

opening

Page 46: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

ARM MUSCLES

Scapular MovementsMuscles that attach the upper limb to

the body and move or stabilize the scapula and clavicle

Originate on axial skeleton

• Trapezius - covers back, portion of neck and base of skull

• Rhomboid - attached to thoracic vertebrae and scapula posterior

• Levator scapulae - attached to cervial vertebrae and scapula

• Supraspinatus - scapula to humerus• Pectoralis minor - scapula to

thoracic ribs

Page 47: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Arm MovementsMuscles attach to arm and thorax

• Pectoralis major - humerus to superior thoracic vertebrae

• Latismus dorsi - humerus to lower thoracic vertebrae

Flexion and extension of shoulder

• Deltoid - across front of shoulder

- works with pectoralis

- abducts medially and rotates laterally

Page 48: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Rotator CuffPrimary muscles holding humerus in

glenoid cavity

Form cuff over proximal humerus

Involved in movement of the shoulder

• Supraspinatus - across scapula

Page 49: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Forearm MovementMovement at elbow:

Extension

• Triceps brachii - scapula to forearm

Flexion

• Biceps brachii - scapula to forearm

Page 50: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Wrist, Hand and Finger Movements

Muscles on anterior surface of forearm - flexion, abduction, adduction of the wrist

Muscles on posterior surface of forearm - extension and abduction

Page 51: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Flexors and Extensors of the Hand

Page 52: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

LEG MUSCLES

Thigh Movement• Gluteus maximus - attached to

ilium, sacrum, coccyx

• Gluteus medius - iliac crest to greater trochanter of femur

• Adductor group - attach ischium

to femur

• Tensor fasciae latae - iliac crest to tibia

- thick band of connective tissue

- rotates hip and supports knee

Page 53: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Leg Movement• Quadriceps femoris - anterior surface of thigh

- extension at knee

- inserted by patellar tendon

• Sartorius - originates on edge of pelvis, crosses medially to insert on tibia and fibula

- flexes knee and hip, rotates thigh

• Hamstrings - posterior thigh muscle

Page 54: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Muscles that move leg

Page 55: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Lower Leg MovementDivided into 3 sections: anterior,

posterior, lateral

Anterior - extensors of foot and toes

• Tibialis anterior - front of shin

Posterior - flexors of foot

• Gastrocnemius - condyles of femur to calcaneal(Achilles) tendon to calcaneus, superficial position

• Soleus – fibula and tibia through calcaneal tendon to calcaneus, deep position

Page 56: HUMAN ANATOMY LECTURE NINE MUSCLES. MUSCLE FUNCTIONS Body movement Posture Respiration and heart beat Production of body heat - maintains body temperature

Movement of the FootAnalogous to muscles of hand but

also serve in support and locomotion

20 foot muscles flex, extend, abduct and adduct toes