BIOH111 SN13 Muscular System · PDF fileFunction of muscular system: how skeletal muscles produce movement • Describe muscle attachment sites –origin and insertion and relate to

© Endeavour College of Natural Health endeavour.edu.au

BIOH111

oCell Module

oTissue Module

oSkeletal system

o Integumentary system

oMuscle system

oNervous system

oEndocrine system


TEXTBOOK AND

REQUIRED/RECOMMENDED READINGS

o Principles of anatomy and physiology. Tortora et al; 14th

edition: Chapter 11


BIOH111 – MUSCLE SYSTEM MODULE

o Session 11 (Lectures 17 and 18) – Muscle

physiology: Building of muscle organ – cells,

tissue, organ and muscle contraction process and

regulation

o Session 12 (Lectures 19 and 20) - Skeletal muscle

metabolism

o Session 13 (Lectures 21 and 22) – Major muscle

groups

BIOH111

Lectures 21 and 22

Major muscle groups

Department of Bioscience

endeavour.edu.au


PREPARATION FOR THIS SESSION

o Complete any missing concepts and linking words from

Session 12

o Write down some muscle names you know (we will learn

Latin names for these in the next session)


OBJECTIVES

Lecture 21 and 22:

Structure of muscular system

Name major skeletal muscles

Function of muscular system: how skeletal muscles produce movement

• Describe muscle attachment sites – origin and insertion and relate to the level

systems and leverage

• Describe the effects of fascicle arrangement and co-ordination within the

muscle groups


MUSCULAR SYSTEM

• The voluntarily controlled muscles of

the body make up the muscular

system.

• Structure: principal skeletal muscles

• Function: production of movement;

stabilization of body position;

regulation of organ volume,

movement of substances within the

body and production of heat


COORDINATION WITHIN

MUSCLE GROUPS

o Most movement is the result of several muscle working at the

same time

o Most muscles are arranged in opposing pairs at joints

• prime mover or agonist contracts to cause the desired

action while antagonist stretches and yields to prime

mover; e.g. flexors-extensors

• synergists contract to stabilize nearby joints while prime

movers contract

• fixators stabilize the origin of the prime mover; e.g. scapula

held steady so deltoid can raise arm


NAMING OF SKELETAL MUSCLESo The names of most of the nearly 700 skeletal muscles are

based on several types of characteristics:

• direction in which the muscle fibers run

• location

• size

• numbers of origins

• shape

• sites of origin and insertion of the muscle

• action

o Examples:

• triceps brachii - 3 sites of origin

• quadratus femoris - square shape

• serratus anterior - saw-toothed edge


MUSCLE ATTACHMENT SITES:

ORIGIN AND INSERTION

o Skeletal muscles shorten & pull

on the bones they are attached to

o Origin: the bone that does not

move when muscle shortens

(normally proximal)

o Insertion: the movable bone

(some 2 joint muscles)

o Belly: fleshy portion of the

muscle between attachment sites


HEAD AND NECK MUSCLESo Muscles of facial expression and muscles of mastication:

• Origin: skull; insertion point: skin

• Encircle eyes, nose & mouth

• Express emotions

• Facial Nerve (VII)

o Muscles that move mandible:

• Origin: skull; insertion point: mandible

• Cranial nerve V (trigeminal nerve)

• Protracts, elevates or retracts mandible

o Muscles that move head:• Origin: sternum & clavicle; insert point: mastoid process of skull

• Cranial nerve XI (spinal accessory)

• contraction of both flexes the cervical vertebrae & extends head

• contraction of one, laterally flexes the neck and rotates face in opposite direction


MUSCLES OF FACIAL EXPRESSION


MUSCLES THAT MOVE THE MANDIBLE


MUSCLES THAT MOVE THE HEAD


MUSCLES OF ABDOMINAL WALL

o 4 pairs of sheet like muscles

1. rectus abdominus = vertically oriented

2. external & internal obliques and transverses

abdominus

–wrap around body to form anterior body wall

– form rectus sheath and linea alba

o Inguinal ligament from anterior superior iliac spine to

upper surface of body of pubis

o Inguinal canal = passageway from pelvis through body

wall musculature opening seen as superficial inguinal ring


MUSCLES OF ABDOMINAL WALL


STABILIZING THE PECTORAL GIRDLE

o Muscles important for breathing:

• Pectoralis minor

• Intercostals (internal and external)


STABILIZING THE PECTORAL GIRDLE

o Posterior thoracic muscles:

• Latissimus dorsi

• Rhomboid major


MUSCLES THAT MOVE THE ARM

• Pectoralis major

• Latissimus dorsi

• Deltoid

• Rotator cuff muscles

(supraspinatus,

infraspinatus, teres minor

and subscapularis)


FLEXORS OF THE FOREARM (ELBOW)o Cross anterior surface of elbow

joint & form flexor muscle

compartment

o Biceps brachii

o Brachialis

o Brachioradialis (posterior view)


EXTENSORS OF THE FOREARM (ELBOW)

o Cross posterior surface of

elbow joint & forms extensor

muscle compartment

o Triceps brachii


MUSCLES/TENDONS USED FOR

IDENTIFYING PULSE

o Flexor carpi

muscles/tendon

• radialis

• ulnaris

o Flexor digitorum

muscles/tendon

• profundus


FLEXOR RETINACULUM

o Tough connective tissue band that helps hold tendons in place

o Extensor & Flexor retinaculum cross wrist region attaching from bone to bone (carpal tunnel syndrome = painful compression of median nerve due to narrowing passageway under flexor retinaculum

For interest only/clinical application


INTRINSIC MUSCLES OF THE HAND

o Origins & insertions are within

the hand

o Help move the digits

o Thenar muscles move the thumb

o Hypothenar muscles move the

little finger

o Opposition, flexion, extension,

abduction & adduction


MUSCLES THAT MOVE THE VERTEBRAEo Quite complex due to overlap

o Erector spinae fibers run longitudinally

• 3 groupings

– spinalis

– iliocostalis

– longissimus

• extend vertebral column

o Smaller, deeper muscles

• transversospinalis group

– semispinalis, multifidis &

rotatores

• run from transverse process to

dorsal spine of vertebrae

above & help rotate vertebrae

Non-examinable


MUSCLES CROSSING THE HIP JOINTo Iliopsoas flexes hip joint

• arises lumbar vertebrae & ilium

• inserts on lesser trochanter

o Quadriceps femoris has 4 heads

• Rectus femoris crosses hip

• 3 heads arise from femur

• all act to extend the knee

o Adductor muscles

• bring legs together

• cross hip joint medially

• see next picture

o Pulled groin muscle

• result of quick sprint activity

• stretching or tearing of iliopsoas

or adductor muscle


ADDUCTOR MUSCLES OF THE THIGHo Adductor group of muscle

extends from pelvis to linea

aspera on posterior surface

of femur

• pectineus

• adductor longus

• adductor brevis

• gracilis

• adductor magnus (hip

extensor)

Non-examinable


MUSCLES OF THE HIP & THIGH

o Gluteus muscles

• maximus, medius & minimus

• maximus extends hip

• medius & minimus abduct

o Deeper muscles laterally rotate femur

o Hamstring muscles

• semimembranosus (medial)

• semitendinosus (medial)

• biceps femoris (lateral)

• extend hip & flex knee

– Pulled hamstring

– tear of origin of muscles from

ischial tuberosity


MUSCLES OF THE CALF (POSTERIOR LEG)

o 3 muscles insert onto calcaneus

• gastrocnemius arises femur

– flexes knee and ankle

• plantaris & soleus arise from leg

– flexes ankle

o Deeper mm arise from tibia or fibula

• cross ankle joint to insert into foot

– tibialis posterior

– flexor digitorum longus

– flexor hallucis longus

• flexing ankle joint & toes


MUSCLES OF THE LEG AND FOOTo Anterior compartment of leg

• extensors of ankle & toes– tibialis anterior

– extensor digitorum longus

– extensor hallucis longus

• tendons pass under retinaculumo Shinsplits syndrome

• pain or soreness on anterior tibia

• running on hard surfaceso Lateral compartment of leg

• peroneus mm plantarflex the foot

• tendons pass posteriorly to axis of ankle joint and into plantar foot

Non-examinable


MUSCLES OF THE PLANTAR FOOT

o Intrinsic muscles

• arise & insert in foot

o 4 layers of muscles

• get shorter as go into

deeper layers

o Flex, adduct & abduct toes

o Digiti minimi muscles move little

toe

o Hallucis muscles move big toe

o Plantar fasciitis (painful heel

syndrome) chronic irritation of

plantar aponeurosis at calcaneus

• improper shoes &

weight gain

Non-examinable


FUNCTION OF MUSCULAR SYSTEM

Movement


FASCICLE (MUSCLE BUNDLE)

ARRANGEMENTS

o Contracting muscle shortens to about 70% of its length

o Fascicular arrangement correlated with the power of the

muscle and its range of motion and• muscles with longer fibers have a greater extensibility

• a short fiber can contract as forcefully as a long one

Parallel Fusiform Pennate

Circular Triangular Bipennate Multi-pennate


RELATING MUSCLE ATTACHMENT

SITES TO MOVEMENT

Lever systems and leverage

(mechanical advantage)


THREE TYPES OF LEVERS

o First class levers (EFL): seesaw; e.g. the head on the

vertebral column

o Second-class (FLE): wheelbarrow; e.g standing on tiptoes

o Third-class (FEL): forceps; e.g. the elbow joint


FIRST CLASS LEVER

o Can produce mechanical advantage

or not depending on location of effort

& resistance

• if effort is further from fulcrum than

resistance, then a strong resistance

can be moved

o Head resting on vertebral column

• weight of face is the resistance or

load

• joint between skull & atlas is fulcrum

• posterior neck muscles provide effort


SECOND CLASS LEVER

o Similar to a wheelbarrow

o Always produce mechanical

advantage

• Resistance or load is always closer

to fulcrum than the effort

o Sacrifice of speed for force

o Raising up on your toes

• resistance is body weight

• fulcrum is ball of foot

• effort is contraction of calf muscles

which pull heel up off of floor


THIRD CLASS LEVER

o Most common levers in the body

o Always produce a mechanical

disadvantage

• effort is always closer to fulcrum

than resistance

o Favors speed and range of motion

over force

o Flexor muscles at the elbow

• resistance is weight in hand

• fulcrum is elbow joint

• effort is contraction of biceps

brachii muscle


Recap of Session 13

Muscle groups in red boxes are examinable and needed for completing

the content in subsequent subjects (e.g. BIOE221)

Movement by muscles is accomplished using levers (first, second and

third class)


PREPARATION FOR NEXT SESSION

o NO MISSING CONCEPTS OR LINKING WORDS from Session

13

o Review:

• animal cell components

• plasma membrane

• tissue types

o Think about cells as immature and specialised (mature) – why is

there a difference?

BIOH111 SN13 Muscular System · PDF fileFunction of muscular system: how skeletal muscles produce movement • Describe muscle attachment sites –origin and insertion and relate to

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