the muscular system
DESCRIPTION
TRANSCRIPT
MUSCULAR SYSTEM
MTHOBISI SHABANGU
INTRODUCTION• The muscular system is composed of specialized
cells called muscle fibers.
• These fibers are different lengths and shapes and
form to become muscles.
• Muscles make up about 42% of a person’s total
body weight.
• Muscle fibers are held together by connective
tissue , enclosed in “fascia”.
• Muscles must have proper oxygen and nutrition to
function properly.
TYPES OF MUSCLE TISSUEMuscle Tissue
SkeletalVoluntary
Satiated cells
SmoothInvoluntary
Blood vessels, Urinary bladder,Digestive system
TYPES OF MUSCLE TISSUES CONT…• Skeletal muscle
• Smooth Muscle
• Cardiac Muscle
Skeletal Muscle • How many
different muscles can there be?
• ~660
CHARACTERISTICS OF MUSCLES• Contractility – the ability of muscles to
shorten
• Elasticity – the ability of muscles to go back to its original shape
• Excitability – the ability of muscles to respond to stimuli
• Extensibility – the ability of muscle to lengthen
• Sphincter – muscles that constrict openings
CLASSIFICATION OF MUSCLES
FUNCTIONALLY
• Voluntary – can be moved at will
• Involuntary – can’t be moved intentionally
STRUCTURALLY
• Striated – have stripes across the fibers
• Smooth – no striations
CATEGORIES OF SKELETAL MUSCLE ACTIONSCATEGORIES
• Extensor
• Flexor
• Abductor
• Adductor
• Levator
• Depressor
• Rotator
• Sphincter
ACTIONS
• Increases the angle at a joint
• Decreases the angle at a joint
• Moves limb away from midline of body
• Moves limb toward midline of body
• Moves insertion upward
• Moves insertion downward
• Rotates a bone along its axis
• Constricts an opening
NAMING SKELETAL MUSCLES
• Shape:
• deltoid (triangle)
• trapezius (trapezoid, 2 parallel sides)
• serratus (saw-toothed)
• rhomboideus (rhomboid, 4 parallel sides)
• orbicularis and sphincters (circular)
Rhomboideusmajor
Trapezius
Deltoid
Serratus anterior
• Maximus (largest)
• minims (smallest)
• Longus (longest)
• Brevis (short)
• Major (large)
• Minor (small)
Psoas major
Psoas minor
MUSCLES NAMED BY SIZE
• Biceps (2)
• Triceps (3)
• Quadriceps (4)
MUSCLES NAMED FOR NUMBER OF ORIGINS
Biceps brachii
MUSCLES NAMED FOR ACTION
• Flexor carpi radialis (extensor carpi radialis)
– flexes wrist
• Abductor pollicis brevis (adductor pollicis)
– flexes thumb
• Abductor magnus – abducts thigh
• Extensor digitorum – extends fingers
Adductor magnus
COVERINGS OF SKELETAL MUSCLE
• Epimysium
• Connective tissue that covers the entire
muscle
• Lies deep to fascia
• Perimysium
• Surrounds organized bundles of muscle
fibers, called fascicles
• Endomysium
• Connective tissue that covers individual
muscle fibers (cells)
SARCOMERENow let us take a look at Sarcomere:
• A sarcomere is the functional unit of skeletal
muscle
• A sarcomere is the area between adjacent
Z-lines.
• During a muscle contraction the z-lines move
together and the sarcomere shortens.
Picture of a Sarcomere
Type I slow fibers of skeletal muscle
Type II fast fibers of skeletal muscle
Intermediate fibers of skeletal muscle
Slow tonic specially designed for postural muscles, red in colour due to high concentration of myoglobin and rich in mitochondria and oxidative enzymes
Fast tonic contractions needed for body movement, pale colour rich in glycogen and phosphorylases
Varient of Type II
Highly resistance to fatigue due to well-developed in aerobic respiration
Easily fatigue Resistant to fatigue
The types of Fibers
THERE ARE ABOUT 60 MUSCLES IN THE FACE.
Smiling is easier than frowning.
It takes 20 muscles to smile and over 40 to frown.
Smile and make someone happy.
MACROSTRUCTURE
Skeletal muscle c.s. 40x
It is the number of muscle fibers packed into a given muscle cross-sectional area that determine overall force-generating capacity
MICROSTRUCTURE
• basic functional unit of muscle
• Striated (light & dark bands)
• Contains ACTIN & MYOSIN filaments that are responsible for contraction
REFERENCES Dimapilis, H. 2014. Muscular System. www.slideshare.net/hansdimapilis/muscular-systemidsn Accessed 05/03/2014
Agamez, M. 2011. An overview comparing the three different types of muscular tissue. http://www.slideshare.net/monica_agamez/muscular-system. Accessed on the 05/03/2014
Marydelaney, L. 2009, Muscular System. http://www.slideshare.net/marydelaney/chapter-22-muscular-system. Accessed 05/03/2014
By Itsebo, 2011. The muscular-system. http://www.slideshare.net/itsebo/the-muscularsystempowerpoint-dr-bantiles Accessed 05/03/2014
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Cerny, L. 2009. Applied Excecise Physiology, Muscular Skeletal. http://www.slideshare.net/pcerny/muscular-system Accessed 05/03/2014