reportccmapeh.ppt

The Muscular SystemThe Muscular System

Specialized tissue that enable the Specialized tissue that enable the body and its parts to move.body and its parts to move.

Anterior ViewAnterior View

Posterior ViewPosterior View

How many muscles are there in the human body? Answer: 700 Muscles The muscles make up about 40% of the body mass.

What is the longest muscle in the body? Answer: The Sartorius The Sartorius runs from the outside of the hip, down and across to the inside of

the knee. It twists and pulls the thigh outwards.

What is the smallest muscle in the body? Answer: The Stapedius The Stapedius is located deep in the ear. It is only 5mm long and thinner than

cotton thread. It is involved in hearing.

What is the biggest muscle in the body? Answer: The Gluteus Maximus The Gluteus Maximus is located in the buttock. It pulls the leg backwards

powerfully for walking and running. What is the strongest muscle in the human body? - - Masseter Masseter

The strongest muscle based on its weight is the masseter. With all muscles of the jaw The strongest muscle based on its weight is the masseter. With all muscles of the jaw working together it can close the teeth with a force as great as 55 pounds (25 working together it can close the teeth with a force as great as 55 pounds (25 kilograms) on the incisors or 200 pounds (90.7 kilograms) on the molars.kilograms) on the incisors or 200 pounds (90.7 kilograms) on the molars.

The main function of the muscular system is movement. Muscles are the only The main function of the muscular system is movement. Muscles are the only tissue in the body that has the ability to contract and therefore move the other tissue in the body that has the ability to contract and therefore move the other parts of the body.parts of the body.

Related to the function of movement is the muscular system’s second function: Related to the function of movement is the muscular system’s second function: the maintenance of posture and body position. Muscles often contract to hold the the maintenance of posture and body position. Muscles often contract to hold the body still or in a particular position rather than to cause movement. The muscles body still or in a particular position rather than to cause movement. The muscles responsible for the body’s posture have the greatest endurance of all muscles in responsible for the body’s posture have the greatest endurance of all muscles in the body—they hold up the body throughout the day without becoming tired.the body—they hold up the body throughout the day without becoming tired.

Another function related to movement is the movement of substances inside the Another function related to movement is the movement of substances inside the body. The cardiac and visceral muscles are primarily responsible for transporting body. The cardiac and visceral muscles are primarily responsible for transporting substances like blood or food from one part of the body to another.substances like blood or food from one part of the body to another.

The final function of muscle tissue is the generation of body heat. As a result of The final function of muscle tissue is the generation of body heat. As a result of the high metabolic rate of contracting muscle, our muscular system produces a the high metabolic rate of contracting muscle, our muscular system produces a great deal of waste heat. Many small muscle contractions within the body great deal of waste heat. Many small muscle contractions within the body produce our natural body heat. When we exert ourselves more than normal, the produce our natural body heat. When we exert ourselves more than normal, the extra muscle contractions lead to a rise in body temperature and eventually to extra muscle contractions lead to a rise in body temperature and eventually to sweating.sweating.

Muscle ClassificationMuscle Classification

FunctionallyFunctionallyVoluntarilyVoluntarily – can be moved at will – can be moved at willInvoluntarilyInvoluntarily – can’t be moved – can’t be moved

intentionallyintentionally

StructurallyStructurallyStriated – have stripes across the fiberStriated – have stripes across the fiberSmooth – no striations Smooth – no striations

The 3 Types of MusclesThe 3 Types of Muscles

S ke le ta l M u sc le S m ooth M u sc le C ard iac M u sc le

3 Typ es o f M u sc les

Smooth MuscleSmooth Muscle It is found inside of organs like the It is found inside of organs like the stomach, ,

intestines, and blood vessels. The weakest of intestines, and blood vessels. The weakest of all muscle tissues, visceral muscle makes all muscle tissues, visceral muscle makes organs contract to move substances through organs contract to move substances through the organ. Because visceral muscle is the organ. Because visceral muscle is controlled by the unconscious part of the controlled by the unconscious part of the brain, it is known as involuntary muscle—it brain, it is known as involuntary muscle—it cannot be directly controlled by the conscious cannot be directly controlled by the conscious mind. The term “smooth muscle” is often used mind. The term “smooth muscle” is often used to describe visceral muscle because it has a to describe visceral muscle because it has a very smooth, uniform appearance when very smooth, uniform appearance when viewed under a microscope. This smooth viewed under a microscope. This smooth appearance starkly contrasts with the banded appearance starkly contrasts with the banded appearance of cardiac and skeletal muscles.appearance of cardiac and skeletal muscles.

Smooth MuscleSmooth Muscle They fatigue… but very slowlyThey fatigue… but very slowly Found in the circulatory systemFound in the circulatory system

Lining of the blood vesselsLining of the blood vessels Helps in the circulation of the bloodHelps in the circulation of the blood

Found in the digestive systemFound in the digestive system Esophagus, stomach, intestineEsophagus, stomach, intestine Controls digestionControls digestion

Found in the respiratory systemFound in the respiratory system Controls breathingControls breathing

Found in the urinary systemFound in the urinary system Urinary bladderUrinary bladder Controls urinationControls urination

Cardiac MuscleCardiac Muscle Found only in the Found only in the heart, cardiac muscle is , cardiac muscle is

responsible for pumping blood throughout responsible for pumping blood throughout the body. Cardiac muscle tissue cannot be the body. Cardiac muscle tissue cannot be controlled consciously, so it is an controlled consciously, so it is an involuntary muscle. While hormones and involuntary muscle. While hormones and signals from the signals from the brain adjust the rate of adjust the rate of contraction, cardiac muscle stimulates contraction, cardiac muscle stimulates itself to contract. The natural pacemaker of itself to contract. The natural pacemaker of the heart is made of cardiac muscle tissue the heart is made of cardiac muscle tissue that stimulates other cardiac muscle cells that stimulates other cardiac muscle cells to contract. Because of its self-stimulation, to contract. Because of its self-stimulation, cardiac muscle is considered to be cardiac muscle is considered to be autorhythmic or intrinsically controlled. autorhythmic or intrinsically controlled.

The cells of cardiac muscle tissue are striated they appear to have light and dark stripes when viewed under a light microscope. The arrangement of protein fibers inside of the cells causes these light and dark bands. Striations indicate that a muscle cell is very strong, unlike smooth muscles.

The cells of cardiac muscle are branched X or Y shaped cells tightly connected together by special junctions called intercalated disks. Intercalated disks are made up of fingerlike projections from two neighboring cells that interlock and provide a strong bond between the cells. The branched structure and intercalated disks allow the muscle cells to resist high blood pressures and the strain of pumping blood throughout a lifetime. These features also help to spread electrochemical signals quickly from cell to cell so that the heart can beat as a unit.

Cardiac MuscleCardiac Muscle

Found ONLY in the heartFound ONLY in the heartContractions of the heart muscles Contractions of the heart muscles

pump blood throughout the body and pump blood throughout the body and account for the heartbeat.account for the heartbeat.

Healthy cardiac muscle NEVER fatiguesHealthy cardiac muscle NEVER fatigues

Skeletal MuscleSkeletal MuscleSkeletal Muscle. Skeletal muscle is the only voluntary muscle tissue in the human body—it is controlled consciously. Every physical action that a person consciously performs (e.g. speaking, walking, or writing) requires skeletal muscle. The function of skeletal muscle is to contract to move parts of the body closer to the bone that the muscle is attached to. Most skeletal muscles are attached to two bones across a joint, so the muscle serves to move parts of those bones closer to each other.

Skeletal muscle cells form when many smaller progenitor cells lump themselves together to form long, straight, multinucleated fibers. Striated just like cardiac muscle, these skeletal muscle fibers are very strong. Skeletal muscle derives its name from the fact that these muscles always connect to the skeleton in at least one place.

Skeletal MuscleSkeletal Muscle

Attached to skeleton by tendonsAttached to skeleton by tendonsCauses movement of bones at the Causes movement of bones at the

joints.joints.

Functions of Skeletal MuscleFunctions of Skeletal Muscle

Movement – muscle move bones by Movement – muscle move bones by pulling not pushing.pulling not pushing. SynergistsSynergists – any movement is generally – any movement is generally

accomplished by more than one muscle. All accomplished by more than one muscle. All of the muscles responsible for the movement of the muscles responsible for the movement are synergists. are synergists.

The one that is most responsible for the The one that is most responsible for the movement is the movement is the Prime Mover (agonist)Prime Mover (agonist)..


MovementMovement AntagonistsAntagonists – muscles and muscle groups – muscles and muscle groups

usually work in pairs usually work in pairs

– – example the biceps flex your arm and example the biceps flex your arm and its partner the triceps extend your arm. The its partner the triceps extend your arm. The two muscles are two muscles are antagonistsantagonists, i.e. cause , i.e. cause opposite actions. opposite actions.

– – when one contracts the other relaxes.when one contracts the other relaxes. LevatorsLevators – muscle that raise a body part. – muscle that raise a body part.


Maintenance of posture or muscle toneMaintenance of posture or muscle tone We are able to maintain our body position because We are able to maintain our body position because

of tonic contractions in our skeletal muscles. These of tonic contractions in our skeletal muscles. These contractions don’t produce movement yet hold our contractions don’t produce movement yet hold our muscles in position.muscles in position.

Heat productionHeat production – contraction of muscles – contraction of muscles produces most of the heat required to maintain produces most of the heat required to maintain body temperature.body temperature.

Structure of Skeletal MuscleStructure of Skeletal Muscle

Composed of striated muscle cells (=muscle Composed of striated muscle cells (=muscle fibers) and connective tissue.fibers) and connective tissue. Most muscles attach to 2 bones that have a Most muscles attach to 2 bones that have a

moveable joint between them. moveable joint between them. The attachment to the bone that does not move is the The attachment to the bone that does not move is the

originorigin. . The attachment to the bone that moves is the The attachment to the bone that moves is the insertioninsertion..

TendonsTendons anchor muscle firmly to bones. Tendons anchor muscle firmly to bones. Tendons are made of dense fibrous connective tissue.are made of dense fibrous connective tissue.

LigamentsLigaments connect bone to bone at a joint. connect bone to bone at a joint.

Structure of Skeletal MuscleStructure of Skeletal Muscle BursaBursa – small fluid filled sacs that lie – small fluid filled sacs that lie

between some tendons and the bones between some tendons and the bones beneath them. They are made of beneath them. They are made of connective tissue and are lined with connective tissue and are lined with synovial membrane that secretes synovial synovial membrane that secretes synovial fluid.fluid.

Structure of Skeletal MuscleStructure of Skeletal Muscle

Microscopic anatomyMicroscopic anatomy Muscle cells (fibers) are grouped in a highly Muscle cells (fibers) are grouped in a highly

organized way in the muscle. The membrane that organized way in the muscle. The membrane that surrounds the muscle cell is called the surrounds the muscle cell is called the sarcolemmasarcolemma..

Muscle cells are filled with 2 types of fine threadlike Muscle cells are filled with 2 types of fine threadlike proteins called myofilaments: proteins called myofilaments: myosinmyosin (thick) and (thick) and actinactin (thin). These structures slide past each other (thin). These structures slide past each other causing the muscle cell to contract or shorten. causing the muscle cell to contract or shorten.

The myofilaments are arranged in the cells in small The myofilaments are arranged in the cells in small units called units called sarcomeressarcomeres. .

Structure of Skeletal MuscleStructure of Skeletal Muscle Muscles continue contraction as long as they Muscles continue contraction as long as they

are stimulated by a are stimulated by a neurotransmitter. neurotransmitter. When a When a motor neuron stops the release of the motor neuron stops the release of the neurotransmitter, the process of contraction neurotransmitter, the process of contraction reverses itself. Calcium returns to the reverses itself. Calcium returns to the sarcoplasmic reticulum; troponin and sarcoplasmic reticulum; troponin and tropomyosin return to their resting positions; tropomyosin return to their resting positions; and actin and myosin are prevented from and actin and myosin are prevented from binding. Sarcomeres return to their elongated binding. Sarcomeres return to their elongated resting state once the force of myosin pulling resting state once the force of myosin pulling on actin has stopped.on actin has stopped.

Muscle ContractionMuscle Contraction

SequenceSequence Electrical impulse travels down a motor Electrical impulse travels down a motor

neuron. When it reaches the end, neuron. When it reaches the end, acetylcholine (chemical) is released into the acetylcholine (chemical) is released into the synapse.synapse.

Acetylcholine bind to special receptors on Acetylcholine bind to special receptors on the muscle cell and causes an electrical the muscle cell and causes an electrical impulse to spread over the cell.impulse to spread over the cell.

The sarcomeres shorten and the muscle cell The sarcomeres shorten and the muscle cell contracts.contracts.

MUSCLE

MUSCLE FIBER

MYOFIBRIL

SARCOMERE

Movement of MusclesMovement of Muscles

Origin:Origin: the attachment of the attachment of the muscle to the bone the muscle to the bone that remains stationarythat remains stationary

Insertion:Insertion: the attachment the attachment of the muscle to the bone of the muscle to the bone that movesthat moves

Belly:Belly: the fleshy part of the fleshy part of the muscle between the the muscle between the tendons of origin and/or tendons of origin and/or insertion insertion

origin

insertion

belly

Movement of skeletal muscleMovement of skeletal muscle

These muscles move when the brain These muscles move when the brain sends messages to the musclesends messages to the muscle

Always work in pairsAlways work in pairs2 movements of skeletal muscle2 movements of skeletal muscle

Contraction (shorten)Contraction (shorten)Extension (lengthen)Extension (lengthen)

Categories of Categories of skeletal muscle actionsskeletal muscle actions

CategoriesCategories ActionsActions

Extensor Extensor Increases the angle at a jointIncreases the angle at a joint FlexorFlexor Decreases the angle at a jointDecreases the angle at a joint AbductorAbductor Moves limb away from midline of Moves limb away from midline of

bodybody AdductorAdductor Moves limb toward midline of bodyMoves limb toward midline of body Levator Levator Moves insertion upward Moves insertion upward DepressorDepressor Moves insertion downwardMoves insertion downward RotatorRotator Rotates a bone along its axisRotates a bone along its axis SphincterSphincter Constricts an openingConstricts an opening

MovementsMovements

1.1. Bend armBend arm

- biceps - biceps contract contract

- triceps - triceps extend extend

2.2. Straighten armStraighten arm

- biceps - biceps extend extend

- triceps - triceps contract contract

3. Bend knee3. Bend knee

- quadriceps - quadriceps extend extend

- hamstrings - hamstrings contract contract

4. Straighten knee4. Straighten knee - quadriceps - quadriceps contract contract - hamstrings - hamstrings extend extend

5.5. Crunches Crunches- abdomen - abdomen contract contract- back muscles - back muscles extend extend

6.6. Point toesPoint toes- calf muscle - calf muscle contract contract- shin muscle - shin muscle extend extend

More MovementsMore Movements

Naming Skeletal MusclesNaming Skeletal Muscles

Location of the muscleLocation of the muscleShape of the muscleShape of the muscleRelative Size of the muscleRelative Size of the muscleDirection/Orientation of the muscle Direction/Orientation of the muscle

fibers/cellsfibers/cellsNumber of OriginsNumber of OriginsLocation of the AttachmentsLocation of the AttachmentsAction of the muscleAction of the muscle

Muscles Named by LocationMuscles Named by Location

EpicraniusEpicranius

(around cranium)(around cranium)

Tibialis anteriorTibialis anterior (front of tibia)(front of tibia)

tibialis anterior

Naming Skeletal MusclesNaming Skeletal Muscles

Shape:Shape:

deltoid (triangle)deltoid (triangle)

trapezius (trapezoid, 2 trapezius (trapezoid, 2 parallel sides)parallel sides)

serratus (saw-serratus (saw-toothed)toothed)

rhomboideus rhomboideus (rhomboid, 4 parallel (rhomboid, 4 parallel sides)sides)

orbicularis and orbicularis and sphincters (circular)sphincters (circular)

Rhomboideusmajor

Trapezius

Deltoid

Serratus anterior

maximus (largest)maximus (largest)minimis (smallest)minimis (smallest) longus (longest)longus (longest)brevis (short)brevis (short)major (large)major (large)minor (small)minor (small)

Psoas major

Psoas minor

Muscles Named by SizeMuscles Named by Size

Muscles Named by Muscles Named by Direction of FibersDirection of Fibers

Rectus (straight) Rectus (straight)

––parallel to long parallel to long axisaxis

TransverseTransverse

ObliqueOblique

Rectusabdominis

External oblique

Biceps (2)Biceps (2)

Triceps (3)Triceps (3)

Quadriceps (4)Quadriceps (4)

Muscles Named for Muscles Named for Number of OriginsNumber of Origins

Biceps brachii

Muscles Named for Origin and Muscles Named for Origin and InsertionInsertion

SternocleidomastoidSternocleidomastoid originates from originates from sternum and clavicle sternum and clavicle and inserts on and inserts on mastoid process of mastoid process of temporal bonetemporal bone

origins

insertion

Muscles Named for ActionMuscles Named for Action

Flexor carpi radialis Flexor carpi radialis (extensor carpi radialis) (extensor carpi radialis) – – flexes wristflexes wrist

Abductor pollicis brevis Abductor pollicis brevis (adductor pollicis)(adductor pollicis)– – flexes thumbflexes thumb

Abductor magnus Abductor magnus – – abducts thighabducts thigh

Extensor digitorum Extensor digitorum – – extends fingersextends fingers

Adductormagnus

Arrangement of FasciclesArrangement of Fascicles

ParallelParallel strap-likestrap-like ex: sartoriusex: sartorius

FusiformFusiform spindle shapedspindle shaped ex: biceps femorisex: biceps femoris


PennatePennate "feather shaped”"feather shaped”

UnipennateUnipennate ex: extensor ex: extensor

digitorum longusdigitorum longus

BipennateBipennate ex: rectus femoris ex: rectus femoris

MultipennateMultipennate ex: deltoidex: deltoid


ConvergentConvergent ex: pectoralis ex: pectoralis

major major

CircularCircular sphincterssphincters ex: orbicularis orisex: orbicularis oris

There are about 60 muscles in There are about 60 muscles in the face.the face.

Smiling is easier than frowningSmiling is easier than frowning..

It takes 20 muscles to smile and over 40 to frown.It takes 20 muscles to smile and over 40 to frown.

Smile and make someone Smile and make someone happyhappy..

reportccmapeh.ppt

Documents