Chapter 7 Muscular System. Functions and Types of Muscle Has three types –Smooth –Cardiac...

Chapter 7Chapter 7

Muscular SystemMuscular System

Functions and Types of Muscle


• Has three types– Smooth– Cardiac– Skeletal

• Has three types– Smooth– Cardiac– Skeletal



• Smooth Muscle:– Wall of hollow internal organs– Involuntary contractions– Moves materials– Single nucleus– Parallel lines, forming sheets– No striations– Sustain prolonged contraction, doesn’t fatigue

easy

• Smooth Muscle:– Wall of hollow internal organs– Involuntary contractions– Moves materials– Single nucleus– Parallel lines, forming sheets– No striations– Sustain prolonged contraction, doesn’t fatigue

easy



• Smooth Muscle:• Smooth Muscle:



• Cardiac Muscle:– Wall of heart– Uninucleiated– Striated, tubular, and branched– Intercalated disks = quick contractions– Involuntary and rhythmic

• Cardiac Muscle:– Wall of heart– Uninucleiated– Striated, tubular, and branched– Intercalated disks = quick contractions– Involuntary and rhythmic



• Cardiac Muscle:• Cardiac Muscle:



• Skeletal Muscle:– Multinucleated– Striated– Voluntary

• Skeletal Muscle:– Multinucleated– Striated– Voluntary



• Skeletal Muscle:• Skeletal Muscle:



• Connective Tissue Coverings:– Endomysium: each muscle fiber is

surrounded by – Fascicles: groups of muscle fibers– Perimysium: Connective tissue covering of

fascicles– Epimysium: Covers the entire muscle

• Connective Tissue Coverings:– Endomysium: each muscle fiber is

surrounded by – Fascicles: groups of muscle fibers– Perimysium: Connective tissue covering of

fascicles– Epimysium: Covers the entire muscle



• Connective Tissue Coverings:• Connective Tissue Coverings:



• Skeletal muscle:– Supports the body– Makes bones and other body parts move– Helps maintain a constant body temperature– Contraction assists movement in

cardiovascular and lymphatic vessels– Protects internal organs and stabilizes joints

• Skeletal muscle:– Supports the body– Makes bones and other body parts move– Helps maintain a constant body temperature– Contraction assists movement in

cardiovascular and lymphatic vessels– Protects internal organs and stabilizes joints

Contraction of Skeletal Muscle


• Sarcolemma: plasma membrane

• Sarcoplasm: cytoplasm– Contains glycogen for energy– Contains myoglobin that binds oxygen

• Sarcoplasmic reticulum: endoplasmic reticulum– Encases myofibrils- contractile portion of

muscle fibers

• Sarcolemma: plasma membrane

• Sarcoplasm: cytoplasm– Contains glycogen for energy– Contains myoglobin that binds oxygen

• Sarcoplasmic reticulum: endoplasmic reticulum– Encases myofibrils- contractile portion of

muscle fibers



• Sarcomeres- units of myofibrils– Contain myosin: thick protein filament– Contain actin: thin protein filament

• Sarcomeres- units of myofibrils– Contain myosin: thick protein filament– Contain actin: thin protein filament



• Thick filaments– Made of hundreds of protein myosin

• Thick filaments– Made of hundreds of protein myosin



• Thin filaments– Made of two intertwining strands of protein

actin

• Thin filaments– Made of two intertwining strands of protein

actin

Actin and MyosinActin and Myosin



• Neuromuscular junction: the area between the axon terminal and the sarcolemma

• Neuromuscular junction: the area between the axon terminal and the sarcolemma

Neuromuscular JunctionNeuromuscular Junction



• Actin- surrounded by threads of tropomyosin and troponin

• Calcium ions bind with troponin and expose myosin binding sites

• ATP binds to myosin and is broken down to ADP and P

• Energy is released, contraction occurs

• Actin- surrounded by threads of tropomyosin and troponin

• Calcium ions bind with troponin and expose myosin binding sites

• ATP binds to myosin and is broken down to ADP and P

• Energy is released, contraction occurs



• Muscles acquire ATP in 3 ways– Creatine phosphate breakdown– Cellular respiration– Fermentation

• Muscles acquire ATP in 3 ways– Creatine phosphate breakdown– Cellular respiration– Fermentation



• Creatine Phosphate Breakdown– Creatine Phosphate builds up when muscle is

at rest– Speediest way to make ATP available– 8 seconds of intense energy

• Creatine Phosphate Breakdown– Creatine Phosphate builds up when muscle is

at rest– Speediest way to make ATP available– 8 seconds of intense energy

Creatine Phosphate Breakdown

Creatine Phosphate Breakdown



• Cellular Respiration:– Completed in mitochondria– Only when oxygen is available– From glycogen and fatty acids– End products are carbon dioxide, water, and

heat

• Cellular Respiration:– Completed in mitochondria– Only when oxygen is available– From glycogen and fatty acids– End products are carbon dioxide, water, and

heat

Cellular RespirationCellular Respiration



• Fermentation:– Anaerobic– Glucose breaksdown into lactic acid– Build up of lactic acid leads to cramping

• Fermentation:– Anaerobic– Glucose breaksdown into lactic acid– Build up of lactic acid leads to cramping

FermentationFermentation



• All or nothing law

• A single fiber either contracts or rest

• However, a group of fibers some contract and other will not to appear to have the ability for partial contractions

• All or nothing law

• A single fiber either contracts or rest

• However, a group of fibers some contract and other will not to appear to have the ability for partial contractions



• Muscle twitch- single contraction that last for a fraction of a second– Latent period: time between stimulation and

initiation of contraction– Contraction period: muscle shortens– Relaxation period: muscle returns to its former

length

• Muscle twitch- single contraction that last for a fraction of a second– Latent period: time between stimulation and

initiation of contraction– Contraction period: muscle shortens– Relaxation period: muscle returns to its former

length



• Summation – increase in muscle contraction until maximal sustained contraction is achieved

• Tetanic contraction- maximum contraction

• Summation – increase in muscle contraction until maximal sustained contraction is achieved

• Tetanic contraction- maximum contraction



• Innervated- muscle fibers are innervated with nerve fibers called a motor unit

• Motor units either contract or do not contract

• Recruitment- stronger and stronger muscle contractions

• Innervated- muscle fibers are innervated with nerve fibers called a motor unit

• Motor units either contract or do not contract

• Recruitment- stronger and stronger muscle contractions



• While some muscles are contracting others are resting, this helps prevent fatigue

• Tone: some fibers are always contracting– Helps maintain posture

• While some muscles are contracting others are resting, this helps prevent fatigue

• Tone: some fibers are always contracting– Helps maintain posture



• Atrophy- loss of muscle tone due to inactivity or nerve damage– Muscle will eventually be replaced by adipose

and fibrous tissue– Muscles will shorten, leaving parts contracted

• Atrophy- loss of muscle tone due to inactivity or nerve damage– Muscle will eventually be replaced by adipose

and fibrous tissue– Muscles will shorten, leaving parts contracted



• Pertrophy- increase in muscle size– Prolonged period of forceful muscular activity

increases myofibrils

• Pertrophy- increase in muscle size– Prolonged period of forceful muscular activity

increases myofibrils



• Slow-twitch muscles– Steadier and more endurance– Highly resistant to fatigue– Substantial reserve of glycogen and fat– Abundant mitochondria, few fibers– Aerobic

• Slow-twitch muscles– Steadier and more endurance– Highly resistant to fatigue– Substantial reserve of glycogen and fat– Abundant mitochondria, few fibers– Aerobic



• Fast-twitch muscles– Anaerobic– Designed for strength– Many fibers, few mitochondria– Little or no myoglobin– Few blood vessels– Vulernable to cramping

• Fast-twitch muscles– Anaerobic– Designed for strength– Many fibers, few mitochondria– Little or no myoglobin– Few blood vessels– Vulernable to cramping

Skeletal MusclesSkeletal Muscles

• Origin – of a muscle is on the stationary bone

• Insertion- of a muscle in on the bone that moves

• Origin – of a muscle is on the stationary bone

• Insertion- of a muscle in on the bone that moves


• Prime mover- the muscle that does most of the work

• Synergists- the assisting muscles

• Prime mover- the muscle that does most of the work

• Synergists- the assisting muscles


• Antagonist- pair of muscles working against the synergist

• Antagonist- pair of muscles working against the synergist


• Naming muscles– Size

• Example: gluteus maximus, largest butt muscle

– Shape• Deltoid, shaped like a delta

– Direction of fiber• Rectus abominis, rectus = straight

– Location• Frontalis, overlies the frontal bone

• Naming muscles– Size

• Example: gluteus maximus, largest butt muscle

– Shape• Deltoid, shaped like a delta

– Direction of fiber• Rectus abominis, rectus = straight

– Location• Frontalis, overlies the frontal bone


• Naming muscles– Attachment

• Ex. Brachioradialis, brachium and the radius

– Number of attachments• Ex. Bicep = two attachments

– Action• Extensor digitorum – extends fingers

• Naming muscles– Attachment

• Ex. Brachioradialis, brachium and the radius

– Number of attachments• Ex. Bicep = two attachments

– Action• Extensor digitorum – extends fingers


• Muscles of the Head– Frontalis: frontal bone

• Raising eyebrows, wrinkle brow

– Orbicularis oculi: encircles eye• blinking

– Orbiularis oris: encircles mouth• Pucker lips

• Muscles of the Head– Frontalis: frontal bone

• Raising eyebrows, wrinkle brow

– Orbicularis oculi: encircles eye• blinking

– Orbiularis oris: encircles mouth• Pucker lips


• Muscles of the Head– Buccinator: cheek

• Compresses to whistle

– Zygomaticus: cheekbone to corner of mouth• Smile

• Muscles of the Head– Buccinator: cheek

• Compresses to whistle

– Zygomaticus: cheekbone to corner of mouth• Smile


• Muscles of Mastication– Masseter: zygomatic arch to mandible

• Ex. chewing

– Temporalis: overlies temporal bone• Ex. Elevates mandible

• Muscles of Mastication– Masseter: zygomatic arch to mandible

• Ex. chewing

– Temporalis: overlies temporal bone• Ex. Elevates mandible


• Muscles of the Neck– Deep neck muscles are responsible for

chewing– Superficial muscles are responsible for

moving the head

• Muscles of the Neck– Deep neck muscles are responsible for

chewing– Superficial muscles are responsible for

moving the head


• Muscles of the Neck– Sternocleidomastoid

• Turns head from right to left

– Trapezius• Triangular• Shrug shoulders

• Muscles of the Neck– Sternocleidomastoid

• Turns head from right to left

– Trapezius• Triangular• Shrug shoulders


• Muscles of the Trunk– External intercostal: between ribs

• Ex. Elevate rib cage during inspiration

– Diaphragm• Ex. Assists in inspirations

– Internal intercostal• Ex. Normally no muscular contraction, only with

forced expiration

• Muscles of the Trunk– External intercostal: between ribs

• Ex. Elevate rib cage during inspiration

– Diaphragm• Ex. Assists in inspirations

– Internal intercostal• Ex. Normally no muscular contraction, only with

forced expiration


• Muscles of the Abdominal Wall– External and internal obliques: Lower ribs and

pelvic girdle• Ex. Trunk rotation and lateral flexion

– Transversus abdomininis: horizontal across abdomen

• Synergist muscles

– Rectus abdominis: from pubic bones to the ribs and strernum

• Ex. Flex and rotate lumbar region

• Muscles of the Abdominal Wall– External and internal obliques: Lower ribs and

pelvic girdle• Ex. Trunk rotation and lateral flexion

– Transversus abdomininis: horizontal across abdomen

• Synergist muscles

– Rectus abdominis: from pubic bones to the ribs and strernum

• Ex. Flex and rotate lumbar region


• Muscles of the Shoulder– Serratus anterior: from armpit to chest

• Ex. Helps elevate arm above head

• Muscles of the Shoulder– Serratus anterior: from armpit to chest

• Ex. Helps elevate arm above head


• Muscles of the Arm– Deltoid

• Abducts arm to horizontal position

– Pectoralis major– Latissimus dorsi: from lower spine to humerus

• Ex. Swimming, rowing and climbing rope

– Rotator cuff: muscles over proximal humerus

• Muscles of the Arm– Deltoid

• Abducts arm to horizontal position

– Pectoralis major– Latissimus dorsi: from lower spine to humerus

• Ex. Swimming, rowing and climbing rope

– Rotator cuff: muscles over proximal humerus


• Muscles of the Arm– Biceps brachii: muscles of the forearm

• Turn a doorknob unscrew a jar

– Brachilais: humerus to ulna• Ex. Flexing the forearm

– Triceps brachii: scapula to humerus• Ex. To punch and in tennis

• Muscles of the Arm– Biceps brachii: muscles of the forearm

• Turn a doorknob unscrew a jar

– Brachilais: humerus to ulna• Ex. Flexing the forearm

– Triceps brachii: scapula to humerus• Ex. To punch and in tennis


• Muscles of the Arm– Flexor carpi and extensor carpi

• Flexes and extends wrist

– Flexor digitorum and extensor digitorum• Flexes or extends fingers

• Muscles of the Arm– Flexor carpi and extensor carpi

• Flexes and extends wrist

– Flexor digitorum and extensor digitorum• Flexes or extends fingers


• Muscles of the Hip and Leg– Iliopsoas: ilium to lumbar vertebrae

• Ex. walking, bowing, standing erect

– Gluteus maximus: large buttocks muscle• Ex. Walking, jumping, climbing stairs

– Gluteus medius: small buttocks muscle– Adductor group

• Ex. Thighs inward

• Muscles of the Hip and Leg– Iliopsoas: ilium to lumbar vertebrae

• Ex. walking, bowing, standing erect

– Gluteus maximus: large buttocks muscle• Ex. Walking, jumping, climbing stairs

– Gluteus medius: small buttocks muscle– Adductor group

• Ex. Thighs inward


• Muscles of the Leg– Quadricep femoris: thigh

• Ex. Extends leg

– Sartorius: thigh to knee• Ex. Sit cross legged

– Hamstring:Back of thigh• Ex. Antagonist muscle group

• Muscles of the Leg– Quadricep femoris: thigh

• Ex. Extends leg

– Sartorius: thigh to knee• Ex. Sit cross legged

– Hamstring:Back of thigh• Ex. Antagonist muscle group


• Muscles of the Ankle and Foot– Gastrocnemius

• Ex. Pushing forward while walking, dancing

– Tibialis anterior• Ex. Inversion of foot

– Peroneus• Ex. Plantar flexion

– Flexor and extensor digitorum longus• Ex. Flexes and extends toes

• Muscles of the Ankle and Foot– Gastrocnemius

• Ex. Pushing forward while walking, dancing

– Tibialis anterior• Ex. Inversion of foot

– Peroneus• Ex. Plantar flexion

– Flexor and extensor digitorum longus• Ex. Flexes and extends toes

Effects of AgingEffects of Aging

• Mass and strength decrease

• Muscle tissue initially replaced by connective tissue then eventually fat

• Mass and strength decrease

• Muscle tissue initially replaced by connective tissue then eventually fat

HomeostasisHomeostasis

• Heartbeat and movement of blood

• Protect internal organs

• Moves bones and allows daily activities

• Heartbeat and movement of blood

• Protect internal organs

• Moves bones and allows daily activities

Chapter 7 Muscular System. Functions and Types of Muscle Has three types –Smooth –Cardiac...

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