Muscular System Zool200

8/13/2019 Muscular System Zool200

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Muscular System


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MYOLOGY

The study of structure, functions, andcomposition of muscles

Myocytesmuscle cells

Muscle tissues

Muscular system


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Functions of the muscular system

1. For production ofmovements/locomotion

2. Maintenance of posture

3. Stabilize joints4. Generation of heat

5. Influence body contours

6. For expression of emotion7. For storage and movement of

substances

8. Allows one to manipulate theenvironment


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Overview of muscle tissues

THE THREE TYPES OF MUSCLES

1. SKELETAL2. SMOOTH

3. CARDIAC


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BASIS SKELETAL SMOOTH CARDIAC

1.Location Bones Visceralorgans

heart

2. Shape Elongated

Fusiform Elongated,branched

3. # of nuclei Many Single Single

4. NuclearPosition

Peripheral Central Central

5. Striation Present Absent Present

6. Contraction Rapid Slow Moderate

7. Stimuli Electrical Chemical electochemi-cal

Differences of Muscle Tissues


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SOMATIC VS VISCERAL MUSCLES

Striated,skeletal andvoluntary

Primitively segmented

Myotomal

Body wall,tail,hypobranchial and

tonguemuscles,appendicularmuscles

Unstriated,nonskeletal,involuntary

Unsegmented

Arise from the lateralmesoderm

Branchimericmuscles,cardiac,muscles of the tubes andvessels,hollow organs,


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Extrinsic muscles of

the eyeball

Primarily fororientation and

monitoring ofexternalenvironment

Innervated directlyby spinal nerve andcranial nerve III, IV,

VI, XII

intrinsic muscles ofthe eyeball, erectorsof hairs and feathers

For regulation of the

internal environment

Innervated by thepostganglionic fibersof the ANS


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Organization of muscle tissue1. Superficial Fascia

- separates the muscle from the integument

- made up of areolar and adipose tissue that

a. insulate heat and reduce heat loss

b. provides pathway and framework for

nerves,blood vessels,lymphatic vessels to

enter and leave muscles

c. stores water and fats

d. provides mechanical protection and prevent

physical trauma


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2.Deep Fascia

- with dense irregular conn. tissue that lines

the body wall- 3 layers:

epimysium,perimysium,endomysium

- functions:a. Holds the muscle together

b. Allows movement of muscles

c. Supports nerves,blood vessels and lymphaticd. Fill spaces between muscles

e. separates the muscles into functional units


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Deep Fascia

1. Epimysium - tough,overcoat connectivetissue that covers the entire muscle

a. tendonstrong, thick, cord-like attachment

of muscle to bone

- provide durability and conserve space

b. aponeurosisbroad, thin, sheet-like

attachment of muscle to bone,cartilages, or connective tissue

covering of each other


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2. Perimysium

- coarse fibrous membrane that

covers

muscle fascicles

- fasciclesbundles of muscle fibers

3. Endomysium

- delicate connective tissue sheaththat

enclose the individual muscle

fiber


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ORGANIZATION OF MUSCLES


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Microscopic anatomy of skeletalmuscles

MYOCYTE/myofibrils - muscle cells

SARCOLEMMAplasma membrane of

muscle cells

SARCOPLASMcytoplasm of musclecells occupied by myofilaments

SARCOMEREfunctional units of muscle cells

- z line to z line in locationMYOFILAMENTSthread-like contractile

proteins of myocytes


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Types of Myofilaments

1. MYOSIN - thick myofilament thatcharacterized the A band,

- mostly made of bundled moleculesof protein myosin

- types:

a. HEAVY MEROMYOSIN

- thick, with globular heads which contain

theactinbinding site and ATPase site

b. LIGHT MEROMYOSIN

- thin, tail to tail arrangement of myosin


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2. ACTINthin myofilament that

characterize the I band

Types:

a. Actinthe principal globular CHON

- with myosin binding site

b. Tropomyosinfilamentous CHON that coversthe myosin- binding site of actin

c. Troponintriplet CHON which are in constant

interval in the actinc.1 Tn-T

c.2 Tn-C

c.3 Tn - I


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SKELETAL MUSCLE ACTIVITY

Irritability Contractility

Nerve impulse and Action Potential

- skeletal muscles must bestimulated in order to contract

- one or more neuron may stimulate

a muscle fiber of groups of musclefibers


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THE MOTOR UNIT

The neuron and the muscle fibersstimulated

TYPES OF MOTOR UNITS

1. SINGLE MOTOR UNIT

2. MULTIPLE MOTOR UNIT


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THE NEUROMUSCULARJUNCTION

The region where motor neurons comesin close contact with the skeletal musclecell

Composition:a. Motor neuron

b. Synaptic cleft

c. Synaptic vesicles containingNeurotransmitter (ACh)

d. Axonal terminal


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The Sliding Theory (Mechanism of contraction)

1. Stimulation across the neuromuscular junctin initiates

an action potential, or depolarization, on thesarcolemma of the muscle fiber. This action potentialspreads along the sarcolemma and is transmitted intothe T-tubule

2. The T-tubule potential causes the terminal cisternaeof the sarcoplasmic reticulum to release Ca in theimmediate vicinity of each myofibrils

3. Ca ions bind to and thereby change the CHON

structure of the troponin molecules attached to thetropomyosin to move aside to expose the actin-binding site

4. Myosin across bridges bind to actin.Upon binding, theenergized HMM undergoues a conformational change,causing the head to tilt.This pulls the actin filament


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5. After power stroke, ATP bnds withHMM, causing detachment of the cross

bridge from the actin-binding sites. Theenzyme ATPase within HMM cleaves

ATP to ADP and energy to energize the

HMM. Then the HMM can then bindwith another actin-binding site andproduce another power stroke.

6. Repeated power strokes pulls the actin

filament,much like pulling a rope handover hand.


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GRADED RESPONSE In skeletal muscles, the all-or-nonelaw of

muscle physiology applies to the muscle cell,not to the whole muscle

All muscle contract to its fullest when

stimulated adequately, it never contractpartially

Skeletal muscles react to stimuli withdifferent degrees of shortening

Graded contraction may in 2 ways:

1. By changing frequency of muscle contraction

2. By changing number of muscle cells

stimulated


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MUSCLE TWITCH

The single, brief, jerky contractionssometimes result due to some nervoussystem problems

In a twitch, single stimulus is delivered,a muscle contracts and then relax

3 phases:

1. Latent period2. Contraction period

3. Relaxation period


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ENERGY FOR MUSCLECONTRACTION

1. Direct phosphorylation of adp by creatinephosphate

2. Anaerobic Respiration5 % of the ATP used bythe muscle but 2.5 times faster in providingenergy

3. Aerobic Respiration95% of the energy usedby the muscle


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TYPES OF MUSCLE FIBERS

FIBERCXCS

FAST-TWITCH

INTERME-DIATE

SLOWTWITCH

Fiber size Large Intermediate Small

Glycogencontent

High Intermediate Low

MyosinATPase

High High Low

Myoglobin Low High Low

Energy Anaerobic Combination AerobicTwitch Fast Fast Slow

PrimaryUse

Speed &power

Moderateactivity

Endurance


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TYPES OF MUSCLE FIBER


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DIVISION OF THE MUSCLE(VERTEBRATE MUSCULATURE)

1. Axial Muscles

2.Appendicular Musclesa. Intrinsic Appendicular Muscles

b. Extrinsic Appendicular Muscles


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TRUNK MUSCLES

A. FISHES

- trunk musclesmyomeres

- separated by myosepta into:a. epiaxial muscles

b. hypaxial muscles


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B. TETRAPODS

1.EPIAXIAL MUSCLES

- base of the skull to the tip of the tail

*longissimus group

*spinalis group

* iliocostalis

* intervertebralis

a. intertransversarii c. interarticularisb. interspinalis


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2. HYPAXIAL MUSCLES

- ventral and lateral body wall* subvertebralis

* oblique muscles

* rectus abdominis(linea alba,inscriptiones tendinae)

* tail muscles

- pyriformis - caudofemoralis

- extensor caudae - abductor caudae


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3. HYPOBRANCHIAL MUSCLES

- muscles that operate the jaws andthe branchial skeleton

- assist in feeding and respiration

- tongue muscles:* lingualis

*genioglossus

* styloglossus* hyoglossus


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BRANCHIOMERIC MUSCLES

A series of striated muscles that areoperating the pharyngeal arches

A. MUSCLES OF THE MANDIBULAR ARCH

* levator palatoquadrati* adductor mandibulae

* intermandibularis

*craniomaxillaris


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craniomaxillaris

Raise the upper jaw

Raise the lower jaw in closing the mouth

Elevates the anterior pharyngeal floorduring respiration


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3 muscles in mammals in the 1starch

1.Masseter

2.Temporalis

3. Pterygoideus

Mylohyoideusin tetrapods, homologousto intermandibular muscles of the fish

Digastricusgive rise to mylohyoideus


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MUSCLES OF THE HYOID ARCH

LEVATOR HYOMANDIBULAE

- dorsal constrictor

- O: neurocranium

- I: hyomandibula and ceratohyalcartilage

INTERHYOIDEUS

- a ventral constrictor

Muscles of the 3rd and successive


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Muscles of the 3rdand successivepharygeal arch

1. Cucullarisraises the pharyngeal wall2. Stylopharyngeus- swallowing3. Levator hyomandibulaeassist the

cucullaris4. Intrinsic muscles of the larynx

a. cricothyroideusb. criarytenoideus

c. thyroarytenoideus5. trapezius


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INTEGUMENTARY MUSCLES

1. Costocutaneus2. Panniculus carnosus

* in armadillos- roll into ball

* marsupialssphincters of the marsupium

* horsesvigorous flight

3.Cutaneus pectoralis

4. Patagial muscles

5. Auricular musclesdirects ears to faint sounds* caninus

* plumarum/arrector plumarum


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MIMETIC MUSCLES

ZYGOMATICUS

CURROGATOR SUPERCILII

FRONTALIS

ORBICULARIS ORIS

ORBICULARIS OCULI

DEPRESSOR LABII SUPERIORIS


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Types of Muscle Fiber Arrangements


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Types of Muscle Fiber Arrangements

POINTS OF ATTACHMENT OF


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POINTS OF ATTACHMENT OFMUSCLES

1. ORIGINproximal, less movable orimmovable point of attachment of

muscle

2. INSERTIONdistal, freely-movablepoint of attachment of muscles


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Origin and Insertion


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Types of body Movements

1. Flexion

2. Extension

3. Rotation

4. Abduction

5. Adduction

6. Circumduction


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Special Movements

1. Dorsilexion

2. Plantarflexion

3. Inversion

4. Eversion

5. Supination

6. Pronation7. Opposition

TYPES OF MUSCLE ACCORDING


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TYPES OF MUSCLE ACCORDINGTO MOVEMENT

1. AGONISTS/ Prime Mover

2. ANTAGONIST

3. SYNERGISTS

4. FIXATORS


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NAMING SKELETAL MUSCLES

1. DIRECTION OF MUSCLE FIBERS

2. RELATIVE SIZE

3. LOCATION

4. NUMBER OF ORIGINS5. ATTACHMENT/ LOCATION OF ORIGINS AND

INSERTION

6. SHAPE OF THE MUSCLE7. ACTION/FUNCTION

Electric organ discharge


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Electric organ discharge(EOD)

is the electric discharge generated by theorgans of animals including electric fish.

In some cases the electric discharge is

strong and is used for protection frompredators; in other cases it is weak and itis used for navigation and communication.


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ELECTRIC ORGANS

The electric eel, Electrophorus electricus,is a species of fish. It is capable ofgenerating powerful electricshocks, which

it uses for both hunting and self-defense.It is an apex predatorin its South

Americanrange. Despite its name it is not

an eelat all but rather a knifefish.
http://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Apex_predatorhttp://en.wikipedia.org/wiki/South_Americahttp://en.wikipedia.org/wiki/South_Americahttp://en.wikipedia.org/wiki/Eelhttp://en.wikipedia.org/wiki/Gymnotiformeshttp://en.wikipedia.org/wiki/Gymnotiformeshttp://en.wikipedia.org/wiki/Eelhttp://en.wikipedia.org/wiki/South_Americahttp://en.wikipedia.org/wiki/South_Americahttp://en.wikipedia.org/wiki/Apex_predatorhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Fish


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The electric eel has three abdominal

pairs of organs that produce electricity. They are the main organ, the hunter's

organ, and the sachs organ.

These organs take up 4/5 of its body.Only the front 1/5 contains the vitalorgans
http://upload.wikimedia.org/wikipedia/commons/0/03/Electric-eel2.jpg


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http://upload.wikimedia.org/wikipedia/commons/0/03/Electric-eel2.jpg


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In the electric Torpedo Ray,

electroplaxes are found near thepectoral muscles and the gills.

In all other fishes, it is often near the

tail. In one fish genus, the electric catfish

Malapterurus, the electric organs are

not made of individual electroplax, butare built up from charges of theepithelium, specifically the skin.
http://en.wikipedia.org/wiki/Torpedo_Rayhttp://en.wikipedia.org/wiki/Electric_catfishhttp://en.wikipedia.org/wiki/Electric_catfishhttp://en.wikipedia.org/wiki/Epitheliumhttp://en.wikipedia.org/wiki/Epitheliumhttp://en.wikipedia.org/wiki/Electric_catfishhttp://en.wikipedia.org/wiki/Electric_catfishhttp://en.wikipedia.org/wiki/Torpedo_Rayhttp://en.wikipedia.org/wiki/Image:Torpedo_fuscomaculata2.jpg


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capable of producing an electric

discharge, varying from as little as 8

voltsto up to 220 volts depending on the

species, which is used to stunor killprey.
http://en.wikipedia.org/wiki/Electric_dischargehttp://en.wikipedia.org/wiki/Electric_dischargehttp://en.wikipedia.org/wiki/Voltshttp://en.wikipedia.org/wiki/Specieshttp://en.wikipedia.org/wiki/Preyhttp://en.wikipedia.org/wiki/Preyhttp://en.wikipedia.org/wiki/Specieshttp://en.wikipedia.org/wiki/Voltshttp://en.wikipedia.org/wiki/Electric_dischargehttp://en.wikipedia.org/wiki/Electric_dischargehttp://en.wikipedia.org/wiki/Image:Torpedo_fuscomaculata2.jpghttp://en.wikipedia.org/wiki/Image:Malapterurus_electricus_1.jpg


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have the ability to produce an electric shockof

up to 350 voltsusing electroplaques of anelectric organ
http://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Volthttp://en.wikipedia.org/wiki/Electric_organhttp://en.wikipedia.org/wiki/Electric_organhttp://en.wikipedia.org/wiki/Volthttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Image:Malapterurus_electricus_1.jpg


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