Muscular System- Comaparative Anatomy

7/29/2019 Muscular System- Comaparative Anatomy

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Muscular System

Comparative Vertebrate Anatomy

Lecture 7

John Donnie A. Ramos

Dept. of Biological SciencesCollege of ScienceUniversity of Santo Tomas

Functions Locomotion

Determines bodyposture and shape

Digestion

Opens and closes bodyopenings

*achieved through theability to contract(shorten)

Structure of Muscle FibersEpimysium(around muscle bundle)

Perimysium(around 1 muscle fascicle)

Endomysium(around a muscle fiber)

Muscle Contraction

SlidingFilamentTheory

Types of Muscle TissuesSkeletal Cardiac Smooth

Striation Striated Striated Non-striated

Nervous Control Voluntary Involuntary Involuntary

ShapeStraight-unbranched

Straight-branching(intercalateddisks)

Fusiform

No. of Nuclei Several/cell Several/cell One/cell

Location ofNuclei

Peripheral Central Central

Location Skeletons Heart Internal organs

Muscle Fibers

Smooth MuscleSkeletal Muscle

Cardiac Muscle


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Kinds of Muscle Fibers Twitch (Red) muscle fibers

Rich blood supply

Large amount of myoglobin (dark)

Slow-fast contraction

Innervation single axon

Action potential all-or-none

Variably fatigues (resistant)

Examples: mammalian postural muscles, locomotor muscles

Tonic (White) muscle fibers

Limited blood supply

Lack myoglobin

Slow contraction

Graded contraction

Fatigue quickly

Examples: postural muscles of amphibians and reptiles,extraocular and ear muscles of mammals

Parts of Muscle Bundle Origin

Immovable part where the rest of the muscle fiber isdirected during muscle contraction

Insertion Movable part that is displaced during muscle contraction

Fascia Connective tissue covering

Aponeuroses Tough, thin, sheetlike tendons that covers some muscles

Raphes Long tendons between muscles

Tendonous Inscriptions Transverse tendons on muscle segments

Muscle Origin Insertion Action Muscles according to their actions Extensor - straightens a part Flexor - bends a part

Adductor - brings a part toward the middle Abductor - brings a part away from the middle Protractor - brings a part forward or outward

Retractor - brings a part backward (pulls back a part) Levator - raises a part Depressor - lowers a part Rotator - rotates a part

Supinator - rotator of palm / turns palm upwards Pronator - turns the palm downward Tensor - expands a part

Constrictor - compresses a part

Sphincter - closes a part Dilator - opens a part

Opposing Muscle Actions Criteria used in naming muscles

Action Insertion

Origin

Direction of fibers

Location

Number of divisions

Shape

Size

pectoral abductor intermandibularis

common coracoarcuals

external oblique

intermandibularis

digastric

serratus ventralis

teres major

Examples:


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Types of Muscles according to function Somatic Muscles (Myotomal/Somitic)

Muscles in contact with environment Segmented From myotomes (somatic mesoderm)

Voluntary

Visceral Muscles Muscles found in internal organs Unsegmented From splanchnic mesoderm Involuntary

Branchiomeric Muscles Muscles found in pharyngeal arches

Striated skeletal muscles From myotomes Voluntary

Somatic Muscles Axial muscles

Trunk and tail muscles

Epaxial

Hypaxial

Hypobranchial muscles

Extrinsic eyeball muscles

Appendicular muscles

Extrinsic appendicular muscles

Intrinsic appendicular muscles

Axial Muscles exhibits metamerism

from segmented mesodermal somites

presence of myoseptum

advantage for undulation (swimming)

Origin:

Trunk and tail muscles from trunk somites

Extrinsic eyeball muscles from preotic somites

Hypobranchial muscles from postbranchial somites

Origin of Axial Muscles

Trunk and Tail Muscles Fishes:

Epaxial muscles dorsal longitudinal bundles

Hypaxial muscles lateral and ventral longitudinalbundles

Head region:

Epibranchialmuscles dorsal tothe gills

Hypobranchialmuscles ventral tothe gills

Epaxial Muscles of Tetrapods Intervertebrals

Intertransversarii between 2 transverse processes

Interspinales between 2 neural spines Interarcuales between 2 neural arches

Interarticulares between 2 zygopophyses

Longissimus Longissimus capitis inserted on the skull Longissimus cervices inserted on the neck

Longissimus dorsi inserted on the trunk

Extensor caudae lateralis tail

Spinalis Spinalis dorsi

Spinalis cervicis called multifidus spinae (along lumbar region)

Spinalis capitis

Iliocostalis region of ilium

*Complexus epaxial muscle on the neck of birds which helps in breaking the shell duringhatching.


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Epaxial Muscles of Tetrapods

Crocodile Cat

Hypaxial Muscles of Tetrapods Subvertebrals

Ventral to the vertebral column

Longus colli neck region

Quadratus lumborum lumbar region

Psoas minor tenderloin

Oblique muscles Intercostals (internal and external) between ribs

Internal and external oblique muscles Cremaster muscle around spermatic cord

Supracostal surface of ribcage (scalenes, serratus dorsalis)

Diaphragm

Transverse muscles Transverse abdominis

Rectus muscles Rectus abdominis

Mammalian Axial Muscleson the abdominal region (cross section)

Muscles of the Diaphragm

Tail Muscles of Tetrapods

Epaxial Muscles

Intervertebral Lingissimus extensor caudae lateralis

Spinales (multifidus spinae)

Hypaxial Muscles

Caudofemoralis

Sphincter muscles of anus and cloaca

Hypobranchial

Muscles Fishes (below the gill arches)

Intermandibularis

Interhyoideus Coracomandibularis

Coracohyoideus Coracoarcuales

*Rectus cervices found inurodeles

Tetrapods (associated with hyoidapparatus and larynx)

Sternohyoid

Sternothyroid Thyrohyoid

Omohyoid

Geniohyoid


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Tongue Musclesfrom anterior hypobranchial muscle blastemas

innervated by cervical spinal nerves

Hyoglossus

Styloglossus

Genioglossus

Lingualis intrinsic tongue muscle in mammalsand some reptiles

Extrinsic Eyeball Muscles

Appendicular MusclesFishes

Originate from muscle buds (fin fold) Dorsal blastemas (extensor and levator muscles)

Ventral blastemas (deppressor and flexor muscles)

Tetrapods

Extrinsic appendicular Originate on axial skeleton and insert on girdle or limb

Intrinsic appendicular Originate on girdle or limb and insert on distal part of limb

Extrinsic Musclesof the pectoral Girdle and Forelimbs

Dorsal Group Latissimus dorsi inserted on humerus

Levator scapulae ventralis

Levator scapulae dorsalis

Rhomboideus

Serratus ventralis

Trapezius (Cleido, Acromio, Spino)

Ventral Group Pectoralis muscles (chest muscles)

Pectoralis major

Pectoralis minor

Xiphihumeralis

Pectoantibrachialis

Intrinsic Musclesof the Pectoral Girdle and Forelimbs

Dorsal Group Deltoideus (Cleido, Acromio, Spino)

Teres major and minor

Subscapularis Triceps brachii

Supinators of hand

Extensors of hand & digits

Ventral Group Supraspinatus

Infraspinatus Coracobrachialis

Biceps brachii

Brachialis

Anconeus

Cleidobrachialis

Flexors of digits Pronators


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Muscles of the Pelvic Girdle and Hindlimbs Extrinsic musclesoriginate from axial skeleton and insert on pelvic girdle

Caudofemoralis

Intrinsic muscleslocomotor muscles Hip muscles

Gluteus (iliofemoralis)

Pyriformis (caudofemoralis brevis)

Gemelli

Thigh muscles Quadratus femoris (3 vasti and rectus femoris)

Semimembranosus

Adductor femoris

Adductor longus

Pectineus

Sartorius

Gracilis Obturator muscles

Biceps femoris

Semitendinosus

Shank muscles Extensor and flexor

muscles of foot anddigits

Gastrocnemius

Branchiomeric Muscles

Branchiomeric Muscles Facial

Musclesfrom the hyoid arch

SC sphincter colli

P plastysma

1 frontalis

2 orbicularis oculi

3 quadratus labii superioris

4 risorius

5 traingularis

6 posterior auricular

7 occipital

8 superior auricular

9 anterior auricular


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Visceral Muscles Cardiac muscles

Muscles of the GI tract and blood vessels

Intrinsic eyeball muscles

Integumentary muscles

Costocutaneous muscles hypaxial integumentary muscles of snakes

Panniculus carnosus mammals

Cutaneous pectoris chest wall of anurans

Patagial muscles patagium of bats

Facial muscles

Arrectores plumarum - muscle on feather follicle

Arrectores pilorum muscle on hair follicle

Special muscles Electric organs (pile of electric discs called electroplax)

Muscular System- Comaparative Anatomy

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