Muscular System Flashcards
are contractile and supply force for motility (heat production)
Stimulated by nerve impulses
Final determinants of posture, aid in movement of viscera
Muscles
why are muscles Difficult to establish homologies due to
Variability in muscle shape
Splitting or merging of muscles
O, I & A may change
Main Functions of muscles
Supply force for movement
Acted as movers and levers for every action with the aid of the skeleton
Restrain motion and hold the body in position
Contraction of the viscera
Heat production (temperature regulation)
Classification of Muscles
color
location
controlled by the nervous system
embryonic origin
microscopic appearance
Muscles are classified according to their color
red and white muscles
This classification has fallen out of favor because such a color distinction alone underestimates the complexity of muscles
Muscles are classified according to their color
type of muscles that are classified according to their location
muscles that move bones or cartilages
Somatic muscles
type of muscles that are classified according to their location
control the activity of organs, vessels and ducts
Visceral muscles
type of muscles that are classified by the way in which they are controlled by the nervous system
Voluntary muscles are under immediate conscious control
involuntary muscles are not under immediate conscious control
muscles arise from what three embryonic origins
mesenchyme
Paired hypomere
paraxial mesoderm
muscles arise from three embryonic origins
embryonic origins from which smooth muscles within the wall of the blood vessels and some viscera develop
mesenchyme
muscles arise from three embryonic origins
embryonic origins that are differentiated into smooth muscle layers of the alimentary tract and its derivatives
Paired hypomere
muscles arise from three embryonic origins
embryonic origins that are from which most of the skeletal muscles develop
paraxial mesoderm
Types of Muscles that are classified by their general microscopic appearance
skeletal, cardiac, and smooth muscle
Structure of Skeletal Muscle
Belly
Fascia
Origin and insertion
Types of Skeletal Muscle as to Action
Agonist or prime mover
Antagonist
Synergist
Fixator
Types of Skeletal Muscle as to Action
principal mover for specific action
Agonist or prime mover
Types of Skeletal Muscle as to Action
for opposite movement
Antagonist
Types of Skeletal Muscle as to Action
helps the stabilize the movement of one joint and inhibit undesirable movements
Synergist
Types of Skeletal Muscle as to Action
fixes the position of the limb when the movement is occurring
Fixator
Types of Skeletal Muscles as to Specific Function
Flexors
Extensors
Adductors
Abductors
Pronators
Supinators
Elevators or levators
Depressors
Constrictors
Dilators
Sphincters
Types of Skeletal Muscles as to Specific Function
bend a limb or one part of a limb against another
Flexors
Types of Skeletal Muscles as to Specific Function
straighten a limb or one of its component parts
Extensors
Types of Skeletal Muscles as to Specific Function
draw a part toward a median line or toward a neighboring part or limb
Adductors
Types of Skeletal Muscles as to Specific Function
draw a part away from a median line or from a neighboring part or limb
Abductors
Types of Skeletal Muscles as to Specific Function
turn or rotate a part downward on its axis as in the palm of the hand
Pronators
Types of Skeletal Muscles as to Specific Function
turn or rotate a part forward and upward on its axis as in the palm of the hand
Supinators
Types of Skeletal Muscles as to Specific Function
raise or lift a part as when the lower jaw in closing the mouth
Elevators or levators
Types of Skeletal Muscles as to Specific Function
lower or depress a part as when the lower jaw in opening the mouth
Depressors
Types of Skeletal Muscles as to Specific Function
draws part together or compress a space such as the pharynx and the abdomen
Constrictors
Types of Skeletal Muscles as to Specific Function
widens an opening or a space
Dilators
Types of Skeletal Muscles as to Specific Function
contrictors surrounding an opening such as mouth, pylorus and anus
Sphincters
Basis in Naming Skeletal Muscles
Direction of fibers
Location or position
Number of divisions
Shape
Origin and insertion
Action
Size
Some combination
During muscle evolution, some muscles have fused with one another, others have split into distinct new muscles, some have become reduced in prominence, and other have changed their points of attachment and hence their evolution
true
In order to trace the evolution of individual muscle, several criteria for recognizing ___________ muscles must be used
homologous
Criteria for Establishing Muscle Homology
Attachment similarity
Functional similarity
Similarity in embryonic origin
Innervation similarity
Alterations in Muscles
Splitting
Fusion
Reduction in size
Change in point of attachment
Skeletal muscles of the trunk and tail
Extend forward beneath the pharynx as hypobranchial muscles and in amniotes as tongue muscles
Do not include branchiomeric or appendicular muscles
Axial Muscles
most evident in fish and aquatic amphibians where the axial muscles are used in locomotion
relating to or consisting of several similar segments or somites characteristics of Axial Muscles
Metameric
because of their embryonic origin (arise from segmental mesodermal somites)
Axial Muscles are also described as
Segmental
Axial Muscles (9)
1 - epaxials (red)
2 - hypaxials
3 - external oblique
4 - internal oblique
5 - transversus abdominis
6 - rectus abdominis
7 - trapezius
8 - dorsalis scapulae
9 - latissimus dorsi
Trunk and Tail Muscles of Fishes
Musculature of the body wall and tail of fishes consists of __________ separated by myosepta to which the longitudinally directed muscle fibers attach
myomeres
Trunk and Tail Muscles of Fishes are divided into _______ and ________ portions by a horizontal skeletogenous septum
First and foremost role of this musculature is for locomotion
epaxial
hypaxial
Agnathans
Muscular system of lampreys is more primitive than other vertebrates
__________ is lacking, thus the prominent axial musculature is not divided into epaxial and hypaxial divisions
lateral septum
Each myotome contributes one muscle segment called ________
myomere
Agnathans
The short fibers of the myomeres are inserted on partitions of connective tissues called ___________, which lie between successive myomeres
myosepta
Agnathans
The ventral portions of myomeres behind the pharynx turn forward _____ the hypobranchial musculature
above
Agnathans
Branchial muscles are not prominent
Muscles encircling the specialized mouth and tongue are _____ but not _______ with muscles of higher vertebrates
prominent
homologous
Gnathostomous Fishes
Musculature of jawed fishes is more advanced but less complex than _____
tetrapods
Gnathostomous Fishes
Strong axial muscles ________ and tail from side to side during swimming
flex the spine
Gnathostomous Fishes
Myomeres become __________ to extend the action of each myomere over several vertebrae and to assure that muscle fibers can all shorten at equal rates
more angled (zig-zag shaped) and are molded into interlocking cones
Gnathostomous Fishes
Epaxial muscles continue to the skull as __________
epibranchial muscles
Gnathostomous Fishes
Strap-like ___________ extend from the pectoral girdle to the visceral arches
Serve to open the jaws and pull the gills downward and backward
Evolved from the hypaxial muscles retaining the longitudinal orientation of fibers
hypobranchial muscles
Trunk and Tail Muscles of Tetrapods
As the limbs take over the propulsive role, the limb muscles _______ and the axial musculature _______ and become more related to the skeleton for dorsoflexion and ventroflexion of the spine
enlarge
decreases
Trunk and Tail Muscles of Tetrapods
what happens to the Myosepta
regress and disappear
Trunk and Tail Muscles of Tetrapods
Muscles _________ that span from two to many vertebrae
develop long fibers
Trunk and Tail Muscles of Tetrapods
Certain muscles form_______ and other becomes ______
sheet-like layers
associated with the pectoral girdle
__________ muscles of amphibians other than anurans are conservative
Myosepta are still present but in vertical orientation instead of angled
Epaxial muscles
Epaxials of _________ lack myosepta and become complex
Muscles in the cervical region form layers associated with a flexible neck
reptiles and mammals
Epaxial muscles of ________ are only prominent in the neck
turtles and birds
Collectively functions in extending the vertebral column and in lateral flexion of the body
Epaxial Muscles of the Trunk
Epaxial Muscles of the Trunk
Divided arbitrarily into four groups:
Intervertebrals
Longissimus
Spinales
Iliocostales
Epaxial Muscles of the Trunk
Deepest of the epaxial muscles and the only one to retain primitive metamerism
Intervertebrals
Intervertebrals are Classified based on location:
Intertransversarii
Interapinales
Interarcuales
Interarticulares
Intervertebrals are Classified based on location:
extend between two successive transverse processes
Intertransversarii
Intervertebrals are Classified based on location:
extend between two neural spines
Interapinales
Intervertebrals are Classified based on location:
extend between two neural arches
Interarcuales
Intervertebrals are Classified based on location:
extend between two successive zygapophyses
Interarticulares
is collective term for lumbar intervertebrals grouped with spinales
Multifidous spinae
Axial Muscles
Occupy lateral position above the transverse processes and individual bundles are named according to their location: capitis, cervicis and dorsi
Longissimus
Axial Muscles
Named as such because it is the longest epaxial mass
Dominant extensor in mammals and plays no role in mammalian locomotion
The medial bundle continues into the tail as the extensor caudae lateralis
Longissimus
Axial Muscles
Occupy medial position above the transverse processes and individual bundles are named according to their location: capitis, cervicis and dorsi
Spinales
Axial Muscles
Connect neural spines or transverse process with neural spines several or many segments cephalad
Chief role is to assist in maintaining stability of the column
Spinales
Axial Muscles
_______ connect transverse processes with the neural spines of the second vertebrae forward
Transversospinales
Axial Muscles
Lateral to the longissimus and constitute a thin sheet arising on the ilium and passing forward to insert on the ribs or uncinate processes
Continue forward to the neck but not in the tail
Iliocostalis
Dominant epaxials in reptiles which allows for ________
Rotates the pectoral girdle and to a lesser degree the pelvic girdle on a vertical axis in crocodiles
lateral undulation
Similar in all tetrapods and is classified into three groups:
Subvertebral group
Rectus abdominis group
Oblique and transverse group
Hypaxial Muscles of the Trunk
Similar in all tetrapods and is classified into three groups:
located below the transverse processes of the vertebrae
Subvertebral group
Hypaxial Muscles of the Trunk
Similar in all tetrapods and is classified into three groups:
runs lengthwise along the ventral body wall between the two girdles
Rectus abdominis group
Hypaxial Muscles of the Trunk
Similar in all tetrapods and is classified into three groups:
found on the lateral side of the body
Oblique and transverse group
Form a longitudinal band of fairly powerful flexors of the vertebral column lying beneath the transverse process from the atlas to the pelvis
Subvertebral Muscles
Subvertebral Muscles in neck of birds and mammals
Longus colli
Subvertebral Muscles in the lumbar region with an additional psoas minor in mammals
Quadratus lumborum
Subvertebral Muscles in the spine
Ventroflexes
Extends longitudinally on either side of the linea alba between the pubic symphysis and the sternum
Rectus Abdominis Muscle
Rectus Abdominis Muscle is strictly segmental in _____________ and it exhibits irregular transverse tendinous inscriptions in ________
urodeles
anurans and amniotes
muscle is a slip of muscle in the marsupial pouch and eutherians can either have it as vestigial as species characteristic or as an anomaly
Pyramidalis
Muscles that have become stratified into superficial and deep layers
Muscle that fibers pass obliquely from origin to insertion
Oblique and Transverse Muscles
Oblique and Transverse Muscles May either be split in two or lost
Aquatic urodeles - external oblique is split into two
Crocodilians and some lizards - all layers consist of two sheets each
Anurans - internal oblique is sometimes missing
Birds - sheet are thin
Turtles - all layers are vestigial
is derived from the internal oblique and sometimes the transverse abdominal muscle
Well developed in mammals in which the inguinal canal is open because they retract the testis into the abdominal cavity
Plays a major role in external respiration in most amniotes other than turtles and has an accessory role in mammals
Cremaster muscle
Oblique and transverse muscles, together with the rectus, ____________ for functions such as egg laying, delivery of mammalian young and emptying of digestive tract
supports the abdominal viscera
Somites from the level of the developing 3rd to 5th cervical spinal nerves migrate caudad in the somatopleure to invade the embryonic septum transversum
Consists of a central tendon with a pair of semilunar extensions and a muscular portion
Become the major respiratory muscle in mammals
Diaphragm
Continuation of the epaxial and hypaxial musculature of the trunk
Most evident in urodeles and generalized reptiles
Muscles of the Tail
Muscles of the Tail
Disruption of the continuity occurs to one degree or another at the level of the pelvis of amniotes generally and especially of
birds and mammals
Muscles of the Tail
Intervertebrals and multifidous spinae continue as ______ and longissimus continue as _______
medial
lateral extensors
Muscles of the Tail
Long hypaxial muscle arise from the medial surface and caudal border of the wing of the ilium, from transverse processes of the last lumbar vertebrae or from the sacrum pass into the tail and bend the tail ______________
lateral or downward
Develop from the upper part of the postotic somites and several of the trunk somites
Lie above the gill region
Elevate the cranium when mouth is open (some fishes and amphibians)
Extension of epaxial muscles of the trunk
Epibranchial Muscles
From trunk somites that migrated to the floor of the pharynx
Lie below the gill region
Open jaw and expand pharynx during feeding
Cranial extensions of the hypaxial musculature of the tongue
Hypobranchial Muscles
Hypobranchial Muscles
Sharks
Prehyoid - coracomandibularis (extend mandible toward pectoral girdle)
Posthyoid - rectus cervicis, coracohyoideus and coracoarcuals; extend to pectoral girdle
Hypobranchial and Tongue Muscles
Extend forward from the coracoid region of the pectoral girdle via coracoarcuales in fishes
inserts on the Meckel’s cartilage
Coracomandiburalis
Hypobranchial and Tongue Muscles
Extend forward from the coracoid region of the pectoral girdle via coracoarcuales in fishes
insert on the basihyals
Coracohyoideus
Hypobranchial and Tongue Muscles
Extend forward from the coracoid region of the pectoral girdle via coracoarcuales in fishes
insert on the ventral most segments of the gill cartilages
Coracobranchialis
Stabilize the hyoid apparatus and larynx in tetrapods and draw these cephalad or caudad: sternohyoid, sternothyroid, thyrohyoid, omohyoid and geniohyoid
Hypobranchial and Tongue Muscles
Tongue of amniotes is a ________ anchored to the hyoid skeleton and stuffed with hypobranchial muscles
mucosal sac
The extrinsic tongue muscles are
hyoglossus, styloglossus and genioglossus
The _________ is an intrinsic tounge muscle which develops in mammals and some reptiles
lingualis
Those that insert on the girdles, fins or limbs
Most fishes use axial muscle for locomotion as such, the _________ are uncomplicated, exhibit little variety, have little mass and perform a restricted function
Appendicular Muscles
Appendicular muscles are _________ in agnathans
absent
Appendicular muscles in jawed fishes have evolved with fins and is divided into a dorsal and ventral group:
Dorsal mass of extensors (or abductors or levators) moving the fins upward or forward
Ventral mass of flexor (or adductors or depressors) moving the fins downward or backward
Far more complex than those of fishes because of the joints in tetrapod limbs
Tetrapods
Tetrapods are Divided into two groups depending on their anatomic origins:
Extrinsic appendicular muscles
Intrinsic appendicular muscles
Tetrapods are Divided into two groups depending on their anatomic origins:
arising on the axial skeleton or fascia of the trunk and inserting on a girdle or limb
Extrinsic appendicular muscles
Tetrapods are Divided into two groups depending on their anatomic origins:
arising on a girdle or limb and inserting more distally on the limb
Intrinsic appendicular muscles
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Dorsal group
the most constant muscle
Latissimus dorsi
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Dorsal group
Latissimus dorsi
Levator scapulae
Levator scapulae ventralis or omotransversarius
Levator scapulae dorsalis
Rhomboideus - found only in crocodilians among living reptiles
Serratus ventralis
Trapezius
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Dorsal group
survivor of the cucullaris muscle of fishes
Originates from neural crest and is a muscle of the pharyngeal arch
Cleidotrapezius, acromiotrapezius and spinotrapezius
Trapezius
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Ventral group
the group of skeletal muscles that connect the upper extremities to the anterior and lateral thoracic walls
Subsumed the general term
pectoral muscles (pectoralis and supracoracoideus)
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Ventral group
chief adductor
Pectoralis
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Ventral group
Pectoral muscles are seen in their primitive state in what order of amphibia
urodeles
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Ventral group
Pectoralis ___________ while the ________ elevate the wings in birds
depress
supracoracoideus
Extrinsic Muscles of the Pectoral Girdle and Forelimbs
Ventral group
_______in mammals became an intrinsic muscle
Supracoracoideus
Intrinsic Muscles of the Pectoral Girdle and Forelimbs
Dorsal group
Deltoideus
- Inserts on the scapula
Spinodeltoideus
Acromiodeltoideus
Teres major
Teres minor
Subscapularis
Triceps brachii long head
Supinator
Extensors of manus
Intrinsic Muscles of the Pectoral Girdle and Forelimbs
Ventral group
Supraspinatus and infraspinatus (homologous with the supracoracoideus)
Coracobrachialis
Biceps brachii
Brachialis
Anconeus
Epitrochleoanconeus
Pronators
Flexors of manus
Intrinsic Muscles of the Pectoral Girdle and Forelimbs
which extends from the clavicle to the humerus or ulna is present in some mammals
Appears to be the continuation of the clavotrapezius in cats
Cleidobrachialis
Musculature of birds is essentially reptilian
how so?
Intrinsic muscles of the wings have been reduced
Weight is borne by the extrinsic muscles of the forelimb and intrinsic muscles of the hindlimbs
Muscles of the Pelvic Girdle and Hind Limbs
Dorsal group
Psoas
Iliacus
Pectineus
Quadratus femoris
Rectus femoris - adducts the thigh
Vastus group - extend the leg
Sartorius - longest muscle in humans
Tensor fascia latae
Abducts the thigh
Gluteus
Pyriformis
Gemelli
Tibialis anterior
Peroneus
Extensors of the digits
Muscles of the Pelvic Girdle and Hind Limbs
Ventral Group
Obturator - abducts the thigh
Adductor femoris
Caudofemoralis - not locomotor in urodeles but extends its pull in the trunk
Flexors of the leg
Semitendinosus
Biceps femoris
Semimembranosus
Gracilis
Gastrocnemius - extensor
Soleus
Plantaris
Flexors of the digits
Somitomeric and Somitic Muscles of the Head
Sharks
closing force, largest and strongest
Adductor mandibulae
Somitomeric and Somitic Muscles of the Head
Sharks
protracts jaws
Preorbitalis
Somitomeric and Somitic Muscles of the Head
Sharks
open/close spiracle
Spiracularis
Somitomeric and Somitic Muscles of the Head
Sharks
prey capture
Levator palatoquadrati
Somitomeric and Somitic Muscles of the Head
Sharks
compress throat
Intermandibularis
Somitomeric and Somitic Muscles of the Head
Tetrapods
in mammals they are composed of temporalis, masseter, pterygoideus
Adductor mandibulae
Somitomeric and Somitic Muscles of the Head
Tetrapods
levator and protractor pterygoidei except mammals
Levator palatoquadrati
Somitomeric and Somitic Muscles of the Head
Tetrapods
mammalian mylohyoid and cranial digastricus
(pump air into lungs of amphibians)
Intermandibularis
Muscles of the Hyoid Arch
Sharks
Suspend jaw and compress pharynx
Levator hyomandibulae
Dorsal hyoid constrictor
Ventral hyoid constrictor
Interhyoideus
Muscles of the Hyoid Arch
Amphibians & Reptiles
Ventral hyoid constrictor - sphincter coli
Depressor mandibuli - new muscle in tetrapods
Muscles of the Hyoid Arch
Mammals
Ventral hyoid constrictor
stapedius
Muscles of the Hyoid Arch
Mammals
new muscle for opening jaw
Digastricus
Muscles of the Hyoid Arch
Mammals
new muscle for opening jaw
platysma and facial muscles (for facial expression)
Muscles of the Successive Pharyngeal Arches
Sharks
- raise pharyngeal wall
Branchial adductors and superficial - expand and compress pharynx and gills
- connect branchial arch segments
Cucullaris
constrictors
Interbranchialis
Muscles of the Successive Pharyngeal Arches
Amphibians & Reptiles
- raise pharynx
- vocalization
Cucullaris and levatores arcuum
Dilator laryngis
Branchiomeric Muscles
Stapedius
temporalis
Cleido-occipitalis
Stylohoideus
Sternomastoideus
Masseter
Cricothyroideus
Extrinsic Integumentary Muscles
‘Anterioir Auricular
Superior Auricular
Caninus
Platysma
Intrinsic Integumentary Muscle
Arrector pili muscles
there are Electric Organs
true