[2] Lecture 13-Axial musculature Flashcards
3 groups of skeletal muscle:
Axial
Branchiomeric
Appendicular
Derived from myotome portions of somites
Demonstrate a segmental arrangement (metamerism)
Innervated by spinal nerves
Axial muscle
Formed from embryonic mesenchyme asso. W/ pharyngeal arches
Demonstrate segmental arrangement (metamerism)
Innervated by CN
Branchiomeric
Formed from body wall or limb bud mesenchyme
Innervated by spinal nerves
Appendicular
Musculature of vertebrate body wall and tail make up:
Axial musculature
Dervied from embryonic somites
Axial musculature
Metamerism is evident in:
Fishes and in urodeles
Metamerism not as evident in :
Most tetrapods
Innervated by dorsal rami of spinal nerves
Epaxial musculature
Innervated by ventral rami of spinal nerves
Hypaxial musculature
Amniotes have hyaxial muscles ventral to transverse processes or organized into __________ bundles
Longitudinal
Mammalian diaphragm and cremaster muscles are:
hypaxial muscles
Arise originate from 3 pairs preotic somitomeres and are innervated by CN III, IV, and VI.
Muscles of the eyeball
Divided into extrinsic and intrinsic
Appendicular muscles
Originate from the axial skeleton and insert on girdle or limb
Extrinsic muscle
Originate from the girdle or proximal limb and insert more distally
Intrinsic muscle
Intrinsic muscles in tetrapods develop w/ in one ______
Limb
Develop from branchial arch
Branchiomeric muscles
1st brachial arch open and close jaws
mandibular arch
Muscles of first arch are innervated by which CN?
V
Derived from second brachial arch attach to the hyoid skelton lower jaw and operculum in fishes:
Hyoid arch
Depend primarily on powerful movement of the trunk and/or tail for locomotion
Fish
Trunk muscle of the fish are the _____ muscles
Axial
In craniates, hypaxial muscles extend into the ________ as hypobranchial muscles
Pharynx
In amniotes, hypaxial muscles extend forward into the _________
Tongue
Appendicular muscles in fishes are mostly ________
Extrinsic
Extrinsic muscles of tetrapods develop in one of 2 ways:
W/in the embryonic wall and spread to the limb
In the limb and spread to the axial skeleton
Innervated by the 7th CN
Sphincter colli of lower tetrapods spreads over head of amniotes
Second branchial arch - hyoid arch
Remaining arches (besides 1 and 2 branchial arches) operate gills in fishes and take on new functions in tetrapods These muscles are innervated by CN\_\_\_\_?
9 and 10.
_________ of fishes and urodeles gives rise to the trapezius and sternocleidomastoid of amniotes
Cucullaris
Segments that make up the axial musculature
Myomeres
Muscles are dervied from Semitic myotomes and exhibit a segmental arrangement:
Axial muscles
In gnathostomes, theyre typically divided into epaxial (more _______) and hypaxial(more _________) muscles
Dorsal; ventral
The number of myomeres corresponds w/ the number of ____________ but the spatial arrangement of the myomeres alternates w/ that of the __________
Vertebrae; vertebrae
Lateral view of a typical gnathostome fish myomere segmentation resembles what letter
W
“W” is the split btw what two structures in gnathostomes:
Upper portion[epaxial musculature]
Lower portion [hypaxial musculature]
Separates epaxial and hypaxial parts from each other
Horizontal septum
Individual myomeres are separated from each other by vertical CT
Transverse septa
Segmented portions of the fish axial musculature(2):
Myomeres
Myosepta
Axial musculature in fishes are major player in:
Locomotion
Includes: epaxial and hypaxial
Amphibian musculature trend from fishes to tetrapods:
Reduction in epaxial musculature. Most tetrapods use limbs for locomotion not epaxial musculature.
Division of hypaxial muscles into layers
Increase in mass and complexity of limb muscles
Urodeles and epaxial muscles
Still somewhat well-developed…these are salamanders… useful for swimming
Designed for flexing body back and forth for swimming
Dorsalis truncus
Divisions/Layers of muscles into layers:
Subvertebral,
Lateral flank,
Rectus abdominus
Opposes dorsalis truncus in nectarus
Subvertebral muscle
Muscle that becomes rectus cervcis in neck
Rectus abdominal
Muscles to pay attention to in nectarus:
Rectus abdominus and dorsalis truncus
Trend w/ muscle and reptiles/mammals:
Similar muscle arrangement to nectarus;
Except for division of epaxial muscles
Dorsalis trunucus in reptiles/mammals:
Division into 3 longitudinal columns:
Transversospinalis
Logissimus Dorsi
Iliocostalis
Hypaxial muscles in reptiles/mammals:
Similar to amphibian, division into 3 layers
Hypaxial muscles in reptiles/mammals:
Assist w/ breathing by raising and lowering ribs
-internal/external intercostals and subcostals
3 groups of back muscles:
Superficial, intermediate, deep
2 extrinsic muscles in back
Superficial and intermediate
Only intrinsic muscle in back:
Deep muscle
Respiratory muscles innervated by ventral rami. Serratus posterior group [inferior/superior]
Intermediate back muscle group
Connect limb to axial skeleton. Innervated by ventral rami. Or CN XI includes: Trapezius Lat. Dorsi. Levator scapulae Rhomboideus major/minor
Superficial back muscle group
True intrinsic muscles of the back are innervated by dorsal rami. 3 groups:
Superficial,intermediate, and deep.
Deep muscle group of back
Muscles are named base on ______________…they tend to migrate from embryo
innervation
Only epaxial muscle group of the back:
Deep-intrinsic b/c it is innervated by dorsal rami
Ex of true intrinsic back muscles:
Splenius capitis/cervicis-superficial
Iliocostalius, longissimus, spinalis-intermediate
Semispinalis, multifidus, rotatores- deep- fine movements of the vertebral column
Superficial intrinsic muscles make up the:
Spinotransversalis system
Spinotrnaversalis system run
Laterally and upward to attach to transverse processes and skull.
Intermediate intrinsic muscles make up the
Sacrospinalis system
Sacrospinalis system function:
Hold body upright
Erector spinae group
Runs straight up and down.
Deep intrinsic muscles make up the
Transversospinalis system
Transversospinalis system run:
Laterally and insert medically
Run from transverse process to transverse process
How many eye muscles?
6 eye muscles
Eye muscles are dervied from
3 pairs of anterior somites
And 3 pairs of CN that innervate
Innervates superior oblique muscle
Trochlear nerve (CN IV)
Innervates lateral rectus muscle
Abducens nerve CN VI
Innervates remaining 4 muscles: Inferior rectus, Medial rectus, Inferior rectus Inferior oblique
Oculomotor nerve CN III
Intrinsic muscle of eye function
Control diameter of pupil
Muscles of the gill arch region arise from __________ _________ not somites
Embryonic mesenchyme
Anterior muscle of gill arch in shark: striated or smooth?
Striated
Posterior muscle of gill arch in shark: striated or smooth?
Smooth
Why would the posterior muscles be smooth and not striated?
This reflects change from vigorous feeding movements for gill function to slower sustained movements for transport of food along gut tract….involuntary now..
Innervated by CN V: trigeminal nerve
Gill arch I - mandibular
Innervated by CN VII: facial nerve
Gill arch II- hyoid
Innervated by CN IX: glossopharyngeal nerve
Gill arch III
Innervated by CN X: vagus nerve
Remaining gill attaches (except: I, II, III)
Muscles of the gill arch of the shark:
Branchiomeric musculature of the shark
Vertebrates have varying aspects of development of muscle:
Different vertebrates muscles travel further distances from vertebrae
Nerve is dragged along w/ muscle during
Muscle migration…that’s why we name based on innervation.
Cranial nerves are associated w/ each of the :
Gill arches
Articulation occurs btw quadrate bone and articular bone
Temporomandibular joint of non-mammalian
Mammalian TMJ:
Synovial joint w/ articular disk.
Articular surfaces are the temporal bone and mandibular condyle.
Fate of articular and quadrate derives meckel’s cartilage
Quadrate becomes the
Incus in middle ear
Articular bone moves into middle ear and becomes
Malleus
What are the 2 fish Anatomy features lost in tetrapods?
Interarcuals
Coracobranchials
Muscles of mastication are innervated by:
CN V
Zygomatic bone to lateral surface of ramus and coronoid process
Elevates and protracts manible
Masseter
Temporal fossa and fascia to coronoid process
Elevates and retracts mandible
Grinding
Temporalis
Lateral pterygoid plate and sphenoid to front of mandible and TMJ
Protracts mandible; depresses chin
Bilateral- grinding(unilateral)
Lateral pterygoid
Lateral pterygoid plate and maxilla to medial surface of mandible near angle
Elevates, protracts, and grinding unilateral
Medial pterygoid
Adductor (lavator) mandibulae of nectarus is = to:
Temporalis and masseter
Fish anatomical features lost in tetrapods (2):
Interarcuals
Coracobranchials
CN for anterior digastric?
CN V