Muscles Flashcards

1
Q

When a myofiber is damaged it is replaced by ___________, but when the muscle grows it increases in_______________.

A). Scar tissue, myofiber
B). Myofiber, Myofiber
C). Scar tissue, myofibrils
D). Myofiber, myofibrils

A

C). Scar tissue, Myofibrils

Scar tissue fills in the crack, it is a non-contractile fibrous connective tissue

Myofibrils - increase in myofibrils increases the mass of the muscle but the amount of myofiber is never increased

Myofiber is synonymous with muscle cell

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2
Q

A muscle fiber contracts slowly, is innervated by more than one nerve cell but cannot propogtate an action potential, what type of muscle fiber is it? What type of vertebrate is it found in?

A). Tonic fiber, all vertebrates
B). Tonic fiber, all but Mammals
C). Phasic fiber, all vertebrates
D). Phasic fiber, all but Mammals

A

B). Tonic fibers, all but mammals

Tonic fibers:
Found in non-mammalian vert.
Slow, sustained posture activities
Single nerve cell innervates many fibers but each fiber is innervated by more than one nerve cell
Contract slowly but do not propagate an action potential

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3
Q

What are the 3 types of skeletal muscle?

A

Axial, Braniomeric and Appendicular

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4
Q

Axial subs into epaxial and hypaxial, what are each innervated by?
Why is it important to know what innervates the axial muscles?

A

Epaxial is innervated by dorsal rami of the spinal nerves

Hypaxial is innervated by ventral rami of the spinal nerves

It’s important because the innervation is how you tell which muscle is epaxial and which is hypaxial

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5
Q

Where is Axial muscle derived from? What’s it’s defining characteristic?
(Hint: chordata character)

A

Embryonic somites

Metameric

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6
Q

What are Myomeres? In what organism are myomeres found? Why does this organism use them for? How are they arranged and split?

A

Myomeres derive from the myotome of somites, they are segments of axial musculature. They are found in fish, who use it for locomotion - swimming - their trunk muscles.

In gnathostomes the axial mytomes are split into hypaxial and epaxial.

Epaxial is the upper portion and are seperated from hypaxial by horozontal septum. -not cyclostomes
Hypaxial is the lower portion and are separated by transverse septa- which seperates entire myotomes.

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7
Q

What is characteristic of the transition from fish to tetrapods in terms of epaxial Musculature?

A

A reduction in epaxial musculature is see in tetrapods. This is because (most) tetrapods rely on their limb for locomotion rather than their trunks.

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8
Q

Axial muscle of Amphibians

-epaxial and hypaxial

A

Salamanders, necturus, still retain epaxial muscle because they do a lot of living in water so it is still needed for locomotion.

Limb muscles see an increase in mass and complexity

Hypaxial muscle functionally specializes/divided into layers:
-subvertebral
-lateral flank muscle: external oblique, internal oblique and
transversus
-Rectus abdominus (our ‘abs’)

(Have more hypaxial muscle that is divided and speacialized and less epaxial mucsle than fish but still more epaxial muscle than other tetrapods and less specialized hypaxial muscle.)

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9
Q

Axial muscle in Amniotes

-reptiles and mammals

A
Segmented epaxial: 
     -Dorsalis truncus: arranged longitudinally 
           \+ Spinalis
           \+ Longissimus
           \+ Iliocostals 
     -quadrate lumborum: paired. 

Segmented hypaxial:
-External and Internal obliques (intercostals)
+ Disrupted by ribs in the thoracic area, assist in breathing
By raising and lowering the ribs. -> why they are called
Intercostal muscles
-Transversus (subcostals)
-Rectus abdominus

Epaxial muscle is reduced in Turtles

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10
Q

What is the general trend(s) observed in the complexity of Axial muscles in the evolution of fish to amphibians to amniotes?

A

A general reduction in epaxial muscle.

In amphibians the hypaxial muscle is segmented

In amniotes (reptiles and mammals) both epaxial and hypaxial muscle is segmented. W/ particularly reduced expansion musculture in Turtles.

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11
Q

What are the subdivisions of mammalian back muscles and how are the instrinsic muscle(s) further subdivided?
How are they innervated?

A

Superficial
Intermediate
-Extrinsic
-Hypaxial: innervated by ventral rami
Deep
-intrinsic
-epaxial: innervated by dorsal rami

Deep intrinsic subgrouping:

  - Superficial intrinsic  
  - Intermidiate intrinsic
  - Deep intrinsic
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12
Q

These CN’s innervate which eye muscles?

Trochlear Nerve (CN IV)
Abductens Nerve (CN VI
Oculomotor Nerve (CN III)
A
Trochlear Nerve (CN IV)
       -superior oblique
Abductens Nerve (CN VI)
       -Lateral rectus
Oculomotor Nerve  (CN III)
      -inferior rectus
      -medial rectus
      -superior rectus
      -inferior oblique
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13
Q

These extrinsic muscles of the eye are innervated by which CN’s?

Superior Oblique
Inferior Oblique
Superior Rectus
Medial Rectus
Inferior Rectus
Lateral Rectus
A

Superior Oblique - Trochlear Nerve (CN VI)

Inferior Oblique - Oculomotor Nerve (CN III)

Superior Rectus - Oculomotor Nerve

Medial Rectus - Oculomotor Nerve

Inferior Rectus - Oculomotor Nerve

Lateral Rectus - Abductens Nerve (CN VI)

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14
Q

Branchiomeric Musculature

-What are it associations and CN innervations?

A

Branchiomeric Musculature is associated with the pharengeal gill arches.

Each gill arch is innervated by a cranial nerve.

Embroyonically arises from Mesenchyme.

Gill Arch I: Mandibular Arch - innervated by CN V
-trigeminal nerve
Gill Arch II: Hyoid Arch - Innervated by CN VII
-facial nerve
Gill Arch III: innervated by CN IX
-Glossopharyngeal nerve via Herring’s nerves
Remaining Gill Arches are innervated by the Vagus Nerve which is CN X

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15
Q

What are the muscles of mastication, what are their functions and what is their innervation?

A

Massenter - elevates and protracts mandible
temporalis - elevates and retracts mandible
Lateral pterygoid -portraits mandible, depresses chin. Grinding teeth
Medial pterygoid - elevates, protracts and grinding of teeth.
-innervated by CN V
-grinding is a unilateral motion.

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16
Q

Why is the anterior digastric muscle in mammals double innervated?

A

because it is derived from 2 pharengeal arches

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17
Q

What are the four types of muscle?

A

Skeletal - striated and typically voluntary. Nuclei peripheral and cells multinucleated

Smooth - spindle-shaped mononucleated cells with central nuclei

Cardiac - striated and involuntary, chains of cells that are mononucleated. Intercalated discs

Branchiomeric - associated with pharyngeal arches and innervated by cranial nerves.

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18
Q

What are tendons?

A

Attachments between muscle fibers and bone

They are dense collagen fibers and dense collagenous connective tissues

Poorly vascularized and surrounded by peritendineum

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19
Q

Describe the structure of skeletal muscle including connective tissue supports (like membranes).

A

Myofibers made of Myofibrils, myofibrils are made of myofilaments.

Myofibers covered in endmysium

Myofibers bundle into Fascicles

Fascicles covered in perimysium

A group of fascicles is the muscle

Muscle coved with epimysium

20
Q

List the differences between dark slow fibers and light fast fibers?

A

Dark

  • fatigue resistant
  • Contracts slowly
  • Lots of mitochondria
  • Lots of myoglobin
  • Little ATPase

Light

  • fatigues easily
  • Contracts rapidly
  • Uses glycolysis
  • Little mitochondria
  • Little myoglobin
  • Lots of ATPase
21
Q

What are Phasic fibers?

A

In all vertebrate groups

Not multiply innervated

Do not propagate action potential

22
Q

What are Tonic fibers?

A

In all non-mammalian vertebrates

Used in slow, sustained postural activities

Single nerves cell innervates many fibers but each fiber is innervated by more than one nerve cell

Does not propagate an action potential

23
Q

Isometric vs Isotonic

A

Isometric contraction do not change muscle length

Isotonic contractions either shorten or lengthen muscles. Eccentric = longer, Concentric = shorter

24
Q

What ways are muscles named?

A

Function, Shape, Size, Origin and Insertion, Fiber arrangments and location of muscle

25
Q

How can fibers be arranged in a muscle?

A
Fulsiform 
Straight 
Unipennate 
Bipennate
Multipennate
26
Q

If the biceps is the agonist, what is the antagonist?

A

Triceps would be the antagonist

27
Q

What’s a synergist? What’s a fixator?

A

A synergist eleminates any unwanted movement by the agonist

A fixator stablizes the base of attachment of the agonist.

28
Q

Flexors pass the axis of the joint on the ___________ side.

extensors pass on the ___________ side of the joint.

Abductors pass _________ to a joint.

A

Flexors: anterior

Extensors: posterior

Abductors: lateral

29
Q

what is active insufficiency?

A

Involves a diminished ability of a muscle to produce or maintain active tension

Doesn’t occur on one-joint muscles

30
Q

What is passive insufficiency?

A

When the inactive antagonist muscle is not long enough to allow a force to complete a full range of motion.

Seen in multi-joint muscles.

31
Q

Define extrinsic muscles

A

Muscles that arise on the axial skeleton or trunk fascia and insert on the girdle or limb

Development from blastemas within body wall

32
Q

Intrinsic muscles

A

Muscles that arise on a girdle or limp element and insert more diastally

Develop from blastemas from within the limb (somites)

33
Q

What are some examples of extrinsic muscles?

A
Latissmus dorsi 
Elevator scapulae 
Serratus ventralis
Rhomboideus
Trapezius
Sternomastoid
Cleidomastoid
34
Q

What are some intrinsic muscles?

A
Biceps and Tricepts
Digit extensors and flexors 
Gluteal complex
Quadriceps complex 
Hamstrings
35
Q

What are the pectoral muscles? Dorsal groups

A
Dorsal Group - Extrinsic 
Latissimus dorsi 
Lavatory scapulae 
Rhomboideus
Serratus ventralis 
Trapezius
36
Q

What’s the pectoral complex, components of the pectoral muscles?

A

Pectoral complex originates from the thoracic cage and sternum and inserts on the humerus

Components: pectoralis major, pectoralis minor, pectoralis descendent and Xiphihumeralis

37
Q

What are the trends in the evolution of pectoral muscles?

A

Trends in evolution: increase in size of latissimus dorsi
Increase in size of pectoralis complex
Supracoracoideus of amphibians and reptiles and in mammals it’s the supraspinatus and infraspinatus.

38
Q

What muscles are in the ventral group of pectoral muscles?

A

Pectoralis and supracoracoideus

  • intrinsic in mammals
  • flight in birds
39
Q

What are the muscles of the scapular sling?

A

Serratus ventralis
-anterior
Lavatory scapulae
Rhomboids

40
Q

Names the rotator cuff muscles: SITS

A

Supraspinatus
Infraspinatus
There Minor
Subscapularis

41
Q

Deltoid complex

A

Composed of:
Scapulodeltoid
Procoracohumeralis (teres minor in mammals)
Supracoracoideus (suprasinatus and infraspinatus in mammals)

Deltoid complex evolved to compose most the rotator cuff muscles

Arm abductor
Pectoral girdle -> humerus

42
Q

Name the muscle(s) and function in the posterior gluteal compartment and the anterior gluteal compartment

A

Posterior gluteal compartment:
Gluteus maximus
-hip extension and lateral rotation
-rising, climbing and running (not walking)

Anterior gluteal compartment:
Gluteus medius and gluteus minimus (same muscle but separated by a nerve) Tensor fascia latae
-hip abduction with free swinging limb

43
Q

Muscles of the Pelvic and Thigh

Abductors? 
Thigh flexors?  
Leg extensors? 
Components and derivation of the obturator foramen? 
Adductors? 
Thigh extensors and shank flexors?
Shank extensors?
A

Abductors of thigh: gluteal complex
-iliofemoralis in reptiles

Quadriceps complex:
Thigh flexor - rectus femoris in mammals and iliotibialis in reptiles
Leg extensors - rectus femoric, vasti and in reptiles: femorotibialis

Obturator foramen

  • obturator internus
  • obturator external
  • Quadratus femoris
  • Piriformis

Thigh adductors

  • in mammals: a complex - adductor brevis, longus and magnus
  • in reptiles: adductor femoris
Thigh extensors and shank flexors
-Gracillis: mammals 
-pubioischiotibialis: reptiles 
Semitendinosus and semimembranosus: tibialis externus and internus (reptiles)
Biceps femoris: mammals 

Shank extensors:
-Mammals: quads: rectus femoris, vastus lateralis, vastus medialis and vastus intermedius
Reptiles: iliotibialis and femorotibialis

Sartorius (mammals) = ambient (reptiles)

44
Q

Muscles of posterior leg

A

Deep:
Popliteus
Flexor hallucis longus
Tibialis posterior

Superficial
Medial and lateral gastrocnemius
Soleus

45
Q

Anterior Leg muscles

A

Tibialis anterior
Extensor digitorum longus
Peroneus tertius
Extensor hallucis longus

46
Q

Later leg muscles

A

Peroneus longus

Peroneus brevis