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Comparative Anatomy Exam 2 > Chapter 9: Appendicular Skeleton > Flashcards

Chapter 9: Appendicular Skeleton Flashcards

0
Q

Posterior

A

Pelvic girdle supporting pelvic fin or hind limb

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1
Q

Anterior

A

Pectoral girdle supporting pectoral fins or limbs

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2
Q

Ostracoderms

A

No paired appendages
Pectoral “spikes”, “lobes”, “folds”
Non-mobile
No skeleton associated with them

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3
Q

Origin of paired fins

A

•Gill arch theory -not really
>gill arches modified, cartilages moved to shoulder & became part of fin
•Fin-fold theory
>flaps of tissue get bone vs gill tissue and retain gills for respiration

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4
Q

Placoderms

A

1st paired appendages (fins)
Skeleton associated with them
“Prints” of muscle >mobile
Bony or cartilage fin rays

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5
Q

Fin skeleton

A 
Basal pterygiophores (most proximal, closest to body)
Radial pterygiophores (radiate out from basal) 
Fin rays (most dorsal)
  >ceratotrichia in sharks (cartilage)
  >lepidotrichia in bony fish 
*trichia = hair/thread
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6
Q

Fish Pelvic Girdle

A

Small and not attached to vertebrae

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7
Q

Fish Pectoral Girdle

A 
Large and attached to head
Dermal components:
1- clavicle
2- cleithrum
3- supracleithrum
4- post-temporal 
Replacement bones (from cartilage precursors): coracoid, scapula, suprascapula
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8
Q

Sarcopterygii

A

Basals and radials line up into fin and homologies w/ tetrapod limbs are clear
Muscles are no longer in body wall
Muscles extend down into the fin

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9
Q

Tetrapod pelvic girdle

A 
3 bones fused
  -ilium >cranial
  -ischium >caudal
  -pubis >ventral (usually) 
Trend toward firmer attachment to vertebral column via sacrum
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10
Q

Tetrapod pectoral girdle

A 
Dermal bone is less important 
Replacement bone (endochondral) more important 
Connection of pectoral girdle to skull broken
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11
Q

Appendicular skeleton trend

A

-early appendicular skeleton = dermal
-increase in sub-dermal elements; loss of dermal bone
Ex: humans have only one dermal bone in appendicular skeleton = clavicle

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12
Q

Fish vs Tetrapod appendages

A

Fish:
Uniform function, they only swim
Varied number and position of bones in limb

Tetrapods:
Varied function; run, walk, swim, crawl, burrow, hop, fly
Uniform structure

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13
Q

Fish to Amphibian

A
  • Tiktaalik to Labyrinthodont
  • Fins to limbs
  • Amphibians have weak limbs, splayed to the side
  • lateral “swimming” movements
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14
Q

Reptiles

A 
Strong limbs and girdles -sacrum
Most have splayed stance
Some have legs under body
  -synapsids
  -thecodonts
  -dinosaurs
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15
Q

Birds and mammals

A

Specializations

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16
Q

Tetrapod trends

A
  1. Reduction in # of limb elements
    - frogs fused radioulna, tibiofibula
    - birds tibiotarsus
    - loss of digits in deer, horse rhinoceros
  2. Disproportionate lengthening of limb elements
    - bat fingers (modified for flight)
    - horse foot
  3. Sub axial flexion
    - limbs held more under the body than splayed to the side
  4. Alteration of foot posture to lengthen limb
    >plantigrade, digitigrade, unguiligrade
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17
Q

Plantigrade

A

Heel, wrist touch ground

Primitive: humans, bears

18
Q

Digitigrade

A

Walk with heel and wrist above ground = cat, dog

19
Q

Unguiligrade

A

Walk on toe tips
Ex: horse, deer

Perissodactyl = odd # toes
Artiodactyl = even # toes
20
Q

Evolution of flight: Why did flight evolve?

A
  • to help escape from predators
  • to help catch prey
  • to help move efficiently
  • to free the hind legs for use as weapons
  • to gain access to new food sources or an unoccupied niche
21
Q

Muscle Homologies

A
  • use nerve to tell where muscle is coming from and going to
  • embryology
  • attachment similarity
  • function
22
Q

Function of muscles

A
  • move bones >locomotion
  • heat (endotherms)
  • keep internal organs functioning (cardiac & smooth muscle)
  • restrict space (abdominal muscle)
  • fight gravity (quadrupeds)
  • electric organs (eels)
  • protection
23
Q

Skeletal muscle

A

Striated
Multiple nuclei
Straight lines
Voluntary

24
Q

Smooth muscle

A

Pointed ends
Singular nuclei
Involuntary
Pod shaped

25
Q

Cardiac muscle

A 
Striated
Anastemosis
Intercalated discs 
  >division b/w s 
  >gap junctions -cell communication
26
Q

Sheaths

A
  • epimyseum (outermost layer that goes around each muscle organ)
  • perimyseum (middle layer that goes around fascicles)
  • endomyseum (innermost layer that goes around each muscle cell)
27
Q

Apopneurosis

A

Flat tendon made of sheathing at the distal end of a muscle

28
Q

Skeletal muscle at a microscopic/sub cellular level

A
  • Actin & myosin = 2 proteins that make up skeletal muscle for connection
  • sacromere
29
Q

Naming muscles

A 
1. Direction that fibers run
  Ex: external, internal, transverse obliques
2. Size
  Ex: vastus lateralis
3. Location
  Ex: vastus medialis
4. Number of divisions 
  Ex: biceps
5. Origin & insertion 
  Ex: xiphihumeralis
6. Action
  Ex: levator palatoquadrati
7. Shape
  Ex: trapezius
30
Q

Origin

A

Midline (body)
Proximal (limb, speed)
Stable (doesn’t move a lot)
Antagonistic pairs

31
Q

Insertion

A

Distal (strength)

Movable

32
Q

Muscle motions

A
  • adduct (move toward) / abduct (move away from)
  • flex (decrease angle) / extend (increase angle)
  • levator (elevate) / depress (lower)
33
Q

Embryology

A
  1. Axial
    •epaxial myomeres
    •hypaxial myomeres
    >epimere
  2. Hypobranchial
    •modified axials
    >epimere
  3. Appendicular
    >epimere
  4. Branchial
    •associated w/ gill slits
    >epimere
  5. Extrinsic eye muscles
    >epimere
  6. Cardiac
    >hypomere
  7. Smooth
    >hypomere
34
Q

Phylogeny of muscles: Agnatha

A 
Axial well-developed 
-no subdivision into epaxial, hypaxial
-segmentation (primitive trait)
No appendicular 
Hypobranchials, branchials = poorly developed 
Mouth muscles specialized
35
Q

Jawed fish

A 
Epaxial & hypaxial divisions
-segmented head to tail into myomeres 
Hypobranchial 
-pectoral girdle, branchial arches, jaw 
Appendicular 
-dorsal = abductors 
-ventral = adductors
36
Q

Evolutionary trends

A

Fish -> Tetrapod
Axial muscles less prominent
Loss of segmentation of axials
Remaining axial muscles more closely related to vertebral column
Appendicular muscles larger, more diverse
Branchial muscles repurposed

37
Q

Amphibians axial muscles

A 
Epaxial
-segmented, unspecialized; dorsalis trunci
Hypaxial = better developed, 3 groups 
1) subvertebral
    -small, ventral flexion, under vertebrae
2) rectus abdominis
3) lateral group
    -external oblique (hands in pockets)
    -internal oblique (opposite)
    -transverse abdominal (horizontal)
38
Q

Amphibians new muscles: appendicular

A 
Pelvic 
-small
Pectoral
-more complex, larger
-connection to head is gone (more space for muscles)
39
Q

Reptiles, mammals muscles

A

Epaxial (from lateral to medial)

  • iliocostalis (costalis = rib)
  • longissimusdorsi (cat- erector spinae)
  • transversospinalis (cat- multifidi)

Hypaxial

  1. Subvertebral
    • reduced
  2. Rectus abdominis
    • doesn’t insert on pectoral girdle
  3. Lateral group
    • abdominal (same)
    • chest; ribs (new)
40
Q

Tetrapods appendicular muscles

A 
Sources:
-branchial (ex: trapezius from cucullaris)
-axial (ex: serratus anterior)
-from fish appendicular 
  •dorsal mass 
   >forelimb (latissimus dorsi, triceps)
   >hindlimb
  •ventral mass
   >forelimb (pectoralis, biceps)
   >hindlimb (adductor femoris, hamstrings, biceps femoris, gracilis)
-remember rotation of elbows & knees 
-far greater subdivision of Tetrapod vs. fish muscles
41
Q

Branchial = Tetrapod derivatives

A

Jaw muscles, 1st and 2nd pharyngeal arches
Ear muscles
Shoulder, head >ex: trapezius
Larynx, throat muscles

42
Q

Cutaneous muscles

A 
*under skin
Rare in reptiles 
Most common in mammals 
Platysma of neck
  -diversifies into facial muscles to move lips, ears
  -chewing, communication, expression
43
Q

Specialization: Flight

A

Supracoracoideus muscle: like a pulley for easy upstroke w/ small muscle

Pectoralis muscle: huge, originates on keel of sternum for powered downstroke when contracts

Comparative Anatomy Exam 2 (5 decks)

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