Post-Cranial Skeleton Flashcards

1
Q

post cranial skeleton (2)

A
  • axial skeleton

- appendicular skeleton

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2
Q

axial skeleton (4)

A
  • vertebral column
  • notochord
  • ribs
  • sternum
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3
Q

appendicular skeleton (2)

A
  • paired fins or limbs

- girdles

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4
Q

neural arch

A
  • protects spinal cord
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5
Q

hemal arch

A
  • protects blood vessels/dorsal aorta
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6
Q

processes

A
  • spine, zygapophyses, diapophyses

- provide sites for muscle attachment or specialized regions for articulation with other skeleton elements

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7
Q

agnatha vertebral column (3)

A
  • large and prominent notochord
  • hagfish do not have vertebrae
  • petromyzontida have cartilaginous vertebra consisting of small neural arches on the dorsal surface of the notochord; no centra or hemal arches
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8
Q

chondrichthyes vertebral column (3)

A
  • cartilaginous vertebral column
  • each vertebra has a centrum
  • centra provide major axial structural support for body and surround the notochord
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9
Q

actinopterygii vertebral column (3)

A
  • ossified endochondral bone
  • centra provide major axial support for the body and surround the notochord
  • large neural spines and ribs provide sites for muscle attachment
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10
Q

sarcopterygii vertebral column (2)

A
  • ANCESTRAL: ossified (endochondral bone) and had centra surrounding notochord
  • EXTANT: centra reduced or secondarily lost; neural and hemal arches rest on large and prominent notochord
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11
Q

tetrapoda vertebral column (2)

A
  • solid centra that does not surround the notochord

- composed of ossified (endochondral bone) and provides axial structural support for the body

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12
Q

notochord presence in: (2)

- chondrichthyes

A
  • hollow centra that notochord passes through

- notochord thickens to provide a pad between each vertebrae

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13
Q

notochord presence in: (2)

- actinopterygii

A
  • hollow centra that notochord passes through

- notochord thickens to provide a pad between each vertebrae

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14
Q

notochord presence in: (2)

- tetrapods

A
  • articular ends of centra capped with intervertebral bodies/pads
  • intervertebral bodies composed of cartilage/fibrous connective tissue
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15
Q

notochord presence in: (2)

- mammals

A
  • articular ends of centra capped with pads called intervertebral disks
  • composed of cartilage, fibrous connective tissue, and notochord remnants
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16
Q

what is the purpose of intervertebral disks

A
  • cushion between vertebrae to assist in shock absorption
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17
Q

which taxa has a regionalized vertebral column

A
  • gnathostomes
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18
Q

vertebral column regionalization: chondrichthyes

A
  • two regions: trunk and caudal
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19
Q

vertebral column regionalization: actinopterygii

A
  • two regions: trunk and caudal
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20
Q

vertebral column regionalization: sarcopterygii

A
  • two regions: trunk and caudal
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21
Q

how do trunk and caudal vertebrae differ? (2)

A
  • trunk: rib attachment sites, only have neural arch/spine

- caudal: hemal arch/spine and neural arch/spine

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22
Q

notochord/vertebral column main function

A
  • lateral undulations
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23
Q

lateral undulations (2)

A
  • alternating contractions of muscles on each side of body produce that provide propulsive force to push the body froward
  • notochord/vertebral column serve as a firm, but flexible rod that axial muscles pull from side to side to bend body, moving tail back and forth
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24
Q

which taxa use notochord to produce lateral undulations (3)

A
  • sarcopterygii
  • petromyzontida
  • myxinoidea
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25
Q

which taxa use the vertebral column to produce lateral undulations (3)

A
  • actinopterygii
  • tetrapoda
  • chondrichthyes
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26
Q

appendicular skeleton: agnathans

A
  • do not have appendicular skeleton
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27
Q

appendicular skeleton: gnathostomes

A
  • paired fins or limbs and girdles
28
Q

which taxon have appendicular skeleton consists of paired fins and girdles (3)

A
  • chondrichthyes
  • actinpterygii
  • sarcopterygii
29
Q

paired fin composition (2)

A
  • proximal regions: fins are supported by relatively thick sturdy skeletal elements
  • distal regions: fins are supported by thin ray fins; chrondrichthyes have keratin ray fins
30
Q

girdles (3)

A
  • attachment sites for muscles of the appendages
  • stabilize the appendages by bracing them against the body
  • must be braced by attachment to another skeletal structure or by embedding in muscles
31
Q

pectoral girdle attachment

  • actinopterygii
  • sarcopteryigii
  • chonrichthyes
  • tetrapods
A
  • actinopterygii and sarcopteryigii:: attached to the dorsal, posterior region of the skull
  • chonrichthyes: does not attach to the skull or vertebral column; embedded in the muscle of the body wall
  • tetrapods: loss of girdle attachment to the skull; axial skeleton is suspended from girdle by muscles
32
Q

pelvic girdle attachment

  • actinopterygii
  • sarcopteryigii
  • chonrichthyes
  • tetrapods
A
  • actinopterygii, sarcopteryigii, chonrichthyes: pelvic girdle does not attach directly to vertebral column; embedded in the muscles of the body wall
  • tetrapods: pelvic girdle fused to sacral region of vertebral column
33
Q

what is the result of lateral undulation in aquatic environments (4)

A

propulsion from lateral undulations of tail produces thrust that propels the body forward; but it can also cause:

  • pitch
  • yaw
  • cause rolling of animal
34
Q

pitch

A
  • shift the angle of the head dorsally or ventrally
35
Q

yaw

A
  • wag the head left and right
36
Q

paired fin function: chondrichthyes (3)

A
  • provide stability during locomotion by preventing roll, pitch and yaw
  • active adjustment of angle for steering, allowing shark to control direction while swimming
  • claspers
37
Q

claspers (2)

A
  • on pelvin fins

- act as intromittent organs: they transfer sperm to the female during copulation for internal fertilization

38
Q

paired fin function: actinopterygii (4)

A
  • used for stabilization (minimize roll, pitch, yaw) while swimming using lateral undulations of tail for propulsion
  • are used for steering when swimming
  • are used to maintain body position in the water when stationary and for braking
  • used for propulsion in some; very precise and slow
39
Q

teleotomi: ray fins (2)

A
  • actinopterygii

- thin layer of skin and connective tissue supported by slender fin rays of bone or cartilage

40
Q

teleostomi: fleshy fins (4)

A
  • sarcopterygii
  • fins supported by series of bones that articulate using mobile joints; muscles that move these bones extend into the fin
  • distal ends usually have fin rays supporting a thin layer of skin and connective tissue
  • advantage: highly maneuverable; used for precise swimming, pivoting and maneuvering in shallow waters, holding position on bottom habitats in deep water, walking along bottom surfaces
41
Q

fin rays (2)

A
  • found in chondrichthyes, actinopterygii and sarcopterygii

- increase surface area of fin, making it better for pushing/propelling against water

42
Q

support of weight: aquatic vertebrates

A
  • body is evenly supported by water all around them (buoyancy), so skeleton does not play major role in supporting body weight
43
Q

support of weight: terrestrial vertebrates (2)

A
  • skeleton is crucial for supporting body weight
  • to support body against gravity, terrestrial animals: rest ventral body surface on the ground OR use the legs as pillars to hold up the body
44
Q

how did the girdles and paired appendages change from sarcopterygii to tetrapods (2)

A
  • were enlarged and became more completely ossified

- done to increase support for animal body weight and make it sturdier

45
Q

how did the thin fin rays change from sarcopterygii to tetrapods (2)

A
  • thin fin rays supporting distal tips of fins were replaced with digits
  • better weight support; better balance and mobility
46
Q

how did the pectoral girdle attachment change from sarcopterygii to tetrapods (2)

A
  • lost attachment to the skull and became suspended by muscles
  • more flexibility and better locomotion
47
Q

how did the pelvic girdle attachment change from sarcopterygii to tetrapods (3)

A
  • fused to the sacral region of the vertebral column
  • reinforced and strengthens structures so they can withstand powerful forces generated by hind limbs
  • propulsive force generated by hind limbs is transmitted more efficiently to axial skeleton, propelling entire body forward
48
Q

what changees occurd from sarcopterygii to tetrapods (4)

A
  • girdles and appendages enlarged and completely ossified
  • thin fin rays replaced by digits
  • pectoral girdle lost attachment to skull
  • pelvic girdle fused to sacral region of vertebral column
49
Q

sprawled limb posture (3)

A
  • sauropods (except aves) and amphibians
  • rest ventral body surface on ground when stationary so vertebral column doesn’t need to bridge weight of the bofy
  • during locomotion, they must use limbs to support body weight
50
Q

erect limb position

A
  • most mammals and birds (aves)

- use limbs as pillars to support the body weight during locomotion and when stationary

51
Q

the stable arch (3)

A
  • quadrapedal mammals
  • vertebral column acts as bridge that transfer weight of internal organs to the legs
  • epaxial muscles that attach to neural spines of vertebrae help pull vertebral column into an arch, stabilizing so it can effectively bridge weight to limbs without sagging
52
Q

vertebral column regionalization: tetrapods

A
  • 4 regions: caudal, sacral, trunk, cervical
53
Q

vertebral column regionalization: amniotes

A
  • 5 regions: cervical, thoracic, lumbar, sacral, caudal
54
Q

cervical region

A
  • differentiated for cranial mobility

- in amniotes, additional cervical vertebrae further increase neck flexibility (more mobile joints)

55
Q

sacral region (2)

A
  • differentiated for attachment of pelvic girdle
  • some have single sacral vertebrae, where others have 2+ that fuse and form a sacrum for increased strength and durability
56
Q

how to differentiate between thoracic and lumbar vertebrae

A
  • thoracic vertebrae will have processes for rib attachment
57
Q

synsacrum

A
  • birds
  • sacral, lumbar and several thoracic and caudal vertebrae fuse together to form the synsacrum
  • fuses with pelvic girdle, producing a strong and stable platform to support the body during flight and to withstand the forces of landing
  • strong, but relatively light in weight
58
Q

cervical vertebrae of mammal

A

7 :

  • 1 axis
  • 1 atlas
  • 5 regular
59
Q

atlas (4)

A
  • in tetrapods
  • most anterior vertebrae
  • does not have a centrum
  • articulates with occipital bones of the skull, allowing the skull to rock in a nodding motion
60
Q

axis (3)

A
  • in amniotes
  • second most anterior vertebrae
  • has an odontoid process: an anterior projection that inserts into the neural canal of the atlas, allowing the head to turn from side to side
61
Q

zygopotheses (3)

A
  • tetrapod vertebrae
  • interlocking structures help to prevent twisting (torque) of vertebral column to prevent damage to spinal cord
  • postzygapophyses of vertebra articulate with prezygapophyses of posterior vertebrae
62
Q

postzygapophysis (2)

A
  • articulates on dorsal side and projects posteriorly

- “high five”

63
Q

prezygapophysis (2)

A
  • articulates on ventral side and projects anteriorly

- “low five”

64
Q

sternum (2)

A
  • composed of cartilage/endochondral bone

- only in tetrapods; however, it is the result of convergent evolution

65
Q

sternum: aves (2)

A
  • has a large keel for attachment to flight muscles

- in flightless birds, the keel tends to be reduced in size compared to flying birds

66
Q

ribs

A
  • gnathostomata
  • composed of cartilage or endochondral bone
  • protect vital and delicate internal organs
67
Q

ribs: amphibians

A
  • ribs do not articulate with sternum