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Comparative Anatomy > Skeletal System 2: The Skull and Appendicular Skeleton > Flashcards

Skeletal System 2: The Skull and Appendicular Skeleton Flashcards

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1
Q

What are the two main types of skeleton?

A

Exoskeleton

Endoskeleton

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2
Q

What is the Exoskeleton?

A

Within the integument

  • Keratinised exoskeleton (from epidermis)
  • Bony exoskeleton (from dermis)
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3
Q

What is the endoskeleton?

A

Deep within the body

  • Bony endoskeleton
  • Cartilaginous endoskeleton
  • Notochord
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4
Q

What are the two subdivisions of the skeleton?

A

Cranial skeleton

Postcranial skeleton

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5
Q

What is the cranial skeleton?

A

Splanchnocranium

Chondrocranium

Dermatocranium

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6
Q

What is the postcranial skeleton composed of?

A

Axial skeleton
- Vertebral column
- Notochord

Appendicular skeleton
- Limbs
- Girdle

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7
Q

What is the axial skeleton composed of?

A

Vertebral column

Notochord

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8
Q

What is the appendicular skeleton composed of?

A

Limbs

Girdle

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9
Q

What is dermal bone?

A

“Intramembranous”

Osteoblasts deposit bone superficially

Much of jaws, gills, shoulder girdle, fin rays, most ‘flat’ skull bones

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10
Q

What is endochondral bone?

A

Cartilage ‘model’ is replaced by bone

Often multiple centres

Most postcranial (internal) skeleton, much of chondrocranium

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11
Q

What is the splanchnocranium?

A

Part of the cranium (skull)

Most ancient component, arose to support the pharyngeal (‘gill’) slits in protochordates

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12
Q

What is the chondrocranium?

A

Part of the cranium

Underlies and supports the brain; composed of bone and/or cartilage

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13
Q

What is the dermatocranium?

A

Part of the cranium

Contributes to the outer casing and dermal bones of the skull

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14
Q

What does splanchnocranium do in vertebrates?

A

Support gills via branchial arches and attachment for respiratory muscles

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15
Q

What does splanchnocranium do in Gnathostomes?

A

Contributed to jaws and hyoid apparatus; supports floor of mouth and functional gills or tongue

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16
Q

What are some of the features of the splanchnocranium?

A

Mandibular Arch

Meckel’s cartilage

Palatoquadrate

Hyoid arch

Hyomandibula

Pharyngeal slits

Branchial arches

Pharyngobranchial

Epibranchial

Ceratobranchial

Hypobranchial

Basibranchial

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17
Q

What is the chondrocranium in vertebrates?

A

Primarily an embryonic structure supporting developing brain and sensory capsules

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18
Q

What do elements of the chondrocranium appear to do?

A

Lie in series with bases of vertebrae

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19
Q

What is the chondrocranium like in sharks?

A

Elasmobranchs

Expanded and enveloping, supports and protects the brain.

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20
Q

What are the three main parts of the chondrocranium?

A

Sensory capsules etc.

Ventral plates

Other parts

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21
Q

What do the sensory capsules etc of the chondrocranium consist of?

A

Nasal capsule

Trabecular

Optic capsule

Polar cartilage

Otic capsule

Parachordal

Occipitals

Notochord

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22
Q

What do the ventral plates of the chondrocranium consist of?

A

Ethmoid plate

Basal plate

Occipital arch

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23
Q

What do the other parts of the chondrocranium consist of?

A

Ethmoid

Sphenethnoid

Basisphenoid

Basioccipital

Supraoccipital

Exoccipital

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24
Q

What is the function of dermatocranium?

A

Forms sides and roof of skull to complete the bony case around the brain

Forms the bony lining of the mouth, encases the splanchnocranium

Supports the teeth inside the mouth (e.g. fish and frogs)

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25
What is the dermatocranium derived of in integument of early fish?
Derived from the dermal bony armour in integument of early fish
26
What does the dermatocranium consist of?
Facial series Orbital series Vault series Temporal series Palatal series
27
What are some bones of the splanchnocranium?
Branchial arches Hyomandibula Palatoquadrate Meckel's cartilage
28
What are some bones of the chondrocranium?
Sensory capsules (nasal, optic, otic, etc.) Ethmoid Sphenoids Occipitals etc.
29
What are some of the bones of the dermatocranium?
Premaxilla Maxilla Nasal Frontal (orbital) Parietal/postparietal Quadrate Jugal Squamosal Temporal Vomer Palatine Pterygoid Jaw: - Denture - Articular - Angular - Coronoids - Splenial etc.
30
What is Gnathostomata?
Jaw Gnatho = Jaw Stomata = Mouth
31
How do sharks feed?
Hyoid arch (hyomandibula and ceratohyal) swing mandibular arch = Jaws (Palatoquadrate and Meckel's cartilage) move forward as the head retracts
32
What's another word for bony fish?
Osteichthyes
33
How do bony fish feed?
Suction feeding common/ancestral Coordinated motions of gill (opercular), 'shoulder' (pectoral), hyoid, jaw bones to change volume of mouth Huge diversity (teleosts)
34
What do we know about Teleostei?
>26,000 species Mobile premaxilla = novelty "Four bar linkage" - skull kinesis Cousins = Holostei (gars, bowfin) and more distant relatives Cladistia (bichirs, reedfishes)
35
What are the two major living groups of Tetrapoda?
1. Lissamphibia 2. Amniota
36
What are Lissamphibian skulls like?
Simplified due to dermal bone loss or fusion into composite bone (absent: Operculars, jugals, etc.)
37
How do lissamphibians feed?
On land use sticky projectile tongue Muscles catapult tongue over mandibles to prey Retraction of tongue returns food to mouth; teeth complete kill/swallow whole Suction feeding in water possible when floor of throat rapidly expands
38
What are the four types of amniote skulls?
Anapsid - Squamosal bone - Postorbital bone - Orbit - No temporal fenestrae Synapsid - Squamosal bone - Temporal fenestra in between Sq and Po - Post orbital bone - Orbit Diapsid - Squamous bone - Supratemporal fenestra (upper opening) between Sq and Po - Infratemporal fenestra (lower opening) between Sq and Po - Post orbital bone - Orbit Euryapsid - Squamous bone - Supratemporal fenestra (upper opening) between Sq and Po - Post orbital bone - Orbit
39
What are the major bones around fenestrae in Amniote skulls?
Quadratojugal Jugal Squamosal Parietal Postorbital
40
Describe anapsid amniote skull structure
- Squamosal bone - Postorbital bone - Orbit - No temporal fenestrae
41
Describe synapsid amniote skull structure
Synapsid - Squamosal bone - Temporal fenestra in between Sq and Po - Post orbital bone - Orbit
42
Describe diapsid amniote skull structure
- Squamous bone - Supratemporal fenestra (upper opening) between Sq and Po - Infratemporal fenestra (lower opening) between Sq and Po - Post orbital bone - Orbit
43
Describe euryapsid amniote skull structure
- Squamous bone - Supratemporal fenestra (upper opening) between Sq and Po - Post orbital bone - Orbit
44
How did the amniote skull evolve?
Anapsid then Synapsid - Modified synapsid mammal Diapsid - Modified diapsid bird - Modified diapsid lizard - Modified diapsid snake - Modified anapsid testudines (emargination) - Euryapsid Modified anapsid testudines (emargination)
45
What are the jaw muscle components of primitive amniotes?
Dermatocranium Neurocranium Temporal muscle Lower jaw Palate
46
What are the jaw muscle components of Terapsids?
Dermatocranium Neurocranium Temporal muscle Temporal fenestra Zygomatic arch Palate Lower jaw
47
What are the jaw muscle components of mammals?
Dermatocranium Neurocranium Temporal muscle Temporal fenestra Zygomatic arch Palate Lower jaw
48
What is cranial kinesis?
Movement of skull bones beyond the jaw hinge
49
What is cranial kinesis in reptilia?
Extensive motion in snakes and lizards Most snakes and lizards have quadrate bone with some rotation: Streptostyly Naming depends on position of jaw hinge
50
What is metakinesis?
Joint or flexible movement between the dermatocranium (skull roof) and the neurocranium (braincase)
51
What is mesokinesis?
Moveable joint in the middle of the skull, typically between the frontal and parietal bones
52
What is prokinesis?
Moveable joint at the front of the skull, typically between the nasal bones and the frontal bones Allows beak to move independent of the brain/skull
53
What is Streptostyly
Quadrate bone (connects jaw to skull) is moveable Jaws can open wider Think snakes!!!
54
What are the bones in the skull?
Quadratojugal Squamosal Parietal Postorbital Postfrontal Frontal Prefrontal Lacrimal Nasal Maxilla Premaxilla Jugal
55
What are the tetrapod ear/jaw trends?
Early tetrapods: Stapes robust; buttresses braincase and palatoquadrate Lissamphibians: Splanchnocranium reduced; hyomandibula not involved in jaw suspension; used in hearing = stapes (middle ear) conveying vibrations to inner ear Jaw suspension taken over by articular and quadrate bones (metautostyly) Mammals: Fossil record shows transition to temporal-dentary jaw joint (Craniostyly)
56
What is the ear/jaw trend for early tetrapods?
Stapes robust; buttresses braincase and palatoquadrate
57
What is the ear/jaw trend for lissamphibians?
Splanchnocranium reduced; hyomandibula not involved in jaw suspension; used in hearing = stapes (middle ear) conveying vibrations to inner ear
58
What is the ear/jaw trend for mammals?
Jaw suspension taken over by articular and quadrate bones (metautostyly)
59
What is the bird skull trend in birds after evolution from primitive amniote?
Reduction in number of bones Expanded premaxilla/beak
60
What are the main differences of bird skulls?
Bones contain air (light!) Jugal bar = like cheekbones Quadrate = fused to the skull, limits movement Skull contains many of the same bones: - Premaxillary bone - Postorbital - Sqamous bone etc
61
What is the nasofrontal hinge in bird skulls?
Joint - allows upper beak (premaxilla and maxilla) to move up or down Allows prokinesis in birds
62
What are the synapsid skull trends?
1. Temporal - dentary jaw joint 2. Articular, quadrate = inner ear bones (w/stapes) 3. Heterodont teeth 4. Many bone fusions/losses
63
What are the parts of the inner ears?
1. Pinna (outer ear) 2. Canal 3. Eardrum 4. Malleus, incus, stapes 5. Semicircular canals (vestibular) 6. Cochlea
64
What are some parts of the mammalian skull?
Parietal Frontal Nasal Premaxilla Dentary Maxilla Jugal Supraoccipital Exoccipital Basioccipital Meckel's cartilage Alisphenoid etc.
65
Which of these bones should NOT develop endochondrally: Nasal capsule, ethmoid, branchial arch or occipital?
Branchial arch
66
What evolved first; A stapes, temporal-dentary jaw joint, mobile premaxilla or semicircular canals?
Semicircular canals
67
If you found a fossil with an upper and lower temporal bar, what kind of skull would that be?
Diapsid
68
Would you expect an anapsid skull to show kinesis and why/not?
No Lacks fenestrae, skull has a solid and fused nature
69
What might a disadvantage of a kinetic skull be; for example why might crocodiles lack them?
Decreased strength Disrupt feeding Vulnerable to injury
70
Can you name five skull bones that are dermatocranium but never part of the jaws?
Frontal Parietal Squamosal Lacrimal Nasal
71
What bones did the malleus, incus and stapes of mammals come from in a fish?
Malleus evolved from the articular bone Incus evolved from the quadrate bone Stapes evolved from the hyomandibula
72
What are the two parts of the Appendicular Skeleton?
Pectoral Pelvic
73
What is the pectoral skeleton composed of?
Girdle - Scapula - Cleithrum - Coracoid - Clavicle Forelimb - Humerus - Radius - Ulna - Carpals - Metacarpals - Phalanges
74
What ia the pelvic skeleton composed of?
Girdle - Ilium - Pubis - Ischium Hindlimb - Femur - Patella - Tibia - Fibula - Tarsals - Metatarsals - Phalanges
75
What are fish fins?
Girdles of fish = ancestral to those of tetrapods; ancient Fins have deep homology with limbs - made by the same genes but same bones not present in bony fish ancestor
76
What are the components of bony fish vs shark fins?
Bony Fish - Scales - Basal - Radials - Lepidotrichia - Actinotrichia Sharks - Ceratotrichia
77
What is the fins/limbs trend?
1. Loss of fin rays (lepidotrichia, etc) 2. Carocpterygii (lobe-fins): Discrete limb-like fins; units (humerus/femur, radius-ulna/tibia-fibula, digits, etc.) 3. Reduction/loss (swimming, burrowing, etc.)
78
What are the trends of tetrapod evolution?
1. Reduction oof coracoids, clavicles 2. Changes in carpal/tarsal, digit numbers 3. Sesamoid bones
79
What are the components of tetrapod pelvic girdles?
Ilium Acetabulum (=hip socket) Pubis Ischium Femur Fibula Tibia Tarsals Metatarsals Phalanges
80
What are the components of the pectoral girdle?
Scapula Glenoid fossa (=shoulder socket) Posterior coracoid Clavicle Anterior coracoid Interclavicle Humerus Radius Metacarpals Ulna Parpals Phalanges (sing. phalanx)
81
What are the developmental limb units?
Stylopodium Zeugopodium Mesopodium Acropodium (Mesopodium + Acropodium = autopodium)
82
Mesopodium + Acropodium = what?
Autopodium
83
What does the pectoral girdle form?
Forelimb
84
What does the pelvic girdle form?
Hindlimb
85
What are the main components of the sarcopterygian?
Girdle Pterygiophores - Basal - Radial Dermal fin rays
86
What are the morpholoical terms of the limb and then their forelimb/hindlimb counterparts?
Girdle Stylopodium - Upper arm - Thigh Zeugopodium - Forearm - Shank (crus) Autopodium - Manus (wrist-palm-fingers) - Pes (ankle-sole-toes)
87
What are the dermal bones in the appendicular skeleton?
Only: Clavicles Cleithra etc. and Lepidotrichia (fin rays of fish)
88
How do digits develop?
Postaxial to preaxial arc (digit 5 to 1) Bifurcating embryonic ossification centres
89
What are the components of the actinopterygian pectoral girdle?
Posttemporal Supracleithrum Postcleithrum Scapulocoracoid Cleithrum Clavicle
90
What are the trends in pectoral girdle evolution?
1. Loss of cleithrum/gill parts (neck) 2. Reduced interclavicle, procoracoid 3. Dominant scapula, coracoid (=acromion in mammals) 4. Highly variable clavicle
91
What are the major appendicular changes from fish in early tetrapods?
1. Digits (eight??) 2. Connection of pelvis to the vertebral column (sacrum) 3. Enlarged limb muscles, girdles
92
What are the components of early tetrapod hind lims (pelvic girdle)?
Ilium Femur Pubis Tibia Fibula Ischium
93
What are the components of the early tetrapod forelimb (pectoral girdle)?
Cleithrum Scapulocoracoid Clavicle Interclavicle Humerus Radius Ulna
94
What are the trends in the pelvic girdle evolution?
1. Divergence of 3 parts as they enlarge 2. Caudal rotation of pubis 3. Opening of hip socket (acetabulu) - dinosaurs MUCH MORE CONSERVATIVE THAN PECTORAL GIRDLE
95
What are the components of autopodia?
Proximal carpals: - Radiale - Ulnare Proximal tarsals: - Tibiale - Fibulare (= astragalus, calcaneum) Proximal tarsals and carpals may both include an intermedium May be middle row of tarsals called centralia/centrale Distal tarsals: Many names Manus: Digit 1: Pollex Pes: Digit 1: Hallux
96
What do we know about pes variation?
Siminalr in manus Varied number of tarsals, digits Proportions vary Fusion of bones) tarsometatarsus of birds etc) Unguals (end phalanges): Hooves, claws
97
What do we know about limb posture?
Sprawling to erect continuum (abduction vs adduction) Former involves more lateral undulation of axial column More erect postures evolved in synapsid, archosaur (crocodile-dinosaur/bird) lineages Involves reconfiguration of joints for parasaggital gait (swing fore-aft; emphasise flexion-extension)
98
What did more erect postures evolve in?
Synapsid Archosaur (crocodile-dinosaur/bird) lineages
99
What do archosaurian reptile locomotor systems look like?
Emphasised the hindlimbs; more erect posture, hingelike joints and parasaggital gait Birds inherited bipedalism from ancient dinosaurs
100
What do we know about mammalian design?
Enlarged pectoral (and pelvic) girdle - especially scapula (mobile) More erect posture and parasagittal gait Vertebral motion - dorsoventrally flexible (lumbar region)
101
What do we know about autopodial posture?
Continuum (straightening of distal joints = more unguligrade) Tradeoffs: Stable base of support in plantigrade; longer stride and more pillar-like limb in unguligrade; also lighter distal limb (easier to swing)
102
How to increase speed and efficiency?
1. Longer (distal) limb segments; more upright 2. Larger (proximal) muscles (pectoral, pelvic girdles, etc.); longer (distal) tendons 3. Larger levers (carpals, tarsals, etc) 4. Lightened manus, pes 5. Vertebral dorso-ventral flexibility
103
What are the features of the Rana skeleton?
Modifications for jumping (saltatorial adaptation) Pelvic girdle - Pubis - Ischium - Ileum - Urostyle Tarsal bones just beyond ankle joint Gastrocnemius or [=plantaris] muscle: Originates on femur and inserts on bones beyond the ankle joint; its contraction contributes to the extension of the limb
104
What do we know about gliding adaptations?
Increasing surface area to produce lift, drag
105
What are the three independent origins of flight/gliding?
1 in mammals (bats) 2 in archosaurs (pterosaur, bird) Lift and thrust; production essential
106
What are the components of a bird wing?
Humerus Radius Ulna Metacarpal
107
What are the components of a pterosaur wing?
Humerus Radius Ulna Skeletal support of patagium Metacarpals
108
What are the components of a bat wing?
Humerus Radius Ulna (ridimentary) Metacarpals
109
What do we know about feathers and flight?
Primary feathers (manus) = thrust Secondary feathers (forearm) = lift
110
What are some swimming adaptations?
Fish exemplify continnum from emphasising undulation (axial)/oscillation (appendicular) Midline fins: Dorsal, Anal, Caudal
111
What are the four swimming styles?
Anguilliform - Eels Subcarangiform - Salmonids Carangiform - Makrell Thunniform - Tunas
112
What is the anguilliform style of swimming?
Large head movement Eels
113
What is the subcarangiform style of swimming?
Moderate head movement Salmonids
114
What is the carangiform style of swimming?
Mild head movement Makrell
115
What is the thunniform style of swimming?
Very small head movement Tunas
116
What is convergent evolution?
The independent evolution of similar features in species from distant clades
117
What does it mean that lepidotrichia of fish have deep homology with digits of tetrapods?
These structures, although they look very different and serve different functions, are derived from a common ancestral genetic and developmental pathway
118
The patella is an example of what type of unusual bone found in tetrapods?
Sesamoid bone
119
Describe how the sarcopterygian limb develops from stylopodium to autopodium:
Stylopodium to Zeugopodium to Autopodium
120
What bone of the pectoral girdle is most seldom lost in tetrapods?
The scapula
121
How is the relationship between the axial skeleton with the pectoral vs pelvic girdles fundementally different in tetrapods?
Pectoral girdle is not directly attached to the axial skeleton, suspended by muscles Pelvic girdle is firmly fused to the vertebral column via the sacrum
122
What bones might be found in the proximal carpals vs the proximal tarsals?
Proximal carpals: - Radiale - Intermedium - Ulnare - Centrale Proximal tarsals: - Tibiale - Intermedium - Fibulare --> Talus --> Calcaneus --> Centrale(s)
123
Which forelimb bones are most modified in the three tetrapod lineages that evolved flight?
Birds - carpals/metacarpals and digits Bats - Digits II-V, and especially radius Pterosaurs - Digit IV and humerus

Comparative Anatomy (10 decks)

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