Quiz 3 Flashcards
0
Q
Annular Cartilage (lamprey)
A
Ring-like structure that forms the main skeletal element of the oral funnel
1
Q
Chondrocranium (lamprey)
A
Formed from endocranial elements
Partly encloses the brain and sense organs and has cartilages that extend anteriorly to support the annular cartilage
2
Q
Lingual Cartilage (lamprey)
A
Median cartilage that extends posteriorly from the annual cartilage, ventral to the chondrocranium
Supports the rasping tongue
3
Q
Branchial Basket (lamprey)
A
Network of cartilages that extends posterior and connected to the chondrocranium
Supports the pharyngeal region
4
Q
Pericardial Cartilage (lamprey)
A
Crescent-shaped cartilage at the posterior end of the branchial basket
- Lies on the posterior wall of the pericardial cavity
5
Q
Main differences between lamprey and higher fish pharyngeal skeletons
A
- In lampreys, the structure is a connected network, not separate arches
- In lampreys, it is connected to the pericardial cartilage
- Branchial basket in lampreys lies superficially, just beneath the skin and lateral to the gills, rather than deep and medial to the gills
6
Q
Notochord (lamprey)
A
Axial support for the body
Extends from beneath the posterior part of the brain to the tip of the tail
7
Q
Arcualia
A
Representation of vertebrae in the lamprey
Lie dorsal to the notochord on either side of the spinal cord
8
Q
Operculum
A
Large, triangular bony plate on the pharyngeal region, covers the gills
9
Q
Preoperculum
A
J-shaped bone that lies anterior to the operculum
- Has a fringe of serrations on the posterior edge
10
Q
Suboperculum
A
Bone that lies posteroventral to the operculum
11
Q
Interoperculum
A
Rounded bone that lies ventral o the preoperculum
12
Q
Branchial Arches (fish)
A
Lie deep to the opercular bones and support the gills
13
Q
Frontal (fish)
A
Forms much of the skull roof and roofs the orbit
14
Q
Parietal (fish)
A
Bone that lies posterior to the frontal
15
Q
Lacrimal (fish)
A
Large (ish) bone that forms the anteroventral margin of the orbit
16
Q
Maxilla (fish)
A
Slender bone that articulates to the anteroventral part of the lacrimal and the posterior part of the dentary; posterior end is embedded in soft tissue
Edentulate
17
Q
Premaxilla (fish)
A
Most anterior bone of the upper jaw that articulates with the other premaxilla and the nasal and maxilla
Bears teeth on the anteroventral side
Is projected forward during opening of the mouth in derived actinopterygians
18
Q
Nasal (fish)
A
Thin bone that extends anterior from the frontal
19
Q
Comparison of bones in fish and other vertebrates
A
Should be noted that bones with the same name are not homologous with one another
- Frontal in fish = parietal in tetrapods
- Parietal in fish = postparietal in tetrapods
20
Q
Suspensorium
A
Supports the jaw onto the rest of the skull in fishes
Consists of three bones:
- Hyomandibular (dorsal)
- Metapterygoid
- Quadrate (ventral, articulates with lower jaw)
21
Q
Anguloarticular
A
Forms most of the posterior end of the lower jaw, articulates with the quadrate of the upper jaw
Two parts:
- Angular is large, flat, superficial component
- Articular is medial and endochondral
22
Q
Dentary (fish)
A
Can be seen anterior to the anguloarticular
Bears teeth
23
Q
Retroarticular
A
Small endochondral ossification that lies posteroventrally on the lower jaw
24
Vertebral Column (Fish)
Consists of trunk and caudal vertebrae
- Each vertebra has a centrum as its main body
- All vertebrae have elongated dorsal neural spines
25
Caudal Vertebrae
Vertebrae of the tail
| - Have elongated hemal spines ventrally
26
Trunk Vertebrae
Vertebrae anterior to the tail
| - Bear ribs, both dorsal and ventral
27
Fish Ribs
Ventral Ribs
- Prominent
- Curve ventrally and form the myosepta adjacent to the body cavity
Dorsal Ribs
- Extend laterally
- More delicate, are attached via ligaments to the posterior surface of more anterior ventral ribs
- Often missing in prepared specimens
28
Dorsal Fins
Anterior and Posterior
Supported by thin, elongated fin rays
- Termed spines if they are ossified (all anterior rays, first two posterior)
- Termed soft fin rays if not ossified and may branch distally (remaining posterior)
- Each is supported at the base by a radial perygiophore
29
Radial Pterygiophore
Ventrally tapered bony element that underlies each fin ray in the anterior and posterior dorsal fins
- Extends ventrally into the connective tissue between two neural spines
30
Anal Fin
Lies along the midventral line, opposite to the posterior dorsal fin
- First two fin rays are spines, remaining are soft rays
- Radial pterygiophores support these rays by extending dorsally; anterior few fuse into large element that attaches to ventral rib(s) behind which hemal spines begin
31
Caudal Fin
Supported by soft fin rays that form a homocercal tail in the perch
32
Uroneurals
Last few neural spines
33
Hypurals
Flattened hemal spines of the last few caudal vertebrae, immediately posterior and ventral to the uroneurals
Provide most of the support for the fin rays of the caudal fin
34
Epurals
Modified neural spines that are unattached to vertebrae
Provide some support for the dorsal part of the caudal fin
35
Cleithrum
Dorsoventrally elongated bone that lies deep to the (sub)operculum and extends to the ventral midline to articulate with the opposite cleithrum
Main supporting element of the pectoral girdle
36
Supracleithrum
Articulates ventrally with the cleithrum and anterodorsally to the posttemporal
37
Posttemporal
Bone that is attached to the posterior end of the skull and articulates posteroventrally to the supracleithrum
38
Scapula
Large element of the shoulder girdle that lies dorsal to the procoracoid
39
Procoracoid
Large element of the shoulder girdle that lies ventral to the scapula
40
Postcleithrum
Elongated, triangular bone that extends dorsoventrally beneath the pectoral fin
- Widened end lies deep to the cleithrum
- Tapers ventrally, passing medial to the fin and extends towards the pelvic fin
41
Radial Pterygiophores (Pectoral Fin)
Extend from the scapula or procoracoid and distally articulate with the soft fin rays
42
Basipterygia
Paired triangular plates of bones that are oriented anteroposteriorly and form the pelvic girdle
- Wide base located posteriorly
- Tapers and passes dorsal to the articulation between the two cleithra anteriorly
43
Pelvic Fin
Fin rays each attach directly to the posterior end of a basipterygium
- Are all soft fin rays except for the medial ray
44
Premaxillae (mudpuppy)
Paired, most anterior part of the skull/upper jaw
45
Frontals (mudpuppy)
Paired, large bones immediately posterior to the premaxillae
46
Parietals (mudpuppy)
Paired, large bones posterior to the frontals
| - Has long slender anterior projection that extends lateral to the frontals
47
Antorbital Processes (mudpuppy)
Paired, cartilaginous
Part of the chondrocranium
Project laterally near the anterior end of the parietal bones
- Project from the trabecular cartilage
48
Vomer (mudpuppy)
Modified to take on the role of the maxilla (which the mudpuppy lacks)
- Forms the anterolateral margin of the skull
49
Palatopterygoid (mudpuppy)
Forms the central part of the lateral margin of the skull
- Posterior to the antorbital process
- Compound element formed from the palatine and pterygoid
50
Prootic (mudpuppy)
Paired bone that contributes to the otic capsule
Lies lateral to the parietal, near the suture of the parietals and frontals
51
Opisthotic (mudpuppy)
Paired bone that contributes to the otic capsule
Lies posterior to the squamosal
52
Fenestra Ovalis (mudpuppy)
Contained within a cartilaginous region that lies between the prootic and opisthotic
53
Squamosal (mudpuppy)
Extends anterolaterally from the opisthotic to form the posterolateral margin of the skull
54
Quadrate (mudpuppy)
Articulates with the squamosal posteriorly and the palatopterygoid anteriorly
- Inclines anteroventrally
- Forms the jaw joint at its articulation with the mandible
55
Quadrate Cartilage (mudpuppy)
Cartilaginous bridge from the anterior end of the quadrate to the lateral margin of the parietal
56
Columella (mudpuppy)
Disc-shaped bone that lies anterior to the opisthotic and covers the cartilaginous region between the opisthotic and prootic
- Covers the fenestra ovalis
- Has a small stylus projecting from its lateral surface
Transmits vibrations to the inner ear
57
Foramen Magnum (mudpuppy)
Large opening on the posterior surface of the skull
| - Spinal cord passes through it
58
Exoccipitals (mudpuppy)
Paired, form the posterior part of the skull, lateral and ventral to the foramen magnum
- Each contains an occipital condyle
59
Parasphenoid (mudpuppy)
Large, triangular, plate-like bone that forms most of the skull's ventral surface
60
Ethmoid Plate (mudpuppy)
Cartilaginous plate anterior on the chondrocranium
| - Visible anterior to the parasphenoid in ventral view
61
Chondrocranium (mudpuppy)
Consists of:
- Basal plate
- Exoccipital
- Opisthotic
- Synotic tectum
- Prootic
- Parachordal plate
- Quadrate
- Quadrate cartilage
- Fenestra communis
- Ethmoid plate
- Trabecular horn
- Antorbital process
- Trabecular cartilage
62
Synotic Tectum
Thin cartilaginous bridge that connects the left and right otic capsules
63
Basal Plate (mudpuppy)
Cartilaginous bridge between the left and right exoccipitals
64
Parachordal Plate (mudpuppy)
Cartilaginous plate that extends anteriorly from each otic capsule
65
Trabecular Cartilages (mudpuppy)
Slennder, rod-like, cartilaginous elements extending anteriorly from the parachordal plates
66
Trabecular Horns (mudpuppy)
Small projections anterior to the ethmoid plate that lie between the nasal capsules
67
Meckel's Cartilage (mudpuppy)
Cartilaginous structure that extends through the interior of the mandible
- Mostly visible in medial view
- Forms the articular surface for the quadrate of the upper jaw posteriorly
69
Mentomeckelian (mudpuppy)
Where Meckel's Cartilage ossifies anteriorly into the mandibular symphysis
70
Dentary (mudpuppy)
Covers most of the lateral surface of Meckel's cartilage
| - Bears a long row of marginal teeth
71
Coronoid (mudpuppy)
Is exposed largely on the medial side of Meckel's cartilage as well as a tiny exposure on the dorsolateral side
- Bears a short row of marginal teeth
72
Prearticular (mudpuppy)
Covers much of the posterior part of the mandible in medial view
- Tapers anteriorly as a wedge on the dentary
73
Hyoid Apparatus (mudpuppy)
Large, composed of the hyoid arch and parts of the first three branchial arches
- Hyoid arch is largest, anterior, supports the tongue
74
Hypohyal (mudpuppy)
Hyoid Arch
- Small, median
- Paired
75
Ceratohyal (mudpuppy)
Hyoid Arch
- Lateral, elongated
- Paired
76
Basibranchial 1 (mudpuppy)
- Median
| - Extends posterior from the hypohyals to the base of the first branchial arch
77
Branchial Arch 1 (mudpuppy)
Formed of:
- Ceratobranchial 1 (paired, anterior)
- Epibranchial 1 (paired, posterior)
78
Basibranchial 2 (mudpuppy)
Extends posteriorly from the left and right ceratobranchial 1
79
Ceratobranchial 2 (mudpuppy)
Tiny, nodular element at the base of epibranchial 2
80
Epibranchial 3 (mudpuppy)
Smallest epibranchial, lies posterior to epibranchial 2
81
Cervical Vertebra (mudpuppy)
Only one!
- Articulates with the occipital condyles of the skull
- Anteroventral process of the atlas projects into the foramen magnum
- Posteriorly articulates with the first of the trunk vertebrae
82
Trunk Vertebrae (mudpuppy)
Lots of them
| - Have transverse processes that extend from the centrum and articulate with small, Y-shaped ribs
83
Neural Canal (mudpuppy)
Passes dorsal to the centra in vertebrae
| - Neural arch forms the roof of the canal; has a neural process
84
Prezygapophyses (mudpuppy)
Present on each vertebra for articulation with the preceding vertebra
85
Postzygapophyses (mudpuppy)
Present on each vertebra for articulation with the succeeding vertebra
86
Sacral Vertebra (mudpuppy)
Just one!
| - Articulates to the pelvic girdle through its ribs
87
Caudal Vertebrae (mudpuppy)
Tail vertebrae
- Each have a hemal arch
- Most lack ribs, but still have transverse processes
88
Pectoral Girdle (mudpuppy)
Mainly cartilaginous
Left and right halves that overlap ventrally but don't fuse
89
Scapula (mudpuppy)
Short bone with the suprascapular process dorsally
| - On ventral side, have glenoid fossa, the depression that articulates with the forelimb
90
Procoracoid Cartilage (mudpuppy)
Slender, elongated, projects anteriorly from the glenoid fossa
91
Coracoid Cartilage (mudpuppy)
Broad, ventral, plate-like part of the pectoral girdle; they partly overlap
92
Humerus (mudpuppy)
Brachium of the forelimb
93
Radius (mudpuppy)
Anteromedial bone of the antebrachium on the forelimb
94
Ulna (mudpuppy)
Posterolateral bone of the antebrachium on the forelimb
95
Manus (mudpuppy)
Only has four digits
- Six carpals
- Four metacarpals
- Phalanges
96
Pelvic Girdle (mudpuppy)
Mainly cartilaginous
97
Ilium (mudpuppy)
Ossified, extends ventrally from its articulation with the rib of the sacral vertebra to the acetabulum
98
Acetabulum (mudpuppy)
Depression on the ilium that articulates with the hind limb
99
Puboischiadic Plate (mudpuppy)
Ventral formation of the pelvic girdle
- Pubic cartilage
- Ischiadic cartilage
- Ischium
100
Pubic Cartilage (mudpuppy)
Elongated, triangular anterior portion of the puboischiadic plate
101
Isciadic Cartilages (mudpuppy)
Posterior portion of the puboischiadic plate; contains a pair of ossified ischia
102
Obturator Foramen (mudpuppy)
Foramina just anterior to each acetabulum
103
Femur (mudpuppy)
Forms the thigh on the hindlimb
104
Tibia (mudpuppy)
Anterior part of the crus on the hindlimb
105
Fibula (mudpuppy)
Posterior part of the crus on the hindlimb
106
Pes (mudpuppy)
- Six tarsals, cartilaginous
| - Four ossified digits (metatarsals and phalanges)
107
Skull elements missing in anurans
- Lacrimal
- Prefrontal
- Postfrontal
- Opisthotic
108
Interpterygoid Vacuities (frog)
Large paired openings on the ventral part of the skull (palate)
109
Premaxilla (frog)
Small, median bone on the anterior portion of the skull
| - Bears a single row of small teeth (premaxillary)
110
Maxilla (frog)
Long paired bones that make up the lateral sides of the skull
- Bears a single row of small teeth (maxillary)
111
Quadratojugal (frog)
Short paired bone on the posterolateral sides of the skull
112
Vomer (frog)
Lies just posterior to the premaxillae
| - Bears vomerine teeth
113
Nasals (frog)
Paired, broad, flattened bones that meet each other at the dorsal midline
- Form the anterior part of the orbits through a narrow process that extends lateroventrally
114
Nares (frog)
Lie anterior to each orbit
115
Frontoparietals (frog)
Paired, elongated bones that meet along the dorsal midline and form much of the cranial roof
116
Sphenethmoid (frog)
Forms most of the lateral and ventral sides of the braincase
- Mostly tubular, with lateral expansion anteriorly
- Small wedge can be seen dorsally wedged between the nasal and frontoparietal
117
Palatines (frog)
Extend as transverse bars on either side of the sphenethmoid to reach the maxillae
118
Parasphenoid (frog)
Cuciate bone on ventral side of skull
- Anterior part of "stem" covers the sphenethmoid in ventral view
- Posterior part of stem projects to the exoccipitals
- Each transverse arm extends laterally towards a pterygoid
119
Exoccipitals (frog)
Paired bones that form the posterior part of the skull
| - Each has an occipital condyle ventrally
120
Pterygoid (frog)
Paired, Y-shaped bone
- Anterior arm connects with maxilla and nasal
- Posterior arm curves gently laterally to contact the angle of the jaw
- Medial arm is shortest and extends to the prootic and transverse arm of the parasphenoid
121
Squamosal (frog)
Paired, T-shaped
- Top of T slightly curved, extends diagonally
- Long stem of T angled towards angle of the jaw
122
Annular Cartilage (frog)
Cartilage that covers a large portion of the squamosal (if in tact) and supports the tymapanic membrane
123
Quadrate (frog)
Main element that forms the upper part of the jaw joint
- Usually cartilaginous in anurans
- Usually covered laterally by the ventral squamosal and medially by the posterior arm of the pterygoid
124
Prootics (frog)
Paired, irregularly-shaped bones that contain the inner ear
- Between the squamosal, frontoparietal and exoccipital
- Forms the posterior part of the orbit
- Usually fuses with the exoccipital
125
Optic foramen (frog)
Foramen on the medial side of the orbit
126
Trigemial Foramen (frog)
Foramen on the posterior side of the orbit
| - Passage for the trigeminal and facial nerves
127
Foramen Ovale (frog)
Foramen beside the occipital condyle
- Passage for the glossopharyngeal and vagus nerves
- Formed by the prootic and exoccipital
128
Mandible (frog)
Edentulate
| - Meckel's cartilage is covered by dentary anterolaterally and agulosplenial medial & posteriorly
129
Missing mandibular bones in anurans (present in non-mammalian tetrapods)
- Coronoid
- Articular
- Prearticular
130
Dentary (frog)
Thin, flange-like
131
Angulosplenial (frog)
Large
- Posteromedial surface has medially pointed coronoid process
- Articulates with the quadrate posteriorly
132
Mentomeckelian (frog)
Ossifies the mandibular symphysis
133
Hyoid Apparatus (frog)
X-shaped cartilaginous plate that lies on the floor of the oral cavity and supports the tongue and larynx
- Two anterior cornua project anteriorly, curved
- Two posterior cornua are bony rods that project posteriorly
134
Vertebral Column (frog)
Only nine free vertebrae
- First is the atlas
- Last is a sacral vertebra
- All have prominent transverse processes but no ribs
135
Urostyle (frog)
Rod-like bone that extends posteriorly from the sacral vertebra
- Formed from the fusion of serveral postcranial vertebrae
136
Suprascapula (frog)
Extends dorsomedially from the scapula
| - Has a prominent, (usually) calcified cartilaginous portion medially
137
Clavicles (frog)
Slender, extend almost directly medially from the scapula anterior to the procoracoid
138
Procoracoid (frog)
Large paired bones that form a plate-like base to the pectoral girdle
139
Omosternum (frog)
Rod-like bone that lies anterior to the clavicles
140
Episternum (frog)
Cartilaginous extension anterior to the omosternum
141
Sternum (frog)
Posterior to the procoracoids
142
Xiphisternum (frog)
Cartilaginous extension posterior to the sternum
143
Radio-Ulna (frog)
Fusion of the radius and ulna into a single element
144
Prepollex/prehallux (frog)
Small bone that extends medially from the carpals/tarsals, may be a reduced metacarpal/tarsal
145
Ilium (frog)
Elongated, anteriorly-directed element of the pelvic girdle that has a prominent iliac crest
146
Ishium & Pubis (frog)
Form a semi-circle in lateral view
- Ishium is more posterior
- Part of the pelvic girdle
147
Tibiofibula (frog)
Fusion of the tibia and fibula into a single element
148
Tibiale (frog)
Elongated proximal tarsal
| - Medial
149
Fibulare (frog)
Elongated proximal tarsal
- Lateral
- Homologous with the calcaneum
150
Early Tetrapod Skull
Consists of the skeletal structure of the head, minus the lower jaw
Complex fusion of
- Dermal elements
- Visceral endoskeletal elements
- Somatic endoskeletal elements
Three parts
1. Braincase
2. Palatal Complex
3. Skull roof
151
Shark Skull
Consists of the chondrocranium (braincase) and palatoquadrate (palatal complex, upper jaw)
- Dermal parts that would be present in other verts are missing
- Posterior occipital region surrounds foramen magnum and includes occipital condyles
- Otic capsules are formed from widening of the occipital region
- Narrow orbital region (interorbital, sphenoidal)
- Ethmoid region is anterior expansion, contains the nasal capsules
- Articulates ventrally with the palatoquadrate
- Basically an ensemble of separate cartilaginous centres, much like discrete bones in bony veterbrates
152
Early Tetrapod Braincase
Mostly somatic endochondral bone, with some dermal bone mixed in
153
Early Tetrapod Palatal Complex
Mostly dermal bone, with some visceral endochondral
154
Early Tetrapod Skull Roof
Dorsal cover/shield for the skull
- Consists entirely of dermal bone
- Bones are usually paired
- Nearly solid but with openings for the nostrils, eyes and pineal eye
- Primitively notched posteriorly, in the ear region
- Consists of 5 groups of bones
155
Skull Roof Groups of Bones
1. Tooth-Bearing Marginal Series
2. Midline Series
3. Circumorbital Series
4. Temporal Series
5. Cheek Series
156
Tooth-Bearing Marginal Series (Skull Roof)
Forms the rim of the roof
- Lateral edges
- Bear teeth
157
Midline Series (Skull Roof)
Paired adjacent to one another along the midline of the skull
158
Circumorbital Series (Skull Roof)
Bones that surround the orbit
159
Temporal Series (Skull Roof)
Bones that lie between the otic notch and the midline series
160
Cheek Series (Skull Roof)
Bones that lie posterior to the orbit and below the otic notch
- Lateral to the temporal series
161
Palatal Complex
Bones are all paired, but are more complex than the skull roof
- Mostly dermal
- Some visceral endochondral bone
- Has major articulations with other skull structures (lower jaw and braincase in tetrapods)
162
Dermal Bones (Palatal Complex)
Four pairs that form the roof of the oral cavity
- May bear teeth in fishes or early tetrapods
- Median pterygoid (largest, posterior to vomer)
- Anterior Vomer
- Lateral Palatine
- Posterolateral Ectopterygoid
163
Visceral Endochondral Bones (Palatal Complex)
Palatoquadrate is functionally replaced largely by dermal elements, but generally remains as a reduced structure
In tetrapods, two separate ossifications (4 in fishes):
1. Quadrate
2. Epipterygoid
164
Quadrate
Small, posterior palatoquadrate bone
| - Articulates with the lower jaw
165
Epipterygoid
Large, anterior palatoquadrate bone
| - Articulates with the braincase via the basisphenoid
166
Braincase
Complex structure, with not all bones paired
- Mostly somatic endochondral bone
- One dermal bone (parasphenoid)
167
Parasphenoid
Dermal bone of braincase
- Forms in the skin on the roof of the oral cavity
- Forms the ventral part of the braincase
- Narrow anteriorly, wide posteriorly
168
Somatic Endochondral Bone (Braincase)
Four bones form the occiput
- Supraoccipital
- Basioccipital
- Paired exoccipitals
- These usually fuse into a single occipital bone
Two paired bones associated with the otic region
- Contain sacs and canals of inner ear
- Opisthotic
- Prootic
Basisphenoid
Sphenethmoid
169
Supraoccipital
Bone that lies dorsal to the foramen magnum
170
Basioccipital
Bone that lies ventral to the foramen magnum
171
Exoccipital
Paired bones that lie on either side of the foramen magnum
172
Opisthotic
Posterior bones forming the otic region
| - Paired
173
Prootic
Anterior bones forming the otic region
| - Paired
174
Basisphenoid
Bone that forms the floor of the cranial cavity
- Median
- Mostly ventral and anterior to the otic region
- Mostly covered ventrally by the parasphenoid
- Basipterygoid process on either side forms the basal articulation with the palatal complex
175
Sphenethmoid
Bone that contains olfactory nerves
- Median ossification in the sphenoid and ethmoid regions
- Shaped like a trough
176
Basal Amniote Skull
- Very similar to an early tetrapod
- Otic notch is closed
- Intertemporal bones are lost and absent in reptiles
- Other temporal bones are reduced and/or displaced posteriorly
- Postparietal and tabular bones are present (later fused into the occipital in mammals)
- Supratemporal present (not in mammals)
177
Intermediate Stages in Skull Evolution
Two stages
1. Early synapsids (represented by the pelycosaurs)
2. Non-mammalian therapsids
- Early pelycosaurs develop temporal fenestra, which is enlarged in therapsids
- Quadratojugal is reduced and eventually lost
- Squamosal differentiates into zygomatic and braincase parts
- Loss of prefrontals, postfrontals and postorbitals
- Integration of skull roof, palatal complex and braincase elements
- Development of the secondary palate
178
Early Synapsid Skull
Temporal fenestra has formed but isn't exactly a hole yet since there is heavy connective tissue overlying it
- Brain is a little bigger than that of an anapsid
179
Early Therapsid Skull
Temporal fenestra is larger than in the early synapsids
- Cranial kinesis is lost
- Brain is once again bigger
180
Later Therapsid Skull
Both brain and the temporal fenestra is larger
- Downgrowth of dermal bones
- Upgrowth of mostly the alisphenoid
- This encloses the brain
181
Mammalian Skull
Brain is bigger and is now completely enclosed in bone
- Muscles have gone from inside to outside the skull
- Few original skull bones remain
- Many of the same bones are present but with different surfaces than earlier forms
- New growth underneath the muscles
182
Development of the Secondary Palate
- Premaxillae and maxillae downturn
- Premaxillae and maxillae expand medially
- Through this, they cover the original roof of the oral cavity
- Palatines contribute to this posteriorly
- Results in elongation of the choana (internal naris) so it opens posteriorly, near the trachea
183
Functionality of the Secondary Palate
- With a primary palate, the animal is required to stop breathing while eating
- In order to maintain a constant body temperature and high metabolic rate, animals can't stop breathing for long periods
- Secondary palate allows for feeding while breathing
184
Temporal Bone
Bone derived from the complex fusion of several elements
- Squamosal
- Petrosal
- Ectotympanic
- Entotympanic
- Middle Ear Ossicles
185
Squamosal
Large, flat dermal bone of the side of the brain
186
Petrosal
Part of the braincase, forms from fusion of the prootic and opisthotic
- AKA periotic, petromastoid
187
Ectotympanic
Old lower jaw
- Angular
- Dermal bone
188
Entotympanic
New bone development in mammals
| - From the braincase
189
Middle Ear Ossicles
Malleus: originally the articular, dermal bone of the old lower jaw
Incus: originally the quadrate, endochondral bone of the palatal complex
Stapes: originally the hyomandibular, visceral endochondral bone
190
Mammalian Sphenoid Region
Region where many cranial nerves emerge, has many different kinds of bones present
- Complex embryologically
- Formed from the presphenoid, basisphenoid, orbitosphenoid and alisphenoid
191
Anterior Sphenoid Region
Begins as three separate elements that later fuse together (yet retain separate names)
- Presphenoid ventrally
- Obitosphenoid dorsally
- From the braincase
- Retain separate names due to different embryology and the fact that they aren't seen externally at the same time in an adult
192
Posterior Sphenoid Region
- Basisphenoid ventrally (from the braincase)
| - Alisphenoid dorsally (from epipterygoids in the palatal complex)
193
Foramina on the Sphenoid
Orbitosphenoid
- Optic
- Orbital Fissure (on suture)
Alisphenoid
- Orbital Fissure (on suture)
- Foramen rotundum
- Foramen ovale
194
Muscle Categories
Histological
- Striated vs Smooth
Physiological
- Voluntary vs Involuntary
Organizational
- Somatic vs Visceral
Not always a strict distinction
195
Somatic Muscles
- Derived from the myotomes of somites
- Always striated
- Mostly voluntary
- Innervated by somatic motor fibres
- Form the appendages and outer part of the body wall
- Axial and appendicular musculature
196
Visceral Muscles
- Derived largely from mesenchyme
- Ultimately the lateral plate
- Can be smooth or striated
- Mostly involuntary
- Innervated by visceral motor fibres
- Mostly in the wall of the gut
- Branchiomeric and smooth (gut) muscles
197
Origin vs. Insertion
Describe the attachment of muscles
| Two sets of definitions that are not comparable
198
Origin
Proximal end of a muscle
OR
End of a muscle that moves the least during contraction
199
Insertion
Distal end of a muscle
OR
End of a muscle that moves the most during contraction
200
Axial vs Appendicular
If either end of a muscle attaches to part of an appendage (including the girdle) then it is considered appendicular
201
Axial Musculature
Formed from epaxial and hypaxial muscles that are divided along a horizontal skeletogenous septum
- Most of the body's bulk in fish
- Consists of a series of myomeres
- Derived from myotomes, which is why they're segmentally arranged
- Complex zigzag pattern facilitates smooth curving action of the body
202
Epaxial Musculature
Fish
- Basically a single, segmented block
- Dorsalis trunci
Tetrapods
- Greatly reduced in volume as appendages take over
- Restricted to between the neural and transverse processes
Amphibians
- Still the dorsalis trunci
- Segmented, but with little differentiation and subdivision
Reptiles
- Segmented, longitudinally subdivided into three parts
Mammals
- Loses segmentation
- Complex origin and insertion patterns
203
Reptilian & Mammalian Expaxial Musculature
Subdivisions
- Iliocostalis: lateral part that attaches to ribs
- Longissimus dorsi: largest, dorsal to transverse processes
- Transversospinalis: between the longissimus and neural spines
204
Hypaxial Musculature
Fish
- Smaller than epaxial
- Basically a single unit
Tetrapods
- Considerably reduced
- Form thin muscular sheets around the flanks and belly
- Support abdominal cavity and viscera
- Most is complexly connected to ribs, complex subdivisions
Three dorsoventral groups
1. Subvertebral Series
2. Lateral (Flank) Series
3. Ventral (Belly) Series
Sheets do not extend all the way to the ventral midline but insert via aponeuroses
205
Subvertebral Series
Series of hypaxial musculature that lies dorsally and medially
- Underneath the transverse processes of the vertebrae
206
Ventral Series
Rectus abdominis
- Midventral
- Between the sternum and pelvis
207
Lateral Series
Lie between the rectus abdominis and the transverse processes
- Primitively segmented
- Fibres of the sheets are laid down in alternating directions
- Thin sheets, strong
Three unbroken sheets
- External oblique (anterodorsal - posteroventral)
- Internal oblique (anteroventral - posterodorsal)
- Transversus abdominis (dorsal - ventral)
208
Aponeurosis
Sheet-like tendon that serves as an insertion for sheet muscles
- Somewhat translucent, so can make out the underlying muscle fibres
- Allow for same strength against breakage and torsion with less volume
- Does not decrease strength of muscle contraction, only relative length of contraction
209
Cranial Muscles
Muscles found in the head and neck (gill) region
Somatic Component
- Axial musculature
- Derived from myotomes, epimeres
Visceral Component
- Branchiomeric musculature
- Derived from neural crest cells
210
Cranial Axial Musculature
Three groups
- Extrinsic muscles of the eye
- Epibranchial
- Hypobranchial
211
Extrinsic Eye Muscles
Cranial Axial Musculature (6)
- Unchanged throughout vertebrate evolution
- Formed from three pre-otic somites/myotomes
First Myotome
- Ventral oblique
- Medial rectus
- Dorsal rectus
- Ventral rectus
- Innervated by the oculomotor nerve
Second Myotome
- Dorsal oblique
- Innervated by the trochlear nerve
Third Myotome
- Posterior rectus (AKA lateral rectus)
- Innervated by the abducens nerve
212
Epibranchial Muscles
Anterior extension of the epaxial musculature
- Gills, where present, lie between them
- Helps to move and control the head and neck
- Usually attaches to the skull
213
Hypobranchial Muscles
Anterior extension of the hypaxial musculature
- Mainly extends between shoulder girdle and jaw
- Coracoarcuals (fish)
- Throat muscles and tongue in tetrapods
214
Coracoarcuals
Hypobranchial muscles in fishes
- Big muscles
- Ventral to the pericardial cavity
- Open the jaw
215
Tetrapod Hypobranchials
- True tongue
- Genioglossus
- Geniohyoid
- Styloglossus
- Hyoglossus
- Thyrohyoid
- Sternohyoid
- Sternothyroid
216
Branchiomeric Musculature
Associated with the visceral arches
- Formed from the mesenchyme
- Visceral
- Striated
Ancestral Vertebrates
- Similar to that of the dogfish
- Each arch is associated with a set of muscles
Higher Vertebrates
- Gills have been lost
- No longer proper "gut" muscles
- Become jaw/face/shoulder muscles
217
Basal Branchial Arch Muscles
Superficial constrictor and interbranchial form a continuous sheet that separates the pharyngeal slits
Dorsal and lateral interarcual stretch between the pharyngobranchial and the epibranchial
Levator extends to dorsal midline from the epibranchial
Adductor stretches between the epibranchial and the ceratobranchial
218
Dogfish Branchial Arch Muscles
Also the condition of most other fish
| - There are no individual levators, they have been fused into a single cucullaris that attaches to the pectoral girle
219
Fish Branchial Arch Muscles
- No superficial constrictors or interbranchials due to the presence of the operculum
- Levators are often reduced and absent in teleosts
220
Tetrapod "Branchial" Muscles
Due to lack of gills, no need for supporting muscles
- Trapezius is derived from the cucullaris
- Sternocleidomastoid
- Most others disappear
- A few remain as muscles of the larynx
221
Trapezius
Muscle that arises from the midorsal line and inserts on the shoulder
222
Sternocleidomastoid
Muscle that goes from the ventral part of the shoulder to the back of the skull
223
Hyoid Arch Musculature
- Innervated by the facial nerve
- Most are lost because hyoid arch takes on the role of jaw support
- Only the superficial constrictor and levator remain
- This is complicated by the operculum in fishes
224
Tetrapod Hyoid Arch Musculature
- Superficial constrictor is modified into the sphincter colli
- Depressor mandibulae
225
Sphincter colli
Large sheet muscle that wraps around the neck
| - In mammals, modified into facial muscles and helps form the jaw-opening muscles
226
Depressor mandibulae
Opens the mouth in lower tetrapods
- Goes from back of skull to back of lower jaw
- Formed from the anterior part of the sphincter colli
227
Mammalian Hyoid Arch Musculature
- Depressor mandibulae is lost while the sphincter colli remains, but is highly modified into facial muscles used in expression
- Buccinator
- Digastric
228
Buccinator
Cheek muscle
- Keeps food in oral cavity while chewing
- Non-mammals do not have cheeks
229
Digastric
Jaw opening muscle in mammals
- Has two "bellies"
- Posterior one is formed from the sphincter colli
- Anterior one is formed from the mylohyoid
- Also functions in hyoid stuff
230
Dogfish Mandibular Arch Musculature
Three muscle groups in dogfish:
- Adductor mandibulae (closes mouth)
- Dorsal levator (levator palatoquadrati)
- Ventral muscles (intermandibularis)
231
Tetrapod Mandibular Arch Musculature
- Levators are lost once the upper jaw fuses to the braincase
- Ventral muscles stay the same
- Adductors are more complex, but are still a mass under the skull roof extending to the lower jaw
232
Mammalian Mandibular Arch Musculature
- Intermandibularis becomes the mylohyoid
- Temporalis
- Masseter
- Pterygoids
- Digastric
233
Temporalis
Usually the largest muscle
| - Extends from the temporal fossa to the coronoid procces of the lower jaw
234
Masseter
Can be very large in some mammals
| - Extends from the zygomatic arch to the angular process of the mandible
235
Pterygoideus
Medial and lateral
- Extend from the pterygoid region of the skull to the lower jaw
- Deep division of adductor mass
- Control medio-lateral motions of the jaws
