{"id":639,"date":"2015-08-19T15:30:28","date_gmt":"2015-08-19T15:30:28","guid":{"rendered":"http:\/\/sites.msudenver.edu\/haysc\/?page_id=639"},"modified":"2015-08-19T16:02:47","modified_gmt":"2015-08-19T16:02:47","slug":"outline-2-bio-3220-axial-skeleton-skull","status":"publish","type":"page","link":"https:\/\/sites.msudenver.edu\/haysc\/biology-courses\/comparative-vertebrate-anatomy-bio-3220\/outline-2-bio-3220-axial-skeleton-skull\/","title":{"rendered":"Outline-1, BIO 3220, Axial Skeleton, Skull"},"content":{"rendered":"

VII. AXIAL SKELETON – SKULL AND VISCERAL SKELETON<\/strong><\/p>\n

A. Introduction and history<\/p>\n

Cephalization –Need cranium to house brain & sensory structures<\/em><\/p>\n

\n

B. NEUROCRANIUM –<\/strong>Primarily floors and walls of cranium<\/em><\/p>\n

1. Function –Protect<\/em><\/p>\n

2. Phylogeny –All vertebrates have this; Replacement bone<\/em><\/p>\n

3. Development of chondrocranium<\/p>\n

a. Prechordal cartilage = trabeculae cranii<\/p>\n

1. Forebrain<\/p>\n

2. Nasal capsules<\/p>\n

3. Orbits<\/p>\n

4. Rostrum<\/p>\n

5. Ethmoid plate<\/p>\n

b. Parachordal cartilage –Beside and behind notochord<\/em><\/p>\n

1. Hindbrain<\/p>\n

2. Basal plate<\/p>\n

3. 1-2 Occipital condyles and foramen magnum<\/p>\n

4. Sense capsules<\/p>\n

a. Olfactory capsules<\/p>\n

b. Otic capsule<\/p>\n

c. Optic capsule<\/p>\n

5. Ethmoid plate & Basal plate Expansion –Ethmoid plate unites with olfactory capsules; basal plate unites with otic capsule<\/em><\/p>\n

a. Foramina<\/p>\n

b. Hypophyseal fenestra (In basal plate)<\/em><\/p>\n

6. Ossification Centers –SEE Skull & Lower Jaw Components Page<\/a><\/p>\n

a. Occipital<\/p>\n

1. Foramen Magnum<\/p>\n

2. Basioccipital<\/p>\n

3. Exoccipital<\/p>\n

4. Supraoccipital<\/p>\n

5. Occipital Condyles<\/p>\n

b. Otic<\/p>\n

c. Sphenoid<\/p>\n

1. Basisphenoid<\/p>\n

2. Presphenoid\/Sphenethmoid<\/p>\n

d. Ethmoid<\/p>\n

1. Ethmoid plate<\/p>\n

2. Olfactory capsules<\/p>\n

\n

C. DERMATOCRANIUM<\/strong><\/p>\n

1. Phylogeny –Membrane bone which evolved from dermal armor<\/em><\/p>\n

2. Roofing bones –SEE Skull & Lower Jaw Components Page<\/a><\/p>\n

a. Nasal<\/p>\n

b. Frontal<\/p>\n

c. Parietal<\/p>\n

d. Orbit<\/p>\n

1. Lacrimal<\/p>\n

2. Jugal = Infraorbital = Zygomatic<\/p>\n

e. Squamosal<\/p>\n

3. Upper and Lower jaw<\/p>\n

a. Premaxilla<\/p>\n

b. Maxilla<\/p>\n

c. Dentary<\/p>\n

d. Splenial<\/p>\n

e. Surangular<\/p>\n

f. Angular<\/p>\n

g. Coronoid<\/p>\n

h. Prearticular<\/p>\n

4. Primary palatal bones<\/p>\n

a. Definition<\/p>\n

b. Vomer<\/p>\n

c.\u00a0Palatine<\/p>\n

d. Pterygoid<\/p>\n

5. Opercular bones<\/p>\n

\n

D. SPLANCHNOCRANIUM = visceral skeleton<\/strong><\/p>\n

SEE\u00a0VISCERAL\u00a0SKELETON\u00a0PAGE<\/a><\/p>\n

1. Function –Supports and allows movement of jaws, gills, tongue, associated with hearing<\/em><\/p>\n

2. Evolution –Ancient; Replacement bone<\/em><\/p>\n

3. Gill Slits(typically 6)<\/em><\/p>\n

4. Visceral arch<\/p>\n

a. Pharyngobranchial<\/p>\n

b. Epibranchial<\/p>\n

c. Ceratobranchial<\/p>\n

d. Hypobranchial<\/p>\n

e. +\/- Basibranchial<\/p>\n

5. Mandibular arch<\/p>\n

a. Palatoquadrate<\/p>\n

b. Mandibular = Meckel’s Cartilage<\/p>\n

6. Hyoid arch<\/p>\n

a. Hyomandibula<\/p>\n

b. Ceratohyal<\/p>\n

c. Basihyal<\/p>\n

E. Interrelationships<\/p>\n

\n

F. AGNATHA<\/strong><\/p>\n

1. Chondrocranium<\/p>\n

-protects brain, otic, and nasal organs<\/p>\n

2. Visceral skeleton continuous –Pharyngeal basket, branchial in function<\/em><\/p>\n

3. Dermal skeleton –None to armor, depending on group<\/em><\/p>\n

G. PLACODERMS<\/strong><\/p>\n

1. Chondrocranium<\/p>\n

2. Splanchnocranium<\/p>\n

a. Jaws from first visceral arch<\/p>\n

b. Autostylic suspension<\/p>\n

3. Dermal armor<\/p>\n

H. CHONDRICHTHYES<\/strong><\/p>\n

1. Chondrocranium<\/p>\n

a. Calcification<\/p>\n

b. 2 Occipital condyles, foramen magnum<\/p>\n

c. Otic and nasal capsule –Fused to neurocranium<\/em><\/p>\n

2. No dermal bones<\/p>\n

3. Splanchnocranium –SEE Visceral Arches Page<\/a><\/p>\n

a. Mandibular arch<\/p>\n

b. Hyoid arch<\/p>\n

c. Amphistylic –Primitive sharks, some modern ones<\/em><\/p>\n

d. Hyostylic –Most sharks; Hyomandibula hangs from otic capsule<\/em><\/p>\n

e. Autostylic –Chimeras<\/em><\/p>\n

I. BONY FISH<\/strong><\/p>\n

1. Neurocranium<\/p>\n

a. Incomplete above brain<\/p>\n

b. Chondrostean<\/p>\n

cartilaginous in most<\/p>\n

c. Holosteans<\/p>\n

cartilaginous<\/p>\n

d. Teleosts<\/p>\n

1. Large # bones<\/p>\n

2. Ossification centers of walls\/floor<\/p>\n

ethmoid<\/p>\n

sphenoid<\/p>\n

otic<\/p>\n

occipital {1 condyle}<\/p>\n

e. Dipnoans – cartilaginous<\/p>\n

2. Dermatocranium<\/p>\n

a. Complete –Joins to pectoral girdle<\/em><\/p>\n

b. Support teeth –Maxilla, Premaxilla<\/em><\/p>\n

c. Numerous; overlying neurocranium<\/p>\n

d. Similar amongst orders except broad plates in dipnoans<\/p>\n

e. Moveable bony operculum<\/p>\n

3. Splanchnocranium –SEE Visceral Arches Page<\/a><\/p>\n

a. Bone replacement(except dipnoans)<\/em><\/p>\n

b. Quadrate –Replacement of palatoquadrate<\/em><\/p>\n

c. Articular<\/p>\n

d. Hyomandibular + more segments; Arch II is not branchial in function<\/p>\n

e. 5 branchial arches [3-7]\n

f. Hyostylic –Highly moveable; Ray-finned fish<\/em><\/p>\n

g. Amphistylic –Crossopterygians<\/em><\/p>\n

h. Autostylic –Dipnoans<\/em><\/p>\n

J. AMPHIBIAN<\/strong><\/p>\n

1. Neurocranium & Dermatocranium –SEE Skull & Lower Jaw Components Page<\/a><\/p>\n

a. Neurocranium is incomplete dorsally, more cartilage than in bony fish; flat<\/p>\n

b. Not joined to pectoral girdle<\/p>\n

c. 2 Occipital condyles<\/p>\n

2. Splanchnocranium –SEE Visceral Arches Page<\/a><\/p>\n

a. Larval stages<\/p>\n

b. Quadrate – autostylic<\/p>\n

c. Epipterygoid absent<\/p>\n

d. Articular [unchanged]\n

e. Columella [= stapes]\n

f. Hyoid apparatus –Tongue support<\/em><\/p>\n

g. Larynx –New<\/em><\/p>\n

K. REPTILES<\/strong><\/p>\n

1. Neurocranium<\/p>\n

a. Decreased # bones<\/p>\n

b. 1 occipital condyle [except therapsids]\n

c. Well ossified<\/p>\n

2. Dermatocranium –SEE Skull & Lower Jaw Components Page<\/a><\/p>\n

a. Full complement – some reduction in roof bones<\/p>\n

b. Temporal region<\/p>\n

1. Temporal fossa or fenestra<\/strong><\/p>\n

a. Infratemporal arch –Below ventral fossa<\/em><\/p>\n

b. Zygomatic arch<\/p>\n

c. Supratemporal arch –Below dorsal fossa<\/em><\/p>\n

2. Anapsid<\/strong>–\u00a0Turtle; Stem reptiles<\/em><\/p>\n

3. Synapsids<\/strong>–\u00a0Mammal-like<\/em><\/p>\n

4. Diapsids<\/strong>–\u00a0Lizards, Crocodiles (May have modifications)<\/em><\/p>\n

5. Euryapsids<\/strong>–\u00a0Extinct reptiles such as Pleisosaurs and Ichthyosaurs, with one dorsal fossa<\/em><\/p>\n

6. Eating –Allows rotary chewing<\/em><\/p>\n

c. Secondary Palate<\/strong><\/p>\n

1. Palatine process of the Maxilla<\/p>\n

2. Palatines<\/p>\n

3. Internal nares shift posteriorly<\/p>\n

4. Purpose –Allows simultaneous chewing & breathing<\/em><\/p>\n

d. Cranial kinesis<\/strong>–\u00a0Independent movement of one or more skull bones, such as pivoting quadrates<\/em><\/p>\n

3. Splanchnocranium<\/p>\n

a. Quadrate {Autostylic suspension}<\/p>\n

b. Articular<\/p>\n

c.Stapes –Homologous to hyomandibula<\/em><\/p>\n

d. Hyoid apparatus –Arch II (some 3-4)<\/em><\/p>\n

e. Larynx –Arch V<\/em><\/p>\n

4. Changes in Therapsids<\/p>\n

a. Neurocranium<\/p>\n

-2 occipital condyles<\/p>\n

b. Dermatocranium – Synapsid<\/p>\n

c. Splanchnocranium<\/p>\n

1. Quadrate & Articular freed<\/p>\n

2. Squamosal & Dentary articulate<\/p>\n

I. BIRDS<\/strong><\/p>\n

1. Neurocranium<\/p>\n

a. Larger, highly vaulted, modified reptile skull<\/p>\n

b. Incomplete dorsally<\/p>\n

c. Well ossified & fused<\/p>\n

d. 1 occipital condyle<\/p>\n

2. Dermatocranium<\/p>\n

a. Modified diapsid –Supratemporal arch is lost, so one big opening confluent with orbit<\/em><\/p>\n

b. Premaxilla and dentary = bony parts of beak<\/p>\n

c. Cranial kinesis –Quadrate & Upper jaw<\/em><\/p>\n

3. Splanchnocranium<\/p>\n

-Similar to reptiles<\/p>\n

M. MAMMALS<\/strong><\/p>\n

1. Neurocranium<\/p>\n

a. Larger<\/p>\n

b. Fusions & Loss of bones –SEE Skull & Lower Jaw Components Page<\/a><\/p>\n

c. Sutures<\/p>\n

d. Fontanels<\/p>\n

e. Sinuses<\/p>\n

f. 2 occipital condyles<\/p>\n

2. Dermatocranium<\/p>\n

a. Nasal structures<\/p>\n

Conchae = turbinates (from neurocranium too)<\/p>\n

b. Tympanic bulla –New, unique, encloses middle ear<\/em><\/p>\n

c. Malleus<\/p>\n

1. Prearticular<\/p>\n

2. Articular (splanchnocranium)<\/p>\n

d. Squamosal articulation with dentary bone [sole lower jaw bone]\n

e. Synapsid<\/p>\n

f. Decreased # bones<\/p>\n

3. Splanchnocranium –SEE Visceral Arches Page<\/a><\/p>\n

a. Quadrate – incus<\/p>\n

b. Articular – malleus<\/p>\n

N. EVOLUTIONARY TRENDS OF SKULL<\/p>\n

1. Decreased # bones\/ossification centers<\/p>\n

2. Decreased # visceral arches early<\/p>\n

3. Homology<\/p>\n

-Hyomandibula & stapes<\/p>\n

4. Analogy<\/p>\n

-Quadrate\/articular joint<\/p>\n

-Squamosal\/dentary joint<\/p>\n

5. Preadaptation –Columella, as amphibian ear is rudimentary<\/em><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

VII. AXIAL SKELETON – SKULL AND VISCERAL SKELETON A. Introduction and history Cephalization –Need cranium to house brain & sensory structures B. NEUROCRANIUM –Primarily floors and walls of cranium 1. Function –Protect 2. Phylogeny –All vertebrates have this; Replacement bone … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":270,"featured_media":0,"parent":580,"menu_order":0,"comment_status":"closed","ping_status":"open","template":"","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"class_list":["post-639","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages\/639","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/users\/270"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/comments?post=639"}],"version-history":[{"count":0,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages\/639\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/pages\/580"}],"wp:attachment":[{"href":"https:\/\/sites.msudenver.edu\/haysc\/wp-json\/wp\/v2\/media?parent=639"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}