BIOL 204 Study Guide - Midterm Guide: Appendicular Skeleton, Cranial Nerves, Vertebral Column
February 11, 2018
3:00 AM
Definition/Function
Axial Skeleton - Vertebral column, ribs, and sternum
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Appendicular skeleton - girdles and the appendages
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Skill function
Protection
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Feeding
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Breathing
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Chrondrocranium
Encases Special sense organs
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Skeletal elements
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Aka Neurocranium
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Supports and protects the ventral, lateral, and posterior parts of the
brain
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Olfactory capsules - Olfactory organs
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Optic Capsules - Protects the eyes
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Otic Capsules - Protects the inner ears
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Forms ethmoid complex - turbinals
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3 series of bones
Occipitals
Spinal Cord passage
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Sphenoids
Cranial nerves passage
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Ethmoids
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Foramina (plural for foramen) - opening through which a structure
passes; cranial nerves
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Splanchnocranium
Branchial arches - support pharynx and gills
Most vertebrates have 7
Anterior to posterior with Roman numerals □
I - Mandibular Arch
In Gnathostomes it forms the jaws
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Palatoquadrates - upper jaw
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Meckel's Cartilage - Lower jaw
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II - Hyoid Arch □
III - VII - Gill arches□
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Each arch is composed of 5 articulated elements per side
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Jaws
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Middle ear bones
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Hyoid apparatus in gnathostomes
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Dermatocranium
Encase the chrondrocranium and splanchnocranium
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Contribute to braincase, jaws, and skeletal elements of mouth
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Embryology Origins/ Morphological differences
Chondrocranium
Mesenchyme from mesoderm
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And neural crest cells from ectoderm
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Initially forms as cartilage
Cartilage in adults
Myxinoidea□
Petromyzontida□
Chondrichthyes□
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Partial or entire ossification into endochondral bone
Most teleostomi□
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Only telostomi have dermatocranium
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Braincase
Chrondrocranium also in dorsal for chondrichthyes
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Dermatocranium in dorsal for Telostomi
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Splanchnocranium
Arises from neural crest
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Forms as cartilage initially
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Jaws
Chondrichthyes retain palatoquadrate and meckel's jaw
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Teleostomi's palatoquadrate and meckel's jaw encased in
dermal bone
Lower jaw - Articular bone
forms from meckel's cartilage posterior end
protuding out of dermal bone and ossified into
endochondral bone
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Will eventually articulate with the upper jaw
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Adult has 2 parts of the dermal bone in upper jaw
Maxilla
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Premaxilla
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Quadrate bone
Forms when posterior end protruding out of
dermal bone and ossifying into endochondral
bone
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Articulates with articular bone
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Mammal's meckel's is completely encased in dermal bone.
In adults, a single bone called dentary bone make up
bottom jaw
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In top jaw of adults it is made of dermal bones□
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Location and How to Identify
Lab 3 -Vertebrate Skull
February 11, 2018
3:19 AM
