Skeletal System - The Skull Flashcards

1
Q

Skeletal framework of the head

A

Skull = cranium = head skeleton

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2
Q

the skulll of vertebrates are composed of these

A

Main braincase, the cranium (neurocranium) which surrounds and protect the brain

Sense capsules associated in development with the olfactory, auditory and visual sense organs

Numerous components of the visceral skeleton

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3
Q

the skull is composed of three originally independent units:

A

Neurocranium or primary braincase
Dermatocranium
Splanchnocranium or visceral skeleton

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4
Q

part of the skeleton that is loosely associated in early vertebrates and closely associated in amniotes

A

skull

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5
Q

Components of the Cranium
Cartilage or endochondral bone
Floor and wall of braincase and sense capsules

A

Neurocranium

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6
Q

Components of the Cranium
Membrane or dermal bone but never cartilage nor endochondral bone
Superficial covering of the skull (roof and sides of skull and parts of the mandible)

A

Dermatocranium

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7
Q

Components of the Cranium
Cartilage or endochondral bone
Part of the visceral skeleton (gill arches) associated with the skull
Mostly visceral arches I and II

A

Splanchnocranium

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8
Q

Components of Splanchnocranium

A

composed of the embryonic upper jaw cartilage and its replacement bones
Embryonic lower cartilage and its replacement and investing bones

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9
Q

Components of the Cranium

Protects the brain and certain special sense organs

Arises as cartilage

Subsequently partly or wholly replaced by bone except in cartilaginous fishes

A

Neurocranium

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10
Q

how is the Neurocranium formed

A

Starts as several independent cartilages that later expand and unite to form a cartilaginous braincase

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11
Q

Embryology process

A

After the formation of the embryonic brain, the mesenchyme differentiate to form a membranous layer called the membranous cranium

The notochord extends forward beneath the brain, terminating near the infundibulum

The membranous cranium surrounds the anterior portion of the notochord

The parachordal plates are located lateral to the notochord and otic capsules

Prechordal cartilages formed in front of the parachordals

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12
Q

The ventral region of the membranous cranium will become the ______

A

neurocranium

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13
Q

Neurocranium begins as pair of ______________ cartilages below the brain

A

parachordal and prechordal cartilages

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14
Q

plates that are located lateral to the notochord and otic capsules

A

parachordal plates

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15
Q

expand and join along with the notochord to form the basal plate enclosing the tip of the notochord and later becomes the floor beneath the midbrain and the hindbrain

A

Parachordal cartilages

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16
Q

______________ formed in front of the parachordals

A

Prechordal cartilages

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17
Q

cartilages expand and join to form an ethmoid plate that later will become the rostrum

A

Prechordal

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18
Q

contributes to the formation of the internasal septum between the nasal capsules

A

rostrum

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19
Q

Simultaneou with the formation of cartilages, three pair of capsules are formed from the developing sense organs:

A

Nasal capsules from the olfactory sense organ
Otic capsules from the auditory sense organ
Optic capsules from the optic sense organ

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20
Q

fuses with olfactory capsules and the basal plate fuses with otic capsules to complete the roof, sides and floor of the brain

A

ethmoid plate

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21
Q

unite posteriorly leaving a prominent opening in the center, the hypophyseal fenestra, where the pituitary gland lies

A

prechordals and parachordals

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22
Q

Endochondral ossification occurs more or less simultaneously at 4 regional ossification centers:

A

Occipital
Sphenoid
Ethmoid
Otic

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23
Q

Cartilage surrounding the foramen magnum can be replaced by as many as 4 bones:

A

Supraoccipital bone dorsally
Exoccipital bones laterally
Basioccipital bone ventrallly

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24
Q

One or more of the 4 may remain cartilaginous in what modern class of vertebratesn

A

modern amphibians

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25
Q

Cartilage surrounding the foramen magnum can be replaced by as many as 4 bones and All four bones fuse in mammals to form a single bone called the

A

occipital bone

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26
Q

Articulation of the neurocranium with the 1st vertebra is via the ________

A

occipital condyles

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27
Q

what class have a single condyle borne out of the basioccipital bone

A

Stem amphibians

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28
Q

two classes that have a single condyle

A

Living reptiles and birds

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29
Q

two classes that have shifted the condyle to the two exoccipitals

A

Modern amphibians and mammals

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30
Q

what centers Osssifies independently in the synapsid and reptilian lineages

A

Sphenoid Centers

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31
Q

sphenoid that forms from the cartilage underlying the midbrain and pituitary gland

A

Basisphenoid

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32
Q

sphenoid that ossifies anterior to the basisphenoid in mammals
Also contributes to the sidewall above the basisphenoid

A

Presphenoid

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33
Q

sphenoid bone (crocodiles and dinosaurs) forms the lateral ossification of the sphenoid redion

A

Laterosphenoid

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34
Q

sphenoid bone (archosaurs) forms a separate interorbital septum

A

Orbitosphenoid

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35
Q

sphenoid bone helps to form the lateral wall in some mammals though it is derived from the palatoquadrate cartilage

A

Alisphenoid

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36
Q

Sphenoid Centers

A

Basisphenoid, presphenoid, alisphenoid, Laterosphenoid, Orbitosphenoid

37
Q

mammals can form a single sphenoid bone with wings

A

Basisphenoid, presphenoid and alisphenoid

38
Q
A
39
Q

Lies anterior to the sphenoid and includes the _________ and olfactory capsules

Tends to remain cartilaginous in tetrapods from amphibians to mammals

A

Ethmoid Centers

39
Q

No replacement bones develop above the brain

A

true

39
Q

Pituitary gland rests on the ________ of the basisphenoid regions

A

tella surcica

40
Q

Most basal tetrapods develop no ____________ whatsoever

A

ethmoidal ossification centers

41
Q

Ossification centers in amniotes are chiefly _____________

A

mesethmoid bones

42
Q

Ossification centers in amniotes are chiefly mesethmoid bones contribute to:

A

Cartilaginous nasal septum of birds and mammals and the anterior portion of interorbital septum in birds

One or more scroll-like turbinal bones (conchae) of most reptiles, birds and mammals

Cribriform plate perforated by olfactory foramina in mammals

43
Q

in anurans is the sole bone arising in the ethmoid and sphenoid regions

A

Sphenethmoid

44
Q
A
45
Q

develops in the lateral walls of the nasal passageway of Sphenodon

A

Ectethmoid

46
Q

cartilages found in the nasal passages are not from ethmoid ossification

A

Winglike alar bone and small sesamoid cartilages

47
Q

capsule surrounding the membranous labyrinth becomes the prootic, opisthotic and epiotic

A

Otic capsule

48
Q

One or more may unite with adjacent replacement of mebrane bones

A

Otic Centers

49
Q
A
50
Q

fuse with exoccipitals in frogs and nonavian reptiles

A

Opisthotics

51
Q

unite to form a single periotic or petrosal bone in mammals

A

Prootic, opisthotic and epiotics

52
Q

may unite with the squamosal to form a temporal bone

A

Petrosal bone

53
Q

Occipital bones in
Fishes (Teleost)
Amphibians
Reptiles/Birds
Mammals

A

Supraoccipital
Exoccipital
Basioccipital

54
Q

Mesethmoid bone is present in what classes

A

Mammals (ethmoid)
(absent in primitive mammals and ungulates)

Fishes (Teleost)

55
Q
A
56
Q

Ethmoid region in
Fishes (Teleost)
Amphibians
Reptiles/Birds
Mammals

is ossified, unossifed, or turbinals

A

Fishes (Teleost) - ossified
Amphibians - unossifed
Reptiles/Birds - unossifed
Mammals - turbinals

57
Q
A
58
Q

are these sphenoid bones present in each class

Sphenethmoid
Orbitosphenoid
Basisphenoid
Pleurosphenoid

A

fish
Sphenethmoid
Orbitosphenoid
Basisphenoid
Pleurosphenoid

ampibhians
Sphenethmoid
Orbitosphenoid
Basisphenoid

Aves, Reptiles
Sphenethmoid
Orbitosphenoid
Basisphenoid
Pleurosphenoid (crocodiles and amphibians)

Mammals
Sphenethmoid
Orbitosphenoid
Basisphenoid

59
Q

Laterosphenoid is only present in what animal

A

snake

60
Q

whatotic capsule perotic part is present in what classes

A

Fishes (teleost)
Prootic
Epiotic
Sphenotic

Amphibians
Prootic
Opisthotic

Aves
absent

Reptiles
Prootic
Epiotic
Sphenotic

Mammals
Petrosal withvmastoid process

60
Q

This bone is of dermal origin, so it is not strictly homologous to tetrapod _________.

A

mesethmoid

60
Q

This bone is usually absent or reduced in some fishes.

A

Basisphenoid

61
Q

Associated with the filter-feeding surfaces

Generally supports the gills and offer attachment for respiratory muscles

Contributes to the jaws and hyoid apparatus of gnathostomes

May remain cartilaginous or become covered by dermal bones

A

Splanchnocranium

62
Q

Declines in importance in tetrapods but never disappears

A

Splanchnocranium

63
Q

Each visceral arch consists of a:

A

Skeleton
Branchiomeric muscle
Cranial nerve
Aortic arch
Gill filaments

64
Q

came from neural crest cells departed from the sides of the neural tube and migrate into the walls of the pharynx between successive pharyngeal slits

Differentiate into respective pharyngeal arches

A

Blastemas

65
Q

are associated with their respiratory gill system called branchial or gill arches in aquatic vertebrates

A

Pharyngeal arches

66
Q

Each arch is composed of a series of up to five articulated elements on each side (from dorsal to ventral):

A

Pharyngobranchial
Epibranchial
Ceratobranchial
Hypobranchial
Basibranchial

67
Q

The first fully functional arch of the jaw is the ____________, which is the largest and most cranial

Composed of the dorsal palatoquadrate and ventral Meckel’s cartilage

A

mandibular arch

68
Q

The arch that follows the mandibular arch composed of the myomandibula

A

hyoid arch

69
Q

Mouth of agnathans is not supported by jaws

The __________ supports the roof of the pharynx and lateral pharyngeal slits

A

splanchnocranium

70
Q

agnathan fish that were restricted to a diet of small particulate food

A

Ostracoderms

71
Q

adaptation in agnathans for eating food

A

In some groups, small teeth-like structures derived from the surface scales, surrounded the mouth and used to scrape rocks for food

The mucus-lined walls of the pharynx collected these scraped food particles from the passing stream

72
Q

Jaws first appeared in ____________ that used them as food traps or as crushing or chewing devices to process food in the mouth

A

acanthodians and placoderms

72
Q

The branchial arches gave rise to jaws as proposed by two separate theories on its origin:

A

Serial theory
Composite theory

73
Q

what theory says that the jaws arise completely from one of the cranial branchial arches

Elements may be lost within it, but other elements from other arches do not contribute

A

Serial Theory

74
Q

the theory that imples that the mandibular arch is formed from elements of several adjacent arches that also contribute to the neurocranium

The palatoquadrate forms from the fusion of the epibranchial of the premandibular arch with the epibranchial and pharyngobranchial of the mandibular arch

Meckel’s cartilage arises from the enlarged ceratobranchial element

Hyoid arch arises from the epibranchial, ceratobranchial and hypobranchial elements of the 3rd gill arch

The other elements of the primitive arches are lost and fused to the neurocranium

A

Composite Theory

75
Q

Types of Jaw Attachment

A

Paleostylic
Euautostylic
Amphistyly
Hyostyly
Metaautostyly
Craniostyly

76
Q

Characteristic of agnathans
None of the arches attach directly to the skull

A

Paleostylic

77
Q

Found in placoderms and acanthodians
Mandibular arch is suspended from the skull by itself without the aid from the hyoid arch

A

Euautostylic

78
Q

Found in early sharks, some osteichthyans and crossopterygians
Attached to the braincase through two primary articulations
Cranially by a ligament connecting the palatoquadrate to the skull
Caudally by the hyomandibular

A

Amphistyly

79
Q

Found in most bony fishes
The mandibular arch is attached to the braincase primarily through the hyomandibula with the aid of the symplectic bone

A

Hyostyly

80
Q

Found in most amphibians, reptiles and birds
Attached to the braincase directly through the quadrate bone
Formed in the caudal part of the palatoquadrate

A

Metaautostyly

81
Q

Found in mammals
The entire upper jaw is part of the braincase but the lower jaw called dentary bone is suspended from the dermal squamosal bone of the braincase
The palatoquadrate and Meckel’s cartilages remain cartilaginous except at their posterior ends which becomes the incus and malleus of the middle ear respectively

A

Craniostyly

82
Q

Earliest vertebrates are encased in bony dermal armor and the extent to which it covers the body is variable

Bony plates are present in the head

A

Dermatocranium

83
Q
A