Comparative Verterbrate Anatomy - Exam 2 Review

What does the modern vertebra consist on?

• Centrum

• Neural Arch

• Processes (Apohpyses)

Vertrebral Arch

Protect the spinal cord.

Neural/Vertebral Canal

Successive arches and their connecting ligaments

Hemal Arch

Ventral to the centra in the tail of some vertebrates and will house the caudal artery

Transverse Processes (Diapophyses)

Articulate with ribs and serve for muscle and ligament attachment

Articulating Processes (Zygapophyses)

Allow for articulation between successive vertebrae.

Superior Articulating Processes (Prezygapophyses)

Paired structures on the cranial aspect of the vertebrae that allow one

vertebra to attach to the vertebra cranial to it.

Inferior Articulating Processes (Postzygapophyses)

Paired structures on the caudal aspect of the vertebrae that allow one

vertebra to attach to the vertebra caudal to it.

Parapophyses

Paired lateral processes off of the centrum that occur in a few vertebrates having biccipital ribs.

Hypophyses

Prominent midventral projections from the centrum in

snakes and a few other amniotes

Endochondral ossification

Arches arising from cartilage

Diplospondyly

When there are two centra per segment.

Mesenchyme

Membrane bone in teleosts, apodans, and urodeles

Amphicelous

Concave at both neural and caudal ends.

Hypocentrum (aka Intercentrum),

“U-shaped” bone on the anterior aspect of the vertebrae that cradled the notochord.

Pleurocentra

Small wedge-shaped portions of bone that sat on the dorsolateral aspect of the notochord.

What is the neural arch composed of a pair of what surrounds the spinal cord?

Lamellae

What is the portion of the rachitimous vertebra became the body?

Pleurocentrum

What is the portion of the rachitimous was lost?

Hypocentrum

Rachitomous

Many pieces

Procelous vertebrae

Concave on the cranial aspect of the centrum

Amphicelous Vertebrae are found in?

• most fishes

• generalized urodeles and apodans

• sphenodon

• basal lizards

Procelous Vertebrae are found in?

• anurans

• modern reptiles

Opisthocelous Vertebrae are seen in?

some salamanders

Opisthocelous Vertebrae

caudal aspect of the centrum is concave

Acelous Vertebrae are found in?

mammals

Acelous vertebrae

lack a concavity on either end.

Nucleus Puplous

core of notochord within each intervertebral disc

Cervical

Located in the neck these vertebrae are designed to

increase head movement.

Thoracic (Trunk)

Associated with long ribs designed to protect the viscera. These vertebrae provide some support for the pectoral girdle.

Lumbar

Lower Back

Sacral (Pelvis)

Support the pelvic girdle.

Caudal

Vertebrae of the tail

Modern amphibians have how many cervical vertebrae?

One

How many cervical vertebrae do humans have?

7

Which group have the most cervical vertebrae?

Birds

C1 (Altas)

ring-shaped bone

C2 (Axis)

modified vertebra having a cranially projecting

process called the Odontoid Process.

Synsacrum in birds

• the sacral vertebrae

• the last thoracic vertebra

• all of the lumbar vertebrae

• the first few caudal vertebrae

Ribs

flat bones that articulate with the vertebrae and extend into the body wall.

True ribs

arise by endochondral ossification.

Gastralia (Abnormal Ribs)

arise by intermembranous ossification

Dorsal ribs

project laterally into the body wall in the skeletogenous septum that divides the epaxial and hypaxial muscle groups.

Ventral ribs

project ventrally

Bicipital Ribs

attach to the paraphyses

Costal Rib

portion to attach to the vertebrae.

Sternal Rib

portion to attach to the sternum

Birds have what processes?

Uncinate Process

Costal Cartilage

cartilage associated with the ribs

Carina

a keel-like structure for the attachment of

massive pectoral musculature in birds.

Xiphoid Process

The last sternebra in humans

Neurocranium

primary brain case, the chondrocranium and endocranium.

Dermatocranium

Skull bones which are phylogenetically derived from integumentary bones.

Splanchnocranium

the visceral skeleton

neurocranium’s two pairs of cartilage.

• Prechordal cartilages

• Parachordal Cartilages

Prechordal cartilages

located deep to the optic placode beneath the forebrain.

Parachordal Cartilages

located parallel to the notochord beneath the midbrain and hindbrain.

Prechordal cartilages form what?

Ethmoid Plate

Parachordal cartilages form what?

Basal Plate

Agnathans

poorly developed neurocranium with no tectum

Chondrichthyes

completely cartilaginous neurocranium.

Basioccipital Bone

forms from one or more ossification centers

Exoccipital Bones

form from centers located lateral to the foramen magnum.

Supraoccipital Bone

forms superior to the foramen magnum.

All four bones fuses together to make what?

Occipital Bone

What groups have one occipital

condyle on the basioccipital.

• amphibians

• reptiles

• birds

Which group have two occipital condyles located on the exoccipitals.

• amphibians

• mammals

What houses the pituitary gland?

Sella Turcica

Sphenethmoid Bone

the sphenoid and ethmoid formed together

Temporal bones

the petrosal bone joining with the squamosal bone

The ossification of temporal bones

Both intermembranous and endochondral

What bones make up the temporal bones

• Squamosal

• Petrosal

• Mastoid

Roofing bones

Form along the brain and neurocranium.

Marginal bones

Bones of the upper jaw.

Dermal bones

Primary palate.

Primary palate

forms the roof of the oral cavity in tetrapods and the roof of the oropharynx in fishes.

Columnella

First auditory occipital to evolve

How many exoccipital in reptiles?

2 exoccipitals

How many supraocciptals in reptiles?

1 supraoccipital

How many basiocciptals in reptiles?

1 basioccipital

How many laterosphenoids in reptiles?

2 laterosphenoids

How many ethmoids in reptiles?

2 ethmoids

Anapsid skulls

lack a temporal fossa

What group have anapsid skulls?

• reptiles

• turtles

Synapsid skulls

Have one temporal fossa on each side of the

skull.

What groups have Synapsid skulls?

Mammals

Diapsid skulls

have two temporal fossae on each side of the skull.

What groups have diapsid skulls?

modern reptiles

What group has sinuses?

Humans (mammals)

Secondary palate

horizontal osseous partition that divides the oral cavity of amphibians and fishes into a nasal cavity and an oral cavity in amniotes.

Hyostyly

The hyomandibular cartilage is braced against the otic capsule and the palatoquadrate cartilage is braced against the hyomandibular cartilage.

Amphistyly

The hyomandibular cartilages and one or more pairs of palatoquadrate processes are braced independently against the braincase.

Autostyly

The palatoquadrate alone is attached to the neurocranium.

Quadrate Bone.

ossification of the palatoquadrate posterior tip.

Articular Bones

ossification of meckel’s cartilage atits caudal end

Articular bones evolved into?

Malleus

Quadrate Bones evolved into?

Incus

What’s the only bone of the lower jaw that is found in reptiles and modern mammals

Dentary/Mandible

Cranial Horns

deprived from 2nd arch

Caudal Horns

deprived 3rd arch