Axial skeleton

Question 1

Centra type: Chondrichthyes

Answer 1

Amphicoelous

Question 2

Procoelous vertebrae (def)

Answer 2

Anterior: concave
Posterior: convex
Entire centrum solid with cartilaginous intervertebral disks

Question 3

What structure carries blood vessels to the head through the cervical vertebra(e)?

Answer 3

Transverse foramen

Question 4

Describe vertebrae of gnathostomes, generally (compared to early vertebrates & agnathans)

Answer 4

Vertebrae are main axial support, attachment site for body muscles

Question 5

Amphicoelous vertebrae (def)

Answer 5

Centra concave on both ends, surrounds notochord from head to tail

Question 6

Effect of neural spine angle on function

Answer 6

Grow to better withstand forces by making them compressive

Question 7

Describe agnathan ribs

Answer 7

Non-existent

Question 8

Form & function of ribs in gnathostomes

Answer 8

Cartilage/replacement bone struts

Muscle attachment, protect viscera

Question 9

Opisthocoelous vertebrae (def)

Answer 9

Anterior: convex
Posterior: concave
Centrum solid, with cartilaginous intervertebral disks

Question 10

Who has lots of cervical vertebrae & why?

Answer 10

Aves, parareptilia -> allows greater flexibility

Question 11

Centra type: Osteichthyes

Answer 11

Amphicoelous

Question 12

Describe the axial skeleton of Myxinoidea

Answer 12

None -> 2° loss

Question 13

Sacrum: structure & function

Answer 13

Fused sacral vertebrae supporting pelvic girdle

Strong -> can withstand hind limb forces

Question 14

Who has procoelous or opisthocoelous vertebrae?

Answer 14

Most sauropsids (except aves), many amphibians (not all)

Question 15

Heterocoelous vertebrae (def)

Answer 15

Both ends saddle-shaped
Vertebrae can move in different directions relative to each other (flexible)
Cartilaginous intervertebral disks

Question 16

Centra type: Mammals

Answer 16

Acoelous

Question 17

Describe the axial skeleton of Petromyzontida

Answer 17

DORSAL (only) cartilaginous arches protecting spinal cord; no muscle connection or body support

Question 18

Describe the axial skeleton of Osteichthyes

Answer 18

Ossified
Centra: Major axial support, surrounds notochord
Neural arches & hemal arches
Neural spines & ribs are large for muscle attachment

Question 19

Function of intervertebral ligaments

Answer 19

Control/limit flexibility & movement of vertebral column

Question 20

Who has an atlas?

Answer 20

Tetrapods

Question 21

Function of neural spines in terrestrial mammals

Answer 21

Muscle attachment to pull vertebral column into arch to direct compressive forces into centra, then down into legs

Question 22

Describe amniote ribs

Answer 22

Some, at least, connect to sternum

Question 23

Centra type: Sauropsids other than Aves

Answer 23

Procoelous or opisthocoelous

Question 24

Acoelous vertebrae (def)

Answer 24

Flat on both ends

Question 25

Transverse foramen (def)

Answer 25

Holes in cervical vertebrae to carry blood vessels to head

Question 26

Synsacrum structure

Answer 26

Fused sacral, lumbar, some thoracic & caudal vertebrae in aves

Question 27

Describe bird sternum, function

Answer 27

Large carina/keel - for attachment of flight muscles

Question 28

Describe the atlas

Answer 28

- most anterior cervical vertebra - no centrum - allows nodding motion - seen in all tetrapods

Question 29

Describe fish ribs

Answer 29

single-headed

Question 30

Define zygapophyses & give their function

Answer 30

Processes on the anterior and posterior neural spine | Lock with those on adjacent vertebrae to prevent torsion

Question 31

Describe axial skeleton regionalization in gnathostome fish and what it says about them

Answer 31

Trunk (has ribs), caudal (has no ribs) | Similar throughout because 1 function: muscle attachment for swimming

Question 32

Who has amphicoelous vertebrae?

Answer 32

Chondrichthyes, osteichthyes, some amphibians

Question 33

Function of synsacrum

Answer 33

Stability in flight Strength in landing Can be thinner/lighter b/c stronger, don't need muscles & ligaments to maintain posture

Question 34

Describe vertebrae of early vertebrates, agnathans (general)

Answer 34

notochord acts as main axial support, vertebrae are cartilaginous arches protecting spinal cord (neural arches) and dorsal aorta (hemal arches)

Question 35

Who has acoelous vertebrae?

Answer 35

Mammals

Question 36

Describe the axial skeleton of Chondrichthyes

Answer 36

Cartilaginous Centrum: support, surrounds notochord Neural arches: protect spinal cord Hemal arches (caudal vertebrae), ribs (trunk vertebrae): protect dorsal aorta & other blood vessels

Question 37

Centra type: Mammals

Answer 37

Acoelous

Question 38

Describe the axis

Answer 38

2nd cervical vertebra Has odontoid process projecting anteriorly into atlas neural canal; Allows head rotation

Question 39

Describe amphibian ribs

Answer 39

Short (don't connect to sternum)

Question 40

Describe axial skeleton regionalization in early tetrapods and what it says about them

Answer 40

Cervical: allows cranial mobility (not needed in fish b/c decreases streamlining) Trunk Sacral: for pelvic girdle attachment Caudal

Question 41

How does neural spine height affect function?

Answer 41

Increases length of lever arm -> same muscle can do more work in pulling column into arch

Question 42

Who has zygapophyses?

Answer 42

Tetrapods

Question 43

Centra type: Amphibia

Answer 43

Most: procoelous or opisthocoelous Some: amphicoelous

Question 44

Describe aves ribs

Answer 44

Uncinate processes connect vertebral (costal) ribs, expanding ribcage faster

Question 45

Describe axial skeleton regionalization in early amniotes and what it says about them

Answer 45

Cervical (cranial motility), thoracic (ribs), lumbar (no ribs), sacral (pelvic girdle attachment), caudal -Lumbar allows back to flex as hind limbs push forwards for more efficient propulsion; decreases protection

Question 46

Function of sternum

Answer 46

Support & stabilize pectoral girdle

Question 47

Who has an axis?

Answer 47

Amniotes

Question 48

Who has heterocoelous vertebrae?

Answer 48

Aves

Question 49

Effect of locomotion method on sternum size

Answer 49

Bigger if forelimbs important in locomotion (lots of forces)