Skeletal System - 1b

Question 1

Two main divisions of vertebrate skeleton

Answer 1

1. axial skeleton
2. appendicular skeleton

Question 2

axial skeleton

Answer 2

1. skull
2. vertebral column
3. sternum
4. ribs

Question 3

appendicular skeleton

Answer 3

1. limbs
2. fins
3. wings
4. pectoral and pelvic girdles

Question 4

• Supports the head and trunk
• Protects the spinal cord and roots of spinal nerves

Answer 4

vertebral column

Question 5

segments of vertebral column from superior to inferior

Answer 5

1. cervical
2. thoracic
3. lumbar
4. sacral
5. coccyx

Question 6

cervical

Answer 6

neck

Question 7

thoracic

Answer 7

chest

Question 8

lumbar

Answer 8

small of back

Question 9

sacral

Answer 9

sacrum/pelvic

Question 10

coccyx

Answer 10

tailbone

Question 11

consisted of an hypocentrum plus 2 pleurocentra called a rachitomous vertebra

Answer 11

Crossopterygian vertebrae

Question 12

Crossopterygian vertebrae composition

Answer 12

1. hypocentrum
2. rachitomous vertebra

Question 13

large, wedge-shaped piece

Answer 13

hypocentrum

Question 14

smaller intersegmental pieces

Answer 14

pleurocentra

Question 15

two pleurocentra

Answer 15

rachitomous vertebra

Question 16

trend in vertebra evolution

Answer 16

• pleurocentra to increase in size
• hypocentrum to decrease in size

Question 17

consists of centrum, 1 or 2 process, and various processes

Answer 17

vertebrae

Question 18

parts of the vertebrae

Answer 18

1. neural spine
2. neural arch
3. centrum
4. neural canal
5. zygapophyses
6. diapophyses
7. parapophyses

Question 19

Types of centrum

Answer 19

1. amphicelous
2. acelous
3. procelous
4. opisthocoelous
5. heterocoelous

Question 20

• concave at both ends
• most fish, a few salamanders (Necturus), & caecilians

Answer 20

amphicelous

Question 21

• flat-ended centrum
• mammals

Answer 21

acelous

Question 22

• concave in front & convex in back
• anurans & present-day reptiles

Answer 22

procelous

Question 23

• convex in front & concave in back
• most salamanders

Answer 23

opisthocoelous

Question 24

• saddle-shaped centrum at both ends
• birds

Answer 24

heterocoelous

Question 25

amphicelous animals

Answer 25

- most fish - few slamanders (_Necturus_) - caecilians

Question 26

acelous animals

Answer 26

mammals

Question 27

procelous animals

Answer 27

- anurans - present-day reptiles

Question 28

opisthocoelous animals

Answer 28

most salamanders

Question 29

heterocoelous animals

Answer 29

birds

Question 30

vertebral arches

Answer 30

1. neural arch 2. hemal arch/ chevrons

Question 31

on top of centrum

Answer 31

neural arch

Question 32

beneath centrum in caudal vertebrae of fish, salamanders, most reptiles, some birds, & many long-tailed mammals

Answer 32

hemal arch/ chevrons

Question 33

- most common type of process - extend laterally from the base of a neural arch or centrum & separate the epaxial & hypaxial muscles

Answer 33

transverse processes

Question 34

articulate with ribs

Answer 34

- diapophyses - parapophyses

Question 35

- articulate with one another and limit flexion and torsion of the vertebral column - projection from arches and centra - some give rigidity to the column, articulate with ribs, or serve as sites of muscle attachment

Answer 35

- prezygapophyses - postzygapophyses

Question 36

prezygapophyses

Answer 36

cranial zygapophyses

Question 37

postzygapophyses

Answer 37

caudal zygapophyses

Question 38

- do not have typical fish vertebral columns - vertebrae include neural arches (cartilaginous dorsal plates) & dorsal intercalary plates are located between successive arches

Answer 38

cartilaginous fishes

Question 39

vertebra of cartilaginous fishes

Answer 39

1. neural arches (cartilaginous dorsal plates) 2. dorsal intercalary plates

Question 40

located between successive arches

Answer 40

dorsal intercalary plates

Question 41

- well-ossified amphicelous vertebrae - notochord persists within each centrum (but constricted) - neural arch associated with each centrum & hemal arches in tail (caudal) vertebrae

Answer 41

teleost

Question 42

arch in tail of teleost vertebrae

Answer 42

hemal arches

Question 43

single cervical vertebra; allows little head movement

Answer 43

amphibians

Question 44

increased numbers of cervical vertebrae (usually 7) & increased flexibility

Answer 44

reptiles

Question 45

usual no. of cervical vertebrae of reptiles

Answer 45

7

Question 46

variable number of cervical vertebrae (as many as 25 in swans)

Answer 46

Birds

Question 47

no. of cervical vertebrae of swans

Answer 47

25

Question 48

usually 7 cervical vertebrae

Answer 48

mammals

Question 49

mammal with six cervical vertebrae

Answer 49

- manatee - two-toed sloth

Question 50

mammal with eight cervical vertebrae

Answer 50

ant bear

Question 51

mammal with nine cervical vertebrae

Answer 51

three-toed sloth

Question 52

animals that have its 1st two cervical vertebrae modified & called the atlas & axis

Answer 52

- reptiles - birds - mammals

Question 53

- 1st cervical vertebra - ring-like (most of centrum gone) - provides 'cradle' in which skull can 'rock' (as when nodding 'yes')

Answer 53

atlas

Question 54

2nd cervical vertebra

Answer 54

axis

Question 55

animals with ribs confined to anterior region of trunk

Answer 55

- Crocodilians - lizards - birds - mammals

Question 56

vertebrate with ribs

Answer 56

thoracic

Question 57

vertebrate without ribs

Answer 57

lumbar

Question 58

- may be long or short, cartilaginous or bony - articulate medially with vertebrae & extend into the body wall

Answer 58

Ribs

Question 59

have 2 pair of ribs for each centrum of trunk (dorsal and ventral rib)

Answer 59

A few teleosts

Question 60

what does dorsal rib separate

Answer 60

epaxial and hypaxial muscles

Question 61

ventral ribs only

Answer 61

most teleost

Question 62

dorsal rib only

Answer 62

sharks

Question 63

no ribs

Answer 63

agnathans

Question 64

ribs usually articulate with vertebrae in moveable joints

Answer 64

Tetrapods

Question 65

ribs articulated with every vertebra from the atlas to the end of the trunk

Answer 65

Early tetrapods

Question 66

long ribs limited to thoracic region

Answer 66

Later tetrapods

Question 67

most composed of a dorsal element (vertebral rib) & a ventral element (sternal rib)

Answer 67

Thoracic Ribs

Question 68

dorsal element

Answer 68

vertebral ribs

Question 69

ventral element

Answer 69

sternal rib

Question 70

- may be ossified (birds) - or remain cartilaginous (mammals) - usually articulate with sternum (except 'floating ribs')

Answer 70

Sternal ribs

Question 71

- found in birds - provides rib-cage with additional support

Answer 71

uncinate processes

Question 72

- Protects the heart and lungs, and assists breathing - Support by the thoracic vertebrae

Answer 72

rib cage

Question 73

how many pairs of ribs are there

Answer 73

12

Question 74

connect directly to sternum

Answer 74

true ribs

Question 75

no. of true ribs

Answer 75

7 pairs

Question 76

do not connect directly to sternum

Answer 76

false ribs

Question 77

no. of false ribs

Answer 77

5 pairs

Question 78

do not connect to any bony/cartilaginous structure ventrally

Answer 78

floating ribs

Question 79

sternum in amphibians

Answer 79

- absent in early amphibians - only present in anurans among present-day amphibians

Question 80

- sternum is a plate of cartilage & replacement bone - sternum articulates with the pectoral girdle anteriorly & with a variable number of ribs

Answer 80

amniotes

Question 81

name given to vertebrae between cervicals & sacrals when all articulate with similar ribs (e.g., fish, amphibians, & snakes)

Answer 81

dorsals

Question 82

e.g. of animals with dorsals

Answer 82

1. fish 2. amphibians 3. snakes

Question 83

have short transverse processes that brace the pelvic girdle & hindlimbs against the vertebral column

Answer 83

sacral vertebrae

Question 84

no. of sacral vertebrae in amphibians

Answer 84

1

Question 85

no. of sacral vertebrae in living reptiles and most birds

Answer 85

2

Question 86

no. of sacral vertebrae in most mammals

Answer 86

3-5

Question 87

- single bony complex consisting of fused sacral vertebrae - found when there is more than 1 sacral vertebra

Answer 87

sacrum

Question 88

- found in birds - produced by fusion of last thoracics, all lumbars, all sacrals, & first few caudals - fused with pelvic girdle - provides rigid support for bipedal locomotion

Answer 88

synsacrum

Question 89

what is fused in synsacrum

Answer 89

- last thoracics - all lumbars - all sacrals - first few caudals

Question 90

no. of caudal vertebae in primitive tetrapods

Answer 90

50 or more

Question 91

- number of caudal vertebrae is reduced - arches & processes get progressively shorter (the last few caudals typically consist of just cylindrical centra)

Answer 91

present-day tetrapods

Question 92

unique terminal segment called the urostyle

Answer 92

anurans

Question 93

unique terminal segment in anurans

Answer 93

urostyle

Question 94

last 4 or 5 caudal vertebrae fused to form pygostyle

Answer 94

birds

Question 95

what is formed when last 4 or 5 caudal vertebrae in birds is fused

Answer 95

pygostyle

Question 96

last 3 to 5 caudal vertebrae fused to form coccygeal (or tail bone)

Answer 96

apes and humans

Question 97

what is formed by the fusion of 3-5 caudal vertebrae of apes and humans

Answer 97

coccygeal or tail bone

Question 98

small, rounded elevation on an organ or bone

Answer 98

Tuberculum

Question 99

ventral rib head

Answer 99

capitulum

Question 100

- two cylinder-shaped projections of hard bone that stick out from the back part of the vertebral body, providing side protection for the spinal cord and nerves - also serve as a bridge, joining the front and back parts of the vertebra.

Answer 100

pedicles