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Flashcards in Appendicular Skeleton Deck (36):
1

Pelvic girdle attachment in osteichthyes

Suspended

2

Describe limb movement in jumping

Hindlimbs extend rapidly to launch into air, forelimbs extend to cushion landing

3

Type of joint between pelvic girdle & hind limbs of tetrapods

Ball and socket (allows wide range of motion)

4

Effect of sprawled posture on girdles

Forces go up and in (medial), so large ventral girdle bones

5

Girdle composition in chondrichthyes

Cartilage

6

Pelvic girdle attachment in chondrichthyes

Suspended

7

Changes from sarcopterygiian to tetrapod girdles

1. Became stronger, more completely ossified
2. Thin fin rays -> thick digits
3. Pectoral girdle detached from skull
4. Pelvic girdle fused to sacral vertebrae

8

Advantages of terrestrial tetrapods having forward-pointing digits

Increased tractive (pulling) and propulsive (pushing) forces

9

Components of terrestrial limb locomotion during walking/running

Propulsion: contact ground, push/pull body forwards
Recovery: don't contact ground, bring limb back to propulsive position

10

Pectoral girdle composition in teleostomi

Dermal & replacement bone

11

Which pelvic girdle bone in tetrapods fuses to the sacral vertebrae?

Ilium

12

Use of sarcopterygiian fins

Highly maneuverable -> propulsion, pivoting, supporting some weight

13

2 types of terrestrial tetrapod limb posture

Sprawled (to sides) - many amphibians & sauropsids
Erect (limbs beneath body)

14

What is included in the appendicular skeleton?

Paired appendages & supporting girdles

15

Describe pelvic girdle of birds & reasoning

3 bones fuse into innominate bone; provides stability in flight & strength to withstand forces of landing

16

Pectoral girdle attachment in chondrichthyes

Suspended in body wall muscle

17

Advantages of erect limb posture

Recovery stroke is efficient pendulum-swing (cursorial movement) -> sagittal plane movement only

18

Describe fin support in jawed fish

Proximal: Sturdy elements
Distal: Fin rays

19

Bones of pelvic girdle in tetrapods

Ilium, ischium, pubis

20

Pelvic girdle composition in teleostomi

Replacement bone

21

Why would tetrapods have sturdier, more ossified girdles than sarcopterygiians?

Better to support weight and locomotion

22

Effect of erect limb posture on girdles

Forces directed upwards, so strong dorsal pectoral girdle (scapula) vs small ventral girdle (clavicles)

23

Advantages of sprawled limb posture

Retain lateral undulation -> good for swimming

24

Function of paired fins in sharks & why

Provide stability (against pitch, roll, yaw) b/c stiff & inflexible
Adjust angle for steering

25

Advantages of thick digits of tetrapods over sarcopterygiian thin fin rays

better grip, better weight support, sturdier

26

Describe pectoral girdle attachment in tetrapods & reasoning

Axial skeleton suspended like a sling by muscles; acts as shock absorber so landing/impact doesn't transmit forces to skull & brain

27

Why are distal regions of jawed fish fins supported by fin rays?

Allow control over surface area of fin hitting water

28

Benefits of detaching pectoral girdle from cranium in sarcopterygii -> tetrapods

Head moves independently
Pectoral girdle at better angle (digits can point forwards instead of splaying outwards)
Brain not jarred on each step

29

Disadvantages of sprawled limb posture

Recovery stroke requires slow, expensive over-arm swing (dorsal/ventral movement as well as anterior/posterior)

30

What's special about male sharks' pelvic girdles?

Have long claspers to transfer sperm for internal fertilization

31

Function of pelvic & pectoral girdles

Brace, support paired appendages & provide attachment sites for the muscles controlling them

32

Describe pectoral girdle structure in tetrapods compared to osteichthyans

Smaller dermal bone components (clavicles)
Larger replacment bones (scapulas, procoracoid, coracoid)

33

Function of actinopterygiian fins & why they can do this

Steer, balance, propel
-flexible & mobile -> can execute precise maneuvers, but doesn't provide speed

34

Pectoral girdle attachment in osteichthyes

Fused to vertebral column & sometimes also to skull

35

Benefits of fusing pelvic girdle to sacral vertebrae in tetrapods

More efficient transfer of energy from hindlimb propulsion to vertebral column via girdle

36

Describe adaptation of pectoral girdle in birds

Clavicles fuse into furculum; acts as spring to make flight & breathing more efficient