Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Comparative Anatomy > Lecture 11 > Flashcards

Lecture 11 Flashcards

1
Q

Dermal components of pectoral girdle

A

Cleithrum
Clavicle
Interclavicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Function of dermal components of pectoral girdle

A

Support endochondral components and articulate them with axial skeleton

Provide surfaces for muscle attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Endochondral components of pectoral girdle

A

Procoracoid
Coracoid
Scapula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Function of endochondral components of pectoral girdle

A

Carry the limb articulation: glenoid cavity

Serve as major base of attachment for limb muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Shark pectoral girdle

A

Only consists of endochondral components

Main component is coracoid bar:

  • carries fin attachment
  • typically U-shaped
  • scapular processes sit on top of lateral ends of coracoid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pectoral girdle in bony fishes

A

Cleithrum and clavicle of the pectoral girdle are united with the dermal components of the skull

Other components include supracleithrum and posttemporals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Dermal components in tetrapods

A

Separate from the dermal skull components

Cleithrum not found in modern tetrapods

Interclavicle in fossil amphibians

Clavicles and interclavicles are found in lizards and sphenadon; present in monotremes

Clavicles lost in many mammals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Dermal components in tetrapods: birds

A

Birds:
Clavicles + interclavicle= Furculum
Coracoid brace wings against sternum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Pectoral girdle in tetrapods

A

Connection between pectoral girdle and skull is lost in fossil and modern amphibians-allowing for more freedom of movement of head

Cleithrum and clavicle are long, slender rods located along anterior margin of scapula in primitive tetrapods

Fate of original coracoid bar:

  • -becomes paired
  • -forms a scapulocoracoid cartilage on each side with a glenoid fossa in the middle: scapula is above the fossa; coracoprecoracoid region is located below the fossa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Pectoral girdle in tetrapods (anurans)

A

Interclavible is new, diamond-shaped, unpaired element that appears first in fossil amphibians but is lost in modern amphibians

Cleithrum is rudimentary in modern anurans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pectoral girdle in tetrapods (salamanders)

A

Dermal components are lost in modern salamanders

Much of the endochondral girdle remains unossified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pectoral girdle in amniotes

A

Most reptiles:

  • Cleithrum disappears early in reptiles
  • Endochondral girdle similar to that of fossil amphibs.
  • In crocs and dinos, glenoid fossa is formed by articulation of both the scapula and procoracoid, which meet at an angle at the fossa

Turtles:

  • Dermal elements have disappeared into the plastron
  • Pectoral girdle is triradiate

Pelycosaurs:
-Added a true coracoid

Therapsids and monotremes:

  • Development of acromoin process
  • Coracoid is fully developed in monotremes but is reduced to a coracoid process in other mammals

Birds:

  • Endochondral pectoral girdle similar to Dino’s
  • Coracoids serve as wing braces against sternum
  • Clavicle and interclavicle fuse to form furcula (“wishbone”)

Primitive mammals:
-Both paired clavicles and interclavicle present

Others mammals:

  • Interclavicles are lost
  • Clavicles are often reduced or lost in running and bounding forms such as ungulates and carnivores
  • Bats have elongated clavicles and coracoid processes
  • Entire coracoid plate, along with procoracoid, are lost in marsupials and placentals
  • Original anterior margin of scapula develops a shelf-like process and acromion process which serve as attachment sites for muscles
  • Scapular spine separate the supraspinous fossa from the infraspinous fossa
  • Musculature that was originally attached to the coracoid plate has shifted to the scapula
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Triradiate pectoral girdle in turtles

A

Anterior ventral prong=downward extension of scapula

Connected to clavicle plate embedded in plastron

Posterior ventral prone=procoracoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sternum

A

Found in:
Amphibians
Birds
Mammals

Lost in:
Turtles
Snakes
Snakelike lizards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pelvic girdle

A

Lacks dermal components in all vertebrates.
Consists of 3 paired endochondral bones:

1) Pubis: located ventral and anterior to the other two components
2) Ischium: located ventral and posterior to the other two components
3) Ilium: located dorsal to the other two components

All three bones carry limb articulation in most vertebrates:
Acetabulular fossa

  • Ilium articulates with sacral vertebrae either directly or via sacral ribs
  • Pubis and ischium are primarily for muscle attachment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pelvic girdle in the shark

A
  • entirely cartilaginous
  • main portion is the puboischiadic bar with 2 small spurs that are called iliac processes
  • these cartilages are probably not homologous with elements of the same names in the tetrapod pelvic girdle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pelvic girdle in tetrapods

A

Ventral part of pelvic girdle ossifies from 2 centers:

  • collectively this ossification forms the pubioschiadic plate which:
    - provides an area of origin of many of the hindlimb muscles
    - obturator foramen is an opening b/t pubis and ischium
    - -provides a passage for limb muscle nerves

Third element, ilium, lies dorsal to the other two.

Acetabulum develops above the puboischadic plate and forms from all three elements except in crocodilians.

The ilia are attached to the sacral vertebrae, and the pubis and ilium from each side fuse to each other along the midline

This creates a bony ring through which must pass the digestive, urinary, and genital systems (size of the opening is an important factor in vertebrates that lay large eggs or bear live young)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Pelvic girdle in frogs

A

Elements are ossified

Single slender element in the middle is the caudal vertebra (urostyle)

Two long slender elements on either side are the ilia

Ischia are fused into a single plate posteriorly, below which are the fused pubic bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Pelvic girdle in dinosaurs

A

True dinosaurs are divided into 2 groups based on the structure of their pelvic girdle:

1) Saurischians (lizard-like hip):
- Triradiate pelvic girdle

2) Ornithischians (bird-like hip):
- Tetraradiate pelvic girdle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Fore limb elements

A

Humerus, Ulna, Radius

21
Q

Humerus

A
  • single, proximal bone of forelimb
  • head articulates with gleniod fossa of scapula
  • distal end articulates with ulna (trochlea) and radius (capitulum)
22
Q

Ulna

A
  • in anatomical position, ulna and radius are parallel and in the same plane with ulna lying medial to radius
  • semilunar notch of ulna forms hinge joint with trochlea of humerus
  • olecranon process of ulna serves as lever arm for triceps complex
23
Q

Radius

A
  • concave depression on head of radius rotates on capitulum of humerus
  • narrow neck of radius distal to head spins within annular ligament attached to ulna
  • note that during pronation and supination, ulna is fixed, while head of radius spins and distal end of radius rotates over head of ulna
  • wrist articulation is between distal radius and proximal bones of carpus
24
Q

Clavicles and interclavicles

A

Present in monotremes

Clavicles lost in many mammals

25
Q

Fate of original coracoid bar in tetrapods

A

-Becomes paired

  • Forms a scapulocoracoid cartilage on each side with a glenoid fossa in the middle:
    • Scapula is located above the fossa
    • Coracoprecoracoid region is located below the fossa
26
Q

Pectoral Girdle in Anurans

A
  • Interclavicle is a new, diamond-shaped, unpaired element that appears first in fossil amphibians but is lost in modern amphibians
  • Cleithrum is rudimentary in modern anurans
    • Appears first in fossil amphibians but is lost in modern
27
Q

Pectoral Girdle in Salamanders

A
  • Dermal components are lost in modern salamanders

- Much of the endochondral girdle remains unossified

28
Q

Necturus Pectoral Girdle

A

***Note that the only ossified part of the girdle is the scapula

29
Q

Suprascapular notch

A

Allows nerve and blood vessel to enter the scapula

30
Q

Acetabulum

A

Develops above the pubiosciadic plate and forms all three elements except in crocodilians

31
Q

Necturus pelvic girdle

A
  • All 3 pairs of elements are represented in the pelvic girdle
  • The ilia are in the form of long slender bars that articulate with the single sacral vertebra
  • The ischia are paired, flat, posterior plates
  • The pubis is cartilaginous in the form of an anterior triangular-shaped plate of cartilage
32
Q

Pelvic girdle in turtle

A

Fused pubic bones and fused ischium

33
Q

Saurischians

A

Triradiate pelvic girdle

Liz-like hip

34
Q

Ornithischians

A

Tetraradiate pelvic girdle

Bird-like hip

35
Q

Mammalian pelvic girdle

A
  • Ilium extends anteriorly rather than dorsally or posteriorly
  • In marsupials, marsupial bones may extend anteriorly from the pubic bones to support the punch
  • The obturator foramen is large and may represent pubioschiadic fenestra found in the pelvic girdles of other tetrapods such as turtles
    - The passageway for the obturator nerve and artery is found along a groove in the superior pubic ramus
  • Obturator foramen is mostly covered by a fibrous membrane, the obturator membrane, which increases the surface area for muscle attachment
  • The acetabulum is closed, compared to many reptiles, and opens either laterally or lateroventrally. As in most tetrapods, it is formed from all 3 pelvic bones
  • The ilium forms a strong joint with multiple sacral vertebrae
36
Q

Phalangeal formula: primitive and mammal-like reptiles

A

2 : 3 : 4 : 5 : 3

37
Q

Phalangeal formula: Advanced reptiles and modern mammals AND human hand

A

2 : 3 : 3 : 3 : 3

38
Q

Phalangeal formulas in cetaceans and extinct marine reptiles

A

=hyperphalangy

*May reach as high as 13 or 14 in a single digit

39
Q

Major features of hind limb elements

A

Femur
Tibia
Fibula

40
Q

Femur

A

The femur possesses a greater trochanter

  • In many mammals there is also a fourth trochanter
  • The internal trochanter of the reptilian femur is replaced by the lesser femur in mammals

The adductor crest is for the attachment of the adductor muscles:
-It may be replaced by the linea aspera in some mammals (humans)

41
Q

Tibia

A

Possesses an anterior crest, the cnemial crest which forms the anterior border of the tibia (shin)

42
Q

Fibula

A
  • Many mammals (humans) possess a separate fibula that plays a role along with the tibia in forming the ankle (tibio-tarsal) joint
  • In other mammals, the fibula may be partially or completely fused with the tibia
43
Q

Evolution of tetrapod limb

A
  • may have evolved from crossopterygian ancestor
  • the limb can be traced back to the crossopterygian lobe fin
  • all tetrapod limbs are built on the same basic anatomical plan
  • forelimbs and hind limbs are almost identical
44
Q

Components of tetrapod limb

A

Stylopod:

  • Proximal single element:
    • Humerus or femur
  • Articulates with girdle

Zeugopod:

  • Two parallel elements
  • Radius (fibula) and ulna (tibia)

Autopod (proximal to distal):

  • Carpals (tarsals) (Basipodium)
  • Metacarpals (metatarsals) (Metapodium)
  • Phalanges (Acropodium)
45
Q

The carpus and tarsus primitively consisted of 12 elements:

A
  • 3 proximal elements: radiale, intermedium, ulnare in carpus and fibulare, intermedium, and tibiale in tarsus
  • 4 centralia
  • 5 distal carpalia or tarsalia
46
Q

In the forelimb, the centralia are almost always reduced:

A
  • There are never more than 2 in primitive reptiles
  • A single centrale is a common reptilian and mammalian pattern
  • The 5th distal carpal element is typically lost
  • The phalangeal formula for both primitive and mammal-like reptiles= 2-3-4-5-3
  • In advanced reptiles the phalangeal formula=2-3-3-3-3
47
Q

In cetaceans and extinct marine reptiles, the phalangeal formula may reach as high as 13 or 14 in a single digit

A
  • This is referred to as hyperphalangy

- It is an example of convergent evolution

48
Q

Hind limb

A

-The general pattern is for the calcaneus (heel) to develop from the fibulare, while the astragalus (talus or ankle bone) develops from the tibiale + intermedium + centrale

  • Reptiles also have an intracranial joint:
    • in crocs foot movement occurs b/t the astragalus & calcaneus
    • in Dino’s, the astragalus and calcaneus are closely attached to the fibula and the tibia, and distal tarsals are joined to the metatarsals
    • in birds, the situation is similar to that in Dino’s
49
Q

Ungulates

A

The hoofed mammals.
-there tends to be reduction of the digits in both forelimb and hind limb

  • Perissodactyls:
    • the axis of the limb extends thru the middle (3rd) toe
    • these mammals tend to reduce or lose digits lateral to the 3rd toe, and in modern forms have one or 3 toes (odd-toed)
    • examples include the horse with 1 toe and the rhino with 3
    • tapirs have 4 toes, but the axis still runs thru the 3rd toe, so they are also perissodactyls
  • Artiodactyls:
    • the axis of the limb extends between the 3rd and 4th toes
    • these mammals have an even number of toes–often 2
    • examples include camels, pigs, steel, and cattle

Comparative Anatomy (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions