1
Q
what are the 2 skeletal tissues?
A
cartilage and bone
2
Q
what are 2 similarities in the structures of bones and cartilage?
A
- both are composed of a dense, supportive matrix
- both contain living cells located in tiny spaces called lacunae
3
Q
how does the composition of the extracellular matrix in bone and cartilage differ?
A
bone: matrix is made up of inorganic salts (especially calcium phosphate) and protein fibres (mainly collagen)
cartilage: matrix is made up of proteoglycans, protein fibres (elastin and collagen), and some inorganic salts
4
Q
which skeletal tissue contains nerves and blood vessels? describe their structure
A
bone contains nerves and blood vessels that pass through canals in the bone matrix; cartilage have neither
5
Q
chondrocytes vs. osteocytes
A
chondrocytes are found in cartilage; osteocytes are found in bone
6
Q
what is the function of the living cells (chondrocytes and osteocytes) in cartilage and bone?
A
maintaining the extracellular matrix (which gets damaged over time). both osteocytes and chondrocytes respond to mechanical stimuli and allow regeneration of cartilage/bone in response to the forces acting on it
7
Q
what is the function of hard substances (inorganic salts, proteoglycans) that coat the outside of the extracellular matrix in cartilage and bone?
A
structural integrity and resisting compressive forces
8
Q
what is the function of protein fibres in the matrix of cartilage and bone?
A
reducing brittleness (so they’re less prone to breakage - acts as a shock absorber)
9
Q
which heals faster, bone or cartilage? why?
A
bone heals faster because of its vascularization, which allows faster transportation of nutrients to the injured site
10
Q
what are the 2 types of mature bone?
A
trabecular and compact
11
Q
trabecular bone
A
porous with a “spongy” appearance; composed of many spaces that contain marrow in tetrapods (makes blood cells and stores fat)
12
Q
compact bone
A
appears solid, but contains many tiny canals when viewed under a microscope
13
Q
ossification
A
bone formation
14
Q
describe ossification in endochondral bone
A
mesenchymal cells differentiate into chondrocytes, which make the cartilage matrix before dying by apoptosis. the cartilage is then invaded by osteoblasts and blood vessels. osteoblasts replace cartilage with bone before maturing into osteocytes
15
Q
describe ossification in intramembranous bone
A
mesenchymal cells differentiate directly into osteoblasts, which secrete the hard extracellular matrix of bone (no cartilage intermediate)
16
Q
dermal bone
A
intramembranous bone that form sin the dermis of the skin
17
Q
what are the 2 parts of the endoskeleton in vertebrates?
A
cranial and post-cranial
18
Q
3 parts of the cranium (skull)
A
chondrocranium, splanchnocranium, dermatocranium
19
Q
what are the 2 parts of the post-cranial skeleton?
A
axial and appendicular skeleton
20
Q
4 parts of the axial skeleton
A
notochord, vertebral column, ribs, sternum
21
Q
2 parts of the appendicular skeleton
A
paired fins/limbs, pelvic and pectoral girdles
22
Q
what gives rise to the vertebral column and ribs of the axial skeleton?
A
mesenchymal cells of the sclerotome epimere mesoderm
23
Q
what gives rise to the sternum?
A
mesenchymal cells of the somatic hypomere mesoderm
24
Q
what gives rise to cartilage and endochondral bone components of the appendicular skeleton?
A
mesenchymal cells of the somatic hypomere mesoderm
25
what replaces the notochord in many vertebrate taxa?
the vertebral column
26
describe the structure of a typical vertebra
composed of a sturdy central portion (centrum), a dorsal neural arch, and a ventral hemal arch
27
zygapophyses
dorsal projections of the neural arch that lock successive vertebrae together; prevent torsion of the vertebral column
28
what is the difference between pre-zygapophyses and post-zygapophyses?
pre-zygapophyses project anteriorly toward the midline and upward, while post-zygapophyses project posteriorly outward and downward
29
centrum
large, hard central portion of a vertebra; good for taking up compressive forces
30
neural arch
dorsal projection of the vertebra that protects the spinal cord
31
hemal arch
ventral projection of the vertebra that protects large blood vessels (eg. dorsal aorta)
32
neural and hemal spine
extend from the neural and hemal arches, respectively; attachment sites for muscles
33
transverse processes
lateral projections on the right and left sides of the centrum; attachment sites for muscles
34
in mammals, what happens to the transverse processes of the cervical vertebrae? what structure (cavity) forms due to this?
they fuse to embryonic ribs and the hole between them becomes the transverse foramen
35
diapophyses and parapophyses
lateral facets (smooth surfaces) in tetrapods that articulate with 2-headed ribs
36
lateral undulations
method of locomotion where the body moves from side to side to propel it forward
37
describe the post-cranial axial skeleton in agnatha, contrasting myxinoidea and petromyzontida
agnatha have a long notochord that is the main support for the body’s longitudinal axis. myxinoidea have no vertebrae in adults. petromyzontidae have cartilaginous vertebrae with small neural arches (no centra or hemal arches)
38
describe the post-cranial axial skeleton in chondrichthyes, contrasting holocephali and elasmobranchii
chondrichthyes have cartilaginous vertebrae. holocephali are supported by a notochord with neural and hemal arches, and they do not have centra. in elasmobranchii, each vertebra has a centrum that the notochord passes through
39
describe the post-cranial axial skeleton in actinopterygii
vertebrae are ossified (endochondral bone). each vertebra has a centrum that the notochord passes through
40
describe the post-cranial axial skeleton in dipnomorpha
in ancestral dipnomorpha, the vertebral column was ossified (endochondral bone) and vertebrae had centra with a notochord passing through. in extant dipnomorpha, the centra have been secondarily lost and the neural and hemal arches rest on the large notochord.
41
describe the post-cranial axial skeleton in tetrapoda
vetebrae are ossified (endochondral bone). the centra of most tetrapods don't have a central canal through which the notochord passes. centra are main structural support
42
ribs
part of the post-cranial axial skeleton; composed of cartilage and/or endochondral bone
43
which 2 taxa have centra with a central canal for the notochord to pass through?
elasmobranchii and actinopterygii
44
what are intervertebral bodies and what taxon are they found in? what are they composed of?
pads at the articular ends of the centra in most tetrapods; allow slight mobility of the vertebrae and act as shock absorbers. composed of cartilage and/or fibrous connective tissue
45
what are intervertebral disks and what taxon are they found in?
pads at the ends of centra in mammals that contain remnants of the notochord (same function as intervertebral bodies)
46
what are the 2 regions of the vertebral column in gnathostomes? how can you distinguish vertebrae from these regions?
trunk and caudal. trunk vertebrae have diapophyses and parapophyses that articulate with the ribs. caudal vertebrae lack these structures, but they have a hemal arch and spine where trunk vertebrae do not.
47
does the appendicular skeleton include any dorsal/ventral fins or tail?
nope - only includes paired appendages and the girdles that support them
48
do all vertebrates have all parts of the axial skeleton? do all vertebrates have an appendicular skeleton at all?
no to both
49
articulation
location where 2 or more bones or cartilages meet
50
what types of articulations are there?
some bones/cartilages articulate such that both can move relative to one another, creating a mobile joint. other articulations involve bones/cartilages meeting or fusing in a way that movement isn't possible, which creates a joint that isn't mobile
51
what are processes (in vertebrae)? which processes are specialized for muscle attachment, and which are specialized for articulating with other parts of the skeleton?
processes are structures of interest (bumps, spines, ridges, smooth ridges, etc). neural and hemal spines and transverse processes are specialized for muscle attachment; while smooth regions (zygapophyses, diapophyses, parapohyses) are specialized for attachment to other regions
52
compare, in general, the appendicular skeleton between agnathans and gnathostomes
extant agnathans don't have an appendicular skeleton, while extant gnathostomes have paired limbs/fins (except for taxa such as snakes that have secondarily lost paired appendages)
53
what function do girdles serve?
they serve as attachment sites for the muscles of appendages and stabilize the appendages by bracing them against the body
54
is there any major difference between mature endochondral and mature intramembranous bone?
no - they can't be differentiated based on structure, only by the ossification process
55
where do mesenchymal cells required for ossification come from?
the origin of mesenchymal cells depends on the region of the embryo where the bone is forming. they can be shed from somatic hypomere mesoderm or epimere mesoderm, or they can be neural crest cells (mesenchymal ectoderm)
56
describe attachment of the pectoral girdle in actinopterygii, dipnomorpha, and chondrichthyes
actinopterygii and dipnomorpha: the pectoral girdle is attached to the dorsal, posterior region of the skull
chondrichthyes: the pectoral girdle doesn't attach to the skull or the vertebral column, but is embedded in the muscle of the body wall
57
describe attachment of the pelvic girdle in actinopterygii, dipnomorpha, and chondrichthyes
the pelvic girdle doesn't attach directly to the vertebral column; it's embedded in muscles of the body wall
58
what functions do paired fins serve in elasmobranchii?
shark swim using lateral undulations of the tail that propel the body forward. however, this can produce unwanted movements such as pitch, yaw, and roll. the paired fins provide stability during locomotion, preventing these movements. the angle of paired fins can also be adjusted to steer the animal in the right direction
59
pitch and yaw
pitch: shifting the angle of the head dorsally or ventrally
yaw: wagging the head left and right
60
what function do the claspers of pelvic fins serve in chondrichthyes?
in male and intersex chondrichthyes, they act as intromittent organs, transferring sperm to their partner during copulation (synapomorphy of chondrichthyes)
61
contrast ray fins and fleshy fins. which taxa have each?
actinopterygii have ray fins, which are made of skin and connective tissue and supported by slender fin rays of bone and cartilage. dipnomorpha have fleshy fins, which contain bones and muscles. fin rays are also found at the distal ends of fleshy fins
62
describe the different bones that support the fins of actinopterygii and dipnomorpha.
actinopterygii have ray fins, and the proximal region of the fins is supported by thick and sturdy bones called radials. several radials articulate with the pectoral girdle. dipnomorpha have fleshy fins, which are supported by an elongated series of bones that articulate using mobile joints. a single bone called the humerus articulates with the pectoral girdle.
63
list 3 functions of the skeletal system
1. protects delicate tissues
2. provides levers on which muscles can exert force to produce movement
3. provides structural support, supporting body shape and (in terrestrial taxa) body weight
63
list 5 functions of the paired fins in actinopterygii
- stabilization during swimming
- propulsion
- steering
- maintaining body position in the water when stationary
- braking
64
what function do paired fins serve in dipnomorpha?
fleshy fins are highly maneuverable - they can be used for precise swimming, walking along bottom surfaces, holding position in deeper waters, etc
65
describe a difference in the role of the skeleton between aquatic and terrestrial organisms
terrestrial organisms require the skeleton to support their body weight, but since aquatic organisms live in water, this isn't as necessary
66
compare the sizes of girdles and appenadges between early tetrapods and the last common ancestor their shared with dipnomorpha.
tetrapods evolved to have much larger girdles and appendages because, being terrestrial, they needed these stronger and sturdier structures to support their body weight
67
compare the structure of the distal fins between early tetrapods and the last common ancestor they shared with dipnomorpha. why might the adaptation be useful for terrestrial organisms?
thin fin rays supporting the distal ends of fins were replaced with digits. these digits are supported skeletally by phalanges (series of bones with mobile joints between them). digits are thicker and sturdier than fin rays to withstand the forces of each step, they provide better traction while walking as they contain several mobile joints, and they improve balance by distributing weight more evenly on the foot.
68
compare attachment of the pectoral girdle between early tetrapods and the last common ancestor their shared with dipnomorpha. why might the adaptation be useful for terrestrial organisms?
the pectoral girdle was attached to the skull in ancient sarcopterygii, but tetrapods evolved for it not to be directly attached to the axial skeleton at all. it is instead attached indirectly through muscles. a cervical region of the vertebral column differentiated in tetrapods. advantages of this include greater freedom of movement for the head and forelimbs, and lessening the force of impact of walking on the head (which could potentially be damaged)
69
compare attachment of the pelvic girdle between early tetrapods and the last common ancestor their shared with dipnomorpha
the pelvic girdle was not attached to the vertebral column in ancient sarcopterygii, but in early tetrapods, it fused to the sacral region of the vertebral column. this strengthens both structures so they can withstand powerful forces generated by the hind limbs
70
what 2 regions of the evrtebral column differentiated in early tetrapods?
cervical and sacral regions
71
compare the sacral region of the vertebral column in amphibia and amniotes
in amphibia, the sacral region consists of just one vertebra. in amniotes, the sacral region has 2 or more vertebrae, and they fuse together in some amniote taxa to form the sacrum
72
what 2 parts of the trunk region differentiated in many amniota?
thoracic and lumbar regions
73
from anterior to posterior, list the regions of the vertebral column
cervical, thoracic, lumbar, sacral, caudal
74
which taxa are fin rays present in? what purpose do they serve in aquatic locomotion?
fin rays are found in actinopterygii, dipnomorpha, and chondrichthyes. they increase the surface area of a fin, allowing it to exert more force when pushing the water. this means the organism can produce more thrust to stabilize the body, to steer, and to propel itself forward
75
in which taxon is the synsacrum found? what advantages does this structure give to the organism?
the synsacrum is formed by the fusion of sacral, lumbar, and several thoracic and caudal vertebrae in aves (birds). the synsacrum fuses with the pelvic girdle to provide a strong and stable platform to support the body during flight and withstand the forces of landing.
76
what is the most anterior vertebra in tetrapods?
atlas
77
in which taxon is there only one cervical vertebra?
amphibians - they only have the atlas
78
describe the structure of the atlas
it has a large middle hole called the neural canal. lateral to the neural canal on both sides, there are concavities used for articulation with the occipital bones of the skull, which allows the skull to nod. lateral to these concavities on both sides are the transverse foramen.
79
how do cervical vertebrae differ in amphibians vs amniotes? compare their structures
amphibians only have one cervical vertebra called the atlas. amniotes have both the atlas and the axis, which lies just posterior to the atlas and has a projection called the odontoid process that inserts into its neural canal. this allows the head to turn from side to side.
BIOL 204
flashcards
Decks in class (12)
# Cards
-
vertebrate development - frogs43
-
vertebrate development - chicks30
-
morphological concepts, phylogeny29
-
chordate characters23
-
vertebrate phylogeny23
-
post-cranial skeleton80
-
the skull52
-
muscles61
-
digestion60
-
digestive + urogenital systems (lab)48
-
muscles (lab)18
-
respiratory + circulatory systems (lab)28
