Lecture 9 Flashcards
(78 cards)
1
Q
Components of vertebrate internal framework skeleton
A
Axial skeleton
Appendicular skeleton
2
Q
Vertebrate axial skeleton
A
1) Chondrocranium:
- braincase and capsules for organs of special sense
2) Viscerocranium:
- gill arches and jaws
3) Vertebral column
3
Q
Appendicular skeleton
A
- limb girdles (pectoral and pelvic)
- limbs (forelimbs and hindlimbs, including fins
4
Q
Vertebral column
A
Obvious example of segmentation in vertebrates
- consists of a series of segments called vertebrae as well as additional related structures
- vertebrate and related structures may be composed entirely of cartilage or bone or both
5
Q
Components of Vertebral column: fishes
A
Centrum
Neural arch
Several kinds of vertebrae
6
Q
Vertebral column: fishes: Centrum
A
- typically a cylindrical structure that is connected to similar cylindrical centra both cranially and caudally
- this chain of centra replaces the notochord of the protochordates, such as amphioxus, as the principal axial support structure
- this chain of centra is flexible, not as flexible as notochord
- useful for swimming (flexibility) but not as good for terrestrial life-style
- in many verts (humans included) part of notochord persists within and/or between adjacent vertebrae
7
Q
Vertebral column: fishes: Neural arch
A
- sits on top of the centrum (dorsal surface) and provides a protective passageway for the spinal cord
- a neural spine often projects from the dorsi many of the neural arch
- provides lever arm for muscle attachment
- in Latimeria, spines are hollow and filled with cartilage - a corresponding hemal arch is present on the ventral surface of the centrum of each of the caudal (tail) vertebrae
- a caudal artery and vein pass thru the hemal arch
8
Q
Coelacanth
A
Hollow spine
9
Q
Intercalary plate
A
Fills in gaps between adjacent neural arches and protects the spinal cord
10
Q
Vertebral column of sharks and other chondricthyians
A
Composed entirely of cartilage
11
Q
Amphicelous
A
Both ends of each centra are concave, like in sharks
12
Q
Vertebral column: fishes: vertebrae
A
Precaudal vertebrae:
-include all the more cranial vertebrae that lack a hemal arch
Caudal vertebrae:
- include all the vertebrae caudal to the precaudal vertebrae
- possess hemal arches
13
Q
Vertebral column: fishes
A
- centra tend to be more ossified
- each neural arch is topped by a long, slender neural spine
- prominent notochord instead of ossified centra are still retained in more primitive bony fishes such as the sturgeon
- pelvic and pectoral girdles are not tied into fish vertebral column
14
Q
Compartmentalization of vertebrate body
A
- vertebrate body plan is tied together by sheets of connective tissue referred to as myosepta
- myosepta tie into the vertebral column
- collectively, the myosepta form compartments in which are enclosed masses of skeletal muscle
15
Q
Vertebral column: early tetrapods
A
Early tetrapod centrum developed from 2 parts:
1) Intercentrum
2) Pleurocentrum
* ** one or the other or both contributed to the formation of the centrum in early tetrapods
16
Q
Precaudal vertebrae in fish
A
Most lacking hemal arch
17
Q
Caudal vertebrae in fish
A
Possess hemal arch
18
Q
Specialization of precaudal vertebrae in tetrapods
A
Became specialized to be better suited for terrestriality:
- Cervical : articulated with skull
- Trunk : processes for rib attachment
- Sacral : articulated with pelvic girdle
19
Q
Ilia
A
Ties pelvic girdle into vertebral column
20
Q
Crossopterygians: Vertebral column: early tetrapods
A
Each centrum consisted of:
- Single, larger intercentrum:
- U shaped and cranial
- Paired, smaller pleurocentra:
- Caudal and dorsal to intercentrum
21
Q
Stereospondylous labyrinthodonts: Tetrapods: Vertebral column
A
Centrum entirely derived from intercentrum
22
Q
Embolomerous labyrinthodonts: Tetrapods: Vertebral column
A
Intercentrum and pleurocentrum equal in size
23
Q
Vertebral column: Modern Amphibians
A
Reduced intercentrum to a small, cranial, ventral element that attached to the head of the rib
Increased the size of the pleurocentrum
Notochord either completely eliminated or persisted as a slender rod passing thru the pleurocentrum or confined to spaces between intercentra
24
Q
Vertebral column: salamanders
A
Correlation with terrestriality
25
Specializations of precaudal vertebrae in salamanders
First precaudal vertebra= cervical vertebra
-only 1 in amphibians
Last precaudal vertebra= sacral vertebrae
-only 1 in amphibians
Vertebra between cervical and sacral are trunk vertebrae
-numerous in salamanders
-reduced to about 6 or 7 in anurans
-transverse processes have attachment sites for ribs
Neural arches with short, blunt neural spines are located on the dorsal surfaces of the centra
26
Ribs in Necturus
- bicipital
- tuberculum attaches to dorsal part of the transverse process (diapophysis)
- capitulum attaches to the ventral part of the transverse process (parapophysis)
27
Caudal vertebrae in salamanders
Have hemal arches
28
Centra in salamander vertebral column
Articulate with each other via 2 pairs of zygapophyses:
1) the cranial (anterior) zygapophyses have articular facets that face dorsally
2) the caudal (posterior) zygapophyses have articular facets that face centrally
29
Urostyle
Single caudal vertebra in anurans
- modified adaptation for saltatory locomotion
- attachment site for muscles involved in jumping
30
Objective 1:
| Overview of vertebrate skeletal system
Axial:
Chondrocranium
Viscerocranium
Vertebral column
Appendicular:
Limb girdles
Limbs
31
Objective 1:
| List and describe the components of a typical shark vertebra
- entirely cartilage
| - both ends of centra are concave
32
Amphicoelous centrum
Both ends are concave (some reptiles)
33
Procoelous centrum
Only cranial end is concave
34
Acoelous centrum
Both ends are flat (mammals)
35
Amniote vertebra: centrum
Functionally replaces the notochord
Classification based on shape of cranial and caudal ends:
- Amphicoelous
- Procoelous
- Opisthocoelous
- Acoelous
In tails, small pieces of bone may be found between ventral edges of centra:
- Intercentra (hypocentra)
- Form hemal arches (chevron bones)
In primitive reptiles, the bulk of the centrum is formed from the pleurocentrum
In modern reptiles and mammals the intercentrum has disappeared and the centrum is formed entirely from the pleurocentrum
-intercentrum persists in Sphenodon
36
Opisthocoelous centrum
Only caudal end is concave
37
Centrum in modern reptiles and mammals
The intercentrum has disappeared and the centrum is formed entirely from the pleurocentrum
-exception: intercentrum persists in Sphenodon
38
Parts of amniote vertebra: neural arch
- consists of a neural spine and diapophyses: for rib attachment
- composed of lateral and dorsal plates which form the neural canal
39
Laminae
-the dorsal plates which meet in the midline to fuse with the neural spine in neural arches of amniote vertebra
40
Pediceles
- lateral plates which fuse to the centrum centrally and to the laminae dorsal to form the transverse processes in the neural arches of amniote vertebra
- the posterior edge of each pedicele is typically notched so that when vertebrae are articulated, holes are formed between them to allow passage of spinal nerves
41
Development of vertebral column in amniotes
The vertebral column develops from the sclerotome portion of the embryonic somites:
42
Somites
Paired blocks of mesodermal tissue that form along the notochord during embryonic development
Each somite has 3 major components:
1) Dermatome:
- forms dermis of integument
2) Myotome:
- forms axial muscles
3) Sclerotome:
- forms part of vertebrae
43
Regional variation in amniote vertebrae: Reptiles
Cervical vertebrae:
- Atlas (#1)
- centrum becomes odontoid process of axis
- allows atlas axis rotation
- Atlas (#2)
- 8 in most reptiles
- 9 in alligator
Trunk:
-Typically with ribs
Sacral vertebrae:
-2+
Caudal vertebrae:
-Variable with hemal arches
44
Atlas-axis complex
First appears in reptiles!!!
| First time we see this atlas-axis complex
45
Regional variation in amniote vertebrae: birds
Cervical vertebrae:
- With transverse foramina
- Heterocoelous
- 8-25
Anterior thoracic:
-Wing brace
Synsacrum:
- Posterior thoracic
- Lumbar
- Sacral (2+)
- Proximal caudal
Pygostyle:
-Fused caudal vertebrae
46
Vertebral column: mammals: Centrum
Generally acoelous
-except cervical vertebrae of ungulates (opisthocoelous)
Centrum derived from pleurocentrum
-Intercentrum lost
47
Vertebral column: mammals: Atlas (C1)
Articulates with 2 occipital condyles
Lacks a centrum:
- has become associated with C2 intercentrum as the odontoid process (dens)
- serves as axis for lateral rotation
48
Vertebral column: mammals
- Centrum
- Atlas (C1)
- Cervical 3-7
- Thoracic
- Lumbar
- Sacral
49
Vertebral column: mammals: Cervical 3-7
Possess short fused bicipital ribs that create transverse foraminae:
-Pathway for vertebral arteries to brain
50
Vertebral column: mammals: Thoracic
Have articulation facets for ribs (costal facets)
- costal facets on transverse processes articulate with tubercles of ribs
- costal facets on centra articulate with heads (capitula) of ribs
- most heads of ribs in upper part of thoracic region articulate between 2 adjacent centra, resulting in the formation of costal demifacets
51
Vertebral column: mammals: lumbar
Thicker centra
No costal facets or ribs
52
Vertebral column: mammals: sacral
Fused into a single elements called the synsacrum
Articular facets for pelvis
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Vertebral column: mammals: caudal
Found in most mammals
May have indications of hemal arches
-chevron bones
54
Ribs: Tetrapods
Arise in skeletogenous septa
Dorsal ribs:
-formed at intersections b/t myosepta and horizontal septum
55
Ribs: Amphibians
Reduced
56
Ribs: Reptiles
Double-headed (bicipital):
- Capitulum to centrum
- Tubercle to transverse process
8 pairs in turtle fused to carapace
57
Ribs: Birds
Uncinate processes of 1 rib overlap next caudal rib to stabilize rib cage for flight
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Ribs: Mammals
Cervical ribs
- short and fused to vertebrae
- transverse foramina for vertebral arteries
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Types of bones
```
Long bones
Short bones
Flat bones
Irregular bones
Sesamoid bones
```
60
Bone markings
Depressions
| Processes
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Long bones
Femur, tibia, humerus, phalanges
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Short bones
Carpals and tarsals
63
Flat bones
Bones of skull cap, dermal bones
64
Irregular bones
Vertebrae, facial bones
65
Sesamoid bones
Knee cap (patella)
66
Depressions on bones
Foramen
Groove
Fossa
67
Processes on bones
Spine
Tuberosity
Condolences
Epicondyle
68
Joint definition
An area where 2 bones meet
69
Articulation definition
Where a movable joint is formed
70
Joint classification is based on:
Type of material that holds the 2 bones together and the amount of movement possible
71
Ampiarthrosis joint
Slightly movable joint
Joining material= cartilage
2 types:
1) Synchondrosis:
Joining material-hyaline cartilage
2) Symphysis:
Joining material-fibrocartilage
Ex: pubic symphysis
72
Synarthrosis joint
```
Slightly movable joint
Joining material= fibrous CT
3 types:
1) Suture type:
Example: joints between bones of skull cap
```
2) Gomphosis type:
Example: tooth in socket
3) Syndesmosis type:
Example: interosseous membrane
73
Diarthrosis joint
Very movable joint
Joining material=cartilage
```
Components:
Articular cartilage (AC)
Synovial membrane (SM): Vascularized
Synovial cavity (SC)
```
74
Joints: movement and degrees of freedom
Uniaxial
Biaxial
Triaxial
Nonaxial (sliding)
75
Uniaxial joint
- Movement in one plane around one axis:
- example:
- hinge joints (elbow, knee)
- pivot joints (atlantoaxial)
76
Biaxial joint
Movement in 2 planes around 2 axes
- Example:
- Ellipsoid (metacarpalphalangeal)
77
Triaxial joint
Movement in 3 planes around 3 axes
- Example:
- Glenohumeral (shoulder)
- Acetabulofemoral (hip)
78
Nonaxial (sliding) joint
No axis of rotation
Example:
Joints between carpals and tarsals
