Lab 2 Flashcards
What is the general role of the notochord?
Defining structure of vertebrates, the notocord is the source of midline signals which patterns the development of the surrounding tissues.
What is the notocord’s role in organising the mesoderm?
The notocord organises cells of the paraxial mesoderm into somites, which are organised ventromedially and dorsolaterally into the following regions…
- Sclerotome - axial skeleton (and associated cartilage).
- Syndetome - ligaments/ tendons.
- Myotome - muscles of the back/ body wall.
- Dermatome - dermis of skin.
What is the notocord’s role in organising the ectoderm?
The notocord induces thickening of the overlying ectoderm, causing the formation of the NEURAL PLATE (neuroectoderm). Growth of the neuroectoderm is rapid and causing buckling, and the subsequent formation of the NEURAL GROOVE. The groove deepens (forming neural folds), fuses dorsally and and detaches from the ectoderm to become the NEURAL TUBE. This is the process of NEURALATION.
Where does the neural tube lye, relatively to the notocord/ somites?
Neural tube is dorsal to the notocord, and medial to the paraxial mesoderm.
Which part of the somite will ultimately form the vertebrae?
The sclerotome.
What are the main two functions of the vertebral column, and what parts of the vertebrae are responsible for this?
The neural (vertebral) arch and the body (centrum) of the vertebrae are responsible for its 2 major functions:
- Protection - of SC.
- Support - of body weight.
(note: the VC must be able to do this with some level of flexibility, which is achieved by it’s articulations).
State 3 functions of the neural/vertebral arch and for each of the 3 functions of you mention,
name one vertebral structure that performs each function.
1.
2.
3.
- Muscle attachment (rough areas) - spinous process, TVP.
- Articulation (smooth areas) - facets on superior/ inferior articulating processes.
- Intervertebral foramen (for spinal nerve exit) - superior and inferior vertebral notches.
Of the superior and inferior vertebral notches (thoracic vertebrae), which is deeper?
Inferior.
List the cervical vertebrae that belong in each of the two categories;
a. ) typical
b. ) atypical
a. ) typical - C3 - C6.
b. ) atypical - C1, C2, C7.
Where/ what are the uncinate processes, and on which vertebrae are they found?
What is the functional restriction imposed by this feature?
Uncinate processes are the raised lips on the superolateral aspects of certain vertebrae. These include C3 - C7, as well as T1.
The functional restriction is a restriction of rotational movement.
Describe the appearance of the superior and inferior articulating facets on C1.
C1 (atlas):
SAP facet - large, concave (for articulation with occipital condyles).
IAP facet - small, circular, flat (for articulation with SAP of C2).
The inner surface of the anterior arch (C1) has a smooth pit-shaped facet behind.
What is this area called?
Fovea dentis.
C1 has small tubercles on medial aspect of each lateral mass (adjacent to the fovea dentis), what
attaches here?
??? ligament of some sort.
What holds the dens in place?
Transverse part of the cruciate ligament
How can you distinguish the inferior and superior aspects of C1?
Superior facets are much larger.
