Lecture 5 Flashcards
Functions of the axial skeleton (general):
SupportProtectionRespiration (VENTILATION)
The vertebral column comes from…
the somites
Somites migrate ventrally to the notochord and do what?
fuse to each other and break up the notochord into segments
The notochord now exists where?
in between the somites (now sclerotomes; vertebral bodies)
Remember…Somites break up into what 3 categories?
DermatomeMyotomeSclerotome*If you don’t remember what they turn into next, then go back and master the other decks >:(
The myotome that comes from a somite (sclerotome) and connects to the same somite (sclerotome) cannot cause movement. Why?
Because the muscular structure is NOT crossing a joint
Each sclerotome has a line of separation. How is each sclerotome labeled?
Superior portion and inferior portion
When the line of separation “splits” the sclerotomes, what happens to them? What about the myotomes?
The superior portion fuses with the inferior portion from above it. The myotomes DO NOT split.
CONNECTION TIME!When each sclerotome fuses with the portion above it, what can now happen?
The myotomes can now produce movement because they are now crossing a joint!
After the sclerotomes fuse with the portions above them and the myotomes cross joints, what’s the last fusion that must occur?
Each pair of the sclerotomes moves toward the middle toward the notochord and fuses with each other and CHOPS UP the notochord into pieces.
Does the Dorsal hollow nerve tube get chopped up? Why or why not?
No, it is protected by a “bony canal”
The notochord develops into what?
Part of the intervertebral disc (not the entire thing)
What is really being protected, the notochord or the dorsal hollow nerve tube?
Not the notochord - it gets chopped up!The dorsal hollow nerve tube gets protected
What does it mean to have a homolog?
It shares a common origin; derived from the same tissue
Serial homologs:
A series of structures that came from the same thing(example: all vertebrae are serially homologous to each other)
Intervertebral foramina allow what?
They allow peripheral nerves to emerge and go out to the body
Intervertebral discs are made of what on the outside and then what in the middle?
Fibrocartilage pad (anulus fibrosus) on the outsideNucleus pulposus in the middle
What is the only little piece left from the notochord?
The nucleus pulposus
When you put extreme pressure on your vertebrae, you can actually weaken the anulus fibrosus and push out some of the nucleus pulposus. Why is this bad? What can happen?
Called a herniated discIt can put pressure on an emerging nerve or the central nervous system itself; can damage it
What do cervical vertebrae have that is unique?
transverse foramen (also bifid spinous process)
What runs through the transverse foramen?
Vertebral artery, vertebral vein, and vertebral nerve
What is C1? C2?
C1: AtlasC2: Axis
Joint name when you nod “yes”Joint name when you shake your head “no”
“Yes” = Atlanto-occipital joint”No” = Atlas-axis joint
What do thoracic vertebrae have that is unique? What do they do?
costal facetsarticulates with ribs
