Chapter 13 - Spinal Cord Flashcards
Functions of the Spinal Cord
- 2-way conduction pathway:
a. ascending tracts -carry sensory info up spinal cord
b. descending tracts - carry motor info down spinal cord - Major reflex center - automatic responses processed here
Conduction
carry action potentials; AP can move up or down spinal cord bc lots of neurons
tracts
bundles of axons w/in CNS
Gross Anatomy of Spinal Cord
100 million neurons just in spinal cord; about 17 inches long; connected to brain; ends around L1 or L2; 3/4 inches thick; bottom-pointy; 31 pairs of nerves exiting spinal cord
Conus medullaris
bottom of spinal cord; pointy
2 thickened regions of spinal cord:
- Cervical region - Cervical enlargement-nerves that leave spinal cord & supplies the arms
- Lumbar region - Lumbar enlargement-neruons that control the legs
Cauda Equina
spinal roots relaying info below conus medullaris to exit points below conus medullaris
2 types of CT that protects the spinal cord
- filumterminale
2. denticulate ligaments
filumterminale
CT that connects conus medullaris & holds down the spinal cord to the coccyx so it doesn’t bounce around; like a rope
denticulate ligaments
CT that attaches spinal cord to vertebrae to hold in place (to the sides)
Protections of Spinal Cord (3)
- Vertebrae
- Meninges - CT that covers spinal cord (CNS); 3 layers of spinal cord coverings - dura mater, arachnoid mater, pia mater
- CSF - cerebrospinal fluid; cushions outside
Dura mater
outer layer of the spinal cord; toughest layer
Arachnoid mater
middle layer of the spinal cord; web-like attachments to pia mater
Pia mater
inner layer of the spinal cord; softest layer; richly vascularized; in direct contact w/spinal cord; only covering that nourishes (supplies O2 & nutrients) to spinal cord
Epidural space
space between dura mater & vertebrae; on top of dura mater; filled w/adipose tissue
Subdural space
thin layer under dura mater; holds serous fluid (lubricating fluid) to minimize damage
Subarachnoid space
fairly large space; filled w/CSF that cushions spinal cord
Layers of Meninges
- Epidural space
- Dura mater
- Subdural space
- Arachnoid mater
- Subarachnoid space
- Pia mater
White & gray matter
white matter-on outer part; mylinated axons; communication lines
gray matter - inner part; cell bodies; processing info; horns