1. Biology 211 Anatomy & Physiology I
Spinal Cord

3. Human Central Nervous System
Starts as a hollow tube in the embryo;
Remains hollow & fluid-filled throughout life;
These spaces form the ventricles of the brain and the
central canal of the spinal cord.
Cranial end of this hollow tube enlarges & folds to form
brain and its various parts
Caudal end of this hollow tube does not enlarge or fold;
Develops into spinal cord

5. Embryology of nervous system

6. Coronal Section of Brain
Cross Section of Spinal Cord

7. Embryology of nervous system

8. Spinal cord surrounded by 3 layers of connective tissue:

9. Space
(Vertebrae)
Mater

10. The spinal cord is protected in three ways:1) 2)
3) Floats in

11. Cerebrospinal fluid produced within ventricles by
Exits from fourth ventricle through three openings (apertures or foramina) into the subarachnoid space.
Two
Surrounds brain & spinal cord.
Reabsorbed into blood
through arachnoid villi on surface of brain

12. Embryology of nervous system

13. Recall: In brain and spinal cord
Nervous tissue of the CNS consisting of neuron cell bodies, their supporting glia, and unmyelinated axons & dendrites.
Nervous tissue of the CNS consisting of myelinated axons & dendrites and their supporting glia

14. Gray Matter of Spinal Cord
Cell bodies of neurons which receive afferent information from spinal nerves and send it toward the brain
Cell bodies of neurons which receive efferent information from the brain and send it to smooth myocytes, cardiac myocytes, and glands (autonomic motor innervation)
Embryology of nervous system
Cell bodies of neurons which receive efferent information from the brain and send it to skeletal myocytes (somatic motor innervation)

15. White Matter of Spinal Cord
Myelinated axons carrying information between brain and gray matter of spinal cord (both directions).
Embryology of nervous system
Within each column, axons with same functions organized into bundles called

17. Individual tracts of the spinal cord are described on pages 486 to 490 of your Saladin text (4th ed).
You should be able to describe, in moderate detail, at least one ascending tract and one descending tract:
Where it begins
Where it ends
If it deccusates
Where it is located in the spinal cord
What type of information it carries
What would happen if it were damaged

18. Spinal cord gives rise to spinal nerves.
A pair of spinal nerves (one on
each side) exits between each
pair of vertebrae from the atlas
(cervical 1) to the first vertebra
of the coccyx

19. Each nerve connects with spinal cord through two roots:
Carries afferent
information into
dorsal horn of gray
matter
Carries efferent
information away
from ventral horn
of gray matter

20. Spinal nerves named according to which vertebrae they pass between:
cervical nerves
thoracic nerves
lumbar nerves
sacral nerves
coccygial nerve
Levels of the spinal cord named according to which spinal nerve carries information in/out of it.
Embryology of nervous system

21. Spinal nerves named according to which vertebrae they pass between:
cervical nerves
thoracic nerves
lumbar nerves
sacral nerves
coccygial nerve
Levels of the spinal cord
named according to which
spinal nerve carries
information in/out of it.
Thus: Spinal cord level "cervical 5" is defined as the region where spinal nerve "cervical 5" connects
Embryology of nervous system

22. Next: Let's follow the spinal nerves distally as they form the peripheral nervous system.
Embryology of nervous system