An introduction to nervous system

By: shirin Kashfi Helpful Terms

CNS Central Nervous System PNS Peripheral Nervous System Ganglion (ganglia) Group of cell bodies found in the PNS Nucleus (nuclei) Group of cell bodies found in the CNS (not the same as a cell nucleus) Nerve Bundle of nerve fibers (axons) found in the PNS tract Bundle of nerve fibers (axons) found in the CNS

Primary neurolation

• In vertebrates , CNS originates from dorsal ectoderm

• CNS forms as a tube during primary neurolation

• Part of ectoderm where fusion occurs becomes neural crest which then forms PNS.

Neural Groove

Neural Tube

Brain

Spinal Chord

• by 4th week: – Forebrain, Midbrain, Hindbrain

• Prosencephelon (Forebrain) Telencephalon (cerebrum) Diencephelon (thalamus, hypothalamus)

• Mesencephalon (Midbrain)

• Rhombencephalon (Hindbrain) Metencephalon (pons, ) Myelencephalon (medulla)

Directional Terms - Brain

dorsal superior

rostral caudal anterior posterior

ventral inferior Directional Terms - Brainstem and

the brain takes a turn at the cephalic flexure

rostral dorsal superior posterior

ventral caudal anterior inferior

Directional Terms - Sections

Horizontal cut Has symmetry (mirror images) Long (oval) Directional Terms - Sections

Coronal cut Has symmetry (mirror images) round (circle-sort of) Directional Terms - Sections

Sagittal cut Does not have symmetry What kind of cut is this?

Coronal What kind of cut is this?

Horizontal What kind of cut is this?

Horizontal Meninge

• The are the three membranes that envelop the brain and spinal cord

• In mammals, the meninges are the , the , and the

• The primary function of the meninges is to protect the central nervous system Dura mater

Falx cerebri and

• is also known as the cerebral falx, named from its sickle-like form. It is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres of the • The cerebellar tentorium is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes Arachnoid

Arachnoid granules

Pia mater