Structure of the Nervous system

Chapter 3 Learning Objectives1.Describe the appearance of the brain and the terms used to indicate directions and planes of section.

2.Describe the divisions of the central nervous system, the meninges, the ventricular system, and the production of cerebrospinal as it flows through the brain.

3.Outline the development of the central nervous system.

4.Describe the telencephalon, one of the two major structures of the forebrain.

5.Describe the two major structures of the diencephalon.

6.Describe the two major structures of the midbrain, the two major structures of the hindbrain, and the spinal cord.

7.Describe the peripheral nervous system, including the two divisions of the autonomic nervous system.

Describing the Nervous System

Describing the Nervous System•Ipsilateral▫Located on the same side of the body.

•Contralateral▫Located on opposites side of the body.

Brain Slices and Planes

Brain Slices and Planes•Transverse▫Perpendicular to neuraxis

•Frontal Plane▫Transverse cut through brain

•Horizontal Plane•Sagittal Plane•Midsagittal plane

Overview of the Nervous System

Nervous System• Central Nervous System▫ Brain▫ Spinal Cord▫ Encased in bone

• Peripheral Nervous System▫ Cranial nerves▫ Spinal nerves▫ Peripheral ganglia

The Meninges

•Meninges▫ Dura mater▫ Arachnoid membrane

Subarachnoid space

▫ Pia mater• Cerebrospinal fluid (CSF)

Ventricles and CSF

• Reduce shock to CNS• Ventricle

▫ hollow CSF filled spaces within the brain

• Choroid plexus▫ tissue that protrudes into the ventricles and produces CSF

Peripheral Nervous System•Spinal Nerves▫Peripheral nerves attached to spinal cord

•Cranial Nerves▫Peripheral nerves attached to the brain

•Afferent axons▫Directed towards the CNS▫Sensory information

•Efferent axons▫Directed away from the CNS▫Motor information

Autonomic Nervous System

Cranial Nerves

Development of the CNS28th day

Development of the CNS

• Neurogenesis• Apoptosis

• Ventricular Zone• Progenitor cells• Cajal-Retzuis (C-R) cells

The Brain

The Forebrain•Telencephalon▫Cerebral Cortex▫Limbic system▫Basal Ganglia

•Diencephalon▫Thalamus ▫Hypothalmus

The Cortex

• Gyrus• Sulci• Fissure

The Limbic System

• Emotion• Motivation• Learning and Memory

Basal Ganglia

• Control of Movement• Parkinson’s Disease

Diencephalon

• Thalamus▫ Sensory relay

• Hypothalamus▫ Autonomic nervous system

▫ Endocrine system▫ Behaviors related to survival of the species

The Midbrain

Hindbrain•Metencephalon•Cerebellum •Pons

•Myelencephalon▫Medulla

The Spinal Cord

• Cauda equina• Caudal Block