Organization of the

Nervous System Lesson 4

The Central Nervous System

CNS Brain Spinal cord ~

Peripheral Nervous System

Somatic Nervous System - SNS Sensory Division Motor Division

Autonomic Nervous System - ANS Sympathetic Division Parasympathetic Division Homeostasis ~

Divisions of the Brain Different schemes 5 major subdivisions

Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon ~

Forebrain cortex sub-cortical areas

Midbrain tectum & tegmentum

Hindbrain cerebellum & pons medulla ~

Divisions of the Brain

Dorsal - toward the back Ventral - toward the stomach Anterior & Posterior Rostral & Caudal ~

Terminology

Dorsal

Ventral

In reference to the BRAIN

Anterior

Posterior

Rostral Caudal

Inferior

Superior

In reference to brainstem & spinal cord

Ventral Dorsal

Rostral

Caudal

Anterior Posterior

Superior

Inferior

Neural Axis

Terminology

Medial - toward the midline Lateral - away from the midline Ipsilateral - same side Contralateral - opposite side Decussate - crossover ~

Medial:toward themidline

Lateral:away frommidline

Ipsilateral same side mid-line

Contralateral opposite side of mid-line

This tract of fibers decussates.

It crosses the midline

Terminology Afferent - toward Efferent - away from ~

Afferent

Efferent

Coronal or frontal cross-section - salami

Sagittal - side view hot-dog bun

Horizontal top view ~

Planes

Coronal Section

Horizontal Section

View from top

Mid-sagittal Section

Side view

Forebrain

Cortical areas Fiber systems Landmarks

Fissures /Sulci Gyri Lobes ~

Superior surface

Longitudinal Fissure (sulcus)

Central sulcus

Lateral sulcus

Major Lobes

Major Lobes & Primary Function

Frontal planning motor control emotion

Parietal somatosensory maps of body & space

Temporal auditory memory

Occipital vision ~

The Meninges

Tough connective tissue Dura mater - tough outer layer Arachnoid membrane - soft middle

layer Pia mater - soft inner layer, next to

brain ~

Subarachnoid space

Gap between arachnoid membrane and pia mater

Filled with Cerebrospinal Fluid (CSF) Brain floats in CSF ~

Dura materArachnoid membrane

Subarachnoid space CSF

Pia mater

Brain

The Meninges

Ventricular System

*Continuous with subarachnoid space 4 interconnected ventricles chambers Cerebrospinal Fluid (CSF) manufactured in choroid plexus 125 ml, t1/2 = 3 hrs *Buoyancy: 1400 g 50 g Hydrocephalus blockage of CSF flow ~

Ventricular System

L V L V

3rd

Lateral Ventricles

Third Ventricle

Fourth Ventricle

Cerebral Aqueduct

Central Canal

4th