Transcript Organization of the Nervous System

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 ~

Divisions of the Brain
Forebrain
 cortex
 sub-cortical areas
 Midbrain
 tectum & tegmentum
 Hindbrain
 cerebellum & pons
 medulla ~

Terminology
Dorsal - toward the back
 Ventral - toward the stomach
 Anterior & Posterior
 Rostral & Caudal ~

In reference to the BRAIN
Dorsal
Superior
Anterior
Posterior
Rostral
Caudal
Ventral
Inferior
In reference to brainstem & spinal cord
Superior
Rostral
Ventral
Dorsal
Anterior
Posterior
Caudal
Inferior
Neural Axis
Terminology
Medial - toward the midline
 Lateral - away from the midline
 Ipsilateral - same side
 Contralateral - opposite side
 Decussate - crossover ~

Medial:
toward the
midline
Lateral:
away from
midline

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 ~
Planes
Coronal or frontal
 cross-section - salami
 Sagittal - side view
 hot-dog bun
 Horizontal
 top view ~

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 ~

The Meninges
Dura mater
Arachnoid membrane
Subarachnoid space
CSF
Pia mater
Brain
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
Lateral Ventricles
Third Ventricle
LV
LV
3rd
Cerebral Aqueduct
Fourth Ventricle
Central Canal
4th