Chapter 2

This chapter discusses the brain and nervous system from the basics, starting from the structure of neurons. Neurons are organized within the brain to form white matter and gray matter. Gray matter consists of neuronal cell bodies. White matter consists of axons and support cells. The brain also contains a number of hollow chambers termed ventricles. There are conventional directions for navigating around the brain, just as there is a north, south, east, and west for navigating around maps. Anterior and posterior refer to directions toward the front and back of the brain. The hollow chambers of the brain that contain cerebrospinal fluid. The thalamus consists of two interconnected egg-shaped masses that lie in the center of the brain and appear prominent in a medial section. The basal ganglia and limbic system comprise a number of anatomical structures in subcortical gray matter and are involved, respectively, in the control of action and adapting the organism to its environment (memory, emotion). 


A type of cell that makes up the nervous system and supports, among other things, cognitive function

Neuron

Part of the neuron containing the nucleus and other organelles

Cell body

Branching structures that carry information from other neurons

Dendrites

A branching structure that carries information to other neurons and transmits an action potential

Axon

The small gap between neurons in which neurotransmitters are released, permitting signaling between neurons

Synapse

A sudden change (depolarization and repolarization) in the electrical properties of the neuron membrane in an axon, that forms the basis for how neurons code information (in the form of the rate and synchrony of action potentials)

Action potential

Chemical signals that are released by one neuron and affect the properties of other neurons

Neurotransmitters

A fatty substance that is deposited around the axon of some neurons that speeds conduction

Myelin

Matter consisting primarily of neuronal cell bodies

Gray matter

Tissue of the nervous system consisting primarily of axons and support cells

White matter

Support cells of the nervous system involved in tissue repair and in the formation of myelin (among other functions)

Glia

A large white matter tract that connects the two hemispheres

Corpus callosum

The hollow chambers of the brain that contain cerebrospinal fluid

Ventricles

Towards the front

Anterior

Towards the back

Posterior

Towards the top

Superior

Towards the bottom

Inferior

Towards the top

Dorsal

Towards the bottom

Ventral

The outer part (cf. medial)

Lateral

In or toward the middle

Medial

The raised folds of the cortex

Gyri (gyrus = singular)

The buried grooves of the cortex

Sulci (sulcus = singular)

Regions of cortex defined by the relative distribution of cell types across cortical layers (cytoarchitecture)

Brodmann’s areas

Regions of subcortical gray matter involved in aspects of motor control, skill learning, and reward learning; they consist of structures such as the caudate nucleus, putamen, and globus pallidus

Basal ganglia

A region of subcortex involved in relating the organism to its present and past environment; limbic structures include the amygdala, hippocampus, cingulate cortex, and mamillary bodies

Limbic system

A major subcortical relay center; for instance, it is a processing station between all sensory organs (except smell) and the cortex

Thalamus

Consists of a variety of nuclei that are specialized for different functions that are primarily concerned with the body and its regulation

Hypothalamus

A midbrain nucleus that forms part of a subcortical sensory pathway involved in programming fast eye movements

Superior colliculi

A midbrain nucleus that forms part of a subcortical auditory pathway

Inferior colliculi

Structure attached to the hindbrain; important for dexterity and smooth execution of movement

Cerebellum

Part of the hindbrain; a key link between the cerebellum and the cerebrum

Pons

Check out the 3D Brain App from Google Play, or Neuroanatomy online: 
https://play.google.com/store/apps/details?id=com.AndroidDeveloperMx.BrainandnervesAnatomy&hl=en  

www.nba.uth.tmc.edu/neuroanatomy/ 

The Interactive Neuroanatomy website has good quality images of brain regions and systems that you can learn to label:  
www.columbia.edu/itc/hs/medical/neuroanatomy/neuroanat/ 

MRI brain atlas allows you to navigate through slices of normal and damaged brains: 
www.med.harvard.edu/AANLIB/home.html