Chapter 2: Functional Neuroanatomy

Neurons

Golgi stain gave first look

key features:

• cell body

• Neurites:

  • projects from cell body

  • axons

  • dendrites

Soma/Cell Body

4-10% of surface area

Contains majority of organelles

Membrane enclosed structures

Perform a specific function

Dendrites

Connections with other neurons

Covered in receptors: 

Proteins that bind chemical messengers

Axon

Axon collaterals = branching

• Recurrent collaterals

Variable diameter

• 1-25mm

• Affects speed of electrical impulse

Mylein Sheath

Electrical insulation

Increases Signal Speed

Created by Glia Cells

wrapped itself around an axon

Nodes of Ranvier

gaps between myelin on the axon

Saltatory Conduction

increases speed of the signal

“jumps” between the nodes of ravier

Axon Hillock

“entrance gate of the axon”

Soma tappers and forms the axon

Signal integration center

Axon Terminal

A.K.A. Terminal buttons

Where one neuron makes contact with another

• Synapse

• Innervation / innervate

Terminal arbor

Release neurotransmitters into the synapse

Contains spheres of membrane called vesicles

• Synaptic vesicles contain neurotransmitters

Medial—Lateral (anatomical directions)

to the middle —to the outside

ex: ears are lateral to eyes

Dorsal—Ventral (anatomical directions)

to the back—to the belly

bent neutral axis complicates

as it would be in a four legged animal

ex: shoulder is to the back and belly button is to spine

Anterior—Posterior (work in opposing pairs)

to the front—to the back

ex: back of head = posterior

Rostral—Caudal (work in opposing pairs)

to the head—to the tail

also follows non-bent axis

Superior—Inferior (work in opposing pairs)

above—below

disregards spinal axis

ex: belly button higher than toes

Proximal—Distal

close—far

Efferent—Afferent

refers to carrying a signal

going out—coming in

efferent = effect a change

afferent = feel the table —affect feelings (like feelings=sensing something)

Ipsilateral—Contralateral

same side—opposite side

ex: right ear = contralateral to left arm; right ear ipsilateral to right leg

Anatomical Planes

Horizontal/Transverse

• top to bottom

Sagittal

• side to side (slice down the middle)

Coronal/Frontal

• front to back

• coming from the crown

What plane is this?

Coronal section

What plane is this?

Horizontal/Transverse section

What plane is this?

Sagittal sections