Neuro Review 1

Gray matter is interior relative to white matter in the spinal cord, and gray matter is exterior relative to white matter in the brain

True

T/F: Sensory information enters the spinal cord through the dorsal portion and motor information leaves the spinal cord through the ventral portion

True

T/F: The number of dendritic branches correlates with the number of inputs

True

The meninges only encase the brain and not the spinal cord

False

There are no regions of the brain that lack the BBB

False

What is the main difference between brain capillaries and capillaries throughout the rest of the body?

Capillaries throughout the body are fenestrated, meaning they have perforations and pores to allow blood flow between the capillaries and the surrounding tissue or organs. Brain capillaries, paradoxically, are non-fenestrated, meaning they have tight junctions and highly regulated barriers to only allow specific molecules into the brain via the blood.

Label the neuron in the figure below. Which areas correspond to each of the following functions

Input -> dendrites Propagation -> axon Integration -> soma Output -> axon terminal

What are the four general neuron categories and their purpose?

Motor neurons: Cause muscle contractions or control secretions Interneurons: Communicate between nearby regions of the CNS (i.e. local roads within a small town) Projection neurons: Communicate between distant regions of the CNS (i.e. interstate highways in between towns) Sensory neurons: Transduce signals from the environment into neural signals (i.e. touch, pain, sound)

What is one piece of evidence supporting the theory of localism in the brain? Does this make the theory of holism invalid?

The case study of Phineas Gage supports the theory of localism in the brain in that the damage from the tamping iron destroyed his ability to make informed decisions and altered his personality. This shows specific locations in the brain (frontal lobe) are responsible for individual functions (personality, decision making). However, this does not invalidate the theory of holism, whereby areas of the brain work together to process multiple types of information, because he was still able to go through his life with all of his important processes intact, despite the massive brain damage. Also, his personality and decisions were altered but not completely absent.

What four ions contribute to the resting membrane potential? What is their distribution across the membrane.

Na+, K+. Cl-, A- (proteins) Na+ and Cl- are concentrated extracellularly, K+ and proteins are in high concentration intracellularly

The neuron has many of the same structural elements of any other body cell. What cellular element differentiates neurons from other cells in the body and how can this be useful in identifying neurons in a laboratory setting?

Neurofilaments are only present in neurons and can be used in staining techniques to differentiate neurons from other nearby cells.

In what ways do oligodendrocytes differ from Schwann cells?

Oligodendrocytes and Schwann cells both form the myelin of neurons. Oligodendrocytes myelinate several parts of several axons in the central nervous system with a connecting cell body separate from the neurons. Conversely, Schwann cells myelinate a single part of a single axon in the peripheral nervous system with its entire cell body being wrapped around said axon.

Match the glial cell type with the function.

Oligodendrocytes: one cell myelinates axon segment of many neurons Microglia: modulate inflammation and cell survival in the brain Astrocytes: end-feet support the blood-brain barrier Schwann cells: one cell myelinates axon segment of one neuron

Describe the difference between the Reticular Theory and the Neuron Doctrine. Who supported the Reticular Theory? Who supported the Neuron Doctrine? Who was correct? What pieces of evidence support the hypothesis? What was the irony of this situation?

The Reticular Theory was supported by Camillo Golgi and suggested a web-like system in which all neurons are connected in a network. Santiago Ramon y Cajal opposed this theory and believed that there was no continuity between neurons, instead suggesting that the nervous system was made up of discrete, individual cells (The Neuron Doctrine). The irony here lies in the fact that Ramon y Cajal used a stain developed by Golgi (Golgi Stain) to trace individual neurons and support his theory.

What is the function of the corpus callosum? What is it made of? (i.e. what type of neurons? What specific part of those neurons?)

The corpus callosum functions to connect the two hemispheres of the brain. It is made of the axons of projection neurons.

What condition is depicted in this CT scan and how is it treated? The condition can be either named or described.

This CT scan depicts hydrocephalus, or a build-up of CSF in the ventricles. This puts enormous pressure on the brain and causes swelling in the brain and skull. It is treated by placing a shunt system in the ventricles to drain spinal fluid directly into the abdomen via specialized catheters.