How thick is the cerebral cortex and how many layers does it have?
between 2 mm to 5 mm thick and it's made of 6 different layers
About how many neurons (nerve cells) does the cortex contain?
15 billion
What part of the brain is often referred to as "grey matter"?
the cortex
Activities such as language, motor planning, problem solving, sensory perception are performed in what part of the nervous system?
cortex
The areas in the brain known as "white matter" consist of???
myelinated nerve cell axons
Name the 3 sections of the brainstem from top to bottom.
midbrain
pons
medulla
List the 3 most important functions of the brainstem.
1. acts as a passageway for the descending and ascending neural tracts that travel between the cerebrum and spinal cord.
2. controls certain integrative and reflexive actions such as respiration, consciousness, and some functions of the cardiovascular system.
3. it contains the places where the cranial nerves project out from the CNS.
The cranial nerves are attached to the brainstem at points called the _____.
cranial nerve nuclei
The most important function of the cerebellum is to __________.
coordinate voluntary movements
This type of cell transmits electrochemical signals that control nearly every function of the body.
neuron
What are the 3 primary components of a neuron?
cell body (soma), axon, dendrite
This part of the neuron contains the nucleus responsible for the cell's vital metabolic functions.
cell body
Cell bodies of neurons are what color?
grey
What is the name of the many short processes that extend from the cell body of a neuron?
dendrites
What is the single long extension from the cell body that conducts neural impulses away from the neuron?
axon
What is the end of an axon called?
terminal boutons
What is the name of the white lipid protein that covers the length of the axon?
myelin
This type of neuron transmits neural impulses that cause contractions in muscles.
motor neurons
This type of neuron carry information related to sensory stimuli.
sensory neurons
This type of neuron links neurons with other neurons and are the most common type of neuron.
interneurons
Neurons that carry impulses away from the CNS are called?
efferrent
Neurons that carry impulses toward the CNS are called?
afferrent
List the 4 different types of glial cells.
Schwann cells
microglia
oligodendroglia
astrocytes
This type of glial cell provides the myelin sheath around axons in the PNS.
Schwann cells
This type of glial cell acts as a scavenger and removes dead cells and other waste.
microglia
This type of glial cell forms myelin around axons in the CNS.
oligodenroglia
This type of glial cell makes up the connective tissue of the CNS.
astrocytes
It is believed that there are about ___ times as many glial cells as neurons and that they make up more than half the volume of the nervous system.
10
When bundles of axons are found in the CNS they are often called ________.
tracts
When bundles of axons are found in the PNS they are called _________.
nerves
When the electrochemical charge of an axon reaches the axon's terminal ramifications, small amounts of a substance called a ____________ are released from these end points.
neurotransmitter
What is the name of the space between the active neuron and an adjoining neuron?
synaptic cleft
Neurotransmitters can have 2 functions-what are they?
excitatory-they increase the probability of an electrochemical impulse being stimulated in the adjoining neuron
inhibitory-they decrease the probability of an impulse occurring in the adjoining neuron.
What are the 2 most important neurotransmitters in the motor system?
dopamine and acetylcholine
If there are too many inhibitory neurotransmitters, a person will suffer from? too many excitatory neurotransmitters?