What is neuroanatomy?
Neuroanatomy relates to the parts and functions of individual nerve cells, known as neurons.
What is a neuron?
A neuron is an individual nerve cell.
Name the seven parts of a neuron.
Dendrites are branch-like arms attached to the cell body that receive information from other neurons.
The cell body/soma is the "brain" of the neuron, containing the nucleus.
Axons are tube-like structures that transmit information from the cell body to the terminal buttons.
The myelin sheath is the fatty layer around some axons that allows information to travel faster from the cell body to the terminal buttons.
The myelin sheath also acts as insulation so that signals don’t travel to every adjacent neuron, but just to the intended neuron(s).
Terminal buttons are where information from the axon ends up, and contain neurotransmitters.
What are synonyms for "terminal buttons"?
terminal branches of axons
Neurotransmitters are chemicals in the axon terminals that attempt to communicate with dendrites on other neurons.
Neurotransmitters must "fit" with dendritic receptor sites, like a key in a lock, to continue to the next neuron.
The synapse, also called the synaptic cleft, is the gap between the axon terminal of one neuron and the information-seeking dendrite of the next neuron. This role as a gap between the terminal buttons and dendrite helps pass chemical or electrical signals from one neuron to the next.
Chemicals travel within the cells, but are transmitted to other neurons electrically.
Within the cells, information is transmitted as an electric signal, but when it reaches the axon terminal, it is converted into chemicals that move between one neuron and the next.
Can a neuron fire at different magnitudes?
No, a neuron will fire completely if it reaches or exceeds the depolarization threshold, or not at all, which is called the all-or-none principle.
How is an action potential created?
Positively or negatively charged chemical signals enter the dendrite and move to the cell body, which is slightly negatively charged. If these chemical signals depolarize the cell body enough, an action potential will occur, which will fire electrical information down the axon to the axon terminal.
Some __________ are excitatory, prodding the cell body to fire, and others are __________, which prevent the creation of a cell's action potential.
Describe the path of information within a neuron from beginning to end.
Dendrite (chemical signals)⇒cell body (become electrical signals)⇒axon⇒axon terminal (become chemical signals)⇒synapse⇒dendrite of next neuron
When neurotransmitters from the axon terminal are released, they attempt to connect with __________ on the postsynaptic dendrite.
The threshold is the level of depolarization a cell body must reach to produce an action potential.
Function: motor movement
Problem: Alzheimer's disease linked to acetylcholine deficit
Function: motor movement and alertness
Problems: Parkinson's disease (dopamine deficiency) and schizophrenia (excessive dopamine)
Function: pain control
Problem: endorphins are released when pleasure areas of the brain are stimulated, so addictions are linked to endorphins
Function: mood control
Problem: deficiency linked to clinical depression
What is the difference between afferent and efferent neurons?
Afferent neurons, or sensory neurons, carry information to the brain.
Efferent neurons, or motor neurons, carry information from the brain to the body.
What are the subdivisions of the nervous system?
central nervous system
brain and spinal cord
peripheral nervous system
- brain and spinal cord
What is the difference between the central nervous system and the peripheral nervous system?
The central nervous system includes the nerves in bones. The peripheral nervous system includes the nerves not encased in bone.
When you want to answer a question in class, what part of the nervous system controls your ability to raise your hand?
The somatic nervous system controls voluntary muscle movements.
When your stomach begins to growl before lunch, what part of the nervous system is activated?
The autonomic nervous system is activated, which controls the parts of our bodies that work automatically, like heart beats, breathing, and digestive muscles.
What does the sympathetic nervous system do?
Like the gas pedal in a car, the sympathetic nervous system accelerates functions needed for responding quickly to stress, like breathing, heart rate, and pupil dilation, and slows functions not immediately necessary, like digestion.
What is the function of the parasympathetic nervous system?
The parasympathetic nervous system is like the brake pedal of a car, counteracting the sympathetic nervous system after stress has passed. It is also active during periods of "sex, sleep, and sustenance."
How did Phineas Gage contribute to the field of psychology?
Phineas Gage received frontal lobe damage after an accident, and his personality changed dramatically. This helped researchers conclude that the damaged part of the brain is an area where emotion regulation is controlled.
Since it is unethical to damage a human brain for the purposes of learning about brain function, researchers rely on accidents like Phineas Gage's to learn what areas of the brain are responsible for different functions.