Modules 3 & 5 and Lectures 5-9 Flashcards
Overall purpose of the nervous system?
Create behavior
Specialized cells of the nervous system and their purpose/functions?
Neurons - transmit electrical impulses throughout the body
Glial cells - helper cells assisting neurons in role as brain communicator, and provide structural support
What are Dendrites?
Extensions of membrane of cell body and receive chemical messages from many other neurons.
Cerebral cortex length?
2.5 feet long if stretched out fully. ‘Advanced brain’.
Which side of the brain has more neurons?
The left hemisphere with 186 million more
What is a neurotransmitter?
Chemicals released from end of axon that acts as message to other neurons and body parts. Binds with receptors.
Receptors
Built to receive chemical messages from transmitters. Are proteins embedded in the cell membrane
What happens to our nervous system as we learn new things and grow?
Dendrites spread and form new connections with different neurons
What is the soma and its function?
Cell body from which dendrites extend from. Responsible for metabolic processes of the cell and contains the cells organelles.
Name the order that the electrical impulse must travel through starting from where the neuron touches a dendrite and ending at the axon hillock
Terminal Buttons - edge of axon terminal where neurotransmitter exits.
Axon terminal - releases neurotransmitter after action potential is reached
Axon hillock - where soma and axon meet
What are vesicles?
Little bubbles at the terminal button that store neurotransmitter molecules
Why does electrical potential exist?
Because of ion concentration inside and outside of the cell
Where do hallucinations usually come from?
Left visual field
What does the LGN do?
Relays information for the sensory function of eyesight
Lowest anatomical part of the brain?
Medulla
Resting potential of a neuron?
-70.0 mV
Examples of neuroplasticity
Branching out of dendrites, increases in neurotransmitter and receptor numbers
What does stroke/injuries to Wernicke’s area affect?
Speech comprehension
What is a presynaptic neuron and how does it aid in neural communication?
It is the portion of the neuron (also called axon terminal) that releases the neurotransmitter into the synapse, this allows a cell to connect with another cell and send that electrical impulse.
What are postsynaptic neurons?
Dendrites that receive neurotransmitters from another neuron’s axon terminal
What is a synaptic cleft?
It is the space between neurons. Neurotransmitters go across this space to communicate to the next neuron.
What are differences between the synaptic cleft and synapse?
Synaptic cleft is terminology for the space between the end of the neuron that is releasing a neurotransmitter (axon terminal) and the end of the receiving neuron (usually a dendrite).
While the synapse, is a small fluid-filled gap between neurons into which neurotransmitters are released (dendrites extend from this structure)
Order of structures/processes that the neurotransmitter passes through?
Presynaptic neuron down into the axon terminal where they are stored in synaptic vesicles. Neurotransmitter eventually breaks the vesicle and passes through the synaptic cleft into the dendrites of the postsynaptic neuron
What is the Myelin Sheath and its purpose?
Protein and fatty substance that wraps around the axon to protect and increase speed of action potentials (electrical impulses)
Nodes of Ranvier
Gaps in the myelin that allow ions to enter into the axon and change the charge inside
What are the characteristics of the polarized cell?
Large number of negatively charged ions inside the cell cause the neuron to have a negative charge (-70.0 mV). Charge is far from 0 (neutral).
The effect of a polarized cell
Cell is at rest and will not release neurotransmitters
Depolarization and its characteristics
Moving away from the state of being polarized. More positive charged particles in cell.
More depolarized the more likely it is going to activate (action potential) and send neurotransmitter to message other neurons.
What elements affect the cell’s action potential?
Na+ into the cell gets closer to action potential. Pushing K+ out of cell gets closer to deactivating (lost + ions making neuron more negative and polarized.
Describe propagation
Na+ are lined up along the axon - electrical impulse continues in succession along the axon. Gated channels in each section “sense” the positive shift in voltage and open too, repeating rush of Na+.
Electrical impulses get sent to end of neuron.
Mechanism to turn off neurons (put them at rest)?
Opening of K+ channels brings neurons to resting potential. The ions rush OUT instead of IN like the Na+ ions do.
What is repolarization?
Na+ coming in triggers K+ leaving resulting in quick repolarization of neuron to negative resting potential. (Resets neuron)
True or false: A neuron may receive inputs from both excitatory and inhibitory neurotransmitters?
True
Different kinds of responses that neurotransmitters interacting with different classes of receptor proteins produce?
Inhibitory (hyperpolarization -) and excitatory (causing +)
4 factors influencing kinds of feelings, thoughts, and behaviors, neurotransmitters release?
Receptors they bind with, where they are released, timing of release, and activity of other neurons in the same network, manipulated by different chemicals as well.
How do drugs affect neural communication?
Alter our experiences by acting like a neurotransmitter or stopping neurotransmitter from finding the receptor site.
What are agonists in relation to endogenous (naturally produced in the body) neurotransmitters?
Chemicals from outside of body that mimic action of neurotransmitters.
Antagonists in relation to endogenous neurotransmitters
Chemicals that comes from outside of body to shut off the receptors
What is Botox?
Contains poison stopping release of neurotransmitter acetylcholine, preventing muscle contractions. Muscles in face cannot contract.
What are oligodendrocytes?
Glial cells that wrap the myelin insulation around axons in the central nervous system. They speed up communication in the central nervous system. (Schwann cells are the same in the nervous system
What are 3 different types of glial cells?
Astrocytes - help get nutrition. Maintain balance of charged particles
Microglia - clean debris and help get rid of germs
Oligodendrocytes - wrap the myelin insulation around axons in central nervous system
What are the implications of a neurodegenerative disease?
Neurons dying over time resulting in loss of particular ability
Efferents vs Afferents
Axons that carry signals away from the CNS vs Axons carrying towards
Definition of neuroplasticity
Ability of neurons and their networks to change
What is the neocortex?
Outer part of brain, with bumps (gyri) and valleys (sulci) responsible for all the high-level processing info
Medulla and its function
Part of brain closest to spinal cord that helps regulate life functions like breathing and heart rate and reflexes
CNS and what it consists of
Gray matter (neurons and glia) and white matter (bundles of myelinated axons)
Gray matter vs white matter and their functions
Gray- local processing of info
White - helps different areas of the brain share information by connecting neurons via dendrites
In regards to the nervous system, what is the somatic division?
It is of the body, and controls movement of torso, head, and limbs. Nerves that control skeletal muscles
Autonomic division in nervous system?
Controls the more automatic functions of the body
In the automatic division there are parasympathetic and sympathetic nervous systems. Compare the two
Sympathetic - excitatory system. Increases heart rate and breathing. Can be nervous/frightened
Parasympathetic - calms heart rate, helps with recovery. Become sexually aroused
In the brain, what are the medulla and pons’ function?
Sustaining basic life functions.
Specific function of the pons
Helps regulate arousal (excitement/energy) and serve as bridge for tracts from upper brain to lower brain/spinal cord
What is the reticular activating system (RAS)?
Network of cells in pons and medulla regulating level of awareness and alertness in humans
What is the main role of the prefrontal cortex?
Make decisions
Main role of limbic system?
Regulate emotions, endocrine activity, and forming emotional memories
Amygdala and its main function
More active when we are under threat, and activates fear response