Human Neuroscience Flashcards
What is also known as a nerve cell, is the fundamental structural and functional unit of the nervous system, and are specialized cells that process and transmit information through electrical and chemical signals.
Neuron
The brain is made up of approximately how many neurons?
100 Billion
Neurons, like other cells in the body, have a nucleus that contains what?
Genes
What part of a neuron brings information to the cell body?
Dendrites
What part of a Neuron takes information away from the cell body?
Axons
What kind of process do neurons use to communicate with each other?
Electrochemical
What are the specialized connections that neurons form called?
Synapses
What are the special chemicals that neurons produce that are released at the synapse?
Neurotransmitters
Approximately how many synapsis are there in the human brain?
1 Quadrillion
Is it true that we only use 10% of our brains?
No. Modern neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), have provided detailed insights into brain activity patterns. These studies consistently demonstrate that different regions of the brain are active during different tasks and activities. Additionally, studies of brain damage and neurological disorders have shown that damage to even small areas of the brain can have significant effects on cognition, behavior, and function.
Approximately how much does the adult human brain weight?
3 lbs. or 1300-1400 g.
What is the range of length for neurons in the body?
From less than a millimeter to more than a meter.
What is the central part of the neuron that contains the nucleus and other organelles responsible for the cell’s metabolic activities? It integrates information received from dendrites and initiates signals that are transmitted along the axon.
Cell Body, or Soma
What are branching extensions of the cell body that receive signals (in the form of neurotransmitter molecules) from other neurons or sensory receptors? These signals are transmitted electrically towards the cell body.
Dendrites
What is a long, slender projection of the neuron that conducts electrical impulses (action potentials) away from the cell body? It can vary in length from a few millimeters to over a meter in some cases and is specialized for transmitting signals to other neurons, muscles, or glands.
Axon
At the end of the axon, what are the small structures called that contain synaptic vesicles filled with neurotransmitter molecules? When an action potential reaches it, neurotransmitters are released into the synaptic cleft to communicate with other neurons or target cells.
Axon Terminals or Terminal Boutons
What is the specialized junction between the axon terminal of one neuron and the dendrites or cell body of another neuron (or an effector cell such as a muscle or gland)? Through this junction, neurotransmitters released from the axon terminal of the presynaptic neuron bind to receptors on the postsynaptic neuron, initiating a response in the postsynaptic cell.
Synapse
What part of a neuron does the following:
Plays a vital role in regulating cellular activities by controlling gene expression and protein synthesis. It governs the production of proteins necessary for the neuron’s function, including those involved in neurotransmission, cellular maintenance, and signal transduction.
Communicates with other parts of the neuron, such as dendrites and axons, to coordinate cellular activities and respond to signals from the environment or other neurons.
Nucleus
What does the following in a neuron:
Energy Production: they are often referred to as the “powerhouses” of the cell because they generate adenosine triphosphate (ATP), the primary energy currency of the cell, through a process called cellular respiration. Neurons have high energy demands due to their continuous activity and need for neurotransmitter release, making this thing essential for providing the energy required for neuronal function.
Calcium Regulation: they are involved in regulating intracellular calcium levels within neurons. Calcium is an important signaling molecule involved in various neuronal processes, including neurotransmitter release, synaptic plasticity, and cell survival. These things can sequester and release calcium ions, helping to maintain calcium homeostasis and regulate neuronal signaling.
ROS Regulation: They are a major source of reactive oxygen species (ROS) in cells. While ROS play important roles in cell signaling and defense against pathogens, excessive ROS production can lead to oxidative stress and cellular damage. These things contain antioxidant systems to regulate ROS levels and protect neurons from oxidative damage.
Synaptic Function: They are strategically located at synaptic terminals, where they support synaptic function by providing energy for neurotransmitter synthesis, recycling synaptic vesicles, and maintaining ion gradients necessary for neurotransmitter release and synaptic transmission.
Mitochondria
What is a specialized structure that surrounds the axons of many neurons in the nervous system. It consists of multiple layers of a lipid-rich substance produced by certain glial cells called oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS).
The primary function of this thing is to insulate and protect the axons, facilitating the rapid conduction of nerve impulses along the axon. It acts as an electrical insulator, preventing the leakage of electrical signals (action potentials) from the axon and allowing them to propagate more efficiently along the axon.
Myelin Sheath
What, also known as the myelin sheath gap or neurofibril node, is a specialized region along the axon of a neuron where the myelin sheath is interrupted.
These things are crucial for the propagation of nerve impulses (action potentials) along myelinated axons. These nodes are characterized by a high density of voltage-gated sodium channels and potassium channels in the axonal membrane. These ion channels are responsible for the generation and propagation of action potentials.
Node of Ranvier
In nerve conduction, what type of spread acts as follows:
Nerve impulses propagate along unmyelinated axons.
Unmyelinated axons lack a myelin sheath and nodes of Ranvier.
In this mechanism, the action potential spreads continuously along the entire length of the axon membrane.
The propagation of the action potential is relatively slow and less efficient compared to saltatory spread.
Characteristic of small-diameter fibers, such as those found in pain receptors (nociceptors) and autonomic neurons.
Slow Spread
In nerve conduction, what type of spread acts as follows:
Refers to the rapid propagation of nerve impulses along myelinated axons.
Myelinated axons are covered by a myelin sheath, with periodic gaps called nodes of Ranvier.
The action potential “jumps” from one node of Ranvier to the next, bypassing the myelinated regions in between.
This jumping of the action potential is facilitated by the high concentration of voltage-gated ion channels at the nodes of Ranvier, allowing for rapid depolarization and propagation of the action potential.
Much faster and more energy-efficient compared to slow spread, as the action potential travels over longer distances without the need for continuous depolarization and repolarization of the entire axon membrane.
Characteristic of myelinated fibers, which are found in many sensory and motor neurons of the central and peripheral nervous systems.
Saltatory Spread
What kind of neuron:
Also known as afferent neurons, are nerve cells responsible for converting external stimuli from the environment or internal stimuli from the body into electrical signals.
These neurons transmit sensory information from sensory receptors (such as those for touch, temperature, pain, vision, hearing, and taste) to the central nervous system (CNS), including the brain and spinal cord.
Sensory
What kind of neuron:
Also known as efferent neurons, are nerve cells that transmit signals from the central nervous system (CNS) to muscles, glands, or other effector organs.
They are responsible for initiating and controlling voluntary muscle movements (somatic motor neurons) as well as involuntary movements of smooth muscles and glands (autonomic motor neurons).
Motor Neuron
What kind of neuron:
Also known as association neurons, are nerve cells located entirely within the central nervous system (CNS), including the brain and spinal cord.
They serve as connectors and integrators, relaying signals between sensory neurons, motor neurons, and other interneurons.
Interneurons play a crucial role in processing and integrating sensory information, coordinating motor responses, and mediating complex neural functions such as memory, learning, and emotions.
Interneuron
What location consists of neurons and glial cells located within the brain and spinal cord?
The Central Nervous System
What place includes neurons and Schwann cells found outside of the CNS, responsible for transmitting sensory information to the CNS and controlling motor functions in the body?
Peripheral Nervous System (PNS)
In what kind of neuron does one axon attached to its soma divide, one branch receiving sensory information and the other sending the information into the central nervous system?
Unipolar Neuron
What is a Neuron with one axon and many dendrites attached to its soma?
Multipolar Neuron
What is a neuron with one axon and one dendrite attached to its soma?
Bipolar Neuron
What are the supporting cells of the central nervous system called?
Glial Cells
What is a glial cell that provides support to neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid?
Astrocyte or “Star Cell”
What are:
A type of glial cell in the central nervous system that forms myelin sheaths.
These cells form the myelin sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons.
Oligodendrocyte
What are the smallest glial cells that act as phagocytes and protect the brain from invading microorganisms?
Microglia
What is a cell in the peripheral nervous system that is wrapped around a myelinated axon, providing one segment of its myelin sheath?
Schwann Cell
What is a semipermeable barrier between the blood and the brain produced by cells in the walls of the brain’s capillaries?
Blood-Brain Barrier
What is the electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell?
Membrane Potential
What is the aspect of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials;
approximately -70 mV in the giant squid axon.
Resting Membrane Potential
What is the reduction (toward zero) of the membrane potential of a cell from its normal resting potential?
Depolarization
What is an increase in the membrane potential of a cell, relative to the normal resting potential?
Hyperpolarization
What is the brief electrical impulse that provides the basis for the conduction of information along an axon?
Action Potential
What is the value of the membrane potential that must be reached to produce an action potential?
Threshold of Excitation
What is the Movement of molecules from regions of high concentration to regions of low concentration?
Diffusion
What is the attractive force between atomic particles charged with opposite signs or the repulsive force between two atomic particles charged with the same sign?
Electrostatic Pressure
What is an aqueous solution of a material that ionizes a soluble acid, base, or salt?
Electrolyte
What is a charged molecule? Cations are positively charged, and anions are negatively charged.
Ion
At rest, a neuron’s membrane is permeable to what three things?
Potassium, Chloride, and Sodium
What uses energy in the form of ATP to move threesodium ions out of the cell and two potassium ions in. This moves the ions against their electrochemical gradients, which is why it requires energy. The pump functions to keep the ionic concentrations at proper levels inside and outside the cell.
Sodium-Potassium Pump
What type of neuron makes the neurons they connect to more likely to fire an action potential?
Excitatory
What kind of neuron makes the neurons they connect to less likely to fire an action potential?
Inhibitory
Does glutamate excite or inhibit cells?
Excite
Does GABA excite or inhibit cells?
Inhibit
Neurons that project a long way to a different brain region are called what?
Principal Neurons
Neurons that project locally are termed _____?
Interneurons
What type of glial cell lines the ventricles and produces cerebrospinal fluid (CSF)?
Ependymal Cell
What are the main cells that make up the blood vessels, form tight junctions with adjacent cells and with pericytes and form the blood brain barrier (BBB)?
Endothelial cells
