Ch1 Flashcards
The nervous system has two main types of cells
neurons and glia
Receive information and send it to other cells
Neurons
Support the neurons in many ways.
Glia
The adult human brain has about
86 billion neurons
In the late 1800s, scientist – used new staining techniques to show that there is a small gap between the end of one neuron’s fiber and the next neuron
Santiago Ramón y Cajal
Two scientists of the late 1800s and early 1900s are widely recognized as the main founders of neuroscience—
Charles Sherrington and the Spanish investigator Santiago Ramón y Cajal (1852–1934).
Golgi’s Staining Technique
Camillo Golgi developed a method using silver salts to stain nerve cells. This technique allows researchers to see the structure of individual neurons
Microscopy and the Nervous System
Before the late 1800s, the structure of the nervous system was poorly understood due to limitations in microscopy. The use of Golgi staining revolutionized research, allowing for the clear visualization of individual nerve cells.
The outer boundary of a cell that controls what enters and exits. It is semi-permeable and regulates the flow of essential substances like water, oxygen, sodium, potassium, calcium, and chloride.
Plasma Membrane
Found in all animal cells (except red blood cells), the nucleus contains the chromosomes, which house the cell’s genetic material.
Nucleus
The “powerhouse” of the cell, responsible for producing energy (ATP). Mitochondria have their own DNA, distinct from the nuclear DNA, and can vary genetically. Abnormal mitochondrial function is linked to conditions like autism and depression.
Mitochondria
Structures that produce proteins, which are essential for the cell’s structure and function. Some are free-floating, while others are attached to the endoplasmic reticulum (ER).
Ribosomes
A network of tubes that transports proteins synthesized by ribosomes to various parts of the cell
Endoplasmic Reticulum (ER)
Contains the nucleus and other essential cell structures
Soma (Cell Body)
Branched extensions that receive signals from other neurons
Dendrites
A long, thin extension that transmits signals away from the soma to other cells
Axon
The endings of the axon where the neuron communicates with other neurons or muscles
Presynaptic Terminals
carry signals from the brain and spinal cord to muscles and glands. It has a soma located in the spinal cord, with dendrites that receive incoming signals and an axon that transmits impulses to muscles.
Motor Neurons
carry information from sensory receptors (like touch or light) to the central nervous system (spinal cord and brain). It have a special structure at one end, adapted to detect specific stimuli (e.g., light, sound, or touch).
Sensory neurons
Golgi vs. Cajal
The debate between Golgi (who believed neurons merged) and Cajal (who showed that neurons remained separate) remains central to understanding how the nervous system functions.
A long, thin fiber that carries electrical impulses away from the cell body. The term comes from the Greek word for “axis.” They are typically of constant diameter but can be over a meter long (e.g., axons from the spinal cord to the feet)
Axon
Many axons are covered by an insulating layer. This speeds up the transmission of signals. In vertebrates, it is interrupted by gaps known as nodes of Ranvier.
Myelin Sheath
These neurons carry information into a structure (e.g., sensory neurons bring information from sensory organs to the nervous system
Afferent Neurons
These neurons carry information away from a structure (e.g., motor neurons transmit signals from the brain to muscles or glands).
Efferent Neurons
These neurons are found within the nervous system and have dendrites and axons confined to the same structure (e.g., neurons in the thalamus that connect sensory information).
Interneuron
These neurons have widely branching dendrites and can receive input from up to 200,000 other neurons.
Purkinje Cells (Cerebellum)
These neurons have short dendritic branches and receive input from only a few neurons.
Bipolar Neurons (Retina)
The supporting cells of the nervous system, outnumbering neurons in some parts of the brain. They perform many crucial functions
Glial cells (or neuroglia)
Astrocytes
-Star-shaped cells that wrap around synapses and blood vessels in the brain.
Shield synapses from chemicals in the surrounding environment.
Synchronize neuron activity by taking up and releasing ions and neurotransmitters, helping to coordinate brain waves (e.g., the rhythm of breathing).
Regulate blood flow: Astrocytes dilate blood vessels to increase nutrient supply to active brain areas.
Tripartite Synapse: Astrocytes may modify neuron communication by releasing their own chemicals in response to neurotransmitters from neighboring axons.
Astrocytes are essential for learning and memory, as they contribute to neuroplasticity.
Found in the brain and spinal cord, these cells build the myelin sheath around axons, providing insulation and improving signal transmission
Oligodendrocytes
Found in the peripheral nervous system, these cells perform a similar function to oligodendrocytes by forming myelin sheaths around peripheral axons.
Schwann Cells
Guide the migration of neurons and their axons/dendrites during embryonic development. After development, most differentiate into neurons or astrocytes
Radial Glia
is a crucial defense mechanism that protects the brain from harmful substances while still allowing necessary nutrients to enter
Blood Brain Barrier
Neurons require a constant supply of nutrients to function properly. The primary fuel for neurons is
glucose, a type of sugar, and they are highly dependent on a steady supply of oxygen.
Thiamine deficiency (often due to chronic alcoholism) can lead to
Neuron death and Korsakoff’s syndrome
the baseline electrical charge difference across the neuron’s membrane when it is not actively transmitting a signal.
The resting potential
A large, brief electrical change in the membrane potential that travels down the axon.
Action Potential
An action potential occurs at full strength once the threshold is reached.
All-or-None Law
The action potential travels down the axon, with myelinated axons conducting signals faster through saltatory conduction.
Propagation
Myelinated axons transmit action potentials faster and more efficiently, saving energy.
Myelin
A disease that destroys myelin, leading to slower action potentials and a range of neurological symptoms
Multiple Sclerosis
Absolute Refractory Period
During this time, the neuron cannot fire another action potential, no matter how strong the stimulus.
This happens because the sodium channels are inactivated after the peak of the action potential.
This period lasts about 1 millisecond
Sodium Channels
When the neuron is depolarized to the threshold, voltage-gated sodium channels open, allowing sodium (Na⁺) ions to rush into the axon
Potassium Channels
After depolarization, voltage-gated potassium channels open, allowing potassium (K⁺) ions to flow out of the axon, repolarizing the membrane
The flow of ions (sodium and potassium) changes the charge across the membrane, generating the action potential
Ion Flow
Relative Refractory Period:
After the absolute refractory period, the neuron can fire again, but only if the stimulus is stronger than usual.
This is because the potassium channels are still open, and the membrane is more negative than usual, making it harder for the neuron to fire.
This period lasts about 2-4 milliseconds
Local neurons don’t have axons and use – which are weaker and decay over time
graded potentials
Chemicals actively transported into Brain
Glucose
Amino Acid
Purines
Choline
Iron
Certain Vitamins
Increased polarization, exaggeration of usual negative charge within cells
Hyperpolarization
Decrease in amount of negative charge in cells
Depolarization
how drugs and other substances affect the brain and behavior, as well as
how they can be used to treat psychological disorders.
Psychopharmacology
nvestigates the relationship between brain function and behavior, focusing on how
brain damage or dysfunction can impact cognitive processes and psychological
functioning especially in human patients
Neuropsychology
relation between physical functions of organisms (physiology) and
psychological processes. Common physiological measures include
electroencephalogram (EEG), heart rate, and pupil dilation.
Psychophysiology
Relationships between the nervous system, immune system and
hormones, and behavior.
Psychoneuroimmunology
Explores how evolutionary processes, like natural selection, have adaptively
shaped human traits and behaviors
Evolutionary Psychology
how genetic factors contribute to individual differences in behavior,
cognition, personality, etc. and how genetic factors interact with
environmental influences.
Behavioral Genetics
studies the neural basis of human cognitive processes
Cognitive Neuroscience
examines the behavior and mental processes of nonhuman animals to gain
insights into the evolutionary and environmental factors
Comparative Psychology
is a systematic way of gathering and testing evidence based on observation and
experimentation
The scientific
method
tentative explanation
hypothesis
driven by scientific curiosity or an interest in understanding
the mechanisms of brain function and brain-behavior relationships.
Basic research, also known as pure research
biological psychology takes findings from basic research and uses them to solve real-world issues
applied research
stimulates the brain with magnetic pulses and can treat depression
Transcranial magnetic
stimulation
uses brain implants to treat diseases like parkinson’
deep brain
stimulation
A
vertical plane and splits the brain into front and back sections.
coronal or frontal plane
is a vertical plane which splits the brain into
left and right section
sagittal plane
is a horizontal plane which splits the brain into upper and lower sections
horizontal or axial plane
can be thought of as the body’s command center and communication network; it processes information, relays sensory input, and coordinates actions by
transmitting signals to and from other body parts
nervous system
The nervous system is divided into two
central nervous system (CNS) and the peripheral
nervous system (PNS)
The central nervous system consists of the – and –. The peripheral nervous system consists of –
Brain and spinal cord.
of nerves outside the brain and spinal cord and forms the communication network
connects the central nervous system with
the rest of the body. It serves as a communication relay between the CNS and muscles, organs, and glands.
peripheral nervous system (PNS)
The PNS can be divided into
autonomic nervous system, which controls bodily functions without conscious control, and the somatic nervous system, which transmits sensory information from the skin, muscles, and sensory organs
It controls the lungs, the heart, smooth
muscle, and exocrine and endocrine glands. It controls these organs largely without conscious control.
The autonomic nervous system
is
responsible for the “fight or flight” response that occurs when an animal
encounters a dangerous situation.
The sympathetic nervous system
allows an animal to “rest and digest
parasympathetic nervous system
transmit sensory information from the skin, skeletal muscle, and sensory organs to the CNS.
Sensory neurons
transmit messages about desired movement from the CNS
Motor neurons
The brain and spinal cord are enclosed in three layers of protective coverings called
-meninges (from the Greek word for membrane) (Figure 8).
- The outermost layer dura mater (Latin for “hard mother”)—a thick layer that protects the brain
and spinal cord and contains large blood vessels.
-The middle layer is the
web-like arachnoid mater.
-The innermost layer is the pia mater (Latin for “soft
mother”), which directly contacts and covers the brain and spinal cord like plastic wrap.
Transmits information from the skin, muscles, and internal organs to the brain, and vice versa. Information that travels from the bodily periphery toward the brain
The spinal cord
is a thin sheet of neurons that makes up the
outermost layer of the cerebral hemispheres
The cerebral cortex
The bumps are called –
and the valleys between gyri are called –
Larger and deeper of these are called –
Gyri
Sulci
Fissures
It separates the temporal lobe from the
frontal and parietal lobes
lateral sulcus (also called the Sylvian fissure)
some brain functions are processed more in one
hemisphere than the other.
lateralization of function
smaller subregions of the cerebral cortex are
associated with particular function
localization of function
microscopic anatomy, or cytoarchitecture, of the
cerebral cortex and divided the cortex into 52 separate regions based on the microscopic tissue structure.
Brodmann Areas
It is involved in processing
auditory information, understanding language,
recognizing visual objects, and memory
temporal lobe
A region involved in language comprehension
Wernicke’s area
the inability to recognize and identify faces
prosopagnosia
processes touch, bodily and spatial maps, and integrates senses, speech, taste
Parietal lobe
Visual association area, vision
Occipital lobe
It is sometimes called the insular
lobe, a fifth lobe of the cerebral cortex,sensory processing, representing emotions, motor control, self-awareness, empathy, risk prediction, cognitive functioning, consciousness
Insula
a collection of highly specialized neural structures, both subcortical and cortical, memory, emotion,
behavior, motivation, and olfaction
hippocampus, the amygdala, and the cingulate
cortex.
Limbic system
A seahorse shaped structure involved in memory, learning, and spatial processing
hippocampus
Named for its almond shape
processing of emotions, including generating
emotional responses and emotional learning
amygdala
that are especially critical for regulating and
selecting voluntary movement
Basal Ganglia
Is an information hub that relays information from and to widespread brain areas
Thalamus
is primarily responsible for regulating endocrine hormones in conjunction with the pituitary gland
Hypothalamus
(Latin for “little brain”) critical for coordinated movement and posture. It does not initiate motor commands, but contributes to movement precision, timing, and fine-turning as well as motor learning
Cerebellum
“trunk” of the brain
responsible for many of the neural
functions that keep us alive, including regulating breathing, heart rate, and digestio
Brain stem
The brainstem can be divided into multiple sections in
descending order
midbrain
pons
Medulla oblongata
is a set of interconnected cavities known as cerebral ventricles that produce and transport cerebrospinal fluid (CSF)
cerebral ventricular system
Directs blood to the most active brain regions.
vasculature
Directs blood to the most active brain regions.
vasculature
You’re studying for an exam and want to improve your memory retention. Which concept best explains the importance of simultaneous neuron activity
Cells that fire together, wire together.
During a stress response, which type of cells might assist neurons in managing increased activity
Glia
What major structures do neurons have
. Cell body, dendrites, axon, and presynaptic terminals
What is the primary function of glial cells?
To enhance and modify neuronal activity
What is the primary function of glial cells?
To enhance and modify neuronal activity
What is the primary function of glial cells?
To enhance and modify neuronal activity
What is the primary function of glial cells?
To enhance and modify neuronal activity
What molecules can cross the blood-brain barrier freely?
Small, uncharged molecules like oxygen and carbon dioxide
Which vitamin is essential for neurons to utilize glucose?
Thiamine (Vitamin B1)
If a person has a condition that affects the myelin sheath, how might their sensory transmission be impacted?
It would slow down
If a neuron is at rest, what charge does it have relative to the outside
Negative
. What is the term for the rapid influx of sodium ions that leads to the action potential
Depolarization
What occurs immediately after an action potential in terms of ion movement?
Potassium ions flow out of the neuron
What is the main purpose of the sodium-potassium pump in a neuron?
To maintain resting membrane potential
What is most distinctive about neurons, compared to other cells?
Shape
Which of these do dendritic spines do?
They increase the surface area available for synapses
Which of these do dendritic spines do?
They increase the surface area available for synapses
What does an efferent axon do?
It carries output from a structure
Which of the following is a function of astrocytes?
Astrocytes synchronize activity for a group
of neurons.
When the neuron’s membrane is at rest, where are the sodium ions and potassium ions most concentrated?
Sodium is mostly outside and potassium is mostly inside.
When the membrane is at rest, what are the forces acting on sodium ions?
Both the concentration gradient and the electrical
gradient tend to move sodium ions into the cell.
When the membrane is at rest, what are the forces acting on potassium ions?
The concentration gradient tends to move potassium
ions out of the cell, and the electrical gradient tends to move them into the cell.
Which direction does the sodium–potassium pump move ions?
It moves sodium ions out of the cell and potassium
ions into the cell.
Under what conditions does an axon produce an action potential?
Whenever the membrane’s potential reaches the
threshold
If a membrane is depolarized to twice its threshold, what happens
The neuron produces the same action potential it
would at the threshold.
During the rising portion of the action potential, which ions are moving across the membrane and in which direction?
Sodium ions move in.
After the action potential reaches its peak, the potential across the membrane falls toward its resting level. What accounts for this recovery?
Potassium ions move out because their channels are open and the concentration gradient pushes them out.
