Ch. 1 Flashcards
Chapter 1 of The Mind's Machine
Neurons
(Nerve cell)- the basic unit of the nervous system, each composed of receptive extensions called dendrites, an integrating cell body, a conducting axon, and a transmitting axon terminal
Glial Cells
Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain
Synapses
The cellular location (tiny gap) at which information is transmitted from a neuron to another cell
What are the four principal divisions of the neuron?
input zone=dendrites
integration zone=cell body
conduction zone=axon
output zone=axon terminals
Dendrites
An extension of the cell body that receives information from other neurons
Cell Body
The region of a neuron that is defined by the presence of the cell nucleus
Axon
Also called nerve fiber. A single extension from the cell body that carries action potentials from the cell body toward the axon terminals.
Axon Collaterals
A branch of an axon
Axon Terminals
The end of an axon or axon collateral, which forms a synapse onto a neuron or other target cell and thus serves as the output zone (transmits the neuron’s signal across synapses to other cells)
Motor Neurons
A neuron that transmits neural messages to muscles- shape is large with long axons
Sensory Neurons
A neuron that is directly affected by changes in the environment, such as light, odor, or touch. Conveys information from sense organs to the brain.
Interneurons
A nerve cell that receives input from and send output to other neurons
What are the three classifications of neuron shapes?
multipolar, bipolar, and unipolar neurons
Multipolar Neurons
has many dendrites and a single axon (most common type of neuron)
Bipolar Neurons
have a single dendrite at one end of the cell and a single axon at the other end (common in sensory systems)
Unipolar Neurons
(Also called monopolar neurons) has a single projection, serving as an axon that extends from the input zone to the axon terminals, with the cell body branching off part way along its length
Presynaptic
transmitting side of a synapse
Postsynaptic
region of a synapse that receives and responds to neurotransmitter
What 3 principal components can a synapse be divided into?
presynaptic membrane, synaptic cleft, and postsynaptic membrane
Presynaptic Membrane
The specialized membrane on the axon terminal of a nerve cell that transmits information by releasing neurotransmitter
Synaptic Cleft
The space between the presynaptic and postsynaptic cells at a synapse
Postsynaptic Membrane
The specialized membrane on the dendrite or cell body that receives information by responding to neurotransmitter from a presynaptic neuron
Synaptic Vesicles
A small, spherical structure that contains molecules of neurotransmitter. Contained within the presynaptic axon terminals.
Neurotransmitter
The signaling chemical released from the presynaptic axon terminal that diffuses across the synaptic cleft to alter the functioning of the postsynaptic neuron, which serves as the basis of communication between neurons
How does communication between cells start?
Starts when synaptic vesicles respond to electrical activity in the axon and fuse to the presynaptic membrane and then rupture. This releases their payload of neurotransmitter molecules into the synaptic cleft. Then, the released neurotransmitter molecules interact with neurotransmitter receptors in the postsynaptic membrane. The reaction between the neurotransmitter and the postsynaptic membrane alter the level of excitation of the postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will release its own neurotransmitter from its axon terminals
Do molecules of neurotransmitter enter the postsynaptic neuron?
No, they bind to the outside of the receptors briefly to induce a response, and then detach and diffuse away
Neuroplasticity
The ability of the nervous system to change in response to experience or the environment
Axon Hillock
Cone-shaped area on the cell body form which the axon originates. It gathers and integrates the info arriving from the synapses on the dendrites of the cell body in order to determine when the neuron will produce neural signals of its own.
Axonal Transport
The transportation of materials from the neuronal cell body toward the axon terminals, and from the axon terminals back toward the cell body
What are the two functions of the axon?
- the rapid transmission of electrical signals along the outer membrane of the axon (like a wire)
- much slower transportation of substances within the axon, to and from the axon terminals (like a pipe)
What are four main types of glial cells?
- Oligodendrocytes
- Schwann cells
- Astrocytes
- Microglial cells
Oligodendrocytes
Type of glial cell that forms myelin in the central nervous system
Schwann Cells
Type of glial cell that forms myelin in the peripheral nervous system
Myelin
A fatty insulation around an axon, formed by glial cells. This sheath boosts the speed at which nerve impulses (action potentials) are conducted
Nodes of Ranvier
A gap between successive segments of the myelin sheath where the axon membrane is exposed
Astrocytes
A star-shaped glial cell with numerous processes (extensions) that run in all directions
What is some of the functions of Astrocytes?
- controls local blood flow to increase the amount of blood reaching more-active brain regions
- helps to form the tough outer membranes that swaddle the brain
- secrete chemical signals that affect synaptic transmission and the formation of synapses
Microglial Cells
Extremely small motile glial cells that remove cellular debris from injured or dead cells
Gross Neuroanatomy
Anatomical features of the nervous system that are apparent to the naked eye. Tissues are made up of many neural cell bodies, dendrites, axons, and glial cells
Central Nervous System (CNS)
Portion of the nervous system that includes the brain and the spinal cord
Peripheral Nervous System
Portion of the nervous system that includes all the nerves and neurons outside the brain and spinal cord
What are the two divisions of the peripheral nervous system?
somatic nervous system and the autonomic nervous system
Nerves
collections of axons bundled together
Motor Nerves
transmit information from the spinal cord and brain to muscles and glands
Sensory Nerves
convey information from the body to the CNS
Somatic Nervous System
A part of the peripheral nervous system that supplies neural connections mostly to the skeletal muscles and sensory systems of the body. It consists of cranial nerves and spinal nerves.
Automatic Nervous System
A part of the peripheral nervous system that provides the main neural connections to the internal organs
What two anatomical groups are part of the somatic nervous system?
the cranial nerves and the spinal nerves
What are the 12 pairs of cranial nerves and what is the main function?
- Olfactory (I)- smell
- Optic (II)- vision
- Oculomotor (III)- muscles that move the eyes
- Trochlear (IV)- muscles that move the eyes
- Abducens (VI)- muscles that move the eyes
- Trigeminal (V)- transmit facial sensation and control jaw muscles
- Facial (VII)- controls facial muscles and receives some taste sensation
- Vestibulocochlear (VIII)- hearing and balance
- Glossopharyngeal (IX)- taste and other mouth sensations, throat muscles
- Vagus (X)- internal organs
- Spinal Accessory (XI)- neck muscles
- Hypoglossal (XII)- tongue muscles
How many pairs of spinal nerves are present on the length of the spinal cord?
31
Where are the 31 pairs of spinal nerves?
- 8 cervical (neck)
- 12 thoracic (torso)
- 5 lumbar (lower back)
- 5 sacral (pelvic)
- 1 coccygeal (bottom)
After leaving the spinal cord what do axons from the spinal nerves do?
Axons from the spinal nerve spread out in the body and may merge with axons from different spinal nerves to form the various peripheral nerves
What is the main purpose of the autonomic nervous system?
it is the brain’s main system for controlling the organs of the body
What are the two major divisions of the autonomic nervous system?
sympathetic and parasympathetic nervous system- act more or less in opposition to one another
What is the main job of the sympathetic nervous system?
prepares the body for immediate action by increasing blood pressure, widening pupils, and quickening heart rate. (fight-or-flight response)
What is the main job of the parasympathetic nervous system?
helps the body to relax, recuperate, and prepare for future action
Sagittal Plane
divides the brain into right and left portions
Coronal or Frontal Plane
divides front (anterior) and back (posterior)
Horizontal Plane
divides between upper and lower parts
Medial
towards the middle
lateral
toward the side
Ipsilateral
on the same side
Contralateral
on the opposite side
Superior
above
Inferior
below
Basal
toward the bottom
Anterior
locations toward the front of the brain
Posterior
locations toward the rear
Proximal
near
Distal
far or toward the end of the limb
Afferent
a nerve or pathway is afferent if it carries information into a region that we’re interested in
a=arrive
Efferent
a nerve or pathway is efferent if it carries information away from the region of interest
e=exit
Dorsal
toward the back
Ventral
toward the belly
Cerebral Hemispheres
one of the two halves- right or left- of the forebrain
Cerebral Cortex
The outer covering of the cerebral hemispheres, which consists largely of nerve cell bodies and their branches
Gray Matter
Areas of the brain that are dominated by cell bodies and devoid of myelin. Gray matter mostly receives and processes information
White Matter
A light-colored layer of tissue, consisting mostly of myelin-sheathed axons, that lies underneath the gray matter of the cortex. Mostly transmits information.
Gyri
folding of the cortex that creates ridges of tissue
Sulci
Crevice or valley of the cortical surface
What are the four main cortical regions in each cerebral hemisphere?
frontal, parietal, temporal, and occipital lobes
Sylvian Fissure
divides the temporal lobe from other regions of the hemisphere
Central Sulcus
divides the frontal and parietal lobes
Corpus Callosum
The main band of axons that connects the two cerebral hemispheres
Precentral Gyrus
The strip of parietal cortex, just posterior to (behind) central sulcus, that receives somatosensory information from the entire body. PRIMARY MOTOR CORTEX
Postcentral Gyrus
The strip of parietal cortex, just posterior to (behind) the central sulcus, that receives somatosensory information from the entire body. PRIMARY SOMATOSENSORY CORTEXT
What is the main job of the frontal lobe?
movement planning and high-level cognition
What is the main job of the parietal lobe?
receives sensory information from the body and participate in spatial cognition
What is the main job of the occipital lobe?
crucial for vision
What is the main job of the temporal lobe?
receives auditory inputs and participates in language and memory functions
Neural Tube
An embryonic structure with subdivisions that correspond to the future brain and spinal cord
A few weeks after conception, what happens to the neural tube?
A few weeks after conception, the human neural tube begins to show three separate swellings at the head end: the forebrain, the midbrain, and the hindbrain. The remainder forms into the spinal cord
After around 50 days, what happens to the fetal forebrain?
The forebrain features two clear subdivisions. At the front is the telencephalon (becomes the cerebral hemispheres), and the other part becomes the diencephalon (goes on to become the thalamus and the hypothalamus)
What does the hindbrain develop into?
the cerebellum, pons, and medulla
Nuclei
A collection of neuronal cell bodies within the CNS
Tracts
Bundle of axons in the CNS
Cortical Columns
One of the vertical columns that constitute the basic organization of neurons in the cerebral cortex
Basal Ganglia
A group of forebrain nuclei, including the caudate nucleus, globus pallidus, and putamen, found deep within the cerebral hemispheres. They are crucial for skill learning.
Limbic System
Widespread group of brain nuclei that innervate each other to form a network. These nuclei are implicated in emotions and learning.
What are some structures that are part of the limbic system?
amygdala, hippocampus, fornix, cingulate gyrus, hypothalamus, and olfactory bulb
Amygdala
limbic structure involved in emotional regulation, odor perception, and aspects of memory
Hippocampus
Limbic structure that is important for learning and memory
Fornix
A fiber tract that extends from the hippocampus to the mammillary body. Important for learning and memory.
Cingulate Gyrus
A strip of cortex atop the corpus callosum in each hemisphere that is implicated with many cognitive functions, including directing attention
Olfactory Bulb
processes the sense of small
Hypothalamus
Packed with discrete nuclei involved in many vital functions, such as hunger, thirst, temperature regulation, sex, hormones, and many more
Thalamus
brain’s traffic router as it directs virtually all incoming sensory information to the appropriate regions of the cortex for further processing. Receives instructions back from the cortex about which sensory information is to be transmitted.
Tectum
The dorsal portion of the midbrain, consisting of the inferior and superior colliculi
Superior Colliculi
A paired gray matter structure of the dorsal midbrain that processes visual information and is involved in direction of visual gaze and visual attention to intended stimuli.
Inferior Colliculi
Paired gray matter structures of the dorsal midbrain that process auditory information
Tegmentum
The main body of the midbrain, containing the substantia nigra, periaqueductal gray, part of the reticular formation, and multiple fiber tracts
Substantia Nigra
A brainstem structure that innervates the basal ganglia and is a major source of dopaminergic projections to the basal ganglia
Periaqueductal Gray
midbrain structure implicated in the perception of pain
Reticular Formation
Loose collection of neurons that are important in a variety of behaviors, including sleep and arousal
Cerebellum
A structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement and in some forms of learning
Pons
Contains many nerve fibers and important motor control and sensory nuclei. Portion of the brainstem that connects the midbrain to the medulla.
Medulla
Marks the transition from the brain to the spinal cord. The medulla conveys all of the major motor and sensory fibers to and from the body. It also contains nuclei that drive such essential processes as respiration and heart rate
Meninges
The three protective membranes– dura mater, pia mater, and arachnoid– that surround the brain and spinal cord
Dura Mater
The tough outer sheet of the three meninges that surrounds the brain and spinal cord (tough mother in latin)
Arachnoid
The thin covering (one of the meninges) of the brain that lies between the dura mater and the pia mater (spiderweb-like)
Pia Mater
The innermost of the three meninges that surround the brain and spinal cord (tender mother- because it is delicate)
Cerebrospinal Fluid (CSF)
watery liquid that suspends the brain in the subarachnoid space
Meningitis
An acute inflammation of the meninges, usually by infections
Meningiomas
tumors that can form in the meninges
Ventricular System
A system of fluid-filled cavities inside the brain that convey nutrients and signaling chemicals and picking up waste
Where does the lateral ventricle reach to?
Each hemisphere of the brain has a lateral ventricle that extends into all four lobes of the hemisphere
Choroid Plexus
A specialized membrane lining the ventricles that produces cerebrospinal flood by filtering blood
Third Ventricle
The midline ventricle that conducts cerebrospinal fluid from the lateral ventricles to the fourth ventricle
Fourth Ventricle
The cavity within the pons that receives cerebrospinal fluid from the third ventricle and releases it to surround the brain and spinal cord
Hydrocephalus
A ballooning of the ventricles as they accumulate fluid due to blocking of the flow of CSF.
Glymphatic System
A lymphatic system in the brain that participates in removal of wastes and the movement of nutrients and signaling compounds
What are the two crucial fluids for the brain?
blood and cerebrospinal fluid (CSF)
Cerebral Arteries
The three pairs of large arteries within the skull that supply blood to the cerebral cortex
Blood-Brain Barrier
Capillaries in the brain that are highly resistant to the passage of large molecules across their walls and into neighboring neurons. This barrier evolved to help protect the brain from infections and blood-borne toxins, but it also makes the delivery of drugs to the brain more difficult.
Stroke
Situation in which a clot, a narrowing, or a rupture interrupts the supply of blood to a particular brain region, causing the affected region to stop functioning or die
Transient Ischemic Attack
Brief interruption of blood supply to some part of the brain and many create temporary stroke-like symptoms. Warning of a possible stroke.
Histology
the study of the composition of body tissues
Nissl Stains
A tissue stain that outlines all cell bodies because the dyes are attracted to RNA, which encircles the nucleus
Golgi Stains
A tissue stain that shows a small group of cell’s fine details of their structure (axons and dendrites)
Autoradiography
A staining technique that shows the distribution of radioactive chemicals in tissues
Immunohistochemistry (IHC)
Technique involving creating antibodies against a protein of interest. The antibodies seek out and attach themselves to their target proteins which reveals the distribution of the neurons that make the target protein.
In Situ Hybridization
A method for detecting particular RNA transcripts in tissue sections by providing a nucleotide probe that is complementary to, and will therefore hybridize with, the transcript of interest.
Tract Tracers
A substance used to visualize the axonal connections of neurons
Computerized Axial Tomography (CAT or CT Scans)
A noninvasive technique for examining brain structure through computer analysis of X-ray absorption at several positions around the head.
Magnetic Resonance Imaging (MRI)
A noninvasive brain-imaging technology that uses magnetic fields and radio-frequency energy to create images of the gross structure of the living brain
Diffusion Tensor Imaging (DTI)
A modified form of MRI in which the diffusion of water in a confined space is exploited to produce images of axonal fiber tracts. Helps us learn how networks of brain structures work together.
Functional MRI (fMRI)
Magnetic resonance imaging that detects changes in blood flow and therefore identifies regions of the brain that are particularly active during a given task.
Positron Emission Tomography (PET)
A brain-imaging technology that tracks the metabolism of injected radioactive substances in the brain, in order to map brain activity.
Functional Near-Infrared Spectroscopy (fNIRS)
A method for mapping brain activity using transcranial infrared light.
Transcranial Magnetic Stimulation (TMS)
A noninvasive technique that uses focal strong magnetic fields to stimulate cortical neurons in order to study the function of discrete brain regions, or treat certain disorders
Magnetoencephalography (MEG)
A noninvasive brain-imaging technology that creates maps of brain activity during cognitive tasks by measuring tiny magnetic fields produced by active neurons
Somatic Intervention
An approach to finding relations between body variables and behavioral variables that involves manipulating body structure or function and looking for resultant changes in behavior.
Within-Participants
An experiment in which the same set of individuals is compared before and after an experimental manipulation
Between-Participants
An experiment in which an experimental group of individuals is compared with a control group of individuals
Behavioral Intervention
An approach to finding relations between body variables and behavioral variables that involves intervening in the behavior of an organism and looking for resultant changes in body structure or function
Correlation
The tendency of two measures to vary in concert, such that a change in one measure is matched by a change in the other
Reductionism
The scientific strategy of breaking a system down into increasingly smaller parts in order to understand it
Level of Analysis
The scope of an experimental approach. A scientist may try to understand behavior by monitoring molecules, nerve cells, brain regions, or social environments or using some combination of these levels of analysis
