Lecture 1: Review of the Nervous System Flashcards
Stroke
the sudden appearance of neurological symptoms as a result of severe interruption of blood flow
also called cerebral vascular accident (CVA)
Ischemia
deficient blood flow to the brain due to functional constriction or actual obstruction of a blood vessel by a clot
Hemorrhagic Stroke
a severe stroke that results from a burst vessel bleeding into the brain
Tissue Plasminogen Activator (t-PA)
a drug for testing ischemic stroke that breaks up clots and allows the return of normal blood flow to the affected region if administered within 3 hours
Nuclei
a spherical structure in the soma of a cell
contains DNA and is essential to cell function
also a cluster of cells that can be identified histologically and has specific functions in mediating behavior
Tracts
a large collection of axons coursing together within the central nervous system
also called fiber pathway
Ipsilateral
residing in the same side of the body as the point of reference
Contralateral
residing in the side of the body opposite the reference
Contralateral
residing in the side of the body opposite the reference point
Bilateral
applying to both sides of the body
Proximal
close to some point
Distal
distant from some point
Afferent
conducting toward a central nervous system area
Efferent
conducting away from the central nervous system area and toward a muscle or gland
Precentral Gyrus
the gyrus lying in front of the central sulcus
also called M1 or primary motor cortex
Parasympathetic (Calming) Nerves
calming nerves of the autonomic nervous system that enable the body to “rest and digest”
Sympathetic (Arousing) Nerves
arousing nerves of the autonomic nervous system that enable the body to “flight or flee” or engage in vigorous activity
Meninges
three layers of protective tissue - dura mater, arachnoid, and pia mater - that encase the brain and spinal cord
Hydrocephalus
a buildup of pressure in the brain and, in infants, swelling of the head, caused by blockage in the flow of cerebrospinal fluid
can result in intellectual disabilities
Blood-Brain Barrier
tight junctions between capillary cells that block entry of an array of substances, including toxins, into the brain
Anterior Cerebral Artery (ACA)
a vessel originating from the carotid artery that irrigates the medial and dorsal parts of the cortex, including the orbitofrontal and dorsolateral frontal regions, anterior cingulate cortex, corpus callosum, and striatum
Middle Cerebral Artery (MCA)
an artery that runs along the length of the lateral (Sylvian) fissure to irrigate the lateral surface of the cortex, including the ventral part of the frontal lobe, most of the parietal lobe, and the temporal lobe
Posterior Cerebral Artery (PCA)
a vessel that irrigates the ventral and posterior surfaces of the cortex, including the occipital lobe and hippocampal formation
Neural Stem Cells
a self-renewing, multipotential cell that gives rise to any of the different types of neurons and gilia in the nervous system
Progenitor Cells
a precursor cell derived from a stem cell that migrates and produces a neuron or glial cell
also called precursor cell
Blasts
an immature neuron or glial cell
Sensory Receptor
a cell that transduces sensory information into nervous system activity
Bipolar Neuron
neurons with processes at both poles
characteristic especially of retinal cells
Somatosensory Neuron
a neuron that projects from the body’s sensory receptors into the spinal cord
the dendrite and axon are connected, which speeds information conduction because messages do not have to pass through the cell body
Interneurons
any neuron lying between a sensory neuron and a motor neuron
Motor Neurons
Charles Scott Sherrington’s term for the unit formed by motor neurons and the muscle fiber to which their axon terminations are connected
Ependymal Cells
glial cells that make and secrete cerebrospinal fluid and form the lining of the ventricles
Astroglia
a star-shaped glial cell that provides structural support to neurons in the central nervous system and transports substances between neurons and blood vessels
Microglia
glial cells that originate in the blood, aid in cell repair, and scavenge debris in the nervous system
Oligodendroglia
glial cells in the central nervous system that myelinate axons
Schwann Cells
glial cells in the peripheral nervous system that myelinate sensory and motor axons
Myelin
a lipid substance that forms an insulating sheath around certain nerve fibers
formed by oligodendroglia in the central nervous system and by Schwann cells in the peripheral nervous system
Gray Matter
any brain area composed predominantly of cell bodies and capillaries
White Matter
areas of the nervous system rich in fat-sheathed neural axons that form the connections between brain cells
Reticular Matter
any nervous system area composed of intermixed cell bodies and axons
has a mottled gray and white, or netlike, appearance
Ganglia
a collection of nerve cells that function somewhat like a brain
Nerves
a large collection of axons (nerve fibers) coursing together outside the central nervous system
Prosencephalon
the front brain, the most anterior part of the embryonic mammalian brain
in adult fish, amphibians, and reptiles, it is responsible for olfaction
Mesencephalon
middle brain
one of the three primary embryonic vesicles, which in the embryonic mammalian brain subsequently comprises the tectum and tegmentum
in adult fish, amphibians, and reptiles, the seat of vision and hearing
Rhombencephalon
a posterior chamber of the embryonic mammalian brain, which divides into the metencephalon and myelencephalon
in adult fish, amphibians, and reptiles, controls movement and balance
Telencephalon
the endbrain
includes the mammalian cerebral cortex, basal ganglia, limbic system, and olfactory bulbs
Diencephalon
the region of the brain that includes the hypothalamus, thalamus, and epithalamus
Mentencephalon
the anterior part of the mammalian rhombencephalon
composed of the cerebellum and pons
Myelencephalon
the spinal brain
the posterior part of the mammalian rhombencephalon, including the medulla oblongata and fourth ventricle
Ventricles
a cavity of the brain that contains cerebrospinal fluid
Cerebral Aqueduct
a connection between the third and fourth ventricles that drains cerebrospinal fluid from the fourth ventricle into the circulatory system at the base of the brainstem
Dermatome
a body segment corresponding to a segment of the spinal cord
Anterior Root
a nerve composed of fibers carrying motor information from the anterior part of the human spinal cord
Posterior Root
a nerve composed of fibers carrying sensory information that enters each segment of the posterior spinal cord
Bell-Magendie Law
the principle that the dorsal or posterior roots in the spinal cord are sensory and the ventral or anterior roots in the spinal cord are motor
Paraplegic
of persons whose spinal cord has been cut, making them unable to have control over their legs
Quadriplegic
of persons whose spinal cord has been cut, making them unable to have control over their arms and legs
Reflexes
a specific movement that depends only on a simple spinal-cord circuit and elicited by specific forms of sensory stimulation
Flexion
a reflex that brings a limb towards the body
Extension
a reflex by which a limb is straightened
Cranial Nerves
a set of 12 pairs of nerves that convey sensory and motor signals to and from the head
Referred Pain
pain felt on the surface of the body that is actually due to pain in an internal body organ
Cerebellum
a major structure of the hindbrain that is specialized for learning and coordinating skilled movements
in large-brained animals, may also participate in coordinating other mental processes
Folia
narrow folds of the cerebellum
Reticular Formation
a mixture of nuclei and fibers that runs through the center of the brainstem, extending from the spinal cord to the thalamus
associated with sleep-wake behavior and behavioral arousal
Tectum
the roof of the midbrain
located above the aqueduct
consists of the superior and inferior colliculi, which mediate whole-body responses to visual and auditory stimuli, respectively, and the production of orienting movements
Tegmentum
the floor of the midbrain
located below the cerebral aqueduct
contains a collection of sensory and motor tracts and nuclei with movement-related, species-specific and pain-perception functions
Superior Colliculi
bilateral nuclei of the midbrain tectum that receive projections from the retina of the eye and mediate visually related behavior
Inferior Colliculi
nuclei of the midbrain tectum that receive auditory projections and mediate orientation to auditory stimuli
Substantia Nigra
nuclei in the midbrain containing the cell bodies of dopamine-containing axons that connect to the forebrain and are important in rewarding behaviors
in freshly prepared human tissue, the region appears black
hence the name, which is Latin for “black substance”
Periaqueductal Gray Matter (PAG)
nuclei in the midbrain that surround the cerebral aqueduct
PAG contains circuits for species-typical behaviors and play an important role in modulating pain
Hypothalamus
a collection of nuclei located below the thalamus in the diencephalon
controls behavior including movement, feeling, sexual activity, sleeping, emotional expression, temperature regulation, and endocrine regulation
Thalamus
a group of nuclei in the diencephalon that integrates information from all sensory system and projects it into the appropriate cortical regions
Epithalamus
a collection of nuclei that forms the phylogenetically most primitive region of the thalamus
includes the pineal gland, which secretes the hormone melatonin that influences daily and seasonal body rhythms
Basil Ganglia
subcortical forebrain nuclei (caudate nucleus, putamen, globus pallidus) that connect to the thalamus and midbrain and coordinate voluntary movements of the limbs and body
Neocortex
the newest later of the brain, forming the outer layer, or “new bark”, has four to six layers of cells
Limbic System
disparate forebrain structures lying between the neocortex and the brainstem that form a functional system controlling affective and motivated behaviors and certain forms of memory
includes cingulate (limbic) cortex, amygdala, hippocampus, and hypothalamus, among other structures
Amygdala
an almond-shaped collection of nuclei in the base of the temporal lobe
the part of the limbic system that participates in emotional and species-typical behaviors
Hippocampus
a distinctive limbic-system structure that lies in the anterior medial region of the temporal lobe
participants in species-specific behaviors, memory, and spatial navigation and is vulnerable to the effects of stress
Cingulate (“Girdle”) Cortex
a strip of three- to four-layered limbic cortex that lies just above the corpus callosum along the medial walls of the cerebral hemispheres
Central Sulcus
a fissure that runs from the dorsal border of each hemisphere near its midpoint and obliquely downward and forward until it nearly meets the lateral fissure, dividing the frontal and parietal lobes
Projection Map
a map of the cortex made by tracing axons from the sensory systems into the brain and from the neocortex to the motor systems of the brainstem and spinal cord
Primary Areas
neocortical regions that receive projections from the major sensory systems or send projections to the muscles
Secondary Areas
a cortical region that receives inputs from the primary areas and is thought to participate in more complex sensory and perceptual or motor functions
Tertiary Areas or Association Areas
cortical regions that receive projections from secondary areas or send projection to them
encompasses all cortex not specialized for sensory or motor function and mediates complex activities such as language, planning, memory, and attention
Cytoarchitectonic Maps
a cortical map based on cytology, the organization, structure, and distribution of cells
Brodmann’s Map
a map of the cerebral cortex devised by Korbinian Brodmann circa 1905 and based on cytoarchitectonic structure with anatomical areas identified by number
conforms remarkably closely to functional area identified by the results of later lesion and recording studies
Homotopic
at the same place on the body
Connectome
a comprehensive map of the structural connectivity (the physical wiring) of an organism’s nervous system
Decussations
a band of fibers that cross from one side of the brain to the other
What is the symmetrical organization of the brain?
structures on the same side of ipsilateral (ipsilesional)
structures on opposite side are contralateral (contralesional)
structures that lie in both hemispheres are bilateral
What do the terms proximal and distal mean?
structures close together are proximal
structures far apart are distal
What do the terms efferent and afferent mean?
movement away from brain is efferent
movement toward the brain is afferent
What is the anterior cerebral artery?
irrigates medial and dorsal parts of cortex
What is middle cerebral artery?
lateral surface of cortex
What is posterior cerebral artery?
ventral and posterior surfaces of cortex
What is the spinal cord?
dorsal receives input
ventral conveys motor commands
dermatomes
damage to SC affects connections to areas below point of injury
What is the medulla?
motor fibers cross
reticular activating system (RAS) (reticular formation)
arousal, vital functions
What is the pons?
connects cerebellum
What is the midbrain?
inferior colliculus (ears)
superior colliculus (eyes)
What is the thalamus?
relay center
almost every sensory system routes through the thalamus
acts like a switch board, controls where information goes
What are the three main structures of the forebrain?
basal ganglia
limbic system
cerebral cortex
What is the basal ganglia?
collection of nuclei: putamen, globus pallidus, caudate
input from all areas of brain; functions in controlling and coordinating movement patterns
output to frontal - motor regions via thalamus
basal ganglia diseases are disorders of controlling movement, not producing movement (e.g., Huntington’s & Parkinson’s)
What is the amygdala?
emotion and species-typical behaviors
What is the hippocampus?
memory and spatial navigation
What is the septum?
connector
emotion and species-typical behavior
What is the cingulate cortex (cingulate gyrus)?
emotion, cognition, executive function, motor control
What is the neocortex?
has expanded the most during evolution
comprises 80% of human brain
2500 square cm, thickness of 1.5-3.0 mm
six layers
two cerebral hemispheres, four lobes
What is a fissure?
cleft in cortex deep enough to indent ventricles
What are sulci?
shallow cleft in cortex
What are gyri?
ridge in cortex
What can be found through comparative neuroanatomy of different species?
the complexity of sulci increased through evolution
What are the primary areas in the cortex?
first higher order structures that receive sensory info and send motor message
key area for different signals
frontal lobe –> motor functions
parietal lobe –> body senses
temporal lobe –> auditory functions
occipital lobe –> visual functions
What is the calcarine fissure?
primary visual cortex above and below it
What are the secondary areas of the cortex?
adjacent to primary areas
receive input from primary areas
engaged in interpreting sensory input or organizing movements
What are the tertiary areas of the cortex?
association cortex
located between secondary areas
multiple regions
mediate complex activities (integration of information)
What are the four types of axon projections?
long connections between one lobe and another
shorter connections between one part of lobe to another
interhemispheric connections: commissures, homotopic points, contralateral (bilateral) points that correspond to each other (anatomical versus functional)
connections through the thalamus
What is the interhemispheric (longitudinal) fissure?
separates left and right
What is the Sylvian (lateral) fissure?
separates frontal from temporal and parietal to some extent
length of fissure varies in either hemisphere
What is the cingulate sulcus?
divides cingulate gyrus (turquoise) from precuneus (purple) and paracentral lobule (gold)
corpus callosum –> band of myelinated axons, should appear much brighter
cingulate gyrus –> made up of cortex
What is the central sulcus?
usually freestanding (no intersections)
just anterior to ascending cingulate
once you find central, can figure out what’s pre- and post-
What is the postcentral sulcus?
often in two parts (superior and inferior)
often intersects with intraparietal sulcus
marks posterior end of postcentral gyrus (somatosensory strip)
What is the precentral sulcus?
often in two parts (superior and inferior)
intersects with superior frontal sulcus (T-junction)
marks anterior end of precentral gyrus (motor strip)
What is the intraparietal sulcus?
anterior end usually intersects with inferior postcentral
posterior end usually forms a T-junction with transverse occipital sulcus (just posterior to parieto-occipital fissure - POF)
IPS divides the superior parietal lobule from inferior parietal lobule (angular gyrus-gold, supramarginal gyrus-lime)
What is the superior frontal sulcus?
divides superior frontal gyrus (mocha) from middle frontal gyrus
What is the inferior frontal sulcus?
divides middle frontal gyrus from inferior frontal gyrus
What is the superior temporal sulcus?
divides superior temporal gyrus from middle temporal gyrus
What is the inferior temporal sulcus?
not usually very continuous
divides middle temporal gyrus from inferior temporal gyrus
What are the Brodmann areas?
divided the brain into different regions
mapped them perfectly based on the types of cells
What is the contralateral organization of the brain?
each symmetrical half responds to sensory stimulation from contralateral side or controls musculature on contralateral side
What are decussations?
crossing of sensory or motor fibers along center of nervous system
