Unit2_Chapter2 Flashcards
acetylcholine (ACh)
A neurotransmitter produced and released by parasympathetic postganglionic neurons, by motoneurons, and by neurons throughout the brain.
allocortex
Formerly called archicortex or paleocortex. Brain tissue with three layers or unlayered organization.
amygdala
A group of nuclei in the medial anterior part of the temporal lobe. See Figure 2.17, 15.15.
angiography
A brain-imaging technique in which a specialized X-ray image of the head is taken shortly after the cerebral blood vessels have been filled with a radiopaque dye by means of a catheter. This technique allows visualization of the major blood vessels and is used to assess stroke risk and other conditions.
anterior cerebral arteries
Two large arteries, arising from the internal carotids, that provide blood to the anterior poles and medial surfaces of the cerebral hemispheres. See Figure 2.20.
apical dendrite
The dendrite that extends from a pyramidal cell to the outermost surface of the cortex. Compare basal dendrite.
arachnoid
The thin covering (one of the three meninges) of the brain that lies between the dura mater and pia mater.
arborization
The elaborate branching of the dendrites of some neurons.
astrocyte
A star-shaped glial cell with numerous processes (extensions) that run in all directions. Astrocyte extensions provide structural support for the brain and may isolate receptive surfaces. See Figure 2.7.
autonomic ganglia
Collections of nerve cell bodies, belonging to the autonomic division of the peripheral nervous system, that are found in various locations and innervate the major organs.
autonomic nervous system
The part of the peripheral nervous system that supplies neural connections to glands and to smooth muscles of internal organs. Its two divisions (sympathetic and parasympathetic) act in opposite fashion. See Figure 2.11.
autoradiography
A histological technique that shows the distribution of radioactive chemicals in tissues. See Boxes 2.1, 5.1.
axon
A single extension from the nerve cell that carries nerve impulses from the cell body to other neurons. See Figure 2.2.
axon collateral
A branch of an axon from a single neuron.
axon hillock
A cone-shaped area from which the axon originates out of the cell body. Functionally, the integration zone of the neuron. See Figure 2.6.
axon terminal
Also called synaptic bouton. The end of an axon or axon collateral, which forms a synapse on a neuron or other target cell.
axonal transport
The transportation of materials from the neuronal cell body to distant regions in the dendrites and axons, and from the axon terminals back to the cell body.
basal dendrite
One of several dendrites on a pyramidal cell that extends horizontally from the cell body. Compare apical dendrite.
basal ganglia
A group of forebrain nuclei, including caudate nucleus, globus pallidus, and putamen, found deep within the cerebral hemispheres. See Figures 2.13, 2.17, 11.19.
basilar artery
An artery, formed by the fusion of the vertebral arteries, that supplies blood to the brainstem and to posterior cerebral arteries. See Figure 2.20.
bipolar neuron
A nerve cell that has a single dendrite at one end and a single axon at the other end; found in some vertebrate sensory systems. See Figure 2.4. Compare unipolar neuron and multipolar neuron.
blood-brain barrier
The mechanisms that make the movement of substances from blood vessels into brain cells more difficult than exchanges in other body organs, thus affording the brain greater protection from exposure to some substances found in the blood.
brainstem
The region of the brain that consists of the midbrain, the pons, and the medulla.
c-fos
An immediate early gene commonly used to identify activated neurons.See Box 2.1.
carotid arteries
The major arteries that ascend the left and right sides of the neck to the brain, supplying blood to the anterior and middle cerebral arteries. The branch that enters the brain is called the internal carotid artery. See Figure 2.20.
caudate nucleus
One of the basal ganglia; it has a long extension or tail. See Figure 2.17.
cell body
Also called soma. The region of a neuron that is defined by the presence of the cell nucleus. See Figure 2.2.
cell nucleus
The spherical central structure of a cell that contains the chromosomes.
central nervous system (CNS)
The portion of the nervous system that includes the brain and the spinal cord. See Figures 2.8, 2.14. Compare peripheral nervous system.
central sulcus
A fissure that divides the frontal lobe from the parietal lobe. See Figure 2.12.
cerebellum
A structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement. See Figures 2.12, 2.14, 2.18.
cerebral cortex
Often called simply cortex. The outer covering of the cerebral hemispheres that consists largely of nerve cell bodies and their branches. In mammals, the cerebral cortex has the six distinct layers that are typical of neocortex. See Figure 2.15.
cerebral hemispheres
The right and left halves of the forebrain. See Figure 2.14.
cerebrospinal fluid (CSF)
The fluid that fills the cerebral ventricles. See Figure 2.19.
cervical
Referring to topmost eight segments of the spinal cord, in the neck region. See Figures 2.10, 2.11.
choroid plexus
A highly vascular portion of the lining of the ventricles that secretes cerebrospinal fluid. See Figure 2.19.
cingulate gyrus
Also called cingulate cortex or cingulum. A cortical portion of the limbic system, found in the frontal and parietal midline. See Figures 2.12, 2.17.
circle of Willis
A structure at the base of the brain that is formed by the joining of the carotid and basilar arteries. See Figure 2.20.
coccygeal
Referring to the lowest spinal vertebra (also known as the tailbone). See Figure 2.11.
computerized axial tomography (CAT or CT)
A noninvasive technique for examining brain structure in humans through computer analysis of X-ray absorption at several positions around the head. CT affords a virtual direct view of the brain. The resulting images are referred to as CAT scans or CT scans. See Figure 2.21.
conduction zone
The part of the neuron over which the nerve_s electrical signal may be actively propagated. Usually corresponds to the cell_s axon.
corpus callosum
The main band of axons that connects the two cerebral hemispheres. See Figures 2.12, 2.16.
cortical column
One of the vertical columns that constitute the basic organization of the neocortex.
cranial nerve
A nerve that is connected directly to the brain. Composed of a set of pathways concerned mainly with sensory and motor systems associated with the head, the cranial nerves together constitute one of the three main subdivisions of the peripheral nervous system. There are 12 cranial nerves, typically designated by Roman numerals I_XII. See Figure 2.9.
dendrite
One of the extensions of the cell body that are the receptive surfaces of the neuron. See Figure 2.4.
diencephalon
The posterior part of the forebrain, including the thalamus and hypothalamus. See Figure 2.14.
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 fibertracts.
dorsal root
See roots.
dura mater
The outermost of the three meninges that surround the brain and spinal cord. See also pia mater and arachnoid.
dyadic functional MRI (dfMRI)
An fMRI technique in which the brains of two interacting individuals are simultaneously imaged.
edema
The swelling of tissue, especially in the brain, in response to injury.
enteric nervous system
An extensive meshlike system of neurons that governs the functioning of the gut. This system is semiautonomous but is generally considered to be part of the autonomic nervous system.
forebrain
Also called prosencephalon. The anterior division of the brain, containing the cerebral hemispheres, the thalamus, and the hypothalamus. See Figure 2.14.
fornix
A fiber tract that extends from the hippocampus to the mammillary body. See Figures 2.12, 2.15.
fourth ventricle
The passageway within the pons that receives cerebrospinal fluid from the third ventricle and releases it to surround the brain and spinal cord. See Figure 2.19.
frontal lobe
The most anterior portion of the cerebral cortex. See Figure 2.12.
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.
glial cells
Also sometimes called glia or neuroglia. Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain. See Figure 2.7.
globus pallidus
One of the basal ganglia. See Figure 2.17.
granule cell
A type of small nerve cell. See Figure 2.18.
gray matter
Areas of the brain that are dominated by cell bodies and are devoid of myelin. See Figure 2.13. Compare white matter.
gross neuroanatomy
Anatomical features of the nervous system that are apparent to the naked eye.
gyrus (pl. gyri)
A ridged or raised portion of a convoluted brain surface. See Figure 2.12. Compare sulcus.
hindbrain
Also called rhombencephalon. The rear division of the brain, which, in the mature vertebrate, contains the cerebellum, pons, and medulla. See Figure 2.14.