Exam 2: Neuroanatomy Part 2, deck 1 Flashcards
Cerebral Hemispheres
Cerebrum consists of 2 cerebral hemispheres, roughly equal halves of brain. Cortex refers to the outer surface of the brain; contains 2 basic cell types: Pyramidal cells and Nonpyramidal cells
6 Layers of Cerebrum
Outmost layer=glial cells and axons
2nd and 3rd layer=pyramidal cells
4th layer= nonpyramidal cells
5th and 6th layer=pyramidal cells
Nonpyramidal cells
involved in sensory function
(connect to more local regions)
Pyramidal cells
involved in motor function (project to
more distant regions)
Landmarks of cerebrum
Cerebral longitudinal fissure, gyrus, sulcus, lateral sulcus, central sulcus. Divided into 5 lobes frontal, parietal, occipital, temporal, insular.
Cerebral longitudinal fissure
separates left and
right cerebral hemispheres
Gyrus
a ridge on the cerebral cortex
Sulcus
infolding valleys that separate gyri
◦ if the groove is deeper or more pronounced it is termed a fissure
Lateral Sulcus (Sylvian Fissure)
divides temporal from frontal & anterior parietal
Central Sulcus (Rolandic Sulcus)
separates frontal and parietal entirely
Frontal Lobe
Largest of the lobes
Predominates in planning, initiation, and
inhibition of voluntary motion, as well as
cognitive function
Key areas: Broca’s Area and Motor Strip
Broca’s Area
speech motor planning in
dominant hemisphere
Motor Strip (a.k.a. pre-central gyrus)
site of initiation of voluntary motor movement
Parietal Lobe
Primary reception sight for body (somatic) sense, all senses that reach consciousness terminate within parietal lobe, integrates info related to vision, audition, and
somatic sense.
Key Areas: Postcentral gyrus, Supramarginal gyri, Angular gyri
Supramarginal gyri
some involvement in motor planning
for speech
Postcentral gyrus
sensory counterpart to the motor strip,
primary site of sensory output; receives sensation from various parts of body
Angular gyri
important in comprehension of written material
Temporal Lobe
Site of auditory reception and is very
important for auditory and receptive
language processing
Key areas: Superior temporal gyrus, Heschl’s Gyrus, Wernicke’s area.
Superior temporal gyrus
Runs Heschl’s Gyrus, posterior portion of Wernicke’s area.
Heschl’s Gyrus
Where all auditory information is projected
Wernicke’s area
Important for language decoding.
Occipital Lobe
Posterior limit of brain, responsible for receiving visual stimulation, as well as some of the higher-level visual processing. Related to visual agnosia; Prosopagnosia: inability to recognize faces.
Insula (Island of Reil)
Located deep to a region of cerebrum
known as the operculum, believed to be involved in consciousness and play a role in emotion and the regulation of the body’s homeostasis. Associated with arcuate fasciculus (conduction aphasia)
Limbic System
Not an anatomically distinct region but is composed of:
◦ Uncus (formed by amygdala)
◦ Thalamus
◦ Parahippocampal gyrus
◦ Cingulate gyrus
◦ Olfactory bulb and tract
◦ Hippocampus
◦ Dentate gyrus
Related to functional relationships to:
◦ Motivation
◦ Sex drive
◦ Emotional behavior
◦ Affect
Myelinated Fibers
Gray matter of the cortex is predominately made up of neuron bodies, whereas white matter represents myelinated axon fibers
These fibers make up the communication link between neurons (without them there would be no neural function)
Three types of fibers: Projection fibers, association fibers, commissural fibers.
Projection Fibers
connects cortex with distant locations
Association Fibers
provides communication between regions of
the same hemisphere
Commissural Fibers
runs from one location on a hemisphere to
the corresponding location on the opposite hemisphere (mainly the corpus callosum)