Topo 1 Throp- Week 2 Flashcards
(17 cards)
Divsion of the NS
CNS= brain and spinal cord. Brain includes cerebellum, cerebrum, brain stem and deep structures of the brain
PNS0 composed of all nervous systems outside of the CNS that connect the CNS to the body (spinal, cranial(emerge from brain/brain stem) , autonomic nerves)
What is gray matter?
WH%ere is located in the brain and spinal cord?
Subsets of gray matter include….
Gray matter designates areas in the CNS consisting primarily of neuron cell
bodies (and dendrites) which are clustered in
various arrays; e.g. nuclei of the brainstem, central gray matter of the spinal cord, and the cortical layers of the cerebrum and cerebellum. The space surrounding the neuron cell bodies is occupied by dendrites and synaptic arrays that form local circuits and establish connections between neurons. In life, the “gray matter” is actually pinkish in color due to its abundant blood supply
Nuclei- specific regionsof gray matter where cell bodies are functioally related in brain stem
Cortex- layer that covers the cerebrum and cerebellum. During development it undergoes extensive development and the cortical surface folds to accommodate the increase in surface area producing bumps and gyri.
Discuss the naming of infoldings in the cortex
During development, cells undergo extensive expansion and the cortical
surfaces fold to accommodate theincreases in surface area producing
bumps or gyri of the cerebral cortex (andfolia
of the cerebellum).
The infoldings between gyri are called
sulci and deeper grooves are called
fissures. Approximately 2/3rds of the cerebral cortex cannot be seen
from the surface and lies within these sulci.
What is white matter
In the cerebrum, white matter is deep to the cortical gray matter (opposite of spinal cord) . This underlying white matter is the means by which
inputs and outputs access the cortex and determine connectivity between one area and another (e.g. between the cortex and the spinal cord).
White matter contains many myelinated axons which transmit information from one location to another.
Different terminology for White matter
- Pathways and tracts are collections of hundreds
to millions of myelinated axons that generally have long trajectories. “
Tracts” usually refer to an individual segment of a pathway that arises from a cell body in one location and terminates on a targ et in another location. - Structures containing tracts and fiber bundles in the CNS white matter arereferred to as fasciculi (little bundles), funiculi (strings), peduncles
(little feet), lemnisci (ribbons ), columns, or projections.
3.Decussations are axon bundles that cross midline going from a location
on one side to a different location on the contralateral side.
- Commissures are axon bundles that cross midline but connect comparable locations.
- Efferent fibers refer to fibers leaving one location and projecting to
another. Fibers entering a target location would be afferent.
Peripheral nerves are
are collections of axons, bound up in connective tissue sheaths, which coursing to or from areas such as skin, muscle, glands, or
viscera.
Planes of Orientation
Mid-Sagittal: This plane divides the brain into
symmetrical halves. Parasagittal planes are parallel to the sagittal plane.
Frontal or coronal: Perpendicular to the sagittal plane and parallel to the long axis of the body (e.g. a vertical plane passing through both ears)
Horizontal, Transverse, Axial: Perpendicular to the sagittal and frontal planes
and perpendicular to the long axis of the body
Explain the directional terminology in the brain and spinal cord
Within the brainstem and spinal cord, the “superior-inferior” axis is synonymous with the “rostral-caudal” axis and the “anterior-posteri
or” axis is synonymous with the “ventral- dorsal” axis.
Four major lobes divided by what?
Fifth lobe?
his essentially is the landmark delineating motor
and behavioral functions of the frontal lobe anteriorly from sensory processing in the
more posterior parietal-occipital-temporal regions.
Each hemisphere has four major lobes (frontal, parietal, occipital, temporal) subdivided into component gyri. There is a fifth insular lobe buried deep to the lateral fissure.
Central Sulcus- seperates frontal from parital lobe. his essentially is the landmark delineating motor and behavioral functions of the frontal lobe anteriorly from sensory processing in the more posterior parietal-occipital-temporal regions.
Major gyri in the frontal lobe
The frontal lobe has three main gyri: 1) superior, 2) middle, and 3) inferior; with the inferior gyrus being further divided into triangular, opercular, and orbitolfrontal.
The inferior gyrus (specifically the triangular and opercular regions) is associated with motor language on the left in most people. This area is functionally referred to as Broca’s area (the area for motor speech).
The most anterior regions of the frontal lobe are termed the prefrontal cortex.
The prefrontal cortex is involved in higher executive functions,
attention, judgment, foresight, and motivation. Those areas of cortex just anterior to the precentral gyrus are termed premotor areas
Discuss the function of the prefrontal gyrus
The precentral gyrus is the primary motor area and possesses a distorted and inverted representation (homunculus ) of the contralateral side of the body. The precentral gyrus is the principal outflow pathway for descending motor fibers that will activate motor neurons in the brain and brainstem
Importamce of central sulcus
The central sulcus is a key landmark separating frontal and parietal lobes (specifically the pre and postcentral gyri).
To locate it, appreciate that: 1) It does not extend to the lateral fissure (which separates the frontal and temporal lobes) and 2) it overlaps ontothe medial surface of the cortex where it is surrounded by a paracentral lobule.
What are the regions of the parital (lobes)
Main function
Significant gyri
The parietal lobe is located posterior to the central sulcus and possesses a
postcentral gyrus,as well as superior and inferior parietal lobules
.
The postcentral gyrus is the primary somatosensory cortex, and possesses
an inverted representation of the sensory
homunculus for the contralateral side of the body. Two other significant gyri are the supramarginal and angular gyri . These are important sensory association areas for processing of sensory inputs.
Main gyri in temporal
Imporatn region and function in temporal
The temporal lobe has three major gyri visible on the lateral surface, namely the superior, middle, and inferior gyri. The
primary auditory area is located in the middle of
the superior temporal gyrus. Behind this at the posterior margin of the lateral fissure is Wernicke’s area.
Occiptal
Where is it most visible?
Main function?
What fissure runs through it
The occipital lobe is mostly visible on the medial surface (mid-sagittal view). The primary visual cortex is located at the upper and lower margins of the
calcarine fissure
.
Wh5at is the primary motor region?
Secondary?
Primary Motor Cortex
Precentral Gyrus
(4)Final pathway for cortical outflow-
corticospinal & corticobulbar
fibers
Secondary Motor Areas:
Broca’s Area (44,45) (opercular-triangular)
motor speech
Frontal Eye Fields (inf 8) voluntary horizontal gaze (saccades) to opposite side
Pre- & supplementary motor
(8,6)Development of movement strategy, patterns, & synergy
Prefrontal Cortex(–motions, inhibitions, Limbic associations
Where does each CN emerge from?
Midbrain: CN III and IV (CN IV is the only cranial nerve to exit dorsally from the brainstem).
Pons: CN V
Medulla : CN VI, VII, and VIII exit at the pontomedullary junction , CN IX, X, XI and XII exit is association with the olive.
Cranial nervesIX, X, XI exit as rootlets posterior to the olive.
Cranial nerve XII emerges between the pyramids and olive.
