Flashcards in 1 - Introduction Deck (150):
Define Levels of Analysis
Can be studied at at various levels of analysis
-can be studied from the tiniest level of structure, the molecule, to the largest level of structure, the whole person in the environment.
Ex. Russian Matryoshka doll
(segmental vs. suprasegmental?)
Define Emergent Properties
New kinds of behavior emerge from the unified actions of many cells in many centers.
Ex. Consciousness cannot be explained simply by the physiology of the nervous system so it is an emergent property.
Define Distributed Control
At any one time, the nervous system coordinates many different activities. The system must control voluntary motor activities, such as walking or reaching, cognition and movement, as well as homeostatic regulation which can all happen simultaneously. Coordinate planning initiating, fine-tuning movement.
Ex. chatting with colleague over while drinking cup of coffee.
Define Redundant Representations
Information may be represented in the nervous system in several forms at the same time. Data come in along different routes and processed along parallel pathways.
Ex. know an orange because it looks, feels, smells, and tastes like and orange. To identify it, only one of those sensory modalities bits of information is necessary, yet all might not be available.
Define Serial Processing
Some information travels linearly up (ascending information) or down through the levels of the system.
Ex. stepping in a puddle: sense in foot, nerve, spinal cord, brain, processed, spinal cord nerves in leg, move foot
Define Parallel Processing.
Different attributes are processed by different sensory systems, but messages about them may be received by the brain simultaneously along different parallel pathways. (multiple levels of analysis)
Ex. Orange is defined as edible object with particular shape, texture, range of tastes, and colors. Experience these attributes simultaneously.
Feedback mechanisms keep brain informed. Command center keeps copy of command and sends to other part of the brain to keep them informed. When even occurs, feedback is sent back to the command center confirming it did occur.
(positive or negative)
The nervous system does not merely take in information and generate automatic responses. Instead, information is processed and reprocessed and reprocessed repeatedly. (parallel processing)
Ex. At centers deep in the brain that receive information about vision, other information about touch or sound may affect how those nerve cells response and signal to other cells.
Nervous system ability to learn or to change behavior at most levels of the system. Adapt responses to environmental demands and those demands change.
Ex. (Learning, re-learning -developmental processes, plasticitiy)
Define Localization of function
(anatomical differences; cellular, connectional)
Different parts of the nervous system have different functions that are supported by different structure. A defined area of the brain has unique functions, and unique structural properties in that area that underlie its unique functions.
Ex. Visual Cortex in the occipital lobe processes information from retina, also appears striated due to large number of cells in one layer.
Define Topographic Organiztion
(somatotopic, visuotopic, tonotopic – somite formation)
Information to and from various places maintains some spatial distinctiveness.
Ex. Centers receiving information about things touching the skin have presentation of the body surface so that areas can be distinguished from each other.
Define Hemispheric Specialization
(left vs. right)
The phylogenetically newer sections of the brain have some spatial division of labor.
Ex. Area concerned with language are larger on one side of the brain and areas concerned with spatial perception are larger on the other side of the brain.
Define Columnar Organization
(developmental aspect of motor vs. sensory)
Many parts of the nervous system are organized in vertical columns, particularly older areas.
Ex. groups of cells involved in taste form a long column in the base of the brain.
groups of cells that control eye movements are located one above the other in a broken column.
Define Convergence - Divergence
(used in integration, refinement of stimuli)
Information enters the nervous system from thousands of individual neurons and converges on centers where it may be processed for control of lower level motor behavior, it may be transmitted to other centers, or it may be combined with other information and then sent on to a variety of other centers.
Ex. natural disaster information with government
What is a sagittal plane?
divides the CNS into right and left sides
What is a midsagittal plane?
only one midsagittal section
What is a parasagittal plane?
sagittal sections parallel to the midsagittal plane
What is a transverse plane?
perpendicular to the long axis of the CNS (the longitudinal axis of the CNS exists in different cardinal planes, therefore transverse can be described as being in different cardinal planes)
What is a transverse coronal plane?
transverse to the long axis through the cerebrum and diencephalon
What is a transverse horizontal plane?
transverse to the long axis through the spinal cord
What is a transverse oblique plane?
transverse through the brainstem
The horizontal plane makes right angles to what two coronal sections?
sagittal and coronal sections
In which direction is Rostral?
In which direction is Caudal?
Anterior - Posterior in terms of spinal cord?
same as ventral and dorsal
Anterior - Posterior in terms of cerebrum and the diencephalon brain?
same as rostral and caudal
What directions are at right angles to Anterior and Posterior?
Superior and Inferior
Designates incoming connections.
Ex. axons/nerve impulses conducted/directed toward the next neuron
Synonymous with term sensory for organization of peripheral nerve.
designates outgoing connections
Ex. axons/nerve impulses conducted/directed away from a neuron.
Synonymous with term motor for organization of peripheral nerve.
Define Ipsilateral and contralteral in terms of the nervous system
Same Side vs Opposite Side - this indicates that at some point there has to have been a crossing of pathways to get neuronal information from one side to the other.
Define Bilateral in terms of the nervous system
unique situation where information is traveling/being integrated on both sides of the CNS.
What does the neural tube develop into?
Brain and Spinal Cord (Central Nervous System - CNS)
Neural crest cells that were "left behind" eventually form what?
majority of Peripheral Nervous System (PNS)
-dorsal root ganglia cells that are cell bodies for all the sensory side
-Schwann cells (mylenating cells of the PNS both sesnory and motor)
-Ganglia of the autonomic nervous system (sensory and post ganglionic motor cells)
-Melanocytes in stratum Basale of epidermis
The developing neural tube is divides into what four plates?
Where is the alar plated located?
dorsal to sulcus limitans
What does the alar plate form?
forms the sensory and association part of developing neural tube.
Where is the basal plate located?
anterior to sulcus limitans
What does the alar plate form?
forms the motor part of the developing neural tube, including both alpha and gamma motor neuros.
What do the roof and floor plates generate?
no neuronal components to speak of?
The alar and basal plates are separates by what?
What is sulcus limitans?
groove (oriented in the coronal plane) in the wall of the neural tube that separates the alar and basal plates.
Where is the sulcus limitants present?
in the developing cord and into the brainstem only as far as the developing midbrain.
Where does the neural tube expand?
What does the neural tube expand into?
three primary vesicles
What are the three primary vesicles?
Which of the primary vesicles undergo further expansion into secondary vesicles?
What secondary vesicles does the primary vesicle Rhombencephalon expand into?
What secondary vesicles does the primary vesicle Prosencephalon expand into?
What secondary vesicles does the primary vesicle Mesencephalon expand into?
It doesn't expand into secondary vesicles.
The vesicle myelencephalon results in the formation of which brain region?
The vesicle metenephalon results in the formation of which brain region?
pons and cerebellum
The vesicle mesencephalon results in the formation of which brain region?
The vesicle diencephalon results in the formation of which brain region?
thalamus and hypothalamus
The vesicle telencephalon results in the formation of which brain region?
cerebral hemispheres, basal ganglia
The development and expansion of the secondary brain vesicles result in formation of the ___ and ___. The remainder of the neural tube forms the _____.
The development and expansion of the secondary brain vesicles result in formation of the BRAIN and BRAINSTEM. The remainder of the neural tube forms the SPINAL CORD.
The lumen of the neural tube expands with the developing vesicles and forms the ___.
The ventricular system is continuous with the ___, a remnant of the neural tube.
How many ventricles are there?
Where are the two lateral ventricles located?
in the telecephalon (cerebral hemispheres lateral to each other
Where is the third ventricle located?
midline in the diencephalon
Where is the fourth ventricle located?
midline in the pons and medulla below the cerebellum
What do the Longitudinal and Transverse fissures divide?
divide the central hemispheres from each other and from the cerebellum.
What does the Central Sulcus divide?
divides frontal lobe and parietal lobe;
pre- and postcentral gyri
primary motor and sensory cortices, respectively.
What is the Paracentral lobule
midline extension of the pre- and postcentral gyri
What does the Lateral Sulcus divide?
divides temporal lobe from the frontal and pariental lobe
An imaginary line between the Parieto-occipital notch and preoccipital notch separates what?
separate the occipital lobe from the parietal and temporal lobes.
What is the Calcarine sulcus and what does it separate?
midline sulcus marking the area of primary visual cortex; separates a cuneus and lingual gyri
What does the Parieto-occipital sulcus separate?
separates the midline part of the occipital lobe from the parietal lobe
What is the cingulate sulcus
What are meninges?
CNS covered layers of connective tissue membranes that act as a protective envelope.
How many layers are the meminges?
T/F: All three meningial coverings are continuous around the brain and spinal cord.
False: all but one layer.
Which layer is not continuous around the brain and spinal cord?
dural periosteal layer
What are the three meningies?
Which layer is the most external and toughest?
What layers make up the Dura?
Periosteal layer and meningeal layer.
Which layer is directly under the skull?
What are dural sinuses formed by?
formation of openings between the two layers of dura as a result of enfolding of the meningeal layer.
What function does the dural sinses have? (2)
function as the outflow pathway for venous blood and cerebralspinal fluid.
-enfoldings also attach to the inside of the calvaria and help to anchor brain
What are herniations caused by and what is the result?
Due to the rigidity of enfolding attachments, space occupying lesions (tumors or bleeding) cause clinical problems called herniations.
The result is that the brain tissue is squeezed and function is compromised.
Herniations are the squeezing of nervous tissues through and opening such as the tectorial notch.
Where is periosteal dura found? With what does it fuse with?
The outer most is found only in the cranial cavity and fuses with the perisoteum of the skull in the foramen magum.
Where is the meningeal layer of dura found?
It is continuous with the vertebral canal and covers the spinal cord.
What does the falx cerebri separate?
separates the cerebral hemispheres.
What does the tentorium cerebelli separate?
separates the cerebral hemispheres from the cerebellum, also limits the posterior cranial fossa
Where is the tentorial notch?
opening in the tentorium cerebelli surrounding the brainstem (midbrain) as it passes out of the crainial fossa and into the posterior cranial fossa.
Where is the superior sagittal sinus located?
on the superior edge of falx cerebri
Where is the inferior sagittal sinus located?
on the inferior edge of the falx cerebri
Where is the straight sinus located and what does it connect?
connects the inferior and superior sagittal sinuses across tentorial cerebelli
Where is the confluens of sinuses and what does it connect?
the point posteriorly on tentorium cerebelli where the straight sinus and transverse sinuses joint
Where is the transverse sinus and what is its function?
sinuses at the posterior edge of tentorium cerebelli that carry venous blood toward the internal jugular vein
Where is the sigmoid sinus and what is its function?
last part of sinus system that is continuous with the internal jugular being through the jugular foramen
What are the three common sites of herniation?
2. transtentorial or uncal
Where is the subfalcine herniation site?
cingulate gyrus under the falx cerebri
Where is the transtentorial or uncal herniation site?
uncus through the tentorial cerebelli (tentorial notch)
Where is the tonsillar herniation site?
cerebellar tonsils throug the foramen magnum
What are embded between the two layers of dura and what are their function?
blood vessels supplying the meninges.
Which is the most important blood vessel?
the middle meningeal artery
What is an epidural hematoma?
a skull fracture may tear this vessel resulting in arterial bleed with blood accumulating between the dura mater and the skull (actually separates periosteal and meningeal layers???)
Which meningeal layer is delicate and non-vascular?
How many layers is the arachnoid mater made up of?
What are the two layers of arachnoid mater?
outer arachnoid matter
Define outer arachnoid matter
layer is continuous that is directly opposed (but not attached) to the meningeal layer of the dura
Define arachnoid trabeculae
layer is discontinuous consisting of attachments from the outer arachnoid layer to the pia mater
What is the potential space between the dura and arachnoid?
What is in this potential space and what is its function?
Veins carrying blood from the brain "bridge" to empty into the dural sinuses.
What can happen in this area with whiplash?
these bridging veings can be torn due to shearing forces as the arachnoid and dura are not are not attached.
What is a subdural hematoma?
venous bleeding in this potential space
What are arachnoid granulations or villae? What is their function?
small extensions of arachnoid membrane that can be identified along and protrude through and extend into the superior sagittal sinus. function as a "one-way" gate for the uptake of CSF into the venous vascular drainage of the brain.
What is the vascular component of the meninges?
Define Pia Mater
vascular component directly opposed to the brain itself. follows penetrating branches of arterioles into the brain parenchyma until the capillary beds.
What is the space between the pia mater and arachnoid matter called?
What is contained within the subarachnoid space? (2)
1. cerebrospinal fluid
2. arterial and venous branches that supply the cortical regions of the brain
What are enlarged areas of subarachnoid space referred to as?
What are the two most notable cistern?
1. Cistern Magna (cerebellomedullary cistern)
2. Lumbar Cistern
What is bleeding in this subarachnoid space called?
T/F: bleeding in the subarachnoid space can either be arterial or venous
What can a subarachnoid hemmorage result from? (4)
2. atreriovenous (AV) malformations
How is a subarachnoid hemmorage identified?
blood elements can be identified in the CSF following a lumbar puncture.
How many layers is the pia mater composed of in the spinal cord?
What are the two layers of pia mater in the spinal cord?
1. Pia Intima
2. Denticulate Ligaments
What is pia intima?
adhered tightly to the spinal cord
What are denticulate ligaments? What is it's function?
segmentally paired extensions that cross the subarachnoid space, pierce the arachnoid mater and attach to the dura. function is to anchor spinal cord in the spinal canal.
What are ventricles?
cavities within the central nervous system
What are ventricles derived from developmentally?
What connects the lateral ventricles in the cerebral hemispheres to the single third ventricle?
interventricular foramen (of Monro)
the third ventrical is continuous caudally with the ____
cerebral aqueduct of Sylvius in the midbrain.
The cerebral aqueduct empties into what?
fourth ventricle of the pons and medulla.
What is the fourth ventricle continuous with?
remnants of the central canal of the spinal cord.
What else does the fourth ventricle communicate with?
How does the fourth ventricle communicate with the subarachnoid space?
two lateral aperatures (foramina of luschka) and one midline aperature (foramen of magendie)
Where does CSF go after it reaches the subarachnoid space and how?
eventually enters the venous system via the dural sinuses.
What is cerebrospinal fluid created by?
ependymal cells that line the ventricular system.
What do ependymal cells continue as?
ventricular lining of the choroid plexus, a series of capillary beds that extend into all four ventricles.
In addition to the ventricular system, where else is CSF produced?
subarachnoid space by capillary beds in the meninges.
What is the function of CSF?
reduces relative mass of the brain and also cushions it.
At what rate is CSF produced
continuously at a rate of 500 ml/day
T/F: There are no feedback mechanisms to shut down the production of CSF.
What is the disadvantage of not being able to shut down the production of CSF?
any blockage of the flow of this fluid can result in the buildup of interventricular pressure and/or intracranial pressure.
What do you call a blockage of normal flow of CSF out of the ventricular system?
Whare the common places obstructive hydrocephalus can occur? (3)
1. interventricular foramen
2. cerebral aqueduct
3. out flow from the fourth ventrical
What do you call absorption or circulation problems with CSF?
What is an example of communicating hydrocephalus?
any abnormality in the ability of SF to exit the arachnoid granulations such as extremely high venous pressure in the superior sagittal sinus
What allows the blood capillaries in the central nervous system to maintain a blood-brain barrier?
endothelial cells of the blood capillaries are joined by tight junctions that form a barrier that allows for the selective exchange of only small molecules.
What is restricted from crossing the blood brain barrier?
large proteins, e.g. antibiotics
What is actively transported across the blood brain barrier?
glucose and amino acids for nourishment of the CNS
What s the role of glial cells in the blood-brain barrier?
endothilial cells are opposed to the cellular processes of gial cells which are though to control the permeability of the endothilial cells by influencing the physiology of endothelial cell membranes.
What can happen if glial cells are disrupted as in a pathological condition?
they no longer control the endothelial cells and the barrier is made more permeable.
T/F: Neurons do not have storage capability.
Because neurons do not have storage capability, what does the mean about the blood-brain barrier?
it must be patent at all times however it is selective in its activity.