Central Nervous System Part I Flashcards
What two structures make up the central nervous system?
Brain + Spinal Cord
What are the 4 main regions of the human adult brain?
Cerebrum
Diencephalon
Brain Stem
Cerebellum
What is the primary difference between gray and white matter?
Gray Matter - short, nonmyelinated neurons + cell bodies
White Matter - mostly myelinated axons, some nonmyelinated axons, primarily organized in fiber tracts
Draw out the basic pattern of the CNS. How does this basic pattern differ in the brain stem and the cerebral cortex?
What are ventricles? What do they contain? What type of cell makes up their lining?
Ventricles - fluid-filled chambers
Filled with cerebrospinal fluid (CSF) and lined with ependymal cells
What divides the paired, lateral ventricles?
Lateral Ventricles - large, paired, C-shaped chambers, deep within each hemisphere
Septum Pellucidum - thin membrane that separates the lateral ventricles
What structure connects the paired lateral ventricles with the 3rd ventricle?
Interventricular foramen
What structure connects the 3rd ventricle to the 4th ventricle?
The 3rd ventricle is connected to the 4th ventricle via the cerebral aqueduct – the 4th ventricle is continuous with the central canal of the spinal cord
Name the 3 openings that connect the 4th ventricle to the subarachnoid space.
paired lateral apertures, 1 median aperture
Define gyri, sulci, and fissure. Know what is divided by the longitudinal fissure and the transverse cerebral fissure.
Gyri - ridges
Sulci - shallow grooves
Fissures - deep grooves
Longitudinal Fissure - separates the 2 hemispheres
Transverse Cerebral Fissure - separates cerebrum and cerebellum
What are the 5 lobes of the cerebral hemisphere? Be able to label them in a picture.
Frontal
Parietal
Temporal
Occipital
Insula
Be ready to label the central sulcus, parieto-occipital sulcus, and lateral sulcus.
What are the 3 basic regions within each cerebral hemisphere?
Cerebral Cortex - superficial gray matter
Internal white matter
Basal Nuclei - islands of gray matter deep within white matter
List the functions of the cerebral cortex.
The “executive suite” of the brain
Thin (2-4mm), superficial layer of gray matter
Site of the conscious mind: awareness, sensory perception, initiation of voluntary motor tasks, communication, memory storage, understanding
Composed of neuron cell bodies, dendrites, glial cells, and blood vessels – no axons!
Contains billions of neurons; accounts for 40% of the mass of the brain
Define a domain.
the place a particular motor or sensory function is localized
What are the 3 types of functional areas within the cerebral cortex? What does each type of functional area do?
Motor Areas - control voluntary movement
Sensory Areas - conscious awareness of sensation
Association Areas - integrate diverse information
Define contralateral and the concept of lateralization.
Contralateral - (opposite) side of the body
Lateralization - specialization of cortical function in only one hemisphere
Be ready to identify in a picture AND know the function of the following areas: primary motor cortex, premotor cortex, broca’s area, and frontal eye field.
Define: pyramidal cells, pyramidal/corticospinal tracts, somatotopy, and homunculus.
Pyramidal Cells - large neurons that allow conscious control of precise, skilled skeletal muscle movements
Pyramidal (Corticospinal) Tracts - formed from the long axons of the pyramidal cells that project down to the spinal cord
Somatotopy - all specific areas of the body can be mapped to specific areas on the primary motor cortex
Motor Homunculi - upside-down, caricature-like representation of the motor innervation of the contralateral body regions
A stroke (cerebrovascular accident) can cause damage in the primary motor cortex. What will the symptoms of primary motor cortex damage look like?
Paralyzes the muscle controlled by tose area
What about damage of the premotor cortex?
Loss of motor skills programmed by that region
Write out what you know about the motor and sensory homunculi. Which areas have a lot of representation? Which areas only have a little?
Be ready to identify in a picture AND know the function of the following areas: primary somatosensory cortex, somatosensory association cortex, primary visual cortex, visual association area, primary auditory cortex, auditory association area, vestibular cortex, primary olfactory cortex, gustatory cortex, and visceral sensory area.
Primary Somatosensory Cortex (Function)
Located in postcentral gyrus of the parietal lobe
Receives general sensory information from skin and the proprioceptors of skeletal muscle, joints, and tendons
Capable of spatial discrimination: identification of body region being stimulated
Somatosensory Association Cortex (Function)
Posterior to the primary somatosensory cortex
Integrates the sensory inputs relayed to it from the primary somatosensory cortex to provide an understanding of an object being felt - determines size, texture, and relationship of the parts
Primary Visual (Striate) Cortex (Function)
Largest cortical sensory area
Receives visual information that originates on the retinas
The visual space on the opposite side of the body is mapped to the primary visual cortex
Visual Association Area (Function)
Covers much of the occipital lobe and communicates with the primary visual cortex
Uses past visual experiences to interpret visual stimuli (color, form, or movement) Ex: ability to recognize faces
Complex processing involves entire posterior half of cerebral hemisphere
Primary Auditory Cortex (Function)
Interprets information from the sound receptors in the inner ear – determines pitch, loudness, and location
Auditory Association Area (Function)
Stores memory of sounds, and permits perception of the sound stimulus
Vestibular Cortex (Function)
Responsible for conscious awareness of balance (position of the head in space)
Primary Olfactory Cortex (Function)
Part of primitive rhinencephalon – along with the olfactory bulbs and tracts. In humans, the remainder of the rhinencephalon becomes part of the limbic system.
Involved in conscious awareness of odors
Receives impulses from the superior nasal cavity
Gustatory Cortex (Function)
Involved in perceiving taste stimuli
Visceral Sensory Area (Function)
Provides conscious perception of visceral sensations - ex: upset stomach or full bladder
Define functional blindness and face blindness. What’s the difference between these from a physiological perspective?
What are the 3 multimodal association areas?
Posterior
Anterior
Limbic
Generally, what is the function of a multimodal association area?
Multimodal Association Areas - receive inputs from multiple sensory areas and send outputs to multiple areas
Allow us to give meaning to information received, store information in memory, tie information to previous experiences, and decide on actions
Where sensations, thoughts, and emotions become conscious – and make us who we are
Broadly divided into 3 parts – anterior association area, posterior association area, and limbic association area
Anterior Association Area (Function)
Also called the “prefrontal cortex”
The most complicated cortical region
Involved in intellect, cognition, recall, and personality
Contains the working memory needed for abstract ideas, judgment, reasoning, persistence, and planning
Development happens slowly and depends on feedback from social environments
Posterior Association Area (Function)
Large region including parts of the temporal, parietal, and occipital lobes
Plays a role in recognizing patterns, faces, and localizing the body within space
Involved in understanding written and spoken language (Wernicke’s Area)
Limbic Association Area (Function)
Involves the cingulate gyrus, parahippocampal gyrus, and hippocampus
Provides the emotional impact that makes a scene important to us – and helps us to establish memories
What are some symptoms of disruption in the anterior association area? How about posterior?
Anterior - may cause mental and personality disorders including loss of judgment, attentiveness, and inhibitions
Posterior - may result in disassociating with half of the body - the half opposite the side of the lesion
What does cerebral dominance mean? Most humans are _______ side dominant. This means that most humans are _________ handed.
Cerebral Dominance - refers to which hemisphere is dominant for language
Left sided dominance
Most humans are right handedness
List some functions of the left hemisphere. List some functions of the right hemisphere.
The left hemisphere controls language, math and logic
The right hemisphere controls visual-spatial skills, intuition, emotion, artistic and musical skills
Cerebral white matter is mostly bundled into large ___________.
tracts
Which direction do association fibers run? What kind of communication are they responsible for?
Association Fibers - horizontal running fibers – connect different parts of the same hemisphere
Which direction do commissural fibers run? What kind of communication are they responsible for?
Commissural Fibers - horizontal running fibers that connect corresponding gray matter of the two hemispheres
What is the largest of the commissural fiber tracts?
Corpus Callosum
Which direction do projection fibers run? What kind of communication are they responsible for?
Projection Fibers - vertical running fibers that connect the hemispheres with the lower brain or spinal cord
What is the internal capsule? What is the corona radiata?
Internal Capsule - projection fibers on each side of the brain stem form a compact band that passes between the thalamus and some of the basal nuclei
Corona Radiata - projection fibers that fan out and radiate through the cerebral white matter to the cortex
List 3 specific parts of the basal nuclei/basal ganglia
Caudate Nucleus
Putamen
Globus Pallidus
The striatum is made of the ______________ + the _________________.
Caudate Nucleus
Putamen
What are some functions of the basal nuclei? How does these functions correlate with the symptoms of Parkinson Disease?
It plays roles in motor function, emotion, and cognition
It is especially useful in starting, stopping, and monitoring the intensity of relatively slow or stereotyped movements
It also inhibits antagonistic or unnecessary movements
What is the likely cause of Parkinson disease? What is a medication that can temporarily alleviate Parkinsonian symptoms?
Parkinson Disease is the degeneration of the dopamine-releasing neurons in the substantia nigra
Dopamine-deprived basal nuclei become overactive
Medication L-Dopa can alleviate symptoms temporarily
