Chapter 2: Nervous System's Functional Anatomy Flashcards
Adaptations
evolved anatomical/functional features that solved long-standing historical problems
Neuroplasticity
the nervous system’s potential to physically or chemically modify itself in response to environmental change and to compensate for age-related changes and injury
Phenotypic Plasticity
an individual’s capacity to develop into a range of phenotypes
Somatic Nervous System (SNS)
part of the PNS that includes the cranial and spinal nerves to and from the muscles, joints, and skin, which produce movement, transmit incoming sensory input, and inform the CNS about the position and movement of body parts
Autonomic Nervous System (ANS)
part of the PNS that regulates the functioning of internal organs and glands, includes parasympathetic (calming, rest and digest) nerves and the sympathetic (arousing, fight or flight) nerves
Enteric Nervous System
mesh of nerves embedded in the lining of the gut, running from the esophagus through the colon, controls the gut
Afferent
conducting toward a CNS structure (sensory)
Efferent
conducting away from a CNS structure (motor)
Meninges
three layers of protective tissue (dura mater, arachnoid, and pia mater) that encase the brain and spinal cord
Cerebrospinal Fluid (CSF)
clear solution of sodium, chloride, and other ions that is produced in the ventricles inside the brain and circulates around the brain and spinal cord until it is absorbed beneath the arachnoid layer of the subarachnoid space
Cerebral Cortex
heavily folded and layered tissue that is the outer structure of the forebrain, composed of neocortex and allocortex
Frontal Lobe
part of the cerebral cortex, which performs the brain’s executive functions, such as decision making and voluntary movement
lies anterior to the central sulcus and beneath the frontal bone of the skull
Parietal Lobe
part of the cerebral cortex that directs movements toward a goal or to perform a task
lies posterior to the central sulcus and beneath the frontal bone of the skull
Temporal Lobe
part of the cerebral cortex that includes hearing, language, musical abilities, facial recognition, and emotional properties, lies below the lateral fissure, beneath the temporal bone at the side of the skull
Occipital Lobe
part of the cerebral cortex where visual scene processing begins, the most posterior part of the neocortex, it lies beneath the occipital bone
Gyri
small protrusions or bumps formed by the folding of the cerebral cortex
Sulci
grooves in brain matter, most are in the neocortex or cerebellum
Stroke
sudden appearance of neurological symptoms as a result of severely reduced blood flow
Gray Matter
areas of the nervous system composed of predominantly of neuronal cell bodies that collect and modify information and capillary blood vessels that support this activity
White Matter
areas of the nervous system with fat-rich, myelin-sheathed neuronal axons that form the connections between neurons
Ventricules
cavities in the brain that make and contain CSF
Corpus Callosum
band of white matter containing about 200 million nerve fibers that connects the two cerebral hemispheres to provide a route for direct communication between them
Nuclei
a group of neurons forming a cluster that can be identified using special stains
Nerve
large collection of axons coursing together outside the CNS
Tract
large collection of axons coursing together inside the CNS
Prosencephalon (front brain)
olfaction, sense of smell
Mesencephalon (middle brain)
vision and hearing
Rhombencephalon (hindbrain)
movement and balance
Brainstem
central structure of the brain (including the hindbrain, midbrain, thalamus, and hypothalamus) that is responsible for most life-sustaining, unconsious behavior
Hindbrain
evolutionarily the oldest part of the brain, contains the pons, medulla, reticular formation, and cerebellum, the structures that coordinate and control most voluntary and involuntary movements
Reticular Formation
midbrain area in which nuclei and fiber pathways are mixed, producing a netlike appearance, associated with sleep-wake behavior and behavior-arousal
Midbrain
central part of the brain, contains neural circuits for hearing and seeing as well as for orientating movements
Tectum
“roof” of the midbrain, its functions are sensory processing, particularly visual and auditory, and the production of orienting movements
Tegmentum
“floor” of the midbrain, a collection of nuclei with movement-related, species-specific, and pain perception of orienting movements
Orienting Movement
movement related to sensory inputs, such as turning the head to see the source of a sound
Hypothalamus
diencephalon structure that contains many nuclei associated with temperature regulation, eating, drinking, and sexual behavior
Thalamus
diencephalon structure through which information from all sensory systems is organized, integrated, and projected into the appropriate region of the neocortex
Forebrain
evolutionarily the most recent addition to the brain, coordinates advanced cognitive functions such as thinking, planning and language, contains the allocortex, neocortex, and basal ganglia
Allocortex
part of the central cortex (“outer bark”), composed of three or four layers, plays a role in controlling motivational and emotional states as well as in certain forms of memory
Neocortex
most recently expanded outer layer (“new bark”) of the forebrain, composed of about six layers of gray matter
Limbic System
a conceptual system controlling affective and motivated behaviors and certain forms of memory with key anatomy lying between the neocortex and brainstem, includes the cingulate cortex, amygdala, and hippocampus
Vomeronasal Organ (VNO)
collection of neurons that detect pheromones, this organ plays a role in reproduction and social behavior in many mammals, through its specific function in humans is disputed
Cytoarchitectonic Map
map of the neocortex based on the organization, structure and distribution of the cells
Basal Ganglia
subcortical forebrain nuclei that coordinate voluntary movements of the limbs and body, connected to the thalamus and to the midbrain
Parkinson Disease
disorder of the motor system correlated with a loss of dopamine from the substantia nigra and characterized by tremors, muscular rigidity and a reduction in voluntary movement
Tourette Syndrome
disorder of the motor system, characterized by involuntary vocalizations, and odd, involuntary movements of the body
What is agenesis?
the failure of brain regions to develop offers researchers an opportunity to study brain organization and function
remarkable improvements over time
brain plasticity in response to early perturbations allows for compensation as regions of the cerebral cortex begin to function more efficiently
What are some symptoms of agenesis of the cerebellum?
slow language development and motor function, some early autism symptoms
What is an overview of the brain’s structure and function?
the brain’s primary function is to produce movement (aka behavior)
receiving sensory information about the world: vision, audition, olfaction
these sensory cues are crucial for effective behavior
without stimuli, the brain cannot properly orient the body and direct it to produce appropriate behaviors
the nervous system integrates sensory information to construct a subjective experience of reality (perception)
the subjective reality is essential to carrying out any complex behavior
What are the plasticity patterns of neural organization?
the brain is plastic: neural tissue has the capacity to adapt to the world by changing how it functions are organized
neural connections constantly change in response to experience
learning takes place when neural circuits change to represent/store new knowledge
blind people = enhanced auditory capacities
What is the brain-body orientation of the brain?
frame of reference is the human face
What is the spatial orientation of the brain?
frame of reference is other body parts and body orientation
What is the anatomical orientation of the brain?
frame of reference is direction of cut
section through which the human brain from viewer persepctive
What are some terms associated with the brain-body orientation of the brain?
structures a top the brain or structure within the brain are dorsal
structures towards the brain’s midline are medial, those located toward the sides are lateral
anterior is in front, posterior is at the back
structures toward the bottom of the brain or one of its parts are ventral
What is coronal section of the brain?
is cut in a vertical plane, from the crown of the head down, yielding a frontal view of the brain’s internal structure
What is a horizontal section of the brain?
so-called because the view or cut falls along the horizon, is usually looking down on the brain from above, a dorsal view
What is sagittal section of the brain?
is cut lengthways from front to back and view from the side, a cut on the midsagittal plane divides the brain into symmetrical halves, a medical view
What is bilateral symmetry?
brain has a left and right side (hemispheres)
structures laying on the same side are ipsilateral
structures lying on opposite sides are contralateral to each other
structures that occur in each hemisphere are bilateral
Cranial Nerves
the 12 nerve pairs that control sensory and motor functions of the head, neck and internal organs
Vertebrae
the bones that form the spinal cord, categorized into five anatomical regions: cervical, thoracic, lumbar, sacral, and coccygeal
Dermatome
body segment corresponding to a segment of the spinal cord
Law of Bell and Magendie
sensory fibers are dorsal and motor fibers are ventral
Sympathetic Division
part of the autonomic nervous system that arouses the body for action, such as mediating the involuntary fight-or-flight response to alarm by increasing heart rate and blood pressure
Parasympathetic Division
part of the autonomic nervous system that acts in opposition to the sympathetic division, for example preparing the body to rest and digest by reversing the alarm response or stimulating digestion
What are the ten principles of nervous system function?
- The nervous system produces movement in a perceptual world the brain constructs
- Neuroplasticity is the hallmark of nervous system functioning
- Many brain circuits are crossed
- The CNS functions on multiple levels
- The brain is symmetrical and asymmetrical
- Brain systems are organized hierarchically and in parallel
- Sensory and motor divisions permeate the nervous system
- The brain divides sensory input for object recognition and movement
- Brain functions are localized and distributed
- The nervous system works by juxtaposing excitation and inhibition
Alzheimer Disease
degenerative brain disorder related to aging, first appears as progressive memory loss and later develops into generalized demetia
Excitation
increase in the activity of a neuron or brain area
Inhibition
decrease in activity of a neuron or brain area
How is the nervous system protected?
a triple-layered covering, the meninges, encases the brain and spinal cord, and cerebrospinal fluid cushions them
What is meningitis?
inflammation of the meninges, increase in cranial pressure can cause brain functions to stop working
when harmful viruses or microorganisms (bacteria, fungi, etc.) invade and multiply in the layers of the meninges
particularly in the pia meter and the arachnoid layer, as well as the CSF flowing between them
What are some symptoms of meningitis?
severe headache and stiff neck (cervical rigidity), head retraction
convulsions indicate that the inflammation is affecting the brain
What is encephalitis?
inflammation of the brain tissue caused by an infection or autoimmune response
cases include Rasmussen Encephalitis: attacks one hemisphere in children
treatment: hemispherectomy
What is cerebral circulation?
three major arteries that feed blood to the cerebral hemispheres
branch extensively to supply the regions shaded in pink
What is a stroke?
sudden neurological symptoms following severely reduced blood flow
the consequences of stroke are significant for most and often diminish quality of life
ischemic: blockage in blood vessel
hemorrhagic: blood vessel ruptures
What is cerebrospinal fluid?
suspends the brain to reduce mass weight
shock absorber
chemical content of CSF provides stable environment for optimal functioning
effective waste cleaning
What is the conserved pattern of nervous system development?
the nervous system’s basic structural plan is present in developing embryonic brains
the human brain retains most of the features of less complex mammalian brains
bilateral symmetry is common to simple worms and humans, same is true for the brainstem in fish, amphibians, humans, etc.
What is the relationship between the nervous system and intelligent behavior?
several nervous system layers do more than simply replicate function
each region adds a different dimension to the behavior
this hierarchical organization affects virtually every human behavior
in evolutionary history, development history, and personal history are integrated at the various anatomical and functional levels of the nervous system
What are spinal reflexes?
automatic movement, hard to prevent, brain cannot inhibit
example: knee-jerk reflex (patellar tendon)
What is the hindbrain?
controls various motor functions ranging from breathing to balance to fine movements
is evolutionarily the oldest part of the brain
contains the cerebellum, reticular formation, pons, medulla
the principal hindbrain structures integrate voluntary and involuntary body movements
What is the tectum (roof of midbrain)?
sensory processing (visual and auditory)
superior and inferior colliculi: produces orientating movements (e.g. turning head to see source of sound)
superior: receives optic nerve fibers
inferior: receives input from auditory pathways
What is the tegmentum (floor of midbrain)?
movement-related functions
composed of many nuclei
What is the midbrain?
orienting behaviors: auditory and visual systems must share a map of the external world so that the ears can tell the eyes to look
red nucleus: limb movements
substantia nigra: movement initiation, damages associated with Parkinson’s
the periaqueductal gray matter: species-typical behaviors
pain modulation
What is the diencephalon?
the between brain, integrates sensory and motor information on its way to the cerebral cortex
What is the forebrain?
integrates sensation, motivation, emotion and memory
advanced cognitive functions as thinking, planning and using language
forebrain structures: cerebral cortex, basal ganglia, limbic system, neocortex, allocortex
What is the cerebral cortex?
contains concentric rings of allocortex (three-layered cortex and four-layered cortex) and six-layered cortex (neocortex)
the cortex makes most of the forebrain volume
most expanded by evolution
involves folding of neocortex (sulci and gyri)
What is the allocortex?
made by three- and four-layered structures
these include the hippocampus, part of the amygdala, the cingulate cortex, several structures that make up the olfactory system, and other related areas
What are the structures in the allocortex?
hippocampus: memory consolidation
amygdala: anxiety and fear
cingulate cortex: emotion formation and processing, learning, and memory, linking behavior to motivation
olfactory system: olfactory bulbs and receptors
What are the characteristics of neocortical layers?
different layers have different cell types
density of cell varies among layers
cytoarchitectonic map: map of neocortex based on the organization, structure, and distribution of the cells
the neocortex is connected to virtually all other parts of the brain
What behavior does the neocortical layers influence?
cravings, lust, interpretation of abstract concepts, words, and images
ultimately, it creates reality
What is the basal ganglia?
collection of nuclei just below the white matter of the neocortex
controls voluntary and involuntary movement
principal structures: caudate nucleus, putamen, and globus pallidus
related disorders: Parkinson disease and Tourette syndrome
What is the somatic nervous system?
monitored and controlled by the CNS
cranial nerves are controlled by the brain
spinal nerves are controlled by spinal cord segments
What are cranial nerves?
twelve nerve pairs control sensory and motor functions of the head, neck and internal organs
functions of cranial nerves: afferent functions, efferent functions, both functions
What are spinal nerves?
the spinal cord lies inside the bony spinal column made of small bones called vertebrae
vertebrae are categorized into five anatomical regions: cervical, thoracic, lumbar, sacral, and coccygeal
dermatomes: body segment corresponding to a segment of the spinal cord
spinal cord segments are interconnected, so adjacent segments can operate together to direct complex coordinated movements
What are somatic nervous system connections?
like the CNS, the SNS is bilateral (two-sided)
posterior fibers are afferent, they carry information from the body’s sensory receptors
anterior root fibers are efferent, they carry information from the spinal cord to the muscles
What is the Enteric Nervous Systems (ENS)?
the ENS is a network of neurons embedded in the lining of the gastrointestinal tract
it controls bowel motility, secretion, and blood flow to permit fluid and nutrient absorption and to support waste elimination
the brain and ENS connect extensively through the ANS, especially via the vagus nerve
What is the relationship between the ENS and the microbiome?
microbiota influence nutrient absorption and are a source of neurochemicals that regulate physiological and psychological processes
this relationship has inspired the development of a class of compounds known as psychobiotics, live microorganisms used to treat behavioral disorders
thus, microbiota can influence both the CNS and ENS, leading to changes in behavior
