Chapter 2) Functional Anatory Of The Nervous System Flashcards
Agenesis
-Failure of brain regions to develop
-Offers researchers an opportunity to study brain organization and function
Cerebellar agenesis
-Brain plasticity in response to early perturbations allows for compensation as regions of the cerebral cortex function more efficiently
Brains primary function
-Produce behavior (movement)
-Receiving information about the world (stimuli)
-Integrating information to construct a subjective experience of reality (perception)
-Producing commands to control the movement of muscles
Neural tissue
-Has the capacity to adapt to the world by changing how its functions are organized
-Neuroplasticity
-Phenotypic plasticity
-Influence of epigenetic factors
Afferent
-Sensory
-Information comes INWARDS into the CNS
-Incoming information
Efferent
-Motor
-Information leaves OUTWARD from the CNC
-Outgoing information
Brain (brain structure locations)
Body orientation, frame of reference is human face
Spatial orientation
Frame of reference is other body parts and body orientation
Anatomical orientation
-Frame of reference is direction of cut
-Section through the human brain from the viewers perspective
Dorsal (Superior in terms of location)
-Structures atop the brain
-Structures within the brain
Anterior
In the front
Posterior
In the back
Ventral (Inferior in terms of location)
Structures towards the bottom of the brain or one of its parts
Medial
Structures towards the brains midline
Lateral
Structures located towards the sides
Coronal section
-Cut in a vertical plane from the crown of the head down
-Yields a front view of brains internal structure
Horizontal section
-View/cut falls along the horizon
-Usually viewed looking down on brain from above (dorsal view)
-The cut is similar to leveling the top of a cake
Sagittal section
-Cut lengthways from front to back and is viewed from the side
-Imagine the brain “split from an arrow”
-Divides the brain into symmetrical halves
-Medial view
-The cut is similar to cutting a tall cake in half from the middle
Protection on brain’s surface
-Triple layered covering (meninges) encases brain and spinal cord
-Cerebrospinal (CSF) cushions them
Meninges
-Triple layered and encases brain + spinal cord
-Dura mater-Layer closest to skull
-Arachnoid membrane-Middle
-Pia Mater-Furthest from skull
Cerebral cortex geography
-Cerebral cortex is brain’s thin, outer layer “bark”
-Two hemispheres
-Each hemisphere is divided into four lobes
-Frontal (executive function)
-Parietal (sensory integration)
-Temporal (auditory, taste, smell, memory)
-Occipital (visual)
Gyri
Bumps in the brain’s folded surface
Sulci
Cracks in the folded surface of brain
Longitudinal fissure
Divides the two hemispheres apart
Cerebral circulation
-Each of the three major arteries (come up from spine) that feed blood to the cerebral hemispheres branches extensively to feed different regions
Anterior cerebral artery
-Artery that feeds the front of the brain (Along longitudinal fissure)
Middle cerebral artery
-Artery that feeds the middle (gets sections from both hemispheres)
Posterior cerebral artery
-Artery that feeds the back
-Branches into two and then wraps back around
White matter
-Myelinated
-Inside the brain
-Regenerates due to Schwann cells
-Speeds up saltatory conduction
-Surrounds cell bodies making them more efficient in communicating with one another
Lateral ventricles
-Filled with CSF
-Four different ventricles
-Fourth ventricle is by hindbrain
Corpus callosum
-Connects the right and left hemisphere
-Runs from front to back
How are neurons connected?
-Connected to one another by fibers known as axons
-When the axons run along together they form a nerve (outside CNS) or tract (within the CNS)
Nerve
Bundle of fibers outside the CNS
Tract
Collection of nerve fibers in brain and spinal cord
Spinal cord
-Controls most body movements
-Can act independently of brain (spinal reflexes, reflex arc)
Brainstem
-On top of spinal cord
-Begins where the spinal cord enters the skull
-Receives afferent (Sensory) nerves coming from senses and sends efferent (motor) out to control movements
-Three regions of brainstem: Hindbrain, midbrain, diencephalon
Hindbrain
-Evolutionary the oldest part of the brain (has the most basic elements to survive)
-Contains various motor functions ranging from breathing to balance to find movements
-Cerebellum (automatic movement–jumping, running)
-Reticular formation
-Pons
-Medulla (automatic functions–heart rate)
Reticular formation
-Comes up from spinal cord
-Involved in sleep-wake cycle
-Circadian rhythm
Pons
-sends signals to cerebellum
-Connects consciousness
Midbrain
-Producing orienting movements
-Species specific behaviors
-Pain perception
-Diencephalon
-Hypothalamus
-Thalamus
Diencepharon
-The between brain
-Integrates sensory and motor information on its way to the cerebral cortex
Hypothalamus
-Below the thalamus
-Diencephalon structure that contains many nuclei associated with temperature regulation, eating, drinking, sexual behavior
Thalamus
-Above the hypothalamus
-Diencephalon structure through which information from all sensory systems is organized, integrated and projected into the appropriate region of the neocortex
Forebrain
-Integrates sensation, motivation, emotion and memory
-enables advanced cognitive functions such as thinking, planning and using language
Forebrain structures
-Neocortex (cerebral cortex)
-Basal Ganglia
-Limbic system
-Allocortex
Allocortex
-Hippocampus
-Amygdala
Basal Ganglia
-Controls voluntary precise movements as well as involuntary movements
-Collection of nuclei below white matter of neocortex
-Caudate nucleus, putamen, globus pallidus
-Related disorders and Parkinson’s and Tourette’s
Relationship between Basal ganglia and cerebellum
-Learning a new motor skill is basal ganglia and once the skill is automatic it moves to the cerebellum
Cerebral cortex (Neo cortex)
-Contains concentric rings of allocortex (3 and 4 layered cortex)
-Contains concentric rings of neocortex (6 layered cortex)
-Is most of the forebrain by volume, expanded through evolution
-Involves folding of neocortex (sulci, gyri)
Allocortex
-Composed of several distinct 3 and 4 layered structures that include hippocampus, part of amygdala, cingulate cortex, several structures that make up olfactory system
Amygdala
Anxiety and fear
Cingulate cortex
-Emotion formation and processing
-Learning
-Memory
-Linking behavior to motivation
-Wraps around corpus collosum
Olfactory system
-Olfactory bulbs and receptors
-Pyriform cortex in front of brain
-Vomeronasal organ (VNO)
Neocortical layers
-Different layers have different cell types
-Density of cells varies among layers
-Differences in appearance relate to function and region
-Influences craving, lust, interpretations of abstract concepts, words, and images
-Creates reality
-Cytoarchitectonic map
Cytoarchitectonic map
Map of neocortex based on the organization, structure, and distribution of the cells
Neocritical layering
-Layer IV (5) in sensory cortex is thick compared to motor
-This is due to abundant afferent sensory information from the thalamus connects to layer 5
-Layers 6 and 7 are thick in motor neocortex and thin in sensory
Forebrain: Cortical lobes
-Nearly symmetrical right and left hemispheres that are separated by the longitudinal fissure and central sulcus
Somatic nervous system (SNS)
-Monitored and controlled by CNS
-Cranial nerves of brain
-Spinal nerves by the spinal cord segments
-Bilateral (two sided)
Cranial nerves
-12 nerve pairs control sensory and motor functions of the head, neck and internal organs
Spinal nerves
-Spinal cord encased in vertebrae
-Vertebrae are categorized into five anatomical regions: Cervical, thoracic, lumbar, sacral, coccygeal
-Body segments correspond to spinal cord segments called dermatomes with sensory and motor neurons
-Spinal cord segments are interconnected
