Chapter 2 (MT1) Flashcards
Nervous System Anatomy
Neuroplasticity
The nervous system’s fundamental potential to physically or chemically modify itself in response to a changing environment and to compensate for age-related changes and injury
Anatomical organization of nervous system
Nervous system
- CNS (Brain and spinal cord)
- PNS (Somatic, Autonomic, and Enteric nervous system)
Functional organization of CNS
Mediates behaviour
Recieving, processing, and responding to stimuli
(brain and spinal cord)
Functional organization of somatic nervous system
Transmits sensation and produces movement
(cranial and spinal nerves)
Carrying sensory info to CNS and transmits motor instructions that produce movement
Functional organization of autonomic nervous system
Balances internal functions
Sympathetic (arousing) and parasympathetic (calming)
Functional organization of enteric nervous system
Controls the gut
Mesh of neurons embedded in the gut
Mostly operates autonomously
Describe flow of neural information
Afferent (sensory, towards the CNS)
Efferent (motor, exits the CNS)
Anterior (frontal/rostral)
Towards the front of animal/head
Caudal (posterior)
Towards the tail
Coronal (section)
Cut on vertical plane (ear to ear)
Reveals a frontal view
Dorsal
Towards the back of a four legged animal
Horizontal (section)
Along the horizon
Reveals a dorsal (over top) view
Inferior
Below
Lateral
Towards the side of the body or brain
Medial
Towards the midline
Posterior
Towards the back
Sagittal (section)
Lengthwise from front to back of the skull
Reveals medial (from side) view
Midsagittal - right down the middle
Superior
Above
Ventral
Towards the belly of four legged animal
Human brain nuclei - below
Surface features of the brain
Longitudinal fissure
Precentral gyrus
Central fissure
Postcentral gyrus
Superior temporal gyrus
Layers protecting the brain
(Brain)
Pia mater
Subarachnoid space (filled with CSF)
Arachnoid membrane
Dura mater
(Skull)
What does the meninges contain
Pia mater
Arachnoid membrane
Dura mater
Frontal lobe
Executive functions like decision making and voluntary movement
Parietal lobe
Directing movements towards a goal
Sensory perception and integration
Temporal lobe
Hearing, language, and musical abilities
Facial recognition, emotional processing
Occipital lobe
Visual scene processing
Gyrus and sulcus (brain)
Gyrus = bump
Sulcus = crack
Really deep sulcus = fissure
Three major arteries in the brain
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery
Stroke
Artery blockage/break likely leads to death of the affected region
The sudden appearance of neurological symptoms as a result of severely reduced blood flow
Gray matter vs White matter
Grey matter - predominantly cell bodies and blood vessels, within grey matter neurons collect and modify info before sending it along
White matter - predominantly axons (fat-sheathed (myelinated) nerve fibers), form longer distance connections between/among neurons
Ventricles in brain
(Lateral) ventricles, wing-shaped cavities filled with CSF
Roles of the CSF
Suspends brain (makes it lighter)
Shock absorption
Provides stable environment for brain function (chemical content of CSF is regulated)
Corpus callosum
Contains 200 million nerve fibers that join the two hemispheres and allow them to communicate
How are neurons connected to eachother?
By fibers known as axons
Tract and nerve
Tract - collection of nerve fibers in brain and spinal cord that run along each other (within CNS)
Nerve - collection of nerve fibers that run along each other (outside CNS)
What does the brainstem contain
Hindbrain
Midbrain
Diencephalon
What does the brainstem do?
Receives afferent signals coming in from senses, and sends efferent signals to the spinal cord to control (virtually) all movements
Parts of the hindbrain
What does the hindbrain do?
Cerebellum, pons, medulla, reticular formation
Controls motor functions ranging from breathing to balance to fine movements
What does relative size of cerebellum increase with?
Physical speed and dexterity of species
Reticular formation
Netlike mixture of neurons and nerve fibers
What do the pons and medulla do?
Contain substructures that control many vital body movements
Nuclei in pons receive inputs from cerebellum and form a bridge to the rest of the brain
At rostral tip of spinal cord, medulla’s nuclei regulate vital functions (breathing, cardiovascular)
Parts of the midbrain
What does the midbrain do?
Sensory component (tectum) is dorsal, and motor structure (tegmentum) is anterior
Tectum receives sensory information from eyes and ears, tegmentum composed of nuclei with movement related functions
Superior and inferior colliculus (midbrain)
Process sensory info and produce orienting movements (related to sensory info)
Red nucleus (midbrain)
Controls limb movements
Substatia nigra
Connects to forebrain, important in initiating movements
Periaqueductal gray matter (midbrain)
Contains circuits that control species-typical behaviour
Parts of the diencephalon
What does the diencephalon do?
Hypothalamus and thalamus
Integrates sensory and motor info on its way to the cerebral cortex (the “between brain”)
Hypothalamus
Controls the bodies production of hormones (interacts with pituitary gland)
Thalamus
“Relay station”
Organizer/integrator of sensory information travelling to cerebral cortex from sensory systems
Largest and most recently evolved region of the mammalian brain?
Forebrain
Parts of the forebrain
What does the forebrain do?
Cerebral cortex (neocortex and allocortex)
Allocortex - hippocampus and amygdala
Basal ganglia
(Limbic system = allocortex/subcortical structures)
Cerebral cortex regulates a host of mental activities
Basal ganglia controls voluntary movement and has a role in cognitive functioning
Neocortical layers
6 layers of gray matter
- different levels have different cell types, density of cells, and difference of appearance
Cytoarchitectonic map
Map of neocortex based on organization, structure, and distribution of cells (Brodmann)
Neocortical layer IV
Thick in sensory cortex
Thin in motor cortex
Sensory input (afferent)
Neocortical layers V and VI
Thick in motor cortex
Thin in sensory cortex
Output to other parts of the brain (efferent)
Basal ganglia
Collection of nuclei that lie in the forebrain below white matter of cortex
Controls voluntary and involuntary movement
How many pairs of cranial nerves are there?
12
Spinal nerves
8 cervical nerves
12 thoracic nerves
4 lumbar nerves
5 sacral nerves
Law of Bell and Magendie
Observation that posterior/dorsal spinal cord is sensory and anterior/ventral is motor in vertebrates
Posterior = afferent
Anterior = efferent
Sympathetic system (ANS)
Arouses body for action
‘Fight or flight’
Parasympathetic system
Relaxes the body
‘Rest and digest’
The brain and ENS connect extensively through the ANS, especially via what nerve?
Vagus nerve
