Lecture 1: Organization of the Nervous System Flashcards
The central nervous system is comprised of (2):
(1) The encephalon
(2) The spinal cord
somatosensory system is the part of the sensory system concerned with
the conscious perception of touch, pressure, pain, temperature, position, movement, and vibration
Encephalon is synonymous with:
Brain
The encephalon is composed of (3):
(1) brain
(2) brainstem
(3) cerebellum
The encephalon, often referred to as the brain, is a critical component of the central nervous system. It consists of three primary parts:
(1) Brain
(2) Brainstem
(3) Cerebellum
The autonomic nervous system shares fibres and tracts with:
the CNS and PNS
The autonomic nervous system is a division of the :
Peripheral nervous system???
The autonomic nervous system controls:
Autonomic functions
What are some examples of autonomic functions:
heart rate, respiratory rate, digestion, urination
The autonomic nervous system shares fibres and tracts with:
the CNS and PNS
Often referred to as the “fight or flight” system, the ___ prepares the body for stressful or emergency situations.
sympathetic
Describe the sympathetic nervous system:
Increases the activity of
autonomic functions (e.g. fight and flight
response)
Known as the “rest and digest” system, the __ conserves energy and promotes maintenance activities.
parasympathetic nervous system
Describe the parasympathetic nervous system:
Decreases the activity of autonomic functions
In terms of the functional organization of the nervous system, the sensory division is termed:
“Receiver”
In terms of the functional organization of the nervous system, the integrative division is also called the:
Processor
In terms of the functional organization of the nervous system, the motor division is also called:
the effector
In terms of the functional organization of the nervous system, the sensory division “receiver” does what (2):
(1) Receives sensory information: tactile,
proprioception (muscle), visual, auditory,
olfactory, gustatory and vestibular
(2) Reports information about state of the body and
its environment
In terms of the functional organization of the nervous system, the integrative division - “processor” - does what (2) :
(1) Integration of sensory input and motor output to
cause desired responses.
(2) Provides higher-order brain functions (e.g.,
perception, decision making, thinking, attention,
memory, language, emotions, etc.)
The motor division -“effector” - does what (2) :
(1) Responds adequately to the order of other divisions
(2) Controls bodily activities
Organization of the Central Nervous System: 3 major levels
(1) Cortical level
(2) Subcortical level
(3) Spinal cord level
Highest level of CNS organization, located in the outer layer of the brain (cerebrum) is the :
cortical level
Functions of the cortical level:
consciousness
sensory interpretation
voluntary motor control
language
This level includes structures beneath the cortex, such as the basal ganglia, thalamus, hypothalamus, brainstem, and cerebellum.
subcortical level
functions of the subcortical level:
(1) Regulation of autonomic and involuntary functions
(2) motor coordination
(3) behavioural and emotional responses
The spinal cord level is an intersection that conducts:
sensory & motor signals from the
periphery of body to the brain and
vice versa
Spinal cord is the center of:
processing basic sensory & motor
information (i.e. reflexes, can work
without the need of other levels)
Circuits for motor reflexes (stretch reflex, golgi tendon reflex, withdrawal reflex) are found:
at the spinal cord level
Circuits for reflexes that control internal organ functions (e.g. blood vessels, gastrointestinal, urination) are found at which level?
At the spinal cord level
The subcortical level is also called the :
lower brain
The subcortical level (lower brain) includes (6):
-Brainstem (Medulla & pons)
-Mesencephalon (midbrain)
-Thalamus
-Hypothalamus
-Basal ganglia
-Cerebellum
The subcortical level (lower brain) controls:
subconscious body activities
What are some examples of subconscious body activities that are controlled by the subcortical level:
Equilibrium,
movement modulation,
arterial pressure, respiration,
heart beats,
feeding reflexes,
body temperature, wakefulness and sleep,
hormonal regulation…etc.
The cortical level is also called (3):
the higher brain
telencephalon
cerebral cortex
Cortex rarely __
functions alone,
always in association with
lower centers (aka subcortical/ spinal cord).
Place of the most complex and
sophisticated functions of the
Nervous System:
Cortical level
Information Processing, Memory formation, Decision making, Thoughts, emotions occur at the __ level
cortical level
Cerebral cortex is divided into:
two hemispheres: Left & Right
Each cerebral hemisphere is divided into four
lobes:
Fred’s Parrot Only Talks
(1) Frontal lobe
(2) Parietal lobe
(3)occipital lobe
(4)temporal lobe
Functions of the frontal Lobe (2) :
(1) Area of MOTOR FUNCTIONS (Precentral
gyrus)
(2) Area of higher mental functions (e.g. executive functions, attention)
Functions of the parietal lobe (2):
(1) Area of somatosensory functions (postcentral gyrus)
(2) Area of higher mental functions (e.g. giving sense to sensory information)
The peripheral nervous system is composed of:
Peripheral nerves
peripheral nerves comprise (2):
sensory and motor nerves
What are some examples for reflexes that control internal organ functions?
blood vessels
gastrointestinal
urination
Area of motor functions (Precentral
gyrus):
frontal lobe
Area of higher mental functions (e.g.
executive functions, attention):
Frontal Lobe:
Parietal lobe (2):
- Area of somatosensory functions
(Postcentral gyrus) - Area of higher mental functions (e.g.
giving sense to sensory information)
Area of somatosensory functions (Postcentral gyrus):
Parietal lobe
Area of higher mental functions (e.g.
giving sense to sensory information)
parietal lobe
Temporal Lobe (2):
- Area of auditory functions
- Area of memory formation and storage
Area of auditory functions:
Temporal Lobe:
Area of memory formation & storage:
Temporal Lobe
Occipital Lobe:
Area of visual functions
Area of visual functions
Occipital Lobe:
Somatosensory system:
Transmission of somatic
(i.e. body) information from
receptors in the periphery
of the body (e.g. skin,
muscles, bones, viscera) to
the CNS.
Somatic Information is
transmitted to (5):
in order:
➢ Spinal cord
➢ Brainstem
➢ Cerebellum
➢ Thalamus
➢ Cerebral cortex (somatic
areas)
Motor system functions (2):
(1) Responds adequately to the order of integrative & sensory divisions.
(2) Controls the body motor
activities (muscles):
–Skeletal (striated) muscles
–Smooth muscles (internal
organs, heart, stomach…)
striated muscles are:
skeletal muscles
smooth muscles are:
the muscles of internal organs, heart, stomach,etc
The neuron is:
the basic functional unit of the nervous system.
of neurons in the nervous system?
more than 100 billion
The neuron is an __ cell
electrical
i.e. it generates and transmits electricity
the main body of the neuron is the:
cell body / soma
where does signal processing occur for the neuron?
in the cell body/ soma
Projections of the soma:
Dendrites
Where does signal input (receiving signal from other neurons) occur?
in the dendrites
Extends from soma to the synaptic terminals.
axon
Signal output (send signal to other neurons) occurs where:
Axon
the most common cell type (e.g. motoneuron,
purkinje cell)
Multipolar neuron:
which neuron has multiple processes (several dendrites and one main axon) on DIFFERENT sides of the soma?
Multipolar neuron
Bipolar neuron:
two processes (one main dendrite & one
main axon) on different sides
Type of neuron found in retina, inner ear &
olfactory system
Bipolar neuron
Unipolar neuron:
One process (dendrite & axon) on the
same side
Photoreceptors in retina (rods & cones) are a type of __ neuron
unipolar neuron
Pseudo-unipolar neuron:
One process (dendrite & axon develop
from the same process, but on the
opposite side)
sensory neuron in the spinal cord are a type of __ neuron
pseudo-unipolar neuron
Neurons come in different shapes and sizes to:
accommodate many functions
AFFERENT NEURONS:
Send electrical signal to spinal cord and brain
(sensory input = sensory neurons).
EFFERENT NEURONS:
Send electrical signal from the brain and spinal
cord to the periphery (motor output = motor
neurons).
INTERNEURONS:
Local circuitry located between sensory and
motor neurons (integration).
Neurons are __
interconnected
neural network
Each neuron can be connected to up
1000 neurons
Synapse is:
the point of
communication between two neurons.
true/false: glial cells participate directly in electrical signaling or synaptic transmission
FALSE: glial cells do not participate directly in electrical signaling or synaptic transmission
what do glial cells do?
Supportive functions: help define synaptic contacts, maintain signaling
abilities of neurons, and defend neurons
what are the three types of glial cells?
(1) astrocyte
(2) oligodendrocyte / Shwann cells
(3) microglia
astrocytes are a type of glial cell that:
maintain a good chemical
environment for neuronal signaling and secrete
substances that influence the formation of new
synaptic connections.
oligodendrocytes are a type of glial cell that:
produce the myelin
sheaths around axons in CNS to maintain
signaling abilities of neurons
shwann cells:
Form the myelin sheaths in the PNS
microglia are a type of glial cell that have a:
immune function
(1) consume
cellular debris, bacteria and dead cells
(2) secrete signaling molecules that can modulate local
inflammation and influence cell survival and
death
Gray matter:
region in the CNS where the cell bodies of neurons are located.
White matter:
region in the CNS where axon tracts and commissures are
located.
Tracts:
bundles of central axons (in the CNS).
Nerves:
bundles of peripheral axons (in the PNS).
Nucleus:
gray matter outside of the cortex, where there is concentration of
neurons with similar functions and connections (e.g. putamen, red nucleus,
cerebellar nuclei…).
Ganglion:
local accumulation of nerve cell bodies and supporting cells in the
PNS (e.g. dorsal root ganglion in the spinal cord).
Cortex:
most superficial layer of the gray matter in the cerebral hemispheres.
Fiber Decussation:
fibers cross the midline to the contralateral side
(i.e. information in one side of the body will be transmitted to the
opposite brain side and vice-versa)
Commissures
Long tracts that connect different regions of the brain (e.g.
corpus callosum that connects the two cerebral hemispheres).
What are the three types of lesion studies?
(1) post-accident studies
(2)post mortem studies
(3) animal studies
Post-accident studies (a type of lesion study) :
observing functional/behavioral deficits after a damage in specific brain region (e.g.
frontal lobe lesion).
Post-mortem studies (a type of lesion study):
studding the anatomy of a brain after death (e.g. Alzheimer, Parkinson…).
animal studies (a type of lesion study):
purposefully damaging a brain region of an animal, nerve, or tract and observing
subsequent loss of function.
What are the two types of electrophysiological recording?
(1) Electroencephalography (EEG)
(2) Neuronal recording
Electroencephalography (EEG) ( a type of electrophysiological recording):
Using a cap of EEG electrodes placed on the head scalp to record
extracellular field potential (e.g. epilepsy, coma, sleep study…).
Neuronal recording (a type of electrophysiological recording):
recording the electrical activity inside the neurons (mostly in animals).
What are the three types of neuroimaging techniques?
(1) Magnetic Resonance Imaging (MRI)
(2) Functional Magnetic Resonance Imaging (fMRI)
(3) Positron emission tomography (PET)
Magnetic Resonance Imaging (MRI)
Based on the physics of atomic motion. It uses magnetic signal to
take high-definition images of the brain (e.g. tissue damage, strokes…).
Functional Magnetic Resonance Imaging (fMRI)
It uses magnetic signal to measure the changes in the
oxygen level in the blood (BOLD signal) in a specific brain region. The higher the BOLD signal, the higher
the neural activity in this region. Used in research to study the function of different brain regions.
Positron Emission Tomography (PET):
reveals the metabolic or biochemical function of brain tissues. It
uses a radioactive day (tracer) to show both normal and abnormal metabolic activity (e.g. tumors,
infections…).
Lesion of the Frontal Lobe: the story of Phineas Gage.
Work accident: iron bar blew straight through his head and damaged his frontal lobe.
* Lesion of the Frontal Lobe:
➢ Difficulty with executive functions: hard to manage his daily plans, decision-making
problem, not organized…etc.
➢ Change in personality and behavior: more aggressive, less compassion, social
isolation…etc.
