Nervous System pt 1 Flashcards
PPT part 1 + book
is the primary control center for
coordinating all body activities
nervous system
the nervous system recieves? (3)
sensory input, processes information, and initiates
responses
Ensures homeostasis and supports complex mental activities
Nervous system
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5 functions of the nervous system
- receiving sensory input
- Integration
- motor output (controlling muscles and glands)
- maintaining homeostasis
- establishing and maintaining mental activity
Functions of the Nervous System
Collects data from internal and
external environments.
Sensory input
Functions of the Nervous System
Processes sensory information and makes
decisions.
Integration (integrating information)
Functions of the Nervous System
Commands muscles and glands in
response to processed data
motor output (controlling muscles and glands)
Functions of the Nervous System
Maintains a stable internal environment
Maintaining Homeostasis
Fuctions of the Nervous System
Enables thought, emotion, learning,
and memory
establishing and maintaining Mental activity
Information is transmitted to the brain and spinal cord via __?
sensory
neurons
detect stimuli (light, temperature, pain, etc.)
receptors
Integration - The nervous system ___ and ___ sensory input
interprets and integrates
Decision-making occurs at various levels, from reflexes to conscious
thought
integration
The nervous system sends signals to effectors (muscles/glands) for
response
Motor Output
Enables voluntary and involuntary movements
Motor output
The nervous system regulates heart rate, blood pressure, breathing, and
temperature.
Homeostasis
The nervous system works with the endocrine system to achieve
balance or homeostasis
The brain supports complex functions such as thinking, reasoning,
emotions, and memory.
Mental activity
Mental Activity
+ The brain supports complex functions such as thinking, reasoning,
emotions, and memory.
______ of neurons enable these processes.
Interconnected networks
The nervous system is divided into 2 parts:
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
Composed of the brain and spinal cord,
responsible for data processing and
command initiation
Includes the brain and spinal cord
Central Nervous System
Includes all nerves outside the CNS, connecting it
to the body for sensory and motor function
Peripheral Nervous System (PNS)
CNS in responsible for ? (2)
data processing and command initiation
PNS is responsible for ? (2)
sensory and motor functions
is the communicatio link between the CNS and various parts of the body
Peripheral Nervous system
PNS is divided into 2 parts:
- Sensory division (afferent)
- Motor division (efferent)
afferent means?
toward
efferent means?
away
Conducts impulses **from sensory receptors to
the CNS, **monitoring external and internal
conditions
Sensory division (afferent)
**The neurons that trransmit action potentials from the periphery to the CNS are called?
sensory neurons
Transmits signals from the CNS to effector organs, managing voluntary and involuntary
responses
Motor divison (efferent)
The neurons that transmit action potentials from the CNS toward the periphery are called?
motor neurons
effectors controlled by the motor division include? (2)
muscle tissue and glands
2 subdivisions of the motor division
Autonomic Nervous System
somatic Nervous System
Regulates** involuntary actions (cardiac muscle, smooth muscle, and glands) through sympathetic
“fight or flight” and parasympathetic “rest and
digest”** responses
Autonomic Nervous System
self-governing nervous system
autonomic nervous system
bodily nervous system transmits action potentials from the CNS to skeletal muscles
somatic nervous system
Specialized network in the digestive tract that can
function autonomously, though it also integrates
with the CNS
Enteric Nervous System
sympathetic division =
fight of flight
parasympathetic
rest and digest
2 types of cells that make up the nervous system
neurons and glial cells
- conduct electrical impulses for
communication. - receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs
Neurons
a neuron has 3 parts
cell body, and two types of processes: dendrites, and axons
neuron structure
cell body (?)
soma
neuron structure
dendrites (?)
input
neuron structure
axon (?)
output
receive signals from other cells,
Dendrites
transmit impulses
axons
Junction where signals are passed
from one neuron to another
Synapse
3 types of neurons
- multipolar
- bipolar
- pseudo-unipolar
Many dendrites,
one axon (e.g., motor neurons).
Multipolar
One dendrite, one
axon (e.g., sensory neurons in
retina)
Bipolar
Single
projection divides into two
branches (common in sensory
neurons)
pseudo-unipolar
are short, often highly branching cytoplasmic extensions that are tapered from their bases at the neuron cell body to their tips.
dendrites
a single long cell process extending from the neuron cell body
axon
the area where the axon leaves the neuron cell body is caled the
axon hillock
glial cells or __
neuroglia
neuroglia means
nerve glue
- supportive cells of the CNS and PNS
- carry out different activities that enhance neuron function and maintain normal conditions within nervous tissue
glial cells
CNS glial cells (3)
- Astrocytes
- Oligodendrocytes
- microglia
- highly branched
- provide structural support, Form blood
brain barrier, support neurons,
and regulate nutrient
exchange
Astrocytes
- Cells with processes that can surround several axons
- Produce
myelin sheaths for CNS axons.
Oligodendrocytes
*
- small mobile cells
- Act as immune
cells within the CNS, removing
debris and pathogens
Microglia
Provide structural support; regulate neuronal signaling; contribute to blood-brain barrier; help with neural tissue repair
Astrocytes
Protect CNS from infection; become phagocytic in response to inflammation
Microglia
Cell processes from myelin sheahs around axons or enclose unmyelinated axons in the CNS
Oligodendrocytes
2 Glial Cells of the PNS
- Schwann cells
- satelite cells
Form myelin
around PNS axons, aiding in signal
transmission
Schwann cells
Support neuron
cell bodies within ganglia,
regulating their environment
Satellite Cells
- Single cells surrounding axons
- Form myelin sheaths around axons or enclose unmyelinated axons in the PNS
Schwann cells
- single cells surrounding cell bodies
- suport neurons, providing nutrients; protect neurons from heavy-metal poisons
satelite cells
permeability barrier between the blood and CNS
blood-brain barrier
insulates axons, enhancing transmission speed of impulses
Myelin Sheaths
Produced by Schwann cells (PNS) and oligodendrocytes (CNS)
Myelin Sheaths
Gaps in myelin where action potentials regenerate
to speed up conduction
Nodes of Ranvier
wrap around axons in the CNS and PNS
oligodendrocytes (CNS)
Schwann cells (PNS)
axons with myelin sheaths are called?
Myelinated axons
__ axons lack the myelin sheaths
unmyelinated
- Essential for neuron readiness to transmit signals.
- Maintained by selective permeability to K+ and Na+ ions
Resting Membrane Potential
Resting potential is maintained by ____ pumps, creating a
___ charge inside the cell
sodium-potassium pumps; 70mV charge
2 basic types of ion channels
- leak channels
- gated channels
the inside of most cell membranes is _ charged
negatively charged
the outside of the cell membrane is _ charged
positively charged
_ channels are always open
leak channels
_ channels are closed until opened by specific signals
gated channels
Essential for rapid and coordinated signal transmission along neurons
Action Potential Mechanism
Na+ channels open, allowing Na+ influx and membrane
potential becomes positive.
Depolarization
K+ channels open, K+ exits, restoring negative charge.
Repolarization
release
neurotransmitters to bridge the gap between
neurons
Chemical synapses
allow direct ion flow
between cells for fast communication
Electrical synapses
involves
neurotransmitter release, receptor
activation, and potential continuation of the
signal.
Synaptic transmission
3 major components of a synapse
- presynaptic terminal
- postsynaptic terminal
- synaptic cleft
end of the axon forms a
presynaptic terminal
membrane of the dendrite or effector cell is the
postsynaptic membrane
space separating the presynaptic and postsynaptic membranes is the
synaptic cleft
At most of the synapses in the body, communication between the neuron and its target occurs through?
chemical signals
Chemical substances called __ act as these chemical signals
neurotransmitters
neurotransmitters are stored in __ in the __ terminal
synaptic vesicles in the presynaptic terminal
Extends from the brainstem to the lumbar
region, protected by vertebrae.
Spinal Cord
Functions in transmitting information
between body and brain
Spinal Cord
The spinal cord Controls reflex actions through ___
local circuitry
The spinal nerves exiting from the inferior part of the spinal cord resemble a horse’s tail and are collectively called the
cauda equina
A cross section of the spinal cord consists of a _____ portion and a _______ portion
- superficial white matter portion
- deep gray matter portion
consist of myelinated axons
white matter
mainly a collection of neuron cell bodies
gray matter
The white matter consists of (3)
- ventral column
- lateral column
- dorsal column
gray matter consists of (3)
- ventral horn
- lateral horn
- dorsal horn
Nerve roots continuing from spinal cord end below L2, innervating lower
body
Cauda Equina
- Facilitates control over lower limbs and pelvic organs.
- Important in diagnosing conditions like _____ syndrome
cauda equina
is the central organ in the
central nervous system, housed
within the skull
Brain
Brain is divided into four main regions:
brainstem, cerebellum, diencephalon,
and cerebrum
__ pairs of spinal nerves connect the CNS to the body
31
Spinal nerves contain both
sensory and motor fibers
Located at the base of the brain, connecting it to
the spinal cord
Brainstem
3 sections fo the Brainstem
- Medulla Oblongata
- Pons
- Midbrain
Extends from the spinal
cord, with a role in basic reflexive control
Medulla Oblongata
Contains ascending and descending
tracts that carry sensory and motor
signals
Medulla Oblongata
Has various nuclei visible under
microscopic examination that are
responsible for reflex actions
Medulla Oblongata
Positioned just above the spinal cord
within the brainstem
Medulla Oblongata
Positioned between the medulla and
midbrain, appearing as a rounded
bulge
Pons
Composed of nerve fiber tracts that
bridge the cerebellum with the
brainstem.
Pons
Contains nerve tracts running
longitudinally and transversely
Pons
- Located above the pons, it’s the
smallest region of the brainstem. - Contains important neural tracts
linking the cerebrum and spinal cord
Midbrain
Contains structures such as the
____ and ____ that
contribute to visual and auditory
processing pathways.
tectum and tegmentum
Contains important neural tracts linking the cerebrum and spinal cord
Midbrain
Situated posterior to the brainstem, beneath the occipital lobes of the
cerebrum.
Cerebellum
The dorsal part of the midbrain consists of 4 mounds of tissue called the?
Colliculi
The two – colliculi are major relay centers for the auditory nerve pathways in the CNS.
inferior
The two – colliculi are involved in visual reflexes and receive touch and auditory input.
Superior
The cerebellum, is attached to the brain stem by several large connections called?
Cerebullar peduncles
Characterized by its highly folded surface, called___, which increases
surface area.
cerebellum, folia
The cerebellum is composed of two hemispheres connected by the - - with a cortex of gray matter.
Vermis
Located centrally, just above the brainstem,
enclosed by the cerebrum.
Diancephalon
diencephalon consists of (3).
- Thalamus
- Hypothalamus
- Epithalamus
Egg-shaped masses forming lateral walls of the diencephalon
Thalamus
Small, cone -shaped region below the thalamus
Hypothalamus
Thin posterior structure housing the pineal gland.
Epithalamus
Largest part of the diancephalon
Thalamus
The lateral parts of the thalamus are connected in the center by a small?
Interthalamic adhesion
Situated below the thalamus, forms the floor of the third ventricle
Hypothalamus
Largest brain region occupying most of the cranial cavity.
Cerebrum
The cerebrum is divided into left and right hemispheres connected by the ?
corpus callosum
winkled outer layer of the cerebrum
cerebral cortex
rich in neuron cell bodies (gray matter)
cerebral cortex
The cerebrum is divided into left and right hemispheres by the?
longitudinal fissure
elevated ridges, increasing surface area
Gyri
Shallow grooves separating gyri
sulci
Deeper grooves, such as the longitudinal fissure which divides the two hemispheres
Fissures
4 lobes of the cerebral cortex
- frontal lobe
- parietal lobe
- Occipital lobe
- Temporal lobe
Manages voluntary movement, reasoning, problem solving, and personality.
frontal lobe
Processes sensory information like touch, temperature, and pain
Parietal lobe
The frontal and parietal lobes are separated by the?
central sulcus
Dedicated to visual processing and interpretation
occipital lobe
Involved in auditory processing, language comprehension, and memory
temporal lobe
Most of the femoral lobe is separated from the rest of the cerebrum by the?
Lateral fissure
Deep within the lateral fissure is the ___ often referred to as the fifth lobe, which is involved in the perception of taste.
insula
anterior and posterior portions of the temporal lobe is called the ___ with functions such as abstract thought and judgement.
psychic cortex
are three protective
layers surrounding the brain and
spinal cord
Meninges
3 meninges
- dura mater
- arachnoid mater
- pia mater
These layers are situated between
the skull and brain, providing a
supportive framework
Meninges
The outermost layer, is dense and tough, providing a durable
protective covering.
Dura Mater
2 layers of the dura mater
- periosteal layer
- meningeal layer
layer of the dura mater that is attached to the skull
periosteal layer
layer of the dura mater that is closer to the brain
meningeal layer
The meningeal layer extends into the brain to form partitions, such as the
___ between the hemispheres
falx cerebri
is the middle meningeal layer, lying below the dura
mater.
Arachnoid mater
space between dura mater and vertebrae
epidural space
Thin and web-like, it spans over the brain but doesn’t follow brain
contours closely.
Arachnoid Mater
The subarachnoid space lies beneath the ____, containing web-like projections
and bridging veins
arachnoid mater
The innermost meningeal layer, is thin and delicate, closely
adhering to the brain and spinal cord’s surface.
pia mater
- Follows the brain’s contours, dipping into sulci and fissures.
- Rich in small blood vessels that supply the underlying neural tissue
Pia Mater
space between dura mater and the arachnoid mater
subdural space
space between arachnoid mater and the pia mater
subarachnoid space
Fluid-filled cavities of the CNS
Brain Ventricles
Two large C-shaped ventricles
located in each cerebral hemisphere
Lateral ventricles
Narrow space in the
diencephalon, connected to lateral ventricles via the
foramen of Monro
Third ventricle
lies between the brainstem and
cerebellum, connecting to the central canal of the
spinal cord.
Fourth ventricle
connects the third ventricle to the fourth ventricle,
allowing CSF flow between these chambers.
cerebral aqueduct
Extending from the fourth ventricle, the __ runs down the center of the spinal cord,
carrying CSF along its length
central canal
Produce CSF
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choroid plexus
located in the ventricles and are composed of ependmal cells and blood vessels
that filter plasma to create CSF
choroid plexus
CSF flows from the lateral ventricles into the third ventricle via the ____.
foramen of Monro
CSF Moves from the third to the fourth ventricle through the ___
cerebral aqueduct
From the fourth ventricle, CSF enters the subarachnoid space around the
brain and spinal cord via ___
lateral and median apertures
CSF is gradually reabsorbed into the venous bloodstream through
arachnoid granulations into the
dural venous sinuses
The largest collection points are found in the ____,
which facilitates continuous CSF flow and renewal.
superior sagittal sinus
