Nervous System Pt. 1 Flashcards
Three Overlapping Functions of the Nervous System
- Monitors stimuli and the gathered information (sensory input)
- It processes and interprets the sensory input and decides response—a process (integration)
- It then causes a response, or effect, by activating
muscles or glands (effectors) via motor output
Structural Classification of Nervous sysytem: 2
Central nervous
system (CNS);
peripheral nervous system (PNS)
Central nervous
system (CNS) consists of
the __ and ___,
brain and spinal cord
Act as the integrating and
command centers of the
nervous system
Central nervous
system (CNS)
They interpret incoming
sensory information and
issue instructions based on
past experience and current
conditions
Central nervous
system (CNS)
The___includes all parts of the nervous
system; consists mainly of the nerves that extend from the spinal cord and
brain.
peripheral nervous system (PNS)
carry impulses to and from the spinal cord.
Spinal nerves
carry impulses to and from the brain. These nerves
serve as communication lines
Cranial nerves
Functional Classification of Nervous System
-sensory division, or afferent division
-motor division, or efferent division
The ___, consists of nerves that convey impulses toward the CNS
sensory division, or afferent division
sensory division, or afferent division (2)
Somatic Sensory Fibers
Visceral Sensory Fibers
- delivering impulses from the skin, skeletal muscles, and joints
Somatic Sensory Fibers
- transmitting impulses from the visceral organs
Visceral Sensory Fibers
The _____, carries impulses from the CNS to effector organs.
motor division, or efferent division
motor division, or efferent division (2)
Somatic nervous system
Autonomic nervous system
allows us to voluntarily movement
Somatic nervous system
regulates events that are
involuntary movement.
Autonomic nervous system
two parts of Autonomic nervous system
Parasympathetic
Sympathetic
Support Cells: ___
Neuroglia
Neuroglial cells (4)
astrocyte
ependyma
microglia
Oligodendrocytes
abundant star-shaped cells that account for nearly half of neural tissue
* brace and anchor neurons to their nutrient supply lines
Astrocytes
forms a living barrier between capillaries and neurons, helps
determine capillary permeability, and plays a role in making
exchanges between the two; helps to control the chemical environment in the brain
Astrocytes
spiderlike phagocytes; monitor the health of nearby
neurons and dispose of debris
Microglia
line the central cavities of the brain
and the spinal cord
Ependymal Cells
participate in the production of
cerebrospinal fluid (CSF) and helps to circulate the cerebrospinal fluid that fills those cavities and
forms a protective watery cushion around the CNS.
Ependymal Cells
_____- Neuroglia that wrap their flat extensions (processes) tightly
around CNS nerve fibers, producing fatty insulating
coverings called ____
Oligodendrocytes; myelin sheaths
Supporting cells in the PNS come in two major varieties
Schwann cells;
Satellite cells
form the myelin sheaths around nerve
fibers in the PNS
Schwann cells
act as protective, cushioning cells for
peripheral neuron cell bodies
Satellite cells
= nerve cells
Neurons
Cells specialized to transmit messages
Neurons
Major regions of neurons (2)
Cell body
Processes
– nucleus and metabolic center
of the cell
Cell body
– fibers that extend from the
cell body (dendrites and axons)
Processes
Cell body (2)
Nucleus
Large
nucleolus
Extensions
outside the cell
body (2)
dendrites
axons
conduct
impulses toward
the cell body
Dendrites
– conduct
impulses away
from the cell
body
Axons
Axons end in ___; contain vesicles with neurotransmitters
axonal terminals
gap between adjacent
neurons
Synaptic cleft –
– junction between nerves
Synapse
– produce
myelin sheaths in jelly-roll
like fashion
Schwann cells
– gaps
in myelin sheath along
the axon
Nodes of Ranvier
Protects and insulates the
fibers and increases the
speed of nerve impulse
transmission
Myelin Sheaths
Neuron cell body are found mostly in the
central nervous
system
– cell bodies and unmylenated
fibers
Gray matter
– clusters of cell bodies within the
white matter of the central nervous system
Nuclei
– collections of cell bodies
outside the central nervous system
Ganglia
Functional Classification of Neurons (3)
Sensory (afferent) neuron
Motor (efferent) neurons
Interneurons (association neurons)
Carry impulses from the sensory receptors
Cutaneous sense organs
Sensory (afferent) neurons
– detect stretch or tension
Proprioceptors
Carry impulses from the central nervous system
Motor (efferent) neurons
Found in neural pathways in the central nervous system
Connect sensory and motor neurons
Interneurons (association neurons)
Structural Classification of Neurons (3)
Multipolar neurons
Bipolar neurons
Unipolar neurons
– many extensions
from the cell body
Multipolar neurons
–
one axon and one
dendrite
Bipolar neurons
–
have a short single
process leaving the
cell body
Unipolar neurons
How Neurons Function (2)
Irritability (respond to stimuli)
Conductivity (transmit an
impulse)
plasma membrane at rest is ___; Fewer positive ions are __the cell than
___the cell
polarized;
inside; outside
– a
stimulus depolarizes the
neuron’s membrane
Depolarization
A deploarized
membrane allows __
to flow
inside the membrane
sodium (Na+)
The exchange of ions
initiates an ___ in the neuron
action potential
Action potential:
___ions rush out of the neuron
after ___ions rush in, which repolarizes the membrane
The ____ restores
the original configuration
Potassium ; sodium;
sodium-potassium pump
Impulses travel
faster when fibers
have a ___
myelin
sheath
____is released from a nerve’s axon terminal
The dendrite of the next neuron has receptors that are stimulated by the
___
An action potential is started in the ____
Neurotransmitter ; neurotransmitter;
dendrite
– rapid, predictable, and
involuntary responses to stimuli
Reflex
– direct route from a sensory
neuron, to an interneuron, to an effector
Reflex arc
Types of Reflexes and Regulation (4)
Autonomic reflexes;
Somatic reflexes;
flexor/withdrawal, reflex;
Spinal Reflexes
Autonomic reflexes regulation (4)
Smooth muscle regulation
Heart and blood pressure regulation
Regulation of glands
Digestive system regulation
Activation of skeletal muscles
Somatic reflexes
The __ is a three-neuro reflex
arc in which the limb is withdrawn from painful stimulus
flexor, or withdrawal, reflex
A three-neuron reflex arc also consists of five elements—
receptor,
sensory neuron, interneuron,
motor neuron,
effector.
involve only spinal cord neurons and occur
without brain involvement.
Spinal Reflexes
As long as the spinal cord is functional, spinal
reflexes, such as the __, will work.
flexor reflex
develops from the embryonic neural tube
Central Nervous System (CNS)
in CNS ___becomes the brain and
spinal cord
neural tube
The opening of the neural tube becomes
the ___
Four chambers within the brain
Filled with cerebrospinal fluid
ventricles
Regions of the Brain (4)
Cerebral hemispheres (cerebrum);
Diencephalon;
Brain stem;
Cerebellum
Paired (left and right)
superior parts of the brain
Include more than half of
the brain mass
Cerebral hemispheres (cerebrum)
The surface of cerebrum
is made of
ridges (__)
and grooves
(___)
gyri; sulci
___(deep grooves) divide the
cerebrum into lobes
Fissures
Surface lobes of the cerebrum (4)
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
