1.2 Flashcards
(14 cards)
Nervous system
the body’s speedy, electrochemical communication
network, consisting of all the nerve cells of the peripheral and central
nervous systems
- The nervous system is made up of neurons (tiny cells) that use
neurotransmitters to communicate between areas.
- Neurons send messages, process information, make decisions, and send
signals to execute commands throughout the body.
Central nervous system (CNS)
the brain and spinal cord.
Peripheral nervous system (PNS)
the sensory and motor neurons
that connect the central nervous system(CNS) to the rest of the body.
Nerves
bundled axons that form neural cables connecting the central
nervous system with muscles, glands, and sensory organs.
The nervous system
The nervous system is made up of two main divisions.
-The central nervous system (CNS)
comprises the brain and spinal cord.
• The peripheral nervous system (PNS) helps the CNS to communicate with the rest of the body by transmitting sensory
information to the brain and delivering commands to muscles
and glands.
Sensory (afferent) neurons
neurons that carry incoming information
from the body’s tissues and sensory receptors to the brain and spinal
cord.
- Sensory or afferent neurons bring messages from the sensory receptors like eyes and ears to the brain and spinal cord for processing. We don’t know
what we are seeing or hearing until our brain gets involved.
Motor (efferent) neurons
neurons that carry outgoing information
from the brain and spinal cord to the muscles and glands.
- Motor or efferent neurons carry these commands of response back out to the
muscles and glands of the body to act in response to stimuli.
Interneurons
neurons within the brain and spinal cord; they
communicate internally and process information between the sensory
inputs and motor outputs.
- Interneurons are in the brain and spinal cord. They process all incoming
information and then make decisions about what responses would be
appropriate.
What is the peripheral nervous system?
The peripheral nervous system is separated
into two main divisions ̶ somatic (skeletal) and
autonomic.
What is the somatic or skeletal nervous system?
The somatic or skeletal nervous system enables
communication from the brain and spinal cord to
our muscles connected to bones. Responses are
carried out by this part of the PNS by motor
neurons.
What is the autonomic nervous system?
The autonomic nervous system has two divisions of
its own, each helping to maintain homeostasis in
the body.
- The sympathetic nervous system arouses the body,
prepares it for fight or flight at a time when there may be danger.
• The parasympathetic, like a parachute, calms the body down and brings it back to a normal resting state after an arousal producing event has passed.
What is the central nervous system?
Thinking, feeling and acting all must be routed through the CNS, through
millions of neurons communicating with one another.
• Neural networks are clusters of neurons that layer together to work on
connected tasks.
• Neurons that are constantly in communication with each other become
stronger in their connections.
Reflex
a simple, automatic response to a sensory stimulus, such as
the knee-jerk reflex.
What role does the spinal cord play?
The spinal cord connects the peripheral
nervous system to the brain.
• Reflexes or simple automatic responses are also
controlled by the spinal cord pathway, called a
reflex arc.
• The pain reflex is an example of this
relationship between sensory neurons,
interneurons in the spinal cord, and motor
neurons. Our brain feels pain only after the
spinal cord has sent a command to move our
hand from the flame, as seen in the diagram.
