1
The primary functional structures of the nervous system.
The neurons
There are approximately how many neurons in the human brain?
86 billion
Name all structures of the nervous system.
Brain, spinal cord, and nerves.
What does the CNS stand for?
Central Nervous System
What does the PNS stand for?
Peripheral Nervous System
What is the main function of the nervous system?
To coordinate and control body activities by transmitting messages between the brain, spinal cord, and the rest of the body.
What is a reflex action?
A quick, automatic response to a stimulus that does not involve conscious thought.
What are the two main parts of the nervous system?
The central nervous system and the peripheral nervous system.
What does the central nervous system consist of?
The brain and the spinal cord.
What does the peripheral nervous system consist of?
All the nerves outside the brain and spinal cord.
What is the function of a motor neuron?
To carry nerve impulses from the central nervous system to muscles or glands to produce a response.
Name two examples of neurotransmitter.
Dopamine, Oxytoxin, Serotanin, Endorphin, Adrenaline
What chemical substance is released at a synapse to transmit a nerve impulse from one neuron to another?
Neurotransmitter
The three types of neurons are...
Sensory neuron, interneuron (relay neuron), motor neuron
Name the tiny empty space between dendrites of one neuron and axon terminals of the connecting neuron.
Synapse.
What does a dendrite do?
Receives neurotransmitters from another neuron's axon terminal.
What is the function of the cerebrum?
It controls voluntary actions, thinking, memory, senses, and learning.
Which part of the nervous system is responsible for voluntary actions?
The somatic nervous system.
An action potential travels along this structure until it reaches the axon terminal.
Which part of the nervous system controls involuntary actions like heartbeat and digestion?
The autonomic nervous system.
What is the function of the myelin sheath around a neuron?
It insulates the axon and speeds up the transmission of nerve impulses.
Why do impulses travel faster in reflex actions than in voluntary actions?
Because reflexes bypass the brain and are processed in the spinal cord.
Name four functional parts of a neuron.
Cell body, Dendrites, Axon, Myelin sheath, Axon terminals, Node of Ranvier
Explain what happens to an action potential when it reaches the axon terminal.
It changes to a chemical signal and releases neurotransmitter that are received by the next neuron across a space called a synapse.
Why is a reflex arc important for the body?
It allows the body to respond quickly to danger, protects from injury, helps maintain balance and posture, and controls automatic actions like blinking or swallowing.