Structure of the Nervous System
What are the two main parts of the nervous system?
Central nervous system and peripheral nervous system
Name one type of neuron
Motor neuron or sensory neuron or relay neuron
They travel along the neurones
Electrical impulses or electrical signals
Name one example of a reflex action.
One example of a reflex action is blinking. When something comes close to the eye, we blink automatically to protect it.
Other examples of reflex actions include the knee-jerk reflex, the pupil reflex (when the pupil gets smaller in bright light), and the withdrawal reflex (pulling your hand away from something hot).
The name of the space between two neurons
Synaptic gap or synaptic cleft
Which organs make up the central nervous system?
Brain and spinal cord
Which neuron carries signals from receptors to the central nervous system?
Sensory neuron
It is found between two neurons and allows signal transmission
The synapse
The main function of a reflex
To protect the body from danger
a muscle or gland is called this in a reflex arc
effector
It consists of the nerves outside of the brain and the spinal cord
The peripheral nervous system
The neurons located in the spinal cord connect the other two types.
Relay neuron
The chemical released in the synapse to transmit the signal
Neurotransmitters
Define a reflex
A fast and involuntary response to a stimulus
Where are neurotransmitters stored before being released?
Vesicles in the presynaptic neuron
What is the main function of the peripheral nervous system?
To carry signals between the CNS and the rest of the body
The neuron that sends signals to muscles and glands
Motor neuron
The function of the myelin sheath in neurons
It increases the speed of impulse transmission
Why are reflex actions faster than voluntary actions?
Because they bypass the brain and follow a direct pathway through the spinal cord, reducing response time.
Why do nerve impulses travel in only one direction?
Because receptors are only on the postsynaptic neuron
Explain the different functions between sensory and motor neurons.
Sensory nerves carry information from receptors to the CNS, motor nerves carry signals from the CNS to effectors.
In what order do neurons activate in a reflex arc?
Sensory → Relay → Motor
Explain the process that occurs at a synapse to transmit a signal
1. Electrical impulse reaches the presynaptic terminal → 2. Neurotransmitters are released → 3. They diffuse across the synapse → 4. They bind to receptors on the postsynaptic neuron → 5. A new impulse is triggered in the next neuron.
List the five components of a reflex arc.
Receptor, sensory neuron, relay neuron, motor neuron, and effector.
Describe the steps of impulse transmission across a synapse.
1. The impulse arrives at the presynaptic terminal → 2. Neurotransmitters are released → 3. They diffuse across the synapse → 4. They bind to receptor proteins → 5. A new impulse is triggered in the next neuron.