2.13 and 2.14 - Structure and Function of the Nervous System and The Reflex Arc Flashcards
What does the nervous system allow us to do?
The nervous system allows us to react to our surroundings and coordinate actions in response to stimuli.
What do receptor cells do?
Receptor cells convert a stimulus into an electrical impulse.
How does the electrical impulse travel to the CNS?
The electrical impulse travels along cells called sensory neurons to the central nervous system (CNS).
What happens in the CNS?
In the CNS, the information is processed and the appropriate response is coordinated.
How is the response sent to effectors?
An electrical impulse is sent along motor neurons to effectors.
What do effectors do?
Effectors carry out the response, which may involve muscles contracting or glands secreting hormones.
What are reflexes?
Reflexes are automatic responses that take place before you have time to think.
Why are reflexes important?
Reflexes are important as they prevent the individual from getting hurt.
What is a reflex arc?
A reflex arc is the pathway that allows vital responses to take place quickly, bypassing conscious areas of the brain.
What are the steps of a reflex arc?
- A stimulus is detected by receptors.
- Impulses are sent along a sensory neuron.
- In the CNS, the impulse passes to a relay neuron.
- Impulses are sent along a motor neuron.
- The impulse reaches an effector resulting in the appropriate response.
Can you give examples of reflex arcs?
Examples of reflex arcs include pupils getting smaller to avoid damage from bright lights and moving your hand from a hot surface to prevent damage.
What are synapses?
Synapses are the gaps between two neurons.
What happens when an impulse reaches the end of the first neuron?
A chemical called a neurotransmitter is released into the synapse.
What does the neurotransmitter do?
The neurotransmitter diffuses across the synapse and triggers the impulse to begin again in the next neuron.
What is the effect of different neurotransmitters?
Different neurotransmitters have different effects on the frequency and speed of the impulse in the second neuron.
What are myelinated nerves?
Myelinated nerves are surrounded by a myelin sheath.
What is the advantage of myelinated nerves?
The advantage of having nerves surrounded by myelin is that it allows nerve transmission (or action potential) to travel faster.
What produces myelin?
Myelin is produced by cells called Schwann cells.
