B1 - The Nervous System Flashcards
What are sense organs?
Organs that contain a specific type of receptors to detect a stimulus
What are receptors?
Groups of cells that are sensitive to a stimulus
List the 5 sense organs and describe what their receptors do
Eyes (light receptors which are sensitive to light)
Ears (sound receptors sensitive to sound)
Nose (smell receptors sensitive to chemical stimuli)
Tongue (taste receptors sensitive to chemical stimuli)
Skin (sensitive to touch, pressure, pain and temperature change)
What are the 3 types of neurone and what do they do?
Sensory (carries electrical impulses from receptors to the central nervous system)
Relay (carries impulses from sensory to motor neurones)
Motor (carries impulses to the effector)
What are the 2 types of effector?
Muscles that contract in response to impulses
Glands that secrets hormones in response to impulses
What is a synapse?
The connection between 2 neurones
How do the signals move across the synapse?
Transferred by chemicals called neurotransmitters that move across the gap
What are reflexes?
Automatic responses to certain stimuli that reduce the chance of you being injured or damaged
What is a reflex arc?
The way that our body gets a stimulus and automatically creates a response
Describe what happens during a reflex arc
There is a stimulus that is detected by the receptors
A signal travels from the receptors down the sensory neurone
The signal is passed from the sensory neurone, down the relay neurone in the spinal cord or unconscious part of the brain to the motor neurone
The motor neurone carries the signal to the effector which contracts (muscle) or secretes hormones (glands)
What are the 2 ways that messages are sent round the body?
Hormonal
Nervous
What are the 3 properties of nerves?
Very fast message
Act for a short time
Act on a precise area
What are the 3 properties of hormones?
Slow message
Act for a long time
Act in a general way (less specific than nerves)
