B10 - The nervous system Flashcards
B10 - What internal conditions need to be controlled?
Water levels
Temperature
Blood glucose
Metabolic rate
B10 - What is meant by homeostasis?
The regulation and control of internal conditions around an optimum point.
B10 - What is a neurone?
A specialised cell that carries an electrical impulse around the body.
There are three types: sensory, relay and motor neurons.
B10 - What are the three types of neurone?
Sensory neurone: carry information from sense organs to the central nervous system
Relay neurone: carry information across the central nervous system
Motor neurone: carry information from the central nervous system to the rest of the body
B10 - What are the main components of a stimulus response pathway?
A stimulus is a change in the internal (inside the body) or external (outside the body) environment.
These changes are detected by receptors (cells).
Coordination centres are where the information is sent to and processed e.g. the brain and spinal cord.
Effectors are either muscles or glands that bring about a response
B10 - Explain how a nervous impulse is transmitted across a synapse.
Electrical impulse arrives at the end of the presynaptic neuron.
Neurotransmitters are released from synaptic vesicles.
Neurotransmitters diffuse across the synaptic cleft and bind with receptors on the postsynaptic neuron.
The postsynaptic neuron to transmits the electrical impulse.
B10 - Explain the importance of reflex actions
Fast and automatic.
They happen without conscious thought.
They keep us safe.
B10 - List the steps involved in a reflex arc/pathway
Stimulus
↓
Receptor
↓
Sensory neuron
↓
Relay neuron
↓
Motor neuron
↓
Effector
↓
Response
B10 - Explain why reflex actions are so fast
They bypass the conscious areas of our brain.
The impulse travels to the spinal cord only.
This means that we do not need to think about the response - it happens automatically.
B10 - Describe a method used to measure reaction time.
Use your weaker hand for this experiment.
Sit down on the chair with good upright posture and eyes looking across the room.
Place your forearm across the table with your hand overhanging the edge of the table.
Your partner will hold a ruler vertically with the bottom end (the end with the 0 cm) in between your thumb and first finger.
Your partner will hold the ruler so the zero mark is level with the top of your thumb. They will tell you to prepare to catch the ruler.
Your partner will then drop the ruler without telling you.
You must catch the ruler as quickly as you can when you sense that the ruler is dropping.
After catching the ruler, look at the number level with the top of your thumb.
Record this in your results table
