B1.2 Nerves and hormones Flashcards
Name the five senses
- Hear (sound)
- Smell (chemicals for smell)
- Taste (chemicals for taste)
- Touch (temperature changes)
- Sight (light sensitivity)
What is the CNS?
The central nervous system
The brain and spinal cord
What is the PNS?
The peripheral nervous systems
Transmits electrical impulses to and from the CNS
What are receptors?
Groups of cells that respond to a particular stimulus
What do the sensory neurones do?
Transmit the electrical impulses from the receptors in the sense organs to the spinal cord and brain
What are the relay neurones?
The nerve cells that transmit the electrical signals from sensory neurones to the motor neurones
What are the synapses?
The connection between two neurones
It allows the electrical impulses to reach the spinal cord
Chemicals are released one end and diffuse across to the other
What is a neurotransmitter?
Chemicals produced that transmits the electrical signal across the synapse
What does the myelin sheath do?
Insulates the electrical impulse
What does the axon do?
Transports the impulses
What do the motor neurones do?
Transmits electrical signals through the CNS to the effector cells of muscles or glands
What are the effectors?
The muscles or glands that respond to the electrical impulse
What is a reflex action?
an automatic response to a stimuli
Describe the process of the sense organs (5)
1) A stimulus changes in the environment
2) The receptor sends impulses along the neurones
3) The sensory receptors detect the change
4) The message goes to the CNS which coordinates information
5) The CNS send impulses to the motor neurones to the effectors which then respond
Describe the reflex arc (7)
1) stimulus
2) receptor
3) sensory neurone
4) relay neurone
5) motor neurone
6) effector
7) response
What does homeostasis mean?
Keeping a constant internal environment
What are the things that have to be maintained? (4)
- Water levels
- Temperature
- Blood sugar levels
- Salt/ion levels
What does the kidney do?
Regulates water and mineral salt concentration
What does the skin do?
Regulates body temperature
What do the liver and pancreas do?
Regulate blood glucose levels