Nervous System Flashcards
(23 cards)
What is homeostasis.
Act of regulating internal conditions to keep them optimum (best can be)
What is negative feedback?
When body moves away from the optimum (best self) it triggers a response to return to the optimum.
What makes up the central nervous system (CNS) ?
Brain and spinal cord.
What is a reflex action?
And give an example.
A fast automatic recreation that requires no conscious thought. For example bright light in your eyes, your pupils get smaller to reduce eye damage.
What is the co-ordination center?
Receives information from receptors and processes information through the effectors.
What is a synapse?
Gap between two neurones.
What is a myelin sheath?
Insulated the neurone and speeds up the transition of electrical impulses.
What are stimulus?
A change in the environment.
What is a receptor?
A cell that detects the stimulus.
What is a sensory neurone?
Transmits impulses from receptors to the central nervous system.
What is a relay neurone?
Transmits impulses from sensory to the motor nerve.
What is an effector?
Produces the response eg a muscle or a gland.
What is a response?
The change in the response to the stimuli.
What are the steps of burning yourself? (6 marks)
- Stimulus triggered (heat)
- Sensed by receptors (skin cells)
- sensory neurone transmits impulse from receptor to CNS
- CNS processes response
- Relay neurone sends impulse to motor nerve
- Motor nerve transmits impulse to effector (muscle)
- Effector (muscle) produces a response
- Response takes place, hand moves away from heat.
Name three receptors and where they are located.
Taste receptors - tongue
Sound receptors - ears
Light receptors - retina of the eye
Name two effectors and how the respond.
- Muscles which contract in response to the impulse
- Glands who secrete hormones to the impulse
Who has a complex nervous system?
Large animals like mammals and birds.
Who has a reflex response?
Simple animals like jellyfish.
Name the 7 parts of the nerve cell.
- Dendrite
- Dendron
- Cell body
- Nucleus
- Axon
- Myelin sheath
- Nerve endings
What is a reflex arc?
The passage of information in a reflex. Eg from receptor to effector.
What is a synapse?
The connection between two neurones.
What do neurones do?
Transmit information very quickly to and from the brain.
What happens when the impulse reaches the synapse?
The impulse triggers chemicals to be released these are called neurotransmitter molecules, they spread across the synapse and cause the impulse to be sent along the relay neurone.
