Cells and Control Flashcards
What is the Human Nervous System?
-The nervous system protects organisms from harm by responding to changes in the environment.
-It includes the brain, the spinal cord, and the neurons.
What is The Synapse?
-Synapses are gaps between neurons. Nerve impulses must travel across these gaps
-The electrical impulse reaches the end of the neuron before the synapse. This triggers the release of chemicals called neurotransmitters.
-The neurotransmitters diffuse (move down a concentration gradient) across the synapse.
-The neurotransmitters bind to receptors on the next neuron.
-The presence of the neurotransmitter causes the production of an electrical impulse in the next neuron
What is The Cell Body in a Neuron?
Part of the neuron cell that contains sub-cellular structures like the nucleus.
What is The Axon in a Neuron?
Carries nerve impulses away from the cell body.
What are The Dendrites in a Neuron?
Carries nerve impulses towards the cell body.
What is The Myelin Sheath in a Neuron?
This insulates the neuron, so electrical impulses travel down it more quickly.
What are Reflex Actions?
Reflex actions allow us to respond to dangerous situations rapidly and automatically. Reflex actions do not involve conscious thought.
Name the 3 Different Neurons and their Tasks.
-The sensory neurone carries the signal in the form of an electrical impulse to the central nervous system (CNS).
-The relay neurone (in the CNS) relays the electrical impulse from the sensory neurone to the appropriate motor neurone.
-The motor neurone is another type of nerve cell that carries the electrical impulse from the CNS to an effector.
What is an Effector?
An effector is a muscle or gland that brings an action in response to the internal or external environment.
What is a stimulus?
This can be any change in the environment to which the body needs to respond.
