Neuroscience Basics Flashcards
What are neurons? How many are there?
Nerve cells, building blocks of the nervous system.
86 billions in the brain
Three main parts of neuron
- Cell body (soma) - contains the nucleus and processes the incoming signals
- Dendrites - receive signals from other neurons
- Axon - long extension that carries electrical impulses away from the cell body towards other neurons.
How many dendrites neuron has
Hundreds to thousands
What are axon terminals?
The ends of the axon that release neurotransmitters (chemical messengers) to communicate with other neurons
Types of neurons
- Sensory neurons - carry signals from the senses to the brain
- Motor neurons - transmit signals to muscles and glands
- Interneurons- connect neurons within the brain and spinal cord, playing a role in complex thinking and memory
Two types of nervous system
Central nervous system: brain and spinal cord
Peripheral nervous system: sensory and motor neurons
Three basic functions of a neuron
- receiving signals
- integrating incoming signals (to decide whether or not pass along)
- communicate signals to target cells
Types of signals incoming to neurons
- excitatory - tend to make a neuron fire (generate an electrical impulse)
- inhibitory - tend to keep neuron from firing
Why inhibitory signals are needed
Are crucial for shutting down the excessive activity, to prevent it from firing unnecessarily.
Over-excitation —-> epilepsy
What differentiates axon?
- tends to stay the same diameter and doesn’t have spines like dendrites
- is covered in insulating substance called myelin, which helps to convey the nerve impulses rapidly
- towards the end splits up into many branches called axon terminals
What is axon hillock
Region that serves as the “trigger zone” for initiating an action potential. Located between cell body and axon.
What is action potential
Electric signal that travels along the axon of a neuron, allowing it to communicate with other neurons, muscles or glands.
