Week Two Flashcards
Central Nervous System, The Brain, and EEG
What are the two major systems of the nervous system?
The central nervous system (CNS)
The peripheral nervous system (PNS)
What does the CNS consist of?
Cerebrum (the brain)
Brain stem
Cerebellum
Spinal cord
What does the PNS consist of?
All the remaining nerves outside the CNS
How many pairs of spinal and cranial nerves are in the PNS?
Spinal nerves: 31 pairs
Facial nerves: 12 pairs
What is the main function of the PNS?
Connects the brain (CNS) to the outside world
What is a neuron?
The fundamental unit of the nervous system
What is the function of a neuron?
Specialized cells that transmit information throughout the body in the form of electrical and chemical signals
Critical for communication between different parts of the body and the brain
What are the major parts of a neuron? (7)
Dendrites
Soma/cell body
Axon
Myelin sheath
Nodes of Ranvier
Axon terminal
Synapse
Explain the role of the dendrites
Collect signals from neighbouring cell and pass to the cell body if the signals are strong enough
Explain the role of the soma/cell body
Combines the electrical signals received from the dendrites to send them down the axon
Explain the role of the axon
Responsible for transmitting the neuron’s electrical signals to other cells, either neurons or muscles
Thicker axons transmit impulses faster, and axons can be myelinated to increase speed
Explain the role of the myelin sheath
Increases the speed at which electrical impulses propagate along the axon and also helps in protecting the nerve fibre
Explain the role of the nodes of ranvier
Facilitate the rapid conduction nerve impulses along the axon by forcing the electrical impulse to jump from one node to the next
Process is called saltatory conduction
Explain the role of the axon terminal
Involved in releasing neurotransmitters (chemicals that transmit signals to other neurons or effectors)
Explain the role of the synapse
Allows neurons to pass signals to other neurons, muscles, or glands
Where neurons are transferred/received by the dendrites of neighbouring cells
What are the primary types of neurons?
Motor neuron
Sensory neuron
Interneuron
What is a motor neuron?
Transmit signals from the CNS to the somewhere else (e.g., to the muscles causing them to contract)
They play a key role in movement (both voluntary and involuntary)
What is a sensory neuron?
Transmit sensory information from the PNS to the CNS
Convert external stimuli into internal electrical impulses
What is an interneuron?
Located in the CNS, communicate internally an intervene between sensory inputs and motor outputs
What is grey matter?
Comprises neuronal cell bodies, dendrites, glial cells
Involved in muscle control, memory, sensory perception, speech etc.
Predominately found in the cerebral cortex
What is white matter?
Composed of axons coated in myelin sheath
Connects different brain regions and facilitates rapid transmission of nerve signals
Larger volume of brain compared to grey matter
What is a neural impulse transmission?
Process by which neurons send and receive signals to each other
Also called the conduction of action potentials
What are the steps of an action potential? (7)
Resting potential
Depolarization
Rising phase
Repolarization
Hyperpolarization
Refractory period
Restoration
Explain resting potential
Resting potential of about -70mV that is maintained by the sodium potassium pump
Na+ (sodium) occupies the outer space
K+ (potassium) occupies the inner space