Central Nervous System Flashcards
(26 cards)
Composed of the brain and spinal cord
Integrates sensory information, processes it, and directs responses
Reflexes can be processed at the spinal cord level without the involvement of the brain.Includes the brain and spinal cord.
Processes and integrates information, generating appropriate responses.
CNS
Includes sensory and motor neurons outside the CNS
Transmits sensory information to the CNS and motor commands from the CNS to the body
Divided into the Somatic Nervous System (voluntary control) and the Autonomic Nervous System (involuntary control).Includes all the nerves outside the CNS.
Transmits sensory information to the CNS and motor commands from the CNS to muscles and glands.
PNS
ANS
Subdivision of the PNS.
Regulates involuntary functions such as heart rate, digestion, and respiratory rate.
Branching extensions that receive electrical signals from other neurons or sensory receptors and carry them towards the cell body.
Dendrites
A long, thin projection that carries electrical impulses away from the cell body towards other neurons, muscles, or glands.
Axon
The end of the axon where neurotransmitters are released into synapses to communicate with other cells
Axon Terminals
Fatty layer that insulates axons, speeding up signal transmission.
Produced by Schwann cells (PNS) and oligodendrocytes (CNS).
Myelin Sheath
Gaps in the myelin sheath that allow for saltatory conduction, where action potentials jump from one node to the next, increasing conduction speed
Nodes of Ranvier
The part of the neuron where action potentials are initiated.
Axon Hillock
Neurotransmitters are released from the presynaptic neurone and bind to receptors on the postsynaptic neurone, initiating an electrical signal.
Chemical synapse
Increase the likelihood of an action potential in the postsynaptic neurone
Example: Glutamate
Excitatory Neurotransmitters
Decrease the likelihood of an action potential
Example: GABA
Inhibitory Neurotransmitters
Neurotransmitter Release
Action potentials trigger calcium influx into the axon terminals, causing synaptic vesicles to release neurotransmitters into the synaptic cleft
The inside of a neurone is negatively charged at around -70mV relative to the outside
Sodium (Na⁺) is high outside
Potassium (K⁺) is high inside.
Resting Potential
When the membrane is depolarised;
Sodium channels open
Sodium ions flow into the cell making the inside more positive
Depolarisation
Potassium channels open
Potassium ions flow out
Neuron returns to a negative internal charge
Repolarization
After repolarization, the neuron becomes more negative than its resting potential before stabilizing
Hyperpolarization
The action potential travels down the axon by sequentially depolarizing and repolarizing adjacent sections of the membrane
Action Potential Propagation
In myelinated axons;
Action potentials jump between the nodes of Ranvier
Speeding up signal transmission.
Saltatory Conduction
Involved in muscle contraction
Autonomic functions
Memory
Released at neuromuscular junctions
Acetylcholine
Plays a role in reward
Motivation
Motor control
Deficiencies are linked to Parkinson’s disease.
Dopamine
Involved in mood regulation
Sleep
Appetite control
Low levels are linked to depression.
Serotonin
Involved in the “fight or flight”
Arousal
Alertness
Released by sympathetic nerves during stress
Norepinephrine
The main excitatory neurotransmitter in the brain
Involved in synaptic plasticity and learning.
Glutamate
