#9: Nervous System Flashcards
Central nervous system (CNS)
consists of the nerves of the brain and spinal cord
responsible for coordinating information from the PNS
Peripheral nervous system (PNS)
consists of the nerves outside of the brain and spinal cord
responsible for relaying information between the CNS and the rest of the body
the PNS has voluntary and involuntary components
Somatic nervous system
PNS -voluntary component
relays sensory and motor information
Autonomic Nervous System
PNS -involuntary component
relays information between the internal organs of the body and the CNS
Glial Cells
supporting cells (non-conducting) retain the ability to divide throughout life
3 main functions of Glial Cells
- Insulate and protect neurons
- Supply neurons with oxygen and nutrients
- Facilitate the transmission of nervous impulses
Schwann cells
example of glial
form tightly wrapped layers of plasma membrane called myelin sheaths
acts as electrical conductors to speed up messaging
gaps in between are called “node of Ranvier”
Neurons
conducting cells
Structure: made up of an enlarged cell body and two types of extensions or processes- dendrite & axon
Bundles of axons (extremely thin) are bundled together to form nerve fibres
Nerves branch extensively to relay signals throughout the body
Dendrite
projection that carries signals toward the nerve cell body
Axon
extension that carries nerve signals away from the nerve cell body
Sensory neurons
aka afferent neurons
carry information from sensory receptors to the CNS
may occur in clusters called ganglia
Interneurons
aka associate neurons
a major component of the CNS
relay information from sensory neurons to the motor neurons
Motor neurons
aka efferent neurons
carry information from the CNS to the effectors (muscles, organs, glands, etc.)
Neural Circuits
Connections between the axon terminals of one neuron and the dendrites or cell body of a second neuron form a neuronal circuit
