Nervous system Flashcards
What is the nervous system?
The communication network of the body, keeps the body in touch with the internal and external environment
What are the two anatomical categories of the nervous system?
Central nervous system (CNS)- brain and spinal cord
Peripheral nervous system (PNS)- other nerves
Functions of the nervous system
Coordinate the body’s activites- voluntary and involuntary movement
Allows the body to recognize and respond to changes in its external and internal environments
Function of the neuron
Receives input from the body’s internal and external environment and relays electrical impulses between the nervous system
Anatomy of the neuron
Cell body- the main part of the neuron
Dendrites- special fibers that extend from cytoplasm of cell body
Axon that divides into telodendria
End of axon has synaptic terminals
What is a telodendria?
Small branches found at the distal end of the axon
What is the axon?
A fiber that extends from a neuron cell that conducts impulses away from the cell, each nerve cell has one axon
The larger the diameter of an axon
the faster it can transmit info
What is the axon of the neuron covered by?
Myelin sheath, a fatty tissue that wraps the axon to protect it and speeds up impulses as they travel down the axon
What are dendrites?
Special fibers who extend from a neuron that conducts impulses towards the cell body
What is a synaptic terminal?
Connects one neuron to the other
What is a synapse?
The junction where the axon terminal of one neuron meets with another neuron, where the impulses between neurons are transmitted
What is the synaptic cleft?
A space where the impulses must jump because the axon terminal doesn’t directly touch the neuron
What is a neurotransmitter?
Special chemical in axon terminals that helps impulses jump the synapse cleft
Categorization of neurons
Afferent (sensory neurons), efferent (motor neurons), interneurons (central or connecting neurons)
What is an afferent neuron?
Conduct impulses to the brain and spinal chord
Afferent- direction toward a central organ
Ex: CNS
Stimulated by physical and chemical input from environment
Responsible for senses
What is an efferent neuron?
Carry impulses away from CNS to muscles, glands, and organs resulting in voluntary and involuntary movement
What is an interneuron?
Conduct impulses from sensory neurons to motor neurons, help facilitate reflexes
Function of the brain
Interprets, organizes, stores information, controls and directs bodily functions
What is the cerebrum?
The most superior part of the brain/largest portion, highly developed portion
Seperated into right and left hemispheres
What are hemispheres connected by?
Corpus callosum, allows them to communicate
Function of cerebrum
Controls thinking, sensory, speech, voluntary movement, reasoning
What is the cerebellum?
Posterior to the brain stem, responsible for coordinating voluntary muscle movement, posture, balance, muscle tone
What is the diencephalon?
Found just above brain stem, between cerebral hemispeheres
Divided into the thalamus and hypothalamus
Thalamus function
Directs much of sensory impulses to the proper locations in the cerebral cortex